Even Moland

• Rohtla, Mehis; Moland, Even; Thorstad, Eva Bonsak; Skiftesvik, Anne Berit; Bosgraaf, Sebastian & Olsen, Esben Moland [Show all 8 contributors for this article] (2026). Behaviour of European eel Anguilla anguilla transitioning from the yellow resident to the silver migratory stage in marine waters. Journal of Fish Biology. ISSN 0022-1112. doi: 10.1111/jfb.70564. Full text in Research Archive Show summary

  Current knowledge on the continental shelf and transatlantic spawning migration of the European eel (Anguilla anguilla) is based on silver eels outmigrating from fresh water. However, an unknown proportion of eels grow in marine coastal waters during the continental part of their lifecycle and therefore start their spawning migration while they are already in marine waters. To study the onset of the European eel's spawning migration in marine waters, we tagged yellow eels in Sandnesfjord, Norway. One hundred yellow and pre-migratory eels (stage FII or FIII) were tagged with acoustic transmitters in August, September or October in 2018–2019 and their subsequent movements were recorded within a hydrophone array until May 2023. Twenty-two eels left the fjord in a period spanning from early October to early December, which partly coincides with the usual downstream migratory period among European eels. These eels were never detected again and had thus presumably transitioned to the silver eel stage. This transition occurred from a few months to up to 3 years after tagging. In all silver eels, an increase in vertical and horizontal movements within the fjord preceded their exit from the fjord. This sudden increase in activity occurred only for a few days before they left the fjord in most individuals, but this period was as long as 1 month in other individuals. Five of the silver eels undertook migrations up to several kilometres to a tidal stream before leaving the fjord. Eel migration was largely nocturnal, independent of moon or tidal phase. We conclude that the relatively short migration season and individual migration duration within the fjord, combined with the absence of significant environmental, physiological or anthropogenic stressors, may contribute to higher survival rates during the continental phase of the spawning migration compared to eels that start their spawning migration from fresh water, but this needs to be investigated in future studies.

• Riaz, Javed Zafar; Nilssen, Kjell Tormod; Biuw, Martin; Moland, Even; Poltermann, Michael Tino & Kristiansen, Martin [Show all 7 contributors for this article] (2026). Haul-Out Site Use and Connectivity of Harbour Seals Between Management Units in Southern Scandinavia. Ecology and Evolution. 16(1). doi: 10.1002/ece3.72718. Full text in Research Archive Show summary

  Harbour seals (Phoca vitulina) have a broad distribution in coastal ecosystems across the northern hemisphere. In southern Scandinavia, a lack of spatially-resolved data on harbour seal populations poses a major challenge for developing ecologically informed management frameworks, particularly in Norway, where populations are regulated using county-level administrative boundaries. In this study, we use haul-out data from 26 harbour seals tagged with GPS phone tags during the post-moult period to provide the first assessment of connectivity and movement across management boundaries in the Skagerrak–Kattegat region of southern Scandinavia. Specifically, we examined the frequency and timing of haul-out events relative to management units and quantified spatial networks of connectivity across national and sub-national jurisdictions. We reveal a high degree of spatial connectivity in the region, with haul-outs occurring over a broad, integrated network along the Skagerrak–Kattegat coastline. Generally, harbour seals in the region had a high probability of performing cross-boundary haul-out events, with individuals repeatedly transitioning across distinct Norwegian management units, as well as transnationally between Norway, Sweden and Denmark. This study offers critical insights into harbour seal movement ecology in this data-limited region, whilst also addressing an important topic of applied management. We demonstrate that the current management units in the Norwegian Skagerrak may not adequately reflect the spatiotemporal scales of harbour seal movement. Importantly, these findings can complement forthcoming genetic data and support efforts to redefine management units in the area. More broadly, our study illustrates how telemetry-based assessments of spatial connectivity can provide a powerful tool to inform management frameworks for other wide-ranging marine species facing similar conservation challenges.

• Johannesen, Edda; Ottersen, Geir; Berg, Florian; Bogstad, Bjarte; Dalpadado, Padmini & Denechaud, Côme [Show all 17 contributors for this article] (2026). The Abrupt and Persistent Decline in Recruitment Success in Northeast Arctic Cod: A Review of Probable Causes. Fish and Fisheries. ISSN 1467-2960. doi: 10.1111/faf.70074. Full text in Research Archive Show summary

  Most of the previously large cod stocks in the North Atlantic are depleted to very low levels. A notable exception has been the Northeast Arctic cod inhabiting the Barents Sea. This cod stock reached a record high level around 2013, but since then has declined sharply, with older fish being fished out and few new recruits entering the stock. More specifically, since 2006 the average recruitment at age 3 per unit spawning stock biomass has dropped to a very low level. Here we review recent literature and data to evaluate potential causes of poor recruitment. We find that in most years the large spawning stock was successful in producing offspring up to the 0-group stage, but the survival thereafter was reduced—leading to few recruits into the fishable stock. Evidence points to consequences of northwards shifts of spawning locations, reduced inflow of Calanus and density dependent factors influencing pre-recruit survival at times when the spawning stock was at a record high level. However, large uncertainties in the causes of recruitment failure remain at a time when the Barents Sea ecosystem is experiencing unprecedented warming. A precautionary measure to avoid further decline and potential stock collapse in the current situation is to lower fishing pressure and improve management by setting reference points based on the recent period with low productivity. Including demographic characteristics like age diversity as explicit management targets to ensure spatial and temporal spread in spawning should be a goal for future method development.

• Frigstad, Helene; Andersen, Jesper Harbo; Bekkby, Trine; Hammar, Linus; Hemraj, Ashley D. & Hessen, Dag Olav [Show all 13 contributors for this article] (2026). Under pressure: accounting for multiple human pressures outside and inside marine protected areas in the Skagerrak. Frontiers in Marine Science. 13. doi: 10.3389/fmars.2026.1774106. Full text in Research Archive Show summary

  The combined effects of multiple pressures pose critical threats to marine ecosystems. As an initial spatial assessment of cumulative pressures in the Skagerrak, we mapped where multiple pressures coincided with sensitive habitats and species, combining recent spatial data sets on 20 pressures and 39 habitats and species. The spatial data were linked with sensitivity weights obtained with a novel partly data-driven method. We found major spatial variation in the risk of cumulative impacts, identifying areas with high human impact, termed hot spots (such as shallow areas in southern and eastern Skagerrak), and areas with low human impact, termed cold spots (such as the deeper parts of the Norwegian Trench). The dominating human pressures were 1) fishing activities, 2) climate change, 3) underwater noise, 4) input of contaminants, 5) light pollution and 6) input of nutrients. Analyses of human pressures within and outside 20 Marine Protected Areas (MPAs) indicated significantly reduced levels in nine MPAs; however, these reductions were limited (less than 15%). One MPA (Skagens Gren og Skagerrak, DK) had significantly higher total human pressure inside the protected area, while ten MPAs did not yield significant results. We therefore recommend that the conservation measures in MPAs in the region be critically addressed and human pressures mitigated, to reduce the potential negative impact of human activities.

• Henriksson, Simon; Jorde, Per Erik; Berkström, Charlotte; Søvik, Guldborg; Wit, Pierre De & Knutsen, Halvor [Show all 9 contributors for this article] (2025). Connectivity and Population Structure in a Marginal Sea—A Review. Diversity and Distributions: A Journal of Conservation Biogeography. ISSN 1366-9516. 31(7). doi: 10.1111/ddi.70056. Full text in Research Archive Show summary

  ABSTRACT Aim The current biodiversity crisis calls for conservation measures that limit or reduce the negative human impact on key habitats and vulnerable wild populations. To effectively protect biodiversity at all levels, including intra‐specific diversity, conservation measures should, ideally, be aligned with the connectivity and genetic structure of wild populations. In this review, we synthesise the scientific literature on connectivity and population structure of marine species in a marginal sea. Location The study focuses on the Skagerrak—a marginal sea in the northeast Atlantic Ocean. Methods We reviewed a total of 172 scientific publications assessing connectivity or population structure in 48 species. From this material, we summarised the main patterns of connectivity and population structure across species, as well as the taxonomic and geographic representation of the scientific literature within this field. Results Our review shows that contemporary connectivity with adjacent seas is high, but asymmetric, for most species. Simultaneously, most species have multiple distinct populations in the Skagerrak, separate from those in adjacent seas. Within the Skagerrak, population structure is common both among coastal populations and between coastal and offshore populations, but less frequent among offshore populations. In many mobile species, multiple populations temporarily overlap in certain areas, but retain their genetic divergence through homing or other barriers to gene flow. Main Conclusions Even in one of the most intensively studied marine regions within the field of connectivity and population structure, there are still large knowledge gaps limiting both our understanding of connectivity and its application in management decisions. Nevertheless, it is evident that the presence of population structure despite high connectivity, and temporal variability in population assemblages, poses a challenge for area‐based protection measures. This underscores the need for adaptive management that monitors and manages intra‐specific diversity on multiple temporal and spatial scales.

• Norderhaug, Kjell Magnus; Kleiven, Portia Joy Nillos; Wernberg, Thomas; Synnes, Ann-Elin; Filbee-Dexter, Karen & Espeland, Sigurd Heiberg [Show all 10 contributors for this article] (2025). More but Smaller: Marine Heatwaves Exacerbate Size Truncation in Overfished Fish Communities in the Skagerrak. Ecology and Evolution. 15(5). doi: 10.1002/ece3.71404. Full text in Research Archive Show summary

  As we are progressing through the Anthropocene, it is imperative to understand how ecosystems degraded by historical impacts respond to future pressures. Particular attention should be directed at changes in the distribution and function of foundation species due to their disproportionately important ecological roles. Forest-forming kelps are in decline and are being replaced by turf-forming algae in coastal areas globally, as a consequence of increasingly severe marine heatwaves (MHW). This replacement represents a miniaturization of the three-dimensional habitat and a change in habitat functions for many associated species. Ecologically, economically, and culturally important coastal fish species depend on kelp forests in different life stages from egg to adult and may be affected in various ways. Many of these species already suffer from centuries of overexploitation, severely reducing abundances, truncating sizes, and changing age distributions. Here, we studied an overfished coastal ecosystem and assessed the impact of the transition from kelp to turf on the structure and function of associated fish communities. Specifically, we analyzed differences in abundance, body size, and composition of benthic fish at sites with variable cover of kelp and turf. We found higher abundances of small fish with increasing cover of turf relative to kelp. We also found smaller fish within the common families of gobids and gadids. Thus, MHW exacerbate size truncation and trophic downgrading in coastal fish communities. However, no differences in abundances of fish in the water column were detected during the night, and the average size of fish at turf-dominated sites was even larger. We interpreted this as roving predatory fish during night-time being less affected by the shift in habitat and smaller-bodied prey avoiding the water column in open turf habitats.

• Norderhaug, Kjell Magnus; Knutsen, Halvor; Filbee-Dexter, Karen; Sodeland, Marte; Jorde, Per Erik & Wernberg, Thomas [Show all 8 contributors for this article] (2024). The International Union for Conservation of Nature Red List does not account for intraspecific diversity. ICES Journal of Marine Science. ISSN 1054-3139. 81(5), p. 815–822. doi: 10.1093/icesjms/fsae039. Full text in Research Archive Show summary

  The International Union for Conservation of Nature (IUCN) Red List identifies threatened and endangered species and is a key instrument in global biodiversity conservation efforts. Our understanding of the structure and value of genetic biodiversity below the species level is rapidly increasing. Nonetheless, the IUCN assessment criteria overlook genetic variation within species. Here, we address this blind spot and discuss the principles of species conservation status classification relative to intraspecific biodiversity. We focus on coastal species, which thrive in heterogeneous environments known to drive genetic differentiation. The focal example species, Atlantic cod and sugar kelp, have contrasting life histories, are ecologically and economically important constituents of the coastal ecosystem, and are currently not classified as threatened in Norway and Canada. We expose important variation in population structure, the presence of ecotypes and genetic-environment covariation, as well as loss of ecotypes that threatens the conservation of these species. Because the genetic makeup of species directly influences their resilience, omitting this information from conservation status assessments can result in loss of adaptive capacity to future stressors, such as climate change. Consequently, recognizing and preserving intraspecific variation emerges as vital for species’ abilities to adapt to and survive in future ocean conditions.

• Letessier, Tom B.; Mouillot, David; Mannocci, Laura; Christ, Hanna Jabour; Elamin, Elamin Mohammed & Elamin, Sheikheldin Mohamed [Show all 18 contributors for this article] (2024). Divergent responses of pelagic and benthic fish body-size structure to remoteness and protection from humans. Science. ISSN 0036-8075. 383(6686), p. 976–982. doi: 10.1126/science.adi7562. Full text in Research Archive Show summary

  Animal body-size variation influences multiple processes in marine ecosystems, but habitat heterogeneity has prevented a comprehensive assessment of size across pelagic (midwater) and benthic (seabed) systems along anthropic gradients. In this work, we derive fish size indicators from 17,411 stereo baited-video deployments to test for differences between pelagic and benthic responses to remoteness from human pressures and effectiveness of marine protected areas (MPAs). From records of 823,849 individual fish, we report divergent responses between systems, with pelagic size structure more profoundly eroded near human markets than benthic size structure, signifying greater vulnerability of pelagic systems to human pressure. Effective protection of benthic size structure can be achieved through MPAs placed near markets, thereby contributing to benthic habitat restoration and the recovery of associated fishes. By contrast, recovery of the world’s largest and most endangered fishes in pelagic systems requires the creation of highly protected areas in remote locations, including on the High Seas, where protection efforts lag.

