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High latitude marine systems are experiencing climate change and other human-induced impacts that outpace global averages. Communities dependent on these systems are also undergoing complex economic and socio-ecological changes. Ecological, economic, market and community developments in Arctic and sub-Arctic crab fisheries are increasingly complex and uncertain. These escalating risks and complexities threaten well-being, social and ecological integrity of dependent communities and ecosystems. Through interdisciplinary and transdisciplinary collaboration, we examine the escalation to illustrate how global ecological and economic connections are co-evolving between nature, society, and industry. The article demonstrates how informal, integrative cooperation with broad stakeholder participation at a global scale, focused on information sharing and scientific cooperation, addresses local and regional dynamic markets and ecosystems for improved economic and ecological outcomes.

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.

Introduced into the Barents Sea in the 1960s, the red king crab (Paralithodes camtschaticus) has been fished commercially in Norway since 2002. Because it is an introduced species, its management raises a number of concerns. Minimising the threats posed by non-native species that cannot be eradicated is a challenge facing nature management authorities worldwide. High concentrations of crab on fishing grounds in eastern Finnmark in North Norway have interfered with traditional gillnet and longline fisheries, prompting fishermen to demand compensation for lost income. Difficult trade-offs were posed by the dual management objectives, which included (i) preventing the geographical expansion of the crab and (ii) exploiting the resource to provide income to coastal communities. The Norwegian government, with the consent of Parliament, has developed a management regime that addresses both objectives: an open-access fishery west of 26°E to prevent further west- and southward expansion of the crab population, and a regular commercial fishery east of that longitude. This management regime commands wider consideration, owing to its handling of the dilemmas inherent in the management of introduced species.

The aim of this paper is to evaluate the food safety of the red king crab from Norwegian waters and obtain information on possible geographical and gender differences. Samples of claw and leg meat of 185 red king crabs (Paralithodes camtschaticus), collected from 23 positions in the Barents Sea, were analysed for dioxins, furans, non-ortho and mono-ortho PCBs, non dioxin-like PCBs, polybrominated diphenyl ethers, and perfluorinated alkyl substances and elements, such as arsenic, cadmium, mercury and lead. The concentrations of persistent organic pollutants and metals were low compared to maximum levels laid down in European regulations. Hence, red king crab is a safe food. Significant differences in the concentrations of metals