• Meurs, Elsa Alie Ylona van; Moland, Even; Bjørge, Arne Jostein & Freitas, Carla (2024). Haulout Patterns of Harbour Seal Colonies in the Norwegian Skagerrak, as Monitored through Time-Lapse Camera Surveys. Diversity. 16(1), p. 1–15. doi: 10.3390/d16010038. Full text in Research Archive Show summary

  Harbour seals (Phoca vitulina) are part of the Norwegian coastal ecosystem and can be observed on skerries, islands, and sandbanks along the coastline, sometimes in close proximity to inhabited areas. In this study, we used time-lapse camera surveys to monitor the haulout patterns of harbour seals at two selected sites in the Norwegian Skagerrak, Lyngør and Østre Bolæren, over 12 and 4 months, respectively. The goal was to investigate how the number of seals hauling out on land varied seasonally and how it was influenced by environmental parameters (wind speed, air temperature, and water level), the time of the day, and anthropogenic disturbances. As expected, the number of seals hauled out increased with increasing air temperature and decreased with increasing wind speed and water level. Clear circadian patterns in the seal haulout behaviour were identified during autumn and winter when a significantly higher number of seals were observed on land at night. Moreover, haulout patterns showed significant seasonal variation, with a peak in haul outs being observed during the moulting season in August. Despite an expected high usage of land during the breeding season in early summer, the number of seals hauled out at the Lyngor study site was low during this period, especially during weekends and summer holidays, maybe due to increased disturbance from boats. This study provides valuable insights into the factors influencing the haulout behaviour of the species in the region and suggests possible effects of human disturbance on harbour seal behaviour in the area.

• Poulton, Anna J.; Villegas-Ríos, David; Freitas, Carla; Moland, Even; Olsen, Esben Moland & Sethi, Suresh A. [Show all 7 contributors for this article] (2024). Bayesian estimation of spatially varying mortality risk using tagged animal data. Methods in Ecology and Evolution. 15(11), p. 2101–2117. doi: 10.1111/2041-210X.14428. Full text in Research Archive Show summary

  The survival of animals is impacted by landscapes of spatially varying mortality factors including habitat type, predation risk or harvest risk, among others. Characterization of these spatial mortality processes is important for managing animal populations and their habitats, yet this information has proved challenging to capture. Advances in telemetry now make it possible to monitor tagged individuals' locations through time for a wide range of taxa, providing opportunity to assess movement and mortality simultaneously through spatial time-to-event data. Existing time-to-event modelling frameworks have largely ignored spatially varying mortality processes or have treated an animal's location as fixed at a regional level. Here we present a general spatial survival model for analysing time-to-event data arising from animal telemetry. Our model has a flexible Cox regression form and can estimate the effects of conventional non-spatial risk factors (size, seasonality, etc.), spatial covariates (e.g. habitat type) and spatial variation in risk not explained by covariates on mortality. We show how to fit our model using Bayesian methods and demonstrate applications of our model with several simulated examples and two animal telemetry case studies. Our model produced consistent and unbiased parameter estimates throughout simulations with a variety of spatial and non-spatial hazards. In the first case study, data from 147 tagged caribou in British Columbia, Canada, revealed a spatially heterogeneous mortality landscape with caribou survival varying by elevation, likely in response to space use by predators. Our second case study involved a dataset of 390 acoustically tagged Atlantic cod in a southern Norwegian fjord where a marine protected area (MPA) was established during the study. We found that the MPA led to a shift from mostly fishing mortality to mostly natural mortality within the fjord and that these risks had markedly different spatial hazard patterns. Our spatial time-to-event model can make use of data from a variety of widely used telemetry technologies to characterize landscapes of mortality risks for different taxa. Our work provides new opportunities to inform the spatial ecology and management of fish and wildlife populations.

• Koeck, Barbara; Olsen, Esben Moland; Závorka, Libor; Crespel, Amélie; Freitas, Carla & Enberg, Katja [Show all 11 contributors for this article] (2024). Conservation benefits of marine reserves depend on knowledge integration of genotypic and phenotypic diversity. Biological Conservation. ISSN 0006-3207. 299. doi: 10.1016/j.biocon.2024.110831. Full text in Research Archive Show summary

  Conserving intraspecific trait variation is vital for maintaining the viability of species. It ensures a species to adapt to warming and increasingly stochastic environments, and to recover following extreme events. Here we investigate the selective effects of spatial management on intraspecific genetic and phenotypic variation of two sympatric but genetically distinct Atlantic cod ecotypes in a Norwegian fjord. We found that phenotypic differences between sympatric cod genotypes were mainly driven by morphological and metabolic traits. Offshore cod had higher metabolic maintenance costs at cool temperatures but lower aerobic capacity at warm acclimation than coastal ecotypes, indicative of thermal constraint of aerobic physiological processes beyond metabolic maintenance. Offshore cod also had larger and thicker peduncles and better body condition. We found that protection benefits from the no-take zone (NTZ) of the Tvedestrand marine protected area were independent of individual space-use size, but instead resulted from ecotype-specific differences in habitat occupation. Results specifically show that the current delimitations of the NTZ do not cover habitats occupied by the coastal and highly resident cod ecotype which shows greater metabolic thermal tolerance but is considered to already be in a depleted state. Our study exemplifies why protecting intraspecific diversity is directly relevant for management implementations aimed at reducing the impact of further selection pressures such as ongoing environmental change. Careful investigation of intraspecific diversity and integration of such knowledge to fisheries management and design of protected areas may prevent unwanted additional selective pressures and contribute to offer broad protection to genotypes and phenotypes.

• Monk, Christopher; Power, Michael; Freitas, Carla; Harrison, Philip M.; Heupel, Michelle & Kuparinen, Anna [Show all 10 contributors for this article] (2023). Atlantic cod individual spatial behaviour and stable isotope associations in a no-take marine reserve. Journal of Animal Ecology. ISSN 0021-8790. 92(12), p. 2333–2347. doi: 10.1111/1365-2656.14014. Full text in Research Archive Show summary

  Foraging is a behavioural process and, therefore, individual behaviour and diet are theorized to covary. However, few comparisons of individual behaviour type and diet exist in the wild. We tested whether behaviour type and diet covary in a protected population of Atlantic cod, Gadus morhua. Working in a no-take marine reserve, we could collect data on natural behavioural variation and diet choice with minimal anthropogenic disturbance. We inferred behaviour using acoustic telemetry and diet from stable isotope compositions (expressed as δ13C and δ15N values). We further investigated whether behaviour and diet could have survival costs. We found cod with shorter diel vertical migration distances fed at higher trophic levels. Cod δ13C and δ15N values scaled positively with body size. Neither behaviour nor diet predicted survival, indicating phenotypic diversity is maintained without survival costs for cod in a protected ecosystem. The links between diet and diel vertical migration highlight that future work is needed to understand whether the shifts in this behaviour during environmental change (e.g. fishing or climate), could lead to trophic cascades.

• Durif, Caroline; Arts, M.; Bertolini, F.; Cresci, Alessandro; Daverat, F. & Karlsbakk, Egil Erlingsson [Show all 16 contributors for this article] (2023). The evolving story of catadromy in the European eel (Anguilla anguilla). ICES Journal of Marine Science. ISSN 1054-3139. 80(9), p. 2253–2265. doi: 10.1093/icesjms/fsad149. Full text in Research Archive Show summary

  Anguillid eels were once considered to be the classic example of catadromy. However, alternative life cycles have been reported, including skipping the freshwater phase and habitat shifting between fresh, brackish, and saltwater throughout the growth phase. There is a lack of knowledge regarding these alternate life strategies, for example, the proportion of individuals in the population that adopt them compared to classic catadromy. We provide a description of these alternate life cycle strategies in temperate anguillids, their possible drivers, and the methods available to investigate them. These methods (lethal and non-lethal), include otolith microchemistry, fatty acid and stable isotope analyses, parasite identification, blood transcriptomics, and electronic tags. We argue that since the current management framework for the European eel and other temperate eels is based mainly on the freshwater component of the population, it ignores eels growing in saline waters. Many of the factors that are thought to be responsible for the precipitous decline of the eel population are more prevalent in freshwater systems. Therefore, the contribution of saline eels may be more important than currently estimated. The habitat-shifting ability of eels may be all the more crucial for the persistence and recovery of those species that are endangered.

• Synnes, Ann-Elin; Olsen, Esben Moland; Jorde, Per Erik; Knutsen, Halvor & Moland, Even (2023). Contrasting management regimes indicative of mesopredator release in temperate coastal fish assemblages. Ecology and Evolution. 13(12). doi: 10.1002/ece3.10745. Full text in Research Archive Show summary

  The absence of functional top predators has been proposed as a mechanism acting to shape fish assemblages in temperate marine ecosystems, with cascading effects on lower trophic levels. We explore this scenario by comparing the trophic and functional status of fish assemblages in Norwegian marine national parks, open to fishing, to a nearby coastal seascape that harbors a system of marine protected areas (MPAs) including a no-take zone. Demersal fish assemblages were sampled using fyke nets over three consecutive seasons. Atlantic cod (Gadus morhua) is potentially a dominant top predator in this ecosystem, and historically, this and other gadids have been targeted by the full range of former and present fisheries. In the present study, we find that average body size of the Atlantic cod was significantly larger in the zoned seascape compared to the unprotected areas (mean ± SD: 36.6 cm ± 14.38 vs. 23.4 ± 7.50; p < .001) and that the unprotected seascape was characterized by a higher abundance of mesopredator fish species. These observations are consistent with the hypothesis that the protection of top predators within MPAs aids to control the mesopredator populations and provides empirical support to the notion that the present state of many coastal fish assemblages is driven by mesopredator release linked to functional depletion of large top predators.

• Skjæraasen, Jon Egil; Karlsen, Ørjan; Langangen, Øystein Ole Gahr; Meier, Sonnich; Dunlop, Katherine Mary & Meeren, Terje van der [Show all 14 contributors for this article] (2022). Attraction of cod Gadus morhua from coastal spawning grounds to salmon farms. Aquaculture Environment Interactions. ISSN 1869-215X. 14, p. 229–242. doi: 10.3354/aei00440. Full text in Research Archive Show summary

  Wild fish aggregate at aquaculture net-pens, but the underlying mechanisms are not fully understood. This study examined how salmon farms attract coastal Atlantic cod Gadus morhua from their inshore spawning grounds. Acoustic receivers were deployed at 5 known cod spawning grounds and 6 salmon Salmo salar farms located at varying distances from these grounds in a mid-Norway study site. Cod were caught at each spawning ground annually from 2017-2019, fitted with acoustic transmitters and released (n = 535). A total of 289 tagged cod (54%) were detected at the salmon farms, with more cod detected at farms closest to the focal spawning grounds and at operational farms. The latter result is likely linked to the availability of feeding opportunities at farm locations. Those cod that were detected by the receivers spent less time at farms farther from their release locations. For the farm-associated cod, 70% were detected for <1 wk at the farms. However, 48 cod spent >1 mo close to the farms, with 1 individual staying 720 d underneath the farm. A total of 135 cod visited 2 or more farms, with farms in proximity more connected in terms of inter-farm movement. Some of the cod utilizing these local spawning grounds likely have considerable dietary input from salmon feed.

• Villegas-Ríos, David; Freitas, Carla; Moland, Even & Olsen, Esben Moland (2022). Eco-evolutionary dynamics of Atlantic cod spatial behavior maintained after the implementation of a marine reserve. Evolutionary Applications. doi: 10.1111/eva.13483. Full text in Research Archive Show summary

  The effects of marine reserves on the life history and demography of the protected populations are well-established, typically increasing population density and body size. However, little is known about how marine reserves may alter the behavior of the populations that are the target of protection. In theory, marine reserves can relax selection on spatial behavioral phenotypes that were previously targeted by the fishery and also drive selection in favor of less mobile individuals. In this study, we used acoustic telemetry to monitor the individual spatial behavior of 566 Atlantic cod (Gadus morhua Linnaeus, 1758) moving within a marine reserve and a control site in southern Norway, starting 1 year before the implementation of the marine reserve and lasting up to 9 years after. Following a before-after-control-impact approach, we investigated changes in (1) survival, (2) selection acting on behavioral traits, and (3) mean behavioral phenotypes, after the implementation of the marine reserve. We focused on three behavioral traits commonly used to describe the mobility of aquatic animals: home range size, depth position, and diel vertical migration range. Survival increased after reserve implementation, but contrary to our expectations, it subsequently decreased to preprotection levels after just 3 years. Further, we found no significance in selection patterns acting on any of the three behavioral traits after reserve implementation. Although some changes related to water column use (the tendency to occupy deeper waters) were observed in the marine reserve after 9 years, they cannot unequivocally be attributed to protection. Our results show that survival and behavioral responses to marine reserves in some cases may be more complex than previously anticipated and highlight the need for appropriately scaled management experiments and more integrated approaches to understand the effects of marine protected areas on harvested aquatic species.

• Rohtla, Mehis; Moland, Even; Skiftesvik, Anne Berit; Thorstad, Eva Bonsak; Bosgraaf, Sebastian & Olsen, Esben Moland [Show all 8 contributors for this article] (2022). Overwintering behaviour of yellow-stage European eel (Anguilla anguilla) in a natural marine fjord system. Estuarine, Coastal and Shelf Science. ISSN 0272-7714. 276. doi: 10.1016/j.ecss.2022.108016. Full text in Research Archive Show summary

  Like many animals, northern temperate eel can enter a hibernation-like state and become dormant during the winter. Knowledge of overwintering behaviour in eel is sparse and mainly based on anecdotal observations and a few experimental studies on thermal tolerance. We studied European eel (Anguilla anguilla) overwintering behaviour in a Skagerrak fjord in Southern Norway, during three consecutive years, using an array of acoustic receivers and acoustic tags with depth and temperature sensors. We obtained results from 55 yellow eel, of which 19 were studied for one winter, 35 for two winters and one for three winters. Dormancy was inferred to begin in September for the earliest individuals and lasted until May for the last, with the majority of eel dormant from at least late October–November until mid-April. The timing of dormancy was mainly related to photoperiod and less to temperature. More than 50% of eel became dormant when day length was <9 h and became active when day length was >14 h. Approximately 10% of eel remained active during the winter and 31% of eel changed their pattern between consecutive years. Some dormant individuals exhibited activity periods that interrupted their dormancy. Eel in the outer fjord nearer the open sea became dormant before eel in the inner more freshwater part of the fjord, and were dormant longer. Acoustic telemetry Overwintering North sea Winter ecology Dormancy Photoperiod

• Knutsen, Jan Atle; Kleiven, Alf Ring; Olsen, Esben Moland; Knutsen, Halvor; Espeland, Sigurd Heiberg & Sørdalen, Tonje Knutsen [Show all 15 contributors for this article] (2022). Lobster reserves as a management tool in coastal waters: Two decades of experience in Norway. Marine Policy. ISSN 0308-597X. 136. doi: 10.1016/j.marpol.2021.104908. Full text in Research Archive Show summary

  The positive effects of reduced fishing pressure in marine protected areas (MPAs) are now well documented globally. Yet, evidence of MPA benefits from long-term replicated before-after control-impact (BACI) studies and their usefulness in protecting target species are still rare, especially in northern temperate areas. Scientific rigor in the monitoring of MPAs is considered important for obtaining trust and compliance and can increase interest and enthusiasm for the benefits of marine conservation. Off the coast of southern Norway, a MPA imple- mentation process started up in 2002. Based on comprehensive consultations with local fishers and managers, four experimental lobster reserves were appointed in 2004. Two years later (2006), the reserves came into effect as the Norwegian Directorate of Fisheries implemented regulations as a by-law of the Saltwater Fisheries Act that effectively banned all fixed gear. Long-term monitoring of the MPAs and adjacent control areas has enabled a rigorous scientific evaluation of the effects of these MPAs on lobster populations, including effects on density, growth, demography, behavior, and phenotypic diversity. As protection effects started to manifest, the lobster reserves attracted high public attention and were soon considered a credible supplement to traditional fisheries management. In the period from 2002 to 2021, more than 50 lobster reserves have been implemented in Norway. Here, we review the experiences since the lobster reserves were designated, implemented, and embraced by local communities in Norway, and over two decades have become an important tool for fishery management. Thoughts on the future of MPAs along the coast of Norway are discussed.

• Olsen, Erik Joel Steinar; Axelsen, Bjørn Erik Eversvik; Moland, Even; Utne-Palm, Anne Christine; Elamin, Elamin Mohammed & Mukhtar, Motassim Ali [Show all 10 contributors for this article] (2021). Distribution and diversity of fish species along the Sudanese Red Sea coast based on three combined trap and gillnet surveys. Fisheries Research. ISSN 0165-7836. 242:106032, p. 1–13. doi: 10.1016/j.fishres.2021.106032. Full text in Research Archive Show summary

  On the western shore of the semi-enclosed coral-reef rich Red Sea, the 850 km coastline of the Red Sea State of the Republic of Sudan provides livelihoods to artisanal fishers, but the present state of the living natural resources and the impact of fisheries are poorly known. To provide a baseline on the biodiversity and fish abundance three fisheries research surveys spanning the entire Sudanese coast were carried out in 2012−13 designed around the seven Sudanese fisheries management areas. Baited traps and gillnets were employed to sample the various reef habitats and fish assemblages from inshore to deeper outer reef archipelagos. The highest species richness, functional diversity, as well and the highest catch rates with both traps and gillnets were observed in the protected Dungonab Bay area in the north, while the management area closest to the main population center along the coast – Port Sudan – showed the lowest levels of biodiversity and catch rates. The Dungonab bay area and adjacent northern areas therefore seem more pristine than areas closer to the main human population center. Thus the present study has provides a necessary knowledge baseline and highlights the opportunity for establishing effective ecosystem-based management before the resources and habitats are irreversibly impacted.

• Fernández-Chacón, Albert; Buttay, Lucie; Moland, Even; Knutsen, Halvor & Olsen, Esben Moland (2021). Demographic responses to protection from harvesting in a long-lived marine species. Biological Conservation. ISSN 0006-3207. 257, p. 1–10. doi: 10.1016/j.biocon.2021.109094. Full text in Research Archive Show summary

  Marine protected areas (MPAs) are usually considered to have positive effects on the recovery of over-exploited populations. However, resolving the extent to which MPAs function according to their conservation goals requires that essential demographic information such as individual survival and population size are quantified. To this end, we analyzed a 16-year replicated mark-recapture study on European lobster (Homarus gammarus, n = 8793) conducted at several protected and unprotected sites in southern Norway, quantifying the impact of MPAs on local population dynamics by means of a “before-after control-impact” study approach (BACI). Lobster survival and abundance were estimated by applying multi-state and robust design models to the mark-recapture data. These models revealed underlying positive responses to protection. Annual survival rates and population abundances reached higher values in the MPAs, compared to the unprotected sites (abundance range: MPAs = 96–1172, control areas = 92–747). In general, female survival was higher than male survival (range of survival: male = 0.13–0.75, female = 0.37–0.85), while larger males benefited more from protection compared to smaller males (range of increase in survival after protection: big = 100–125%, small = 55–101%). We also detected regional differences in demographic responses to protection, as not all MPAs showed the same changes in abundance over time. Our results show that MPAs can reach conservation goals by increasing the local survival and abundance of lobster, but they also highlight demographic differences between sexes and geographic areas that are worth considering for the management and design of both current and future MPAs.

• Kristensen, Martin Lykke; Olsen, Esben Moland; Moland, Even; Knutsen, Halvor; Grønkjær, Peter & Koed, Anders [Show all 8 contributors for this article] (2021). Disparate movement behavior and feeding ecology in sympatric ecotypes of Atlantic cod. Ecology and Evolution. 11(16), p. 11477–11490. doi: 10.1002/ece3.7939. Full text in Research Archive Show summary

  Coexistence of ecotypes, genetically divergent population units, is a widespread phenomenon, potentially affecting ecosystem functioning and local food web stability. In coastal Skagerrak, Atlantic cod (Gadus morhua) occur as two such coexisting ecotypes. We applied a combination of acoustic telemetry, genotyping, and stable isotope analysis to 72 individuals to investigate movement ecology and food niche of putative local “Fjord” and putative oceanic “North Sea” ecotypes—thus named based on previous molecular studies. Genotyping and individual origin assignment suggested 41 individuals were Fjord and 31 were North Sea ecotypes. Both ecotypes were found throughout the fjord. Seven percent of Fjord ecotype individuals left the study system during the study while 42% of North Sea individuals left, potentially homing to natal spawning grounds. Home range sizes were similar for the two ecotypes but highly variable among individuals. Fjord ecotype cod had significantly higher δ13C and δ15N stable isotope values than North Sea ecotype cod, suggesting they exploited different food niches. The results suggest coexisting ecotypes may possess innate differences in feeding and movement ecologies and may thus fill different functional roles in marine ecosystems. This highlights the importance of conserving interconnected populations to ensure stable ecosystem functioning and food web structures.

• Villegas-Ríos, David; Claudet, Joachim; Freitas, Carla; Moland, Even; Thorbjørnsen, Susanna Huneide & Alonso-Fernández, Alexandre [Show all 7 contributors for this article] (2021). Time at risk: Individual spatial behaviour drives effectiveness of marine protected areas and fitness. Biological Conservation. ISSN 0006-3207. 263, p. 1–11. doi: 10.1016/j.biocon.2021.109333. Full text in Research Archive
• Synnes, Ann-Elin; Huserbråten, Mats Brockstedt Olsen; Knutsen, Halvor; Jorde, Per Erik; Sodeland, Marte & Moland, Even (2021). Local recruitment of Atlantic cod and putative source spawning areas in a coastal seascape. ICES Journal of Marine Science. ISSN 1054-3139. 78(10), p. 3767–3779. doi: 10.1093/icesjms/fsab226. Full text in Research Archive Show summary

  Increased knowledge on connectivity is crucial to our understanding of the population dynamics, genetic structure, and biogeography of many coastal species. In coastal marine populations, the main factor for structuring is thought to be the degree of isolation and confinement, limiting genetic exchange between populations. However, many offshore populations use the coastal areas as nursery grounds, but venture back to natal spawning grounds as adults. Therefore, increased knowledge on the connectivity between coastal and offshore populations is crucial to ensure correct assessment of coastal living resources. Here, we combine genetic assignment data of Atlantic cod recruits sampled in 2017 and 2018 (as 0- and 1-group cod, respectively) in outer Oslofjord (eastern Skagerrak) with a biophysical model for the Skagerrak region over the time period from spawning to settlement in 2017. We located the most probable spawning locations of Atlantic cod recruits by “back-tracking” larval drift trajectories and found putative source areas on both sides of the outer Oslofjord, as well as potential upstream sources in the North Sea and Kattegat. Findings are discussed with regards to suitable management strategies and potential for restoration of coastal cod populations.

• Kjesbu, Olav Sigurd; Sundby, Svein; Sandø, Anne Britt; Alix, Maud; Hjøllo, Solfrid Sætre & Tiedemann, Maik [Show all 43 contributors for this article] (2021). Highly mixed impacts of near-future climate change on stock productivity proxies in the North East Atlantic. Fish and Fisheries. ISSN 1467-2960. 23(3), p. 601–615. doi: 10.1111/faf.12635. Full text in Research Archive Show summary

  Impacts of climate change on ocean productivity sustaining world fisheries are predominantly negative but vary greatly among regions. We assessed how 39 fisheries resources—ranging from data-poor to data-rich stocks—in the North East Atlantic are most likely affected under the intermediate climate emission scenario RCP4.5 towards 2050. This region is one of the most productive waters in the world but subjected to pronounced climate change, especially in the northernmost part. In this climate impact assessment, we applied a hybrid solution combining expert opinions (scorings)—supported by an extensive literature review—with mechanistic approaches, considering stocks in three different large marine ecosystems, the North, Norwegian and Barents Seas. This approach enabled calculation of the directional effect as a function of climate exposure and sensitivity attributes (life-history schedules), focusing on local stocks (conspecifics) across latitudes rather than the species in general. The resulting synopsis (50–82°N) contributes substantially to global assessments of major fisheries (FAO, The State of World Fisheries and Aquaculture, 2020), complementing related studies off northeast United States (35–45°N) (Hare et al., PLoS One, 2016, 11, e0146756) and Portugal (37–42°N) (Bueno-Pardo et al., Scientific Reports, 2021, 11, 2958). Contrary to prevailing fisheries forecasts elsewhere, we found that most assessed stocks respond positively. However, the underlying, extensive environmental clines implied that North East Atlantic stocks will develop entirely different depending upon the encountered stressors: cold-temperate stocks at the southern and Arctic stocks at the northern fringes appeared severely negatively impacted, whereas warm-temperate stocks expanding from south were found to do well along with cold-temperate stocks currently inhabiting below-optimal temperatures in the northern subregion.

• Skjæraasen, Jon Egil; Karlsen, Ørjan; Langangen, Øystein Ole Gahr; Meeren, Terje van der; Keeley, Nigel B. & Myksvoll, Mari Skuggedal [Show all 12 contributors for this article] (2021). Impact of salmon farming on Atlantic cod spatio-temporal reproductive dynamics. Aquaculture Environment Interactions. ISSN 1869-215X. 13, p. 399–412. doi: 10.3354/AEI00415. Full text in Research Archive Show summary

  Salmon farming in marine net pens is a major activity in many temperate regions. This industry may affect coastal ecosystems in several ways, such as with waste pollution and parasite spillover. Less is known about the extent to which salmon farming disrupts the use of inshore spawning grounds by wild fish, such as the Atlantic cod Gadus morhua . Acoustic telemetry was therefore used to explore cod space use during the spawning season in a coastal region in mid-Norway with multiple salmon farms. Acoustic receivers were placed in clusters at 5 known cod spawning grounds and 6 nearby salmon farms. Data from 481 adult cod caught at the spawning grounds during 2017-2019 and equipped with acoustic telemetry transmitters were analysed. Overall, fewer fish were detected at farms than spawning grounds, even when accounting for distance from release point. Individual cod residency (days detected / duration of spawning period) was generally higher at the spawning grounds close to farms but low at the farms themselves, with little apparent spawning at the farm localities. In contrast, spawning was clearly occurring at the nearby spawning grounds, with cod spending weeks (n = 316) or months (n = 158) there during the spawning period. Males had longer residence times at spawning grounds than females, likely linked to the cod mating system. Overall, we found little support for the assertion that salmon farms disrupt inshore spawning dynamics of cod using nearby spawning grounds presently, either by attracting spawners to farms or causing fish to leave these grounds.

• Thorbjørnsen, Susanna Huneide; Moland, Even; Villegas-Ríos, David; Bleeker, Katinka; Knutsen, Halvor & Olsen, Esben Moland (2021). Selection on fish personality differs between a no-take marine reserve and fished areas. Evolutionary Applications. 14(7), p. 1807–1815. doi: 10.1111/eva.13242. Full text in Research Archive Show summary

  Marine reserves can protect fish populations by increasing abundance and body size, but less is known about the effect of protection on fish behaviour. We looked for individual consistency in movement behaviours of sea trout in the marine habitat using acoustic telemetry to investigate whether they represent personality traits and if so, do they affect survival in relation to protection offered by a marine reserve. Home range size had a repeatability of 0.21, suggesting that it represents a personality trait, while mean swimming depth, activity and diurnal vertical migration were not repeatable movement behaviours. The effect of home range size on survival differed depending on the proportion of time fish spent in the reserve, where individuals spending more time in the reserve experienced a decrease in survival with larger home ranges while individuals spending little time in the reserve experienced an increase in survival with larger home ranges. We suggest that the diversity of fish home range sizes could be preserved by establishing networks of marine reserves encompassing different habitat types, ensuring both a heterogeneity in environmental conditions and fishing pressure.

• Freitas, Carla; Villegas-Ríos, David; Moland, Even & Olsen, Esben Moland (2021). Sea temperature effects on depth use and habitat selection in a marine fish community. Journal of Animal Ecology. ISSN 0021-8790. 90(7), p. 1787–1800. doi: 10.1111/1365-2656.13497. Full text in Research Archive Show summary

  Understanding the responses of aquatic animals to temperature variability is essential to predict impacts of future climate change and to inform conservation and management. Most ectotherms such as fish are expected to adjust their behaviour to avoid extreme temperatures and minimize acute changes in body temperature. In coastal Skagerrak, Norway, sea surface temperature (SST) ranges seasonally from 0 to over 20°C, representing a challenge to the fish community which includes cold-, cool- and warm-water affinity species.

• Moland, Even; Fernández-Chacón, Albert; Sørdalen, Tonje Knutsen; Villegas-Rios, David; Thorbjørnsen, Susanna Huneide & Halvorsen, Kim Aleksander Tallaksen [Show all 14 contributors for this article] (2021). Restoration of Abundance and Dynamics of Coastal Fish and Lobster Within Northern Marine Protected Areas Across Two Decades. Frontiers in Marine Science. 8(674756). doi: 10.3389/fmars.2021.674756. Full text in Research Archive Show summary

  This article reviews a suite of studies conducted in a network of coastal Marine Protected Areas (MPAs) in Skagerrak, Southeast Norway. In 2006, Norway’s first lobster reserves were implemented, with the aim of protecting European lobster (Homarus gammarus) through a ban on fixed gear. A before–after control-impact paired series (BACIPS) monitoring program was initiated to evaluate effects of protection on depleted lobster populations. Experimental trapping and capture-recapture techniques were combined to track demography of populations, also including movement of individuals within and beyond MPAs and adjacent control areas. Further, population genetics and parentage studies were applied, allowing for estimation of gene flow, and novel work on sexual selection in lobsters. Additional studies have evaluated MPA effects on coastal cod (Gadus morhua), and on commercially harvested labrids (Ctenolabrus rupestris and Symphodus melops) and anadromous brown trout (Salmo trutta). Together, these studies reported effects of protection pertaining to increased population density, survival, body size and phenotypic diversity, changes in emigration and interaction with surrounding fisheries, and alteration of selection pressure on morphological- and behavioral traits. Designation of MPAs in close collaboration with fishers and managers, long-term monitoring, inclusion of citizen science and evolving research protocols—also including fisheries data—have revealed novel effects of protection and harvesting on marine populations, thus providing substantial contributions to conservation science. Moreover, knowledge of MPA effects on coastal species has impacted harvest regulations showing the utility of MPAs as empirically documented management tools in Norway.

• Fernández-Chacón, Albert; Villegas-Ríos, David; Moland, Even; Baskett, Marissa L.; Olsen, Esben Moland & Carlson, Stephanie M. (2020). Protected areas buffer against harvest selection and rebuild phenotypic complexity. Ecological Applications. ISSN 1051-0761. 30(5). doi: 10.1002/eap.2108. Full text in Research Archive Show summary

  Harvest mortality typically truncates the harvested species' size structure, thereby reducing phenotypic complexity, which can lead to reduced population productivity, increased population variability, and selection on an array of life history traits that can further alter these demographic processes. Marine protected areas (MPAs) are a potential tool to protect older, larger individuals and therefore mitigate such ecological and evolutionary effects of harvest, depending on the degree of connectivity among areas. Such MPA protection relies on a shift in size‐dependent mortality, the measurement of which can therefore serve as an early indicator of whether MPAs might achieve the desired longer‐term ecological and evolutionary responses. We directly measured MPA effects on size‐selective mortality and associated size structure using mark–recapture data on European lobster (Homarus gammarus) collected at three MPA–control area pairs in southern Norway during one decade (n = 5,943). Mark–recapture modeling, accounting for variation in recapture probabilities, revealed (1) that annual mean survival was higher inside MPAs (0.592) vs. control areas (0.298) and (2) that significant negative relationships between survival and body size occurred at the control areas but not in the MPAs, where the effect of body size was predominantly positive. Additionally, we found (3) that mean and maximum body size increased over time inside MPAs but not in control areas. Overall, our results suggest that MPAs can rebuild phenotypic complexity (i.e., size structure) and provide protection from harvest selection.

• Villegas-Ríos, David; Freitas, Carla; Moland, Even; Thorbjørnsen, Susanna Huneide & Olsen, Esben M. (2020). Inferring individual fate from aquatic acoustic telemetry data. Methods in Ecology and Evolution. 11(10), p. 1186–1198. doi: 10.1111/2041-210X.13446. Full text in Research Archive Show summary

  Acoustic telemetry has become a popular means of obtaining individual behavioural data from a wide array of species in marine and freshwater systems. Fate information is crucial to understand important aspects of population dynamics such as mortality, predation or dispersal rates. Here we present a method to infer individual fate from acoustic telemetry arrays of receivers with overlapping detection ranges. Our method depends exclusively on information on animal movements and the characteristics and configuration of the telemetry equipment. By answering a limited number of simple questions, our method identifies six different fates: tagging mortality, natural mortality, fishing mortality, predation, dispersal and survival. Applying the method to a cod telemetry dataset, we were able to determine the fate of 97% of the individuals. We validate the results using several external sources of information, such as recaptures from fishers and control fish with known fate. The method is readily applicable to a wide array of species with minimal adjustments, expanding the range of hypotheses that can be tested using telemetry data.

• Sørdalen, Tonje Knutsen; Halvorsen, Kim Aleksander Tallaksen; Vøllestad, Leif Asbjørn; Moland, Even & Olsen, Esben Moland (2020). Marine protected areas rescue a sexually selected trait in European lobster. Evolutionary Applications. 13(9), p. 2222–2233. doi: 10.1111/eva.12992. Full text in Research Archive Show summary

  Marine protected areas (MPAs) are increasingly implemented worldwide to maintain and restore depleted populations. However, despite our knowledge on the myriad of positive responses to protection, there are few empirical studies on the ability to conserve species’ mating patterns and secondary sexual traits. In male European lobsters (Homarus gammarus), the size of claws relative to body size correlates positively with male mating success and is presumably under sexual selection. At the same time, an intensive trap fishery exerts selection against large claws in males. MPAs could therefore be expected to resolve these conflicting selective pressures and preserve males with large claws. We explored this hypothesis by contrasting claw size of males and females in three pairs of MPAs and nearby fished areas in southern Norway. By finding that male lobsters have up to 8% larger claws inside MPAs compared to similarly sized males in fished areas, our study provides evidence that MPAs rescue a secondary sexual trait. Recovery from harvest selection acting on claws is the most likely explanation; however, the higher abundance of lobster inside MPAs does not rule out a plastic response on claw size due to increased competition. Regardless of the underlying cause, our study demonstrates (a) the value of protected areas as a management tool for mitigating fisheries‐induced evolution and (b) that MPAs help maintaining the scope for sexual selection in populations with vulnerable life histories and complex mating system.

• Norderhaug, Kjell Magnus; Nedreaas, Kjell Harald; Huserbråten, Mats & Moland, Even (2020). Depletion of coastal predatory fish sub-stocks coincided with the largest sea urchin grazing event observed in the NE Atlantic. Ambio. ISSN 0044-7447. 50, p. 163–173. doi: 10.1007/s13280-020-01362-4. Full text in Research Archive Show summary

  In this contribution, we propose fishery driven predator release as the cause for the largest grazing event ever observed in the NE Atlantic. Based on the evolving appreciation of limits to population connectivity, published and previously unpublished data, we discuss whether overfishing caused a grazer bloom of the sea urchin (Strongylocentrotus droebachiensis) resulting in overgrazing of more than 2000 km2 kelp (Laminaria hyperborea) forest along Norwegian and Russian coasts during the 1970 s. We show that coastal fisheries likely depleted predatory coastal fish stocks through modernization of fishing methods and fleet. These fish were important predators on urchins and the reduction coincided with the urchin bloom. From this circumstantial evidence, we hypothesize that coastal predatory fish were important in regulating sea urchins, and that a local population dynamics perspective is necessary in management of coastal ecosystems.

• Barth, Julia Maria Isis; Villegas-Ríos, David; Freitas, Carla; Moland, Even; Star, Bastiaan & André, Carl [Show all 15 contributors for this article] (2019). Disentangling structural genomic and behavioral barriers in a sea of connectivity. Molecular Ecology. ISSN 0962-1083. 28(6), p. 1394–1411. doi: 10.1111/mec.15010. Full text in Research Archive Show summary

  Genetic divergence among populations arises through natural selection or drift and is counteracted by connectivity and gene flow. In sympatric populations, isolating mechanisms are thus needed to limit the homogenizing effects of gene flow to allow for adaptation and speciation. Chromosomal inversions act as an important mechanism maintaining isolating barriers, yet their role in sympatric populations and divergence with gene flow is not entirely understood. Here, we revisit the question of whether inversions play a role in the divergence of connected populations of the marine fish Atlantic cod (Gadus morhua), by exploring a unique data set combining whole‐genome sequencing data and behavioural data obtained with acoustic telemetry. Within a confined fjord environment, we find three genetically differentiated Atlantic cod types belonging to the oceanic North Sea population, the western Baltic population and a local fjord‐type cod. Continuous behavioural tracking over 4 year revealed temporally stable sympatry of these types within the fjord. Despite overall weak genetic differentiation consistent with high levels of gene flow, we detected significant frequency shifts of three previously identified inversions, indicating an adaptive barrier to gene flow. In addition, behavioural data indicated that North Sea cod and individuals homozygous for the LG12 inversion had lower fitness in the fjord environment. However, North Sea and fjord‐type cod also occupy different depths, possibly contributing to prezygotic reproductive isolation and representing a behavioural barrier to gene flow. Our results provide the first insights into a complex interplay of genomic and behavioural isolating barriers in Atlantic cod and establish a new model system towards an understanding of the role of genomic structural variants in adaptation and diversification.

• Kleiven, Portia Joy Nillos; Espeland, Sigurd Heiberg; Olsen, Esben Moland; Abesamis, Rene A.; Moland, Even & Kleiven, Alf Ring (2019). Fishing pressure impacts the abundance gradient of European lobsters across the borders of a newly established marine protected area. Proceedings of the Royal Society of London. Biological Sciences. ISSN 0962-8452. 286(1894). doi: 10.1098/rspb.2018.2455. Full text in Research Archive Show summary

  Marine protected areas (MPAs) are considered viable fisheries management tools due to their potential benefits of adult spillover and recruitment subsidy to nearby fisheries. However, before–after control–impact studies that explore the biological and fishery effects of MPAs to surrounding fisheries are scarce. We present results from a fine-scale spatial gradient study conducted before and after the implementation of a 5 km2 lobster MPA in southern Norway. A significant nonlinear response in lobster abundance, estimated as catch-per-unit-effort (CPUE) from experimental fishing, was detected within 2 years of protection. After 4 years, CPUE values inside the MPA had increased by a magnitude of 2.6 compared to before-protection values. CPUE showed a significant nonlinear decline from the centre of the MPA, with a depression immediately outside the border and a plateau in fished areas. Overall fishing pressure almost doubled over the course of the study. The highest increase in fishing pressure (by a magnitude of 3) was recorded within 1 km of the MPA border, providing a plausible cause for the depression in CPUE. Taken together, these results demonstrate the need to regulate fishing pressure in surrounding areas when MPAs are implemented as fishery management tools.

• Moland, Even; Carlson, Stephanie; Villegas-Rios, David; Wiig, Jørgen Ree & Olsen, Esben Moland (2019). Harvest selection on multiple traits in the wild revealed by aquatic animal telemetry. Ecology and Evolution. 9(11), p. 6480–6491. doi: 10.1002/ece3.5224. Full text in Research Archive Show summary

  Harvesting can have profound impacts on the ecology and evolution of marine populations. However, little is known about the strength and direction of fisheries‐induced selection acting on multiple traits in the wild. Here, we used acoustic telemetry to directly monitor individual behavior and fate in an intensively harvested species, the European lobster (Homarus gammarus, n = 100), in southern Norway. Overall, 24% of the tracked lobsters survived the two‐month harvest season within the study area. Our results indicated that local survival was not random with respect to phenotype. We found no clear support for fisheries‐induced selection acting directly on body size. However, lobsters with large crusher claws relative to their body size, typical of socially dominant individuals, appeared at higher risk of being captured in the conventional trap fishery. We also detected a fine‐scale spatial gradient in survival. After accounting for this gradient, individuals displaying larger home ranges were more likely to survive the harvest season. Finally, we found significant repeatabilities for lobster behavior on a monthly timescale, indicating that individual behavioral attributes tended to persist and may reflect personality. Our study therefore provides empirical support for the need to consider an evolutionary enlightened approach to fisheries management that considers the influence of harvest on multiple traits of target species.

• Kleiven, Alf Ring; Moland, Even & Sumaila, Ussif Rashid (2019). No fear of bankruptcy: the innate self-subsidizing forces in recreational fishing. ICES Journal of Marine Science. ISSN 1054-3139. 77(6), p. 2304–2307. doi: 10.1093/ICESJMS/FSZ128. Full text in Research Archive
• Thorbjørnsen, Susanna Huneide; Moland, Even; Simpfendorfer, Colin A.; Heupel, Michelle R.; Knutsen, Halvor & Olsen, Esben Moland (2019). Potential of a no‐take marine reserve to protect home ranges of anadromous brown trout (Salmo trutta). Ecology and Evolution. 9(1), p. 417–426. doi: 10.1002/ece3.4760. Full text in Research Archive Show summary

  The extent to which no‐take marine reserves can benefit anadromous species requires examination. Here, we used acoustic telemetry to investigate the spatial behavior of anadromous brown trout (sea trout, Salmo trutta) in relation to a small marine reserve (~1.5 km2) located inside a fjord on the Norwegian Skagerrak coast. On average, sea trout spent 42.3 % (±5.0% SE) of their time in the fjord within the reserve, a proportion similar to the area of the reserve relative to that of the fjord. On average, sea trout tagged inside the reserve received the most protection, although the level of protection decreased marginally with increasing home range size. Furthermore, individuals tagged outside the reserve received more protection with increasing home range size, potentially opposing selection toward smaller home range sizes inflicted on fish residing within reserves, or through selective fishing methods like angling. Monthly sea trout home ranges in the marine environment were on average smaller than the reserve, with a mean of 0.430 (±0.0265 SE) km2. Hence, the reserve is large enough to protect the full home range of some individuals residing in the reserve. Synthesis and applications: In general, the reserve protects sea trout to a varying degree depending on their individual behavior. These findings highlight evolutionary implications of spatial protection and can guide managers in the design of marine reserves and networks that preserve variation in target species' home range size and movement behavior.

• Villegas-Rios, David; Réale, Denis; Freitas, Carla; Moland, Even & Olsen, Esben Moland (2018). Personalities influence spatial responses to environmental fluctuations in wild fish. Journal of Animal Ecology. ISSN 0021-8790. 87(5), p. 1309–1319. doi: 10.1111/1365-2656.12872. Full text in Research Archive Show summary

  Although growing evidence supports the idea that animal personality can explain plasticity in response to changes in the social environment, it remains to be tested whether it can explain spatial responses of individuals in the face of natural environmental fluctuations. This is a major challenge in ecology and evolution as spatial dynamics link individual‐ and population‐level processes. In this study, we investigated the potential of individual personalities to predict differences in fish behaviour in the wild. Specifically, our goal was to answer if individual differences in plasticity of space use to sea surface temperature could be explained by differences in personality along the reactive–proactive axis. To address this question, we first conducted repeated standard laboratory assays (i.e., open‐field test, novel object test and mirror stimulation test) to assess the personality type of 76 wild‐caught Atlantic cod (Gadus morhua). Next, we released the fish back into the sea and monitored their spatial behaviour over large temporal (16 months) and spatial (a whole fjord) scales, using high‐resolution acoustic tracking. We demonstrate that (a) cod personality traits are structured into a proactive–reactive syndrome (proactive fish being more bold, exploratory and aggressive), (b) mean depth use of individuals is mainly driven by sea temperature and (c) personality is a significant predictor of home range changes in the wild, where reactive, but not proactive, individuals reduced their home range as sea temperature increased. These findings expand our understanding of the ecological consequences of animal personality and the mechanisms shaping spatial dynamics of animals in nature.

• Sørdalen, Tonje Knutsen; Halvorsen, Kim Aleksander Tallaksen; Harrison, Hugo B.; Ellis, Charlie D.; Vøllestad, Leif Asbjørn & Knutsen, Halvor [Show all 8 contributors for this article] (2018). Harvesting changes mating behaviour in European lobster. Evolutionary Applications. 11(6), p. 963–977. doi: 10.1111/eva.12611. Full text in Research Archive Show summary

  Removing individuals from a wild population can affect the availability of prospective mates and the outcome of competitive interactions, with subsequent effects on mating patterns and sexual selection. Consequently, the rate of harvest‐induced evolution is predicted to be strongly dependent on the strength and dynamics of sexual selection, yet there is limited empirical knowledge on the interplay between selective harvesting and the mating systems of exploited species. In this study, we used genetic parentage assignment to compare mating patterns of the highly valued and overexploited European lobster (Homarus gammarus) in a designated lobster reserve and nearby fished area in southern Norway. In the area open to fishing, the fishery is regulated by a closed season, a minimum legal size and a ban on the harvest of egg‐bearing females. Due to the differences in size and sex‐specific fishing mortality between the two areas, males and females are of approximately equal average size in the fished area, whereas males tend to be larger in the reserve. Our results show that females would mate with males larger than their own body size, but the relative size difference was significantly larger in the reserve. Sexual selection acted positively on both body size and claw size in males in the reserve, while it was nonsignificant in fished areas. This strongly suggests that size truncation of males by fishing reduces the variability of traits that sexual selection acts upon. If fisheries continue to target large individuals (particularly males) with higher relative reproductive success, the weakening of sexual selection will likely accelerate fisheries‐induced evolution towards smaller body size.

• Huserbråten, Mats Brockstedt Olsen; Moland, Even & Albretsen, Jon (2018). Cod at drift in the North Sea. Progress in Oceanography. ISSN 0079-6611. 167, p. 116–124. doi: 10.1016/j.pocean.2018.07.005. Full text in Research Archive Show summary

  There has been a large-scale geographical re-distribution of the North Sea cod stock over the past century, and recent surveys indicate a north-eastern modal distribution. Here we assess the consequences of the contemporary distribution of North Sea cod (Gadus morhua) spawning biomass to inter-ocean recruitment potential. By simulations of drifting cod eggs and larvae spawned in the northern North Sea over 16 spawning seasons (in the period 1995–2016), we show that a large portion of the North Sea produced pelagic juveniles most likely settle along the Norwegian Sea shelf. For example during the early 2000s when the North Sea cod spawning biomass was at its lowest, 20% to 27% of larvae produced in the northern North Sea most likely settled along the Norwegian Sea shelf, while as few as 8% and 10% were retained within the North Sea in some years. We hypothesise the spillover of North Sea cod into nursery habitat along the Norwegian north-western coast to be beneficial to the stock, as larvae would encounter far higher abundances of their favoured prey, the copepod Calanus finmarchicus. Looking back at a century of overfishing, warming, and variable nursery conditions for cod in the North Sea, getting entrained in the Norwegian coastal current seems like a viable “back-door exit” strategy, allowing the north-eastern spawning cod to thrive even in seemingly adverse climatic periods.

• Dornelas, Maria; Antão, Laura H.; Moyes, Faye; Bates, Amanda E.; Magurran, Anne E. & Adam, Dusan [Show all 270 contributors for this article] (2018). BioTIME: A database of biodiversity time series for the Anthropocene. Global Ecology and Biogeography. ISSN 1466-822X. 27(7), p. 760–786. doi: 10.1111/geb.12729. Full text in Research Archive Show summary

  <p><i>Motivation</i>: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community‐led open‐source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.</p> <p><i>Main types of variables included</i>: The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.</p> <p><i>Spatial location and grain</i>: BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km² (158 cm²) to 100 km² (1,000,000,000,000 cm²).</p> <p><i>Time period and grain</i>: BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.</p> <p><i>Major taxa and level of measurement</i>: BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.</p> <p><i>Software format</i>: .csv and .SQL.

• Thorbjørnsen, Susanna Huneide; Moland, Even; Huserbråten, Mats Brockstedt Olsen; Knutsen, Jan Atle; Knutsen, Halvor & Olsen, Esben Moland (2018). Replicated marine protected areas (MPAs) support movement of larger, but not more, European lobsters to neighbouring fished areas. Marine Ecology Progress Series. ISSN 0171-8630. 595, p. 123–133. doi: 10.3354/meps12546. Full text in Research Archive Show summary

  The European lobster Homarus gammarus is heavily exploited in the Norwegian fishery, and several management actions have been implemented to protect the species. Three marine protected areas (MPAs) excluding all but hook and line type fishing gear were established along the Skagerrak coast in 2006, effectively banning the trap-based fishery for European lobster. Lobster populations within MPAs and adjacent control areas were studied by capture-mark-recapture and recovery methods every year from prior to MPA establishment to the present. During 2006-2014, a total of 4682 and 3317 lobsters were captured (including recaptures) in the MPAs and control areas, respectively. In all MPAs, protection led to a shift in demography, with an increase in mean total length of 15% during 2006-2014, thereby opposing the effects of a size-selective fishery. No difference was found in rates of movement out from MPAs and control areas, but lobsters moving from MPAs and caught in fished areas were significantly larger than lobsters moving out of control areas. In instances where lobsters tagged in a control area moved into an MPA, the immigrating lobsters had a larger body size than the mean in their area of origin. The range of movement undertaken by recovered lobsters extended beyond the home range sizes suggested by previous shorter-term studies, and well beyond the sizes of the small coastal MPAs studied herein. In summary, demographic changes should be accounted for when interpreting the value of spillover from MPAs, and also potential ‘spill in’ from fished areas to MPAs.

• Villegas-Rios, David; Moland, Even & Olsen, Esben Moland (2017). Potential of contemporary evolution to erode fishery benefits from marine reserves. Fish and Fisheries. ISSN 1467-2960. 18(3), p. 571–577. doi: 10.1111/faf.12188. Full text in Research Archive
• Villegas-Rios, David; Réale, Denis; Freitas, Carla; Moland, Even & Olsen, Esben Moland (2017). Individual level consistency and correlations of fish spatial behaviour assessed from aquatic animal telemetry. Animal Behaviour. ISSN 0003-3472. 124, p. 83–94. doi: 10.1016/j.anbehav.2016.12.002. Full text in Research Archive
• Nash, Kirsty L.; Abesamis, Rene A.; Graham, Nicholas; McClure, Eva C. & Moland, Even (2016). Drivers of herbivory on coral reefs: Species, Habitat and management effects. Marine Ecology Progress Series. ISSN 0171-8630. 554, p. 129–140. doi: 10.3354/meps11795. Full text in Research Archive
• Kleiven, Alf Ring; Chacon, Albert Fernandez; Nordahl, Jan-Harald; Moland, Even; Espeland, Sigurd Heiberg & Knutsen, Halvor [Show all 7 contributors for this article] (2016). Harvest pressure on coastal atlantic cod (Gadus morhua) from recreational fishing relative to commercial fishing assessed from tag-recovery data. PLOS ONE. 11(3). doi: 10.1371/journal.pone.0149595. Full text in Research Archive Show summary

  Marine recreational fishing is a popular outdoor activity. However, knowledge about the magnitude of recreational catches relative to commercial catches in coastal fisheries is generally sparse. Coastal Atlantic cod (Gadus morhua) is a target species for recreational fishers in the North Atlantic. In Norway, recreational fishers are allowed to use a variety of traps and nets as well as long-line and rod and line when fishing for cod. From 2005 to 2013, 9729 cod (mean size: 40 cm, range: 15–93 cm) were tagged and released in coastal Skagerrak, southeast Norway. Both high-reward (NOK 500) and low-reward tags (NOK 50) were used in this study. Because some harvested fish (even those posting high-reward tags) may go unreported by fishers, reporting rates were estimated from mark-recovery models that incorporate detection parameters in their structure, in addition to survival and mortality estimates. During 2005 to 2013, a total of 1707 tagged cod were recovered and reported by fishers. We estimate the overall annual survival to be 33% (SE 1.5). Recreational rod and line fishing were responsible for 33.7% (SE 2.4) of total mortality, followed by commercial fisheries (15.1% SE 0.8) and recreational fixed gear (6.8% SE 0.4). Natural mortality was 44.4% (SE 2.5) of total mortality. Our findings suggest that recreational fishing—rod and line fishing in particular—is responsible for a substantial part of fishing mortality exerted on coastal cod in southern Norway.

• Freitas, Carla; Olsen, Esben Moland; Knutsen, Halvor; Albretsen, Jon & Moland, Even (2016). Temperature-associated habitat selection in a cold-water marine fish. Journal of Animal Ecology. ISSN 0021-8790. 85(3), p. 628–637. doi: 10.1111/1365-2656.12458. Full text in Research Archive Show summary

  1. Habitat selection is a complex process, which involves behavioural decisions guided by the multiple needs and constraints faced by individuals. Climate-induced changes in environmental conditions may alter those trade-offs and resulting habitat use patterns. 2. In this study, we investigated the effect of sea temperature on habitat selection and habitat use of acoustically tagged Atlantic cod (Gadus morhua) at the Norwegian Skagerrak coast. 3. Significant relationships between ocean temperature and habitat selection and use were found. Under favourable sea temperature thresholds (<16 °C), cod selected vegetated habitats, such as eelgrass and macroalgae beds, available in shallow areas. Selection for those habitats was especially high at night, when cod tended to ascend to shallower areas, presumably to feed. Selection and use of those habitats decreased significantly as temperature rose. Under increased sea surface temperature conditions, cod were absent from vegetated shallow habitats, both during the day and night, and selected instead non-vegetated rocky bottoms and sand habitats, available in deeper, colder areas. 4. This study shows the dynamic nature of habitat selection and strongly suggests that cod in this region have to trade off food availability against favourable temperature conditions. Future increases in ocean temperature are expected to further influence the spatial behaviour of marine fish, potentially affecting individual fitness and population dynamics.

• Chacon, Albert Fernandez; Moland, Even; Espeland, Sigurd Heiberg; Kleiven, Alf Ring & Olsen, Esben Moland (2016). Causes of mortality in depleted populations of Atlantic cod estimated from multi-event modelling of mark-recapture and recovery data. Canadian Journal of Fisheries and Aquatic Sciences. ISSN 0706-652X. 74(1), p. 116–126. doi: 10.1139/cjfas-2015-0313. Full text in Research Archive
• Aalvik, Ida Margrethe; Moland, Even; Olsen, Esben Moland & Stenseth, Nils Christian (2015). Spatial ecology of coastal Atlantic cod Gadus morhua associated with parasite load. Journal of Fish Biology. ISSN 0022-1112. 87(2), p. 449–464. doi: 10.1111/jfb.12731. Full text in Research Archive Show summary

  Acoustic tags and receivers were used to investigate the spatial ecology of coastal Atlantic cod Gadus morhua (n = 32, mean fork length: 50 cm, range: 33–80 cm) on the Norwegian Skagerrak coast in 2012. Monthly home ranges (HR), swimming activity and depth use varied considerably among individuals and through the months of June, July and August. HR sizes for the period ranged from 0·25 to 5·20 km2 (mean = 2·30 km2). Two thirds of the tagged G. morhua were infected with black spot disease Cryptocotyle lingua parasites; these fish had larger HRs and occupied deeper water compared with non-infected fish. The infected fish also tended to be more active in terms of horizontal swimming. From an ecological and evolutionary perspective, any environmental change that modifies G. morhua behaviour may therefore also alter the parasite load of the population, and its conservation and fishery status.

• Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo & Knutsen, Halvor (2015). Behavioral responses of Atlantic cod to sea temperature changes. Ecology and Evolution. 5(10), p. 2070–2083. doi: 10.1002/ece3.1496. Full text in Research Archive Show summary

  Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30–80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ~15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species.

• Chacon, Albert Fernandez; Moland, Even; Espeland, Sigurd Heiberg & Olsen, Esben Moland (2015). Demographic effects of full vs. partial protection from harvesting: Inference from an empirical before-after control-impact study on Atlantic cod. Journal of Applied Ecology. ISSN 0021-8901. 52(5), p. 1206–1215. doi: 10.1111/1365-2664.12477. Full text in Research Archive
• Eggers, Florian; Olsen, Esben Moland; Moland, Even & Slotte, Aril (2015). Individual habitat transitions of Atlantic herring Clupea harengus in a human-modified coastal system. Marine Ecology Progress Series. ISSN 0171-8630. 520, p. 245–256. doi: 10.3354/meps11103. Full text in Research Archive Show summary

  Pelagic marine fish often display highly dynamic migration patterns. However, such movement behaviour is usually studied at the population or school level, while less is known about individual movement characteristics and habitat transitions. During March 2012 to June 2013, we used acoustic tags and moored receivers to monitor the behaviour of Atlantic herring Clupea harengus L. (N = 47) throughout a range of habitats on the Skagerrak coast in southern Norway. Five of the tagged herring entered a former lake transformed into an artificial estuary by a human-made canal linking the former lake to the open ocean. Herring resided in this system for up to 36 d. All tagged herring left the fjord where they were tagged by early August 2012. This habitat transition was detected by the receivers as 3 main pulses of tagged individuals, which were assumed to be formed by putative populations mixing in the area. Most transitions occurred during nighttime regardless of tidal cycle, and it is suggested that spawning is the primary driver for entering the fjord and artificial estuary. Later detections at a separate receiver system 17 km to the northeast suggest that some herring may overwinter in coastal areas. In the spring of 2013, 3 of the tagged herring returned to their original fjord tagging location. Our study reveals new aspects of herring migration dynamics linked to anthropogenic modifications of connectivity, and suggests that capacity for individual behaviours in schooling fish may be underestimated.

• Eggers, Florian; Slotte, Aril; Libungan, Lisa Anne; Johannessen, Arne; Kvamme, Cecilie & Moland, Even [Show all 8 contributors for this article] (2014). Seasonal dynamics of atlantic herring (Clupea harengus L.) populations spawning in the vicinity of marginal habitats. PLOS ONE. 9(11). doi: 10.1371/journal.pone.0111985. Full text in Research Archive Show summary

  Gillnet sampling and analyses of otolith shape, vertebral count and growth indicated the presence of three putative Atlantic herring (Clupea harengus L.) populations mixing together over the spawning season February–June inside and outside an inland brackish water lake (Landvikvannet) in southern Norway. Peak spawning of oceanic Norwegian spring spawners and coastal Skagerrak spring spawners occurred in March–April with small proportions of spawners entering the lake. In comparison, spawning of Landvik herring peaked in May–June with high proportions found inside the lake, which could be explained by local adaptations to the environmental conditions and seasonal changes of this marginal habitat. The 1.85 km2 lake was characterized by oxygen depletion occurring between 2.5 and 5 m depth between March and June. This was followed by changes in salinity from 1–7‰ in the 0–1 m surface layer to levels of 20–25‰ deeper than 10 m. In comparison, outside the 3 km long narrow channel connecting the lake with the neighboring fjord, no anoxic conditions were found. Here salinity in the surface layer increased over the season from 10 to 25‰, whereas deeper than 5 m it was stable at around 35‰. Temperature at 0–5 m depth increased significantly over the season in both habitats, from 7 to 14°C outside and 5 to 17°C inside the lake. Despite differences in peak spawning and utilization of the lake habitat between the three putative populations, there was an apparent temporal and spatial overlap in spawning stages suggesting potential interbreeding in accordance with the metapopulation concept.

• Ferter, Keno; Klaas, Hartmann; Kleiven, Alf Ring; Moland, Even & Olsen, Esben Moland (2014). Catch-and-release of Atlantic cod (Gadus morhua): post-release behaviour of acoustically pretagged fish in a natural marine environment. Canadian Journal of Fisheries and Aquatic Sciences. ISSN 0706-652X. 72(2), p. 252–261. doi: 10.1139/cjfas-2014-0290. Full text in Research Archive Show summary

  Studying the sublethal effects of catch-and-release (C&R) is challenging, as there are several potential sources of bias. For example, if behavioural alterations immediately after the release event are to be studied, separation of tagging effects from actual C&R effects is required, which is a challenge in the wild, particularly in marine environments. To investigate the effects of C&R on Atlantic cod (Gadus morhua) in their natural environment, 80 cod were caught in fyke nets, fitted with acoustic transmitters, and released. After recovery from tagging and handling for at least 14 days, nine individuals were recaptured and released at least once during experimental angling, following best release practice. All cod survived the C&R event and did not show any large-scale behavioural changes (i.e., changes in diel vertical migrations). However, analysis of small-scale vertical movements showed that three individuals underwent short-term alterations (e.g., reduced or increased swimming activity). This study showed that pretagging fish with acoustic transmitters before experimental angling is an option when investigating fish behaviour immediately after the release event in marine environments. Moreover, release guidelines for cod should be developed, as cod can recover quickly if caught in shallow waters (<20 m) and properly handled and released.

• Moland, Even; Ulmestrand, Mats; Olsen, Esben Moland & Stenseth, Nils Christian (2013). Long-term decrease in sex-specific natural mortality of European lobster within a marine protected area. Marine Ecology Progress Series. ISSN 0171-8630. 491, p. 153–164. doi: 10.3354/meps10459. Full text in Research Archive Show summary

  Marine protected areas (MPAs) and marine reserves hold promise as tools for nature conservation and fisheries management, but data on long-term demographic effects are still sparse. Here, we use a unique capture-mark-recapture data set from Kåvra, an MPA on the west coast of Sweden where fishing for European lobster Homarus gammarus has been banned since 1989, to directly quantify annual survival probabilities in the absence of harvest mortality. The non-migratory behaviour of this species allowed multiple recaptures and releases of a large number of individuals within the MPA. We found strong evidence for a long-term decrease in sexspecific natural mortality throughout the study period (1994 to 2007). Positive trends were evident in mean body size and in catch-per-unit-effort, the latter indicating an increase in abundance. Together, these findings suggest that after nearly 2 decades of protection, density dependence was still not halting development of the population within the MPA. The present study is the first to quantify long-term (14 yr) changes in natural mortality rates in a protected marine population. Moreover, our study supports the notion that MPAs and marine reserves may act to counter fisheries-induced selection.

• Wiig, Jørgen Ree; Moland, Even; Haugen, Thrond Oddvar & Olsen, Esben Moland (2013). Spatially structured interactions between lobsters and lobster fishers in a coastal habitat: fine-scale behaviour and survival estimated from acoustic telemetry. Canadian Journal of Fisheries and Aquatic Sciences. ISSN 0706-652X. 70(10), p. 1468–1476. doi: 10.1139/cjfas-2013-0209. Full text in Research Archive Show summary

  Fishing can have profound impacts on the ecology and evolution of marine populations. Understanding population-level changes ultimately depends on knowledge about individual survival and how it varies in time and space. We used acoustic tags and a network of receivers to monitor individual behaviour and fate of European lobster (Homarus gammarus) exposed to commercial and recreational trap fisheries on the Norwegian Skagerrak coast. In August 2011, 50 male lobsters above minimum legal size were tagged and monitored before and during the lobster fishing season. We also quantified the spatial and temporal variation in fishing activity. There was no significant effect of home-range size on the probability of surviving the fishery. However, there was substantial fine-scale spatial variation in fishing activity, and lobsters with short-term home ranges positioned away from trap-dense areas had a significantly higher survival probability. Also, the overall survival probability of 16.7% suggests that fishing depletes the catchable lobster population at a high rate. The current harvesting regime may drive selection in favour of movement behaviours avoiding habitats typically targeted by fishers.

• Moland, Even; Olsen, Esben Moland; Knutsen, Halvor; Garrigou, Pauline; Espeland, Sigurd Heiberg & Kleiven, Alf Ring [Show all 8 contributors for this article] (2013). Lobster and cod benefit from small-scale northern marine protected areas: inference from an empirical before - after control-impact study. Proceedings of the Royal Society of London. Biological Sciences. ISSN 0962-8452. 280(1754). doi: 10.1098/rspb.2012.2679. Full text in Research Archive Show summary

  Marine protected areas (MPAs) are increasingly implemented as tools to conserve and manage fisheries and target species. Because there are opportunity costs to conservation, there is a need for science-based assessment of MPAs. Here, we present one of the northernmost documentations of MPA effects to date, demonstrated by a replicated before-after control-impact (BACI) approach. In 2006, MPAs were implemented along the Norwegian Skagerrak coast offering complete protection to shellfish and partial protection to fish. By 2010, European lobster (Homarus gammarus) catch-per-unit-effort (CPUE) had increased by 245 per cent in MPAs, whereas CPUE in control areas had increased by 87 per cent. Mean size of lobsters increased by 13 per cent in MPAs, whereas increase in control areas was negligible. Furthermore, MPA-responses and population development in control areas varied significantly among regions. This illustrates the importance of a replicated BACI design for reaching robust conclusions and management decisions. Partial protection of Atlantic cod (Gadus morhua) was followed by an increase in population density and body size compared with control areas. By 2010, MPA cod were on average 5 cm longer than in any of the control areas. MPAs can be useful management tools in rebuilding and conserving portions of depleted lobster populations in northern temperate waters, and even for a mobile temperate fish species such as the Atlantic cod.

• Huserbråten, Mats Brockstedt Olsen; Moland, Even; Knutsen, Halvor; Olsen, Esben Moland; André, Carl & Stenseth, Nils Christian (2013). Conservation, Spillover and Gene Flow within a Network of Northern European Marine Protected Areas. PLOS ONE. 8(9). doi: 10.1371/journal.pone.0073388. Full text in Research Archive Show summary

  To ensure that marine protected areas (MPAs) benefit conservation and fisheries, the effectiveness of MPA designs has to be evaluated in field studies. Using an interdisciplinary approach, we empirically assessed the design of a network of northern MPAs where fishing for European lobster (Homarus gammarus) is prohibited. First, we demonstrate a high level of residency and survival (50%) for almost a year (363 days) within MPAs, despite small MPA sizes (0.5-1 km2). Second, we demonstrate limited export (4.7%) of lobsters tagged within MPAs (N = 1810) to neighbouring fished areas, over a median distance of 1.6 km out to maximum 21 km away from MPA centres. In comparison, median movement distance of lobsters recaptured within MPAs was 164 m, and recapture rate was high (40%). Third, we demonstrate a high level of gene flow within the study region, with an estimated FST of less than 0.0001 over a ≈ 400 km coastline. Thus, the restricted movement of older life stages, combined with a high level of gene flow suggests that connectivity is primarily driven by larval drift. Larval export from the MPAs can most likely affect areas far beyond their borders. Our findings are of high importance for the design of MPA networks for sedentary species with pelagic early life stages.

• Fenberg, Philip B.; Caselle, Jennifer E.; Claudet, Joachim; Clemence, Michaela; Gaines, Steven D. & Garcia-Charton, Jose Antonio [Show all 16 contributors for this article] (2012). The science of European marine reserves: Status, efficacy, and future needs. Marine Policy. ISSN 0308-597X. 36(5), p. 1012–1021. doi: 10.1016/j.marpol.2012.02.021. Full text in Research Archive

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• Vandvik, Vigdis; Armstrong, Claire W.; Barton, David Nicholas; Bekkby, Trine; Bjærke, Marit Ruge & Czúcz, Bálint [Show all 25 contributors for this article] (2025). Demokratisk fallitt i naturpolitikken? Khrono.no. ISSN 1894-8995. Full text in Research Archive
• Vandvik, Vigdis; Armstrong, Claire W.; Barton, David Nicholas; Bekkby, Trine; Bjærke, Marit Ruge & Czúcz, Bálint [Show all 25 contributors for this article] (2024). Stortinget må sette kunnskapen i arbeid for å stoppe naturtapet. Full text in Research Archive
• Stenseth, Nils Christian; Jentoft, Sissel; Haugen, Thrond Oddvar; Bekkby, Trine; Walday, Mats Gunnar & Berg, Paul Ragnar [Show all 11 contributors for this article] (2024). Økosystemet i Oslofjorden kollapser – vi trenger tiltak. Khrono.no. ISSN 1894-8995. Full text in Research Archive
• Norderhaug, Kjell Magnus; Nedreaas, Kjell Harald; Huserbråten, Mats Brockstedt Olsen & Moland, Even (2023). Overfishing caused the largest sea urchin grazing event observed in the NE Atlantic. Full text in Research Archive
• Stenseth, Nils Christian; Jentoft, Sissel; Moland, Even; Knutsen, Halvor; Haugen, Thrond Oddvar & Colman, JE [Show all 9 contributors for this article] (2023). Langsiktig forskning og modige tiltak må til om vi skal redde Oslo­fjorden. Debattinnlegg i Khrono, 14.08.2023. khrono.no/langsiktig-forskning-og-modige-tiltak-ma-til-om-vi-skal-redde-oslofjorden/800689. Khrono.no. ISSN 1894-8995. Full text in Research Archive
• Bjørn, Pål Arne; Berg, Erik; Bøhn, Thomas; Espeland, Sigurd Heiberg; Glover, Kevin Alan & Jorde, Per Erik [Show all 16 contributors for this article] (2022). Effekter av torskeoppdrett i åpne merder på ville torskebestander, Risikorapport norsk fiskeoppdrett 2022 - kunnskapsstatus - Effekter på miljø og dyrevelferd i norsk fiskeoppdrett. Havforskningsinstituttet. p. 314–405. Full text in Research Archive Show summary

  Oppdrett i åpne merder gjør at smittestoffer fra oppdrettsanleggene vil kunne drive fra merdene og ut i miljøet. Lakselus som slippes fra hunnlus som sitter på oppdrettsfisk antas, i oppdrettsintensive områder, å være den største kilden for lakselus også på vill laksefisk (Fjørtoft mfl. 2019; Dempster mfl. 2021). Økte nivåer av lakselus er vist å ha negative effekter på vertsfisken, som igjen kan medføre en populasjonseffekt. Effekten lakselus har på ville bestander av laks langs hele landet vurderes i denne rapporten opp mot antatte tålegrenser for dødelighet for individer. Derfra estimeres effekt på populasjoner. Hvor mange lus den ville fisken har fått (nivå av infestasjon) vurderes basert på overvåking av lakselus på vill laksefisk, samt på estimert påvirkning av lakselus fra koblede fysisk-biologiske modeller. Tålegrenser for individer og effekten på populasjonsnivå er basert på best tilgjengelig kunnskap fra laboratorie- og feltundersøkelser.

• Oomen, Rebekah Alice; Knutsen, Halvor; Moland, Even; Olsen, Esben Moland; Knutsen, Jan Atle & Bernatchez, Louis [Show all 8 contributors for this article] (2022). Nothing so boundless, nothing so patient: Obituary for Professor Jeffrey Alexander Hutchings (1958–2022). Fish and Fisheries. ISSN 1467-2960. 23(3), p. 519–521. doi: 10.1111/faf.12661. Full text in Research Archive
• Thorbjørnsen, Susanna Huneide; Moland, Even; Villegas-Rios, David; Knutsen, Halvor & Olsen, Esben Moland (2018). Personality of sea trout and consequences for survival quantified using detailed movement data from a telemetry study in a southern Norwegian fjord. Full text in Research Archive
• Thorbjørnsen, Susanna Huneide; Moland, Even; Simpfendorfer, Colin A.; Heupel, Michelle R.; Knutsen, Halvor & Olsen, Esben Moland (2017). A no-take marine reserve provide benefits to anadromous sea trout (Salmo trutta). Full text in Research Archive
• Skjæraasen, Jon Egil; Karlsen, Ørjan; Olsen, Esben Moland; Moland, Even; Elvik, Kristine Marit Schrøder & Meeren, Terje van der [Show all 7 contributors for this article] (2017). The influence of salmon Salmo salar aquaculture on spawning ground use of Atlantic cod Gadus morhua. Full text in Research Archive
• Tuddenham, David Berg; Moland, Even; Cuhra, Marek; Walday, Mats Gunnar; Hop, Haakon & Herdlevær, Eirik Søyland Laskemoen [Show all 8 contributors for this article] (2017). Ny forskrift setter vitenskapelige dykkere på land. Full text in Research Archive
• Thorbjørnsen, Susanna Huneide; Moland, Even; Villegas-Rios, David; Knutsen, Halvor & Olsen, Esben Moland (2017). Repeatability of sea trout behavioural traits and potential for detecting behavioural syndromes. Full text in Research Archive
• Moland, Even & Freitas, Carla (2015). Sulter på dypet i sommervarme fjorder. Forskning.no. ISSN 1891-635X. Full text in Research Archive
• Chacon, Albert Fernandez; Moland, Even; Espeland, Sigurd Heiberg & Olsen, Esben Moland (2015). Marine protected areas increase survival of Atlantic cod. Science for Environment Policy. Full text in Research Archive
• Moland, Even (2015). Små bevaringsområders effekt på fiskebestander: hva viser 10 års forskning? Full text in Research Archive
• Moland, Even & Olsen, Esben Moland (2015). Selvfisket torsk - en selvfølge? Agderposten. ISSN 0805-3723. Full text in Research Archive
• Moland, Even (2015). Combining traditional and acoustic tagging in fisheries conservation science. Full text in Research Archive
• Moland, Even & Knutsen, Jan Atle (2015). Tilstandsrapport for fiskebestandene i ytre Oslofjord. Full text in Research Archive
• Meeren, Gro Ingleid van der; Kleiven, Alf Ring; Agnalt, Ann-Lisbeth; Grefsrud, Ellen Sofie; Moland, Even & Olsen, Espen Moland (2014). Den lange og kronglete historien om hummer i Norge. Full text in Research Archive
• Meeren, Gro Ingleid van der; Kleiven, Alf Ring; Agnalt, Ann-Lisbeth; Grefsrud, Ellen Sofie; Moland, Even & Olsen, Espen Moland (2014). Den lange og kronglete historien om hummer i Norge. Full text in Research Archive
• Ferter, Keno; Hartmann, Klaas; Kleiven, Alf Ring; Moland, Even & Olsen, Esben Moland (2014). Catch-and-release of Atlantic cod (Gadus morhua): post-release behaviour of acoustically pre-tagged fish in a natural marine environment. Full text in Research Archive
• Freitas, Carla Marília Abreu; Moland, Even & Olsen, Esben Moland (2013). Behavioural responses of wild Atlantic cod to sea temperature changes. Full text in Research Archive
• Ferter, Keno; Kleiven, Alf Ring; Hartmann, Klaas; Moland, Even & Olsen, Esben Moland (2013). Long-term trauma? Studying the effects of catch-and-release on Atlantic cod behavior using acoustic telemetr. Full text in Research Archive
• Kleiven, Alf Ring & Moland, Even (2013). Verdens verste hummerforvaltning? Full text in Research Archive
• Huse, Geir; Agnalt, Ann-Lisbeth; Axelsen, Bjørn Erik Eversvik; Eriksen, Elena; Fossheim, Maria & Frøyland, Livar [Show all 13 contributors for this article] (2025). Havforskningsinstituttets langsiktige overvåkingsplan 2025. Havforskningsinstituttet. doi: https:/www.hi.no/hi/nettrapporter/rapport-fra-havforskningen-2025-54. Full text in Research Archive Show summary

  En av Havforskningsinstituttet sine store styrker er de lange tidsseriene som er avgjørende for vår rådgivning og forskning. Overvåkingsstrategien ble ferdig i 2014,og basert på strategien utviklet vi i 2016 den første versjonen av overvåkingsplanen etter bestilling fra Nærings og fiskeridepartementet. Overvåkingsplanen beskriver alle våre repeterende overvåkingsserier fordelt på 6 tematiske pilarer. Siden 2016 har vi utviklet overvåkingsplanen i forskjellige versjoner og etterhvert har mer informasjon kommet til inkludert kostnad, finansieringskilde og beskrivelse av datainnsamlingsplattform. For å øke kvaliteten og tilgjengeligheten på overvåkingsplanen publiserer vi den nå i Rapport fra havforskningen. Planen er å oppdatere overvåkingsplanen årlig fremover.

• Skern-Mauritzen, Mette; Jørgensen, Lis Lindal; Kleiven, Alf Ring; Meeren, Gro Ingleid van der; Meeren, Terje van der & Moland, Even [Show all 9 contributors for this article] (2025). Naturavtalens Mål 3 om vern og beskyttelse – krav til implementering i en norsk marin kontekst. Havforskningsinstituttet. Full text in Research Archive Show summary

  På oppdrag fra Fiskeridirektoratet vurderer vi i denne rapporten spesifikt hvordan Mål 3 i Naturavtalen, som etablerer globale mål for vern og bevaring av marint naturmangfold med tilhørende krav, kan forstås og operasjonaliseres i en norsk kontekst for å realisere Naturavtalens overordnede mål. Videre presenterer vi en prosess for identifisering av kandidatområder for vern og bevaring i tråd med kravene i Mål 3, samt identifiserer relevante datakilder og kunnskapsgrunnlag. Vurderingen fokuserer særlig på krav som omhandler økologiske og biologiske elementer, og prosesser, som faller inn under Havforskningsinstituttets kompetanseområder.

• Stock, Brian; Knutsen, Halvor; Nedreaas, Kjell Harald; Otterå, Håkon Magne; Fall, Johanna Jennifer Elisabeth & Denechaud, Côme [Show all 9 contributors for this article] (2025). Oppdatert status om torsk langs Vestlandet- og Skagerrakkysten: potensial for bestandsvurdering. Havforskningsinstituttet. Full text in Research Archive Show summary

  Det har lenge vært enighet om at tilstanden til torsk langs kysten av Vest- og Sørlandet er dårlig og i tilbakegang, selv om det ikke finnes noen formell bestandsvurdering sør for 62°N (Stad). Mange kilder indikerer dårlig status, som synkende fiskeri- og toktfangster. Imidlertid bør disse dataene integreres i en populasjonsvurderingsmodell for å estimere bestandsstatus og -trend med usikkerhet. En slik vurdering vil gi et bedre grunnlag for å iverksette, eller ikke iverksette, tiltak for å gjenopprette kysttorsken, samt for å måle effekten av eventuelle tiltak. Denne rapporten arbeider mot målet om å utvikle en eller flere vurderinger av kysttorsk sør for 62°N ved å gjennomgå og oppdatere potensielt nyttige datakilder, samt spesifisere kunnskap og data som mangler.

• Kleiven, Alf Ring; Thorstensen, Helene Skjeie; Norderhaug, Kjell Magnus; Meeren, Gro Ingleid van der; Dunlop, Katherine Mary & Thorbjørnsen, Susanna Huneide [Show all 12 contributors for this article] (2024). Hvor godt fungerer marine bevaringsområder? En litteraturstudie. SALT Rapport nr. 1090. Full text in Research Archive Show summary

  SALT og Havforskningsinstituttet har på oppdrag fra Miljødirektoratet utarbeidet en «Kunnskapssyntese om virkninger av marine verneområder for økosystemfunksjon og potensial for høsting i omkringliggende områder» (saksnummer 2024/3032). Med bakgrunn i Stortingsmeldingen Heilskapleg nasjonal plan for bevaring av viktige område for marin natur har regjeringen et uttalt mål om å styrke kunnskapen om effekter av marine verneområder i Norge, og ønsker å få gjennomført en kunnskapssyntese om virkninger av marine verneområder for økosystemfunksjon og muligheter for høsting av levende ressurser i omkringliggende områder.

• Frigstad, Helene; Ramon, Paula; Borgersen, Gunhild; Engesmo, Anette; Staalstrøm, Andre & Naustvoll, Lars Johan [Show all 22 contributors for this article] (2024). Tilstandsrapport for Oslofjorden. Norsk institutt for vannforskning (NIVA). ISSN 9788257777739. Full text in Research Archive Show summary

  I 2021 la regjeringen frem en helhetlig tiltaksplan som viser regjeringens viktigste prioriteringer for å gjøre Oslofjorden ren, rik og tilgjengelig for alle fram mot 2026. Tilstandsrapport for Oslofjorden, ledet av NIVA i samarbeid med HI, NINA, NMBU og UiO, gir en oversikt over miljøtilstanden i Oslofjorden de siste 5-10 årene og utviklingen de siste 10-50 årene. Oslofjorden har opplevd negativ utvikling på grunn av blant annet forurensing, overfiske og bygging i strandnære områder. Klimaendringer forventes å forverre situasjonen ytterligere. Økologisk tilstand viser forbedring i Indre Oslofjord, men forverring i Ytre Oslofjord og Skagerrak. For miljøgifter er det ofte overskridelser av grenseverdier for kjemisk tilstand. Blåskjell, dyreplankton, sjøpattedyr, fisk og sjøfugler er viktige indikatorer på fjordens helse, men det er registret nedgang i mange arter, spesielt for torskebestanden. Utbredelse av stortareskog, sukkertareskog og ålegressenger er redusert, og det er økt forekomst av lurv. Flere arter og naturtyper er regnet som truet og rødlistet. Det er registrert flere fremmede arter, som utgjør en økologisk risiko i Oslofjorden.

• Meeren, Terje van der; Husa, Vivian; Kutti, Tina; Steen, Henning; Svåsand, Terje & Espeland, Sigurd Heiberg [Show all 8 contributors for this article] (2024). Høring av planprogram – regional plan for arealforvaltning, Nordland Fylkeskommune. Havforskningsinstituttet. Full text in Research Archive
• Kleiven, Alf Ring; Thorbjørnsen, Susanna Huneide; Meeren, Gro Ingleid van der; Freitas, Carla; Naustvoll, Lars Johan & Moland, Even [Show all 11 contributors for this article] (2024). Raet nasjonalpark — Kunnskap og råd for bevaring av marint naturmangfold. Havforskningsinstituttet. Full text in Research Archive Show summary

  På oppdrag for prosjektet «Bevar Raet» har av forskningsinstituttet utarbeidet en rapport om kunnskapsstatus for sjøområdene i og rundt Raet nasjonalpark. Formålet med rapporten er å bidra med et kunnskapsgrunnlag for at det marine økosystemet i Raet nasjonalpark kan gjenoppbygges til et robust nivå. Rapporten viser at Raet nasjonalpark per i dag kan klassifiseres som «ubeskyttet». Ut i fra dagens restriksjonsnivå kan det ikke forventes positive effekter på alders- og størrelsessammensetning, biomasse, biologisk mangfold samt robusthet mot klimaendringer. Raet nasjonalpark er derfor ikke regulert slik at det kan fungere etter hensikten med å bevare plantelivet, dyrelivet og naturtyper. Ved å dele opp Raet nasjonalpark i soner med ulik grad av beskyttelse (spesielt regulering av fiskeri) vil det være mulig å oppnå effektiv bevaring av naturmangfoldet. Samtidig bør det rettes økt fokus på vannkvalitet i indre kystområder, både med tanke på overvåkning og tiltak.

• Marquez, Jonatan Fredricson; Meeren, Gro Ingleid van der; Meeren, Terje van der; Albretsen, Jon; Ross, Rebecca & Steen, Henning [Show all 43 contributors for this article] (2024). Liste over forvaltningsrelevante naturenheter - Oppfølgende informasjon til rapporten "Forvaltningsrelevante naturenheter i sjø". Havforskningsinstituttet. Full text in Research Archive Show summary

  I forbindelse med forvaltningens oppgave om å lage en framtidig samlet offentlig instruks for kartlegging av marin natur, bestilte fiskeridirektoratet i en oversikt over der havforskningsinstituttet ville foreslå som "Forvaltningsrelevante naturenheter i sjø". Denne rapporten ble levert og publisert 29.04.2024. I den rapporten foreslo Havforskningsinstituttet å utvide begrepet naturenheter til også å omfatte funksjonsområder for arter, og områder viktig for struktur og sentrale økosystemprosesser. Totalt ble det foreslått 20 abiotiske fysiske enheter, 3 biotiske fysiske enheter, 6 hovedgrupper av funksjonsområder (for totalt 46 arter) og 9 struktur og prosessområder som kunne danne grunnlag for kartlegging av marin natur. Denne rapporten er en utdyping av rapporten "Forvaltningsrelevante naturenheter i sjø", der alle naturenhetene som er foreslått blir nærmere forklart samt at det presenteres et perspektiv på ulike aspekter som kan være viktig for prioritering av hva som skal kartlegges. Enkelte naturenheter har fått mindre endringer i navn og innhold til det opprinnelige forslaget, men den første rapporten har vært førende for innhold. Det kan være aktuelt å revidere hvilke naturenheter som vil være viktige og om noen naturenheter ikke nødvendigvis har samme betydning for forvaltningen på et senere tidspunkt.

• Løkkeborg, Svein; Bakkeplass, Kjell Gunnar; Diesing, Markus; Gjøsæter, Harald; Gonzalez-Mirelis, Genoveva & Hvingel, Carsten [Show all 10 contributors for this article] (2023). Effekter av bunntråling - Sammenstilling av kunnskap om bunnpåvirkning fra trål og snurrevad relevant for norske farvann. Havforskningsinstituttet. Full text in Research Archive Show summary

  Rapporten gir en sammenstilling av publisert kunnskap om hvordan bunnhabitater og bunndyr påvirkes (fysiske, kjemiske og biologiske effekter) av fiske med bunntrål og snurrevad. Det legges hovedvekt på påvirkninger fra fisketrål og reketrål som er relevant for norske forhold. Rapporten beskriver utbredelsen av sårbare habitater i norske havområder, og det presenteres kart som viser hvor det fiskes med fisketrål, reketrål og snurrevad. Bunntråling er den menneskelige aktiviteten som i geografisk utstrekning har størst påvirkning på havbunnen.

• Strandli, Bjørn; Moy, Frithjof Emil; Kroglund, Tone; Hestnes, Arne Johan; Endregard, Geir & Walday, Mats Gunnar [Show all 12 contributors for this article] (2022). Sluttrapport fra Frisk Oslofjord. Færder nasjonalpark, Ytre Hvaler nasjonalpark. Full text in Research Archive
• Knutsen, Halvor; Espeland, Sigurd Heiberg & Moland, Even (2022). Evaluering av tiltak for vern av kysttorsk i sør innført juni 2019. Havforskningsinstituttet. Full text in Research Archive Show summary

  Vi ser i våre data ingen tegn til at bestandssituasjonen for torsk er endret i indre Skagerrak, ytre- og indre Oslofjord siden tiltak ble innført i 2019. Havforskningsinstituttets data viser stabilt lave fangster av torsk i hele tiltaksområdet, selv om årene 2017 og 2019 viste forholdsvis sterke årsklasser. Landingene i yrkesfisket viser en vedvarende nedgang siden 2019. Fravær av torsk på strandnotsstasjoner i Oslofjorden innenfor Drøbak knyttes til flere forhold. Særlig er vegetasjonen på tidligere gode habitater klart dårligere sammenholdt med andre deler av Skagerrakkysten. Økt temperatur i overflaten og tilgroing av habitater med hurtigvoksende trådformede alger («lurv») bidrar trolig til dette. Avrenning, næringsbelastning og formørkning av kystvannet er også påvirkninger som bidrar i negativ retning for torsk og andre bunnfiskbestander.

• Bjørn, Pål Arne; Glover, Kevin Alan; Grefsrud, Ellen Sofie; Espeland, Sigurd Heiberg; Karlsbakk, Egil Erlingsson & Karlsen, Ørjan [Show all 12 contributors for this article] (2021). Kunnskapsgrunnlag for mulig påvirkning fra oppdrettstorsk og levendelagret torsk på villtorsk. Havforskningsinstituttet. Full text in Research Archive Show summary

  Det er igjen økende interesse for torskeoppdrett, denne gang med en domestisert oppdrettstorsk som vil ha egenskaper som skiller seg fra vill torsk. Det er behov for et oppdatert kunnskapsgrunnlag om risiko for påvirkning på viltlevende torsk, spesielt genetiske og økologiske interaksjoner og lokalisering i forhold til gyte- og oppvekstområder. Denne rapporten som er bestilt av Fiskeridirektoratet oppdaterer kunnskapsgrunnlag på området med tilhørende foreløpige anbefalinger.

• Moland, Even; Synnes, Ann-Elin; Naustvoll, Lars Johan; Freitas, Carla; Norderhaug, Kjell Magnus & Thormar, Jonas [Show all 15 contributors for this article] (2021). Krafttak for kysttorsken - Kunnskap for stedstilpasset gjenoppbygging av bestander, naturtyper og økosystem i Færder- og Ytre Hvaler nasjonalparker. Havforskningsinstituttet. Full text in Research Archive Show summary

  Ytre Oslofjord har en unik kystnatur av svært stor verdi for både fastboende og tilreisende. Færder- og Ytre Hvaler nasjonalparker ligger side om side ytterst i fjorden, og skal sikre naturverdiene for kommende generasjoner. Nasjonalparkene har utformet egne forvaltningsplaner og -mål, som gjenspeiler et ønske om å legge best mulig til rette for at fiskearter, fugler, planter og insekter skal fortsette å trives innenfor parkenes grenser. Generelle mål for naturverdiene er at de skal opprettholdes med god økologisk funksjon, og et høyt biologisk mangfold.

• Jørgensen, Lis Lindal; Moland, Even; Husa, Vivian; Kutti, Tina; Kleiven, Alf Ring & Meeren, Gro Ingleid van der (2021). Marint vern - Havforskningsinstituttets ekspertvurdering av utfordringer og status for arbeid med marint vern i Norge. Havforskningsinstituttet. Full text in Research Archive Show summary

  Havforskningsinstituttet har satt sammen en ekspertgruppe for å levere en kort oversikt over instituttets utredninger og overvåking av faktiske og potensielle eksempler på marint vern. I denne rapporten tar vi utgangspunkt i de gjeldende internasjonale målsetninger og avtaler for marint vern, og hvordan Havforskningsinstituttet gir kunnskapsbidrag og faglige råd, for å oppnå tilstrekkelig vern til marine økosystemer – for å sikre en bærekraftig havøkonomi i et langtidsperspektiv. Dette er i tråd med Havforskningsinstituttets samfunnsoppdrag: “... å utvikle det vitenskapelige grunnlaget for bærekraftig forvaltning av ressursene og miljøet i de marine økosystemene”. Temaet marint vern er sentralt også for Høynivåpanelet for en bærekraftig havøkonomi (heretter Havpanelet), der de 14 deltakende landene støtter et globalt mål om å verne og beskytte 30% av havet innen 2030.

• Kleiven, Alf Ring; Moland, Even; Sørdalen, Tonje Knutsen; Espeland, Sigurd Heiberg & Meeren, Gro Ingleid van der (2017). Evaluering av effekten av forvaltningstiltak på hummer og forslag til tiltak. Havforskningsinstituttet. Full text in Research Archive
• Aglen, Asgeir; Nedreaas, Kjell Harald; Moland, Even; Knutsen, Halvor; Kleiven, Alf Ring & Johannessen, Tore [Show all 11 contributors for this article] (2016). Oppdatert kunnskapsstatus om kystnær torsk i Sør Norge. Havforskningsinstituttet. Full text in Research Archive Show summary

  English: In a report from 2008 an assessment of coastal cod in southern Norway, from the Swedish border to Stad, was presented, together with suggestions to management initiatives. This report shortly summarize the 2008-report, but new knowledge attained the last 10 years is the main part. The cod along the coast in southern Norway are made up of possibly there different components: 1) stationary, local stocks in the fjords, 2) cod from the North Sea along the outer coast, and 3) possibly a more “ migrating cod” along the outer coast. The latter type of coastal cod, if existing, has genetic similarities with the North Sea cod. Much new knowledge indicate that the cod along the coast in southern Norway are exposed to increasing pressure from multiple factors, not at least from recreational fisheries. Local stocks of cod in fjords are the smallest and accordingly most vulnerable stocks of cod. Future regulations should aim at a best possible conservation of the local stocks of cod in the fjords, but also reduce mortality of cod living along the outer parts of the coast. This report also suggest some, possible management initiatives. Norsk:2008 kom en rapport som vurderte status for kysttorsk på strekningen Svenskegrensa-Stad, og som også inkluderte forslag til forvaltningstiltak. Denne rapporten starter med en kort oppsummering av oversikten fra 2008, men bringer i hovedsak ny kunnskap som er kommet til de siste 10 årene. Historisk er det en klar nedgang i fangstene av årets yngel (0-gruppe torsk) i strandnotserien fra Havforskningsinstituttet. De siste ca. 20 årene har nedgangen vært størst. Torskeforekomstene langs kysten ser ut til å være sammensatt av tre komponenter: 1) lokale, stasjonære stammer av fjordtorsk, som særlig forekommer i de indre kystområdene/fjordene, 2) nordsjøtorsk og 3) muligens også en mer vandrende komponent av kysttorsk med genetisk likhetstrekk med nordsjøtorsken, som særlig forekommer i de ytre kystområdene. Det er nå dokumentert at torsken langs kysten både på Vestlandet og Sørlandet er utsatt for økende press fra flere påvirkningsfaktorer, ikke minst et betydelig fritidsfiske. Lokale stammer av fjordtorsk er de klart minste og mest sårbare bestandene langs kysten. Fremtidige reguleringer bør gi best mulig vern for lokale stammer av fjordtorsk, men også redusere fiskedødeligheten for «nordsjøtype» torsk langs den ytre delen av kysten. En rekke forslag til tiltak er oppsummert i rapporten.

• Dahl, Einar; Knutsen, Jan Atle; Albretsen, Jon; Huserbråten, Mats Brockstedt Olsen; Heiberg, Sigurd Espeland & Knutsen, Halvor [Show all 13 contributors for this article] (2015). Marine naturforhold og naturverdier i Færder nasjonalpark. Havforskningsinstituttet. Full text in Research Archive

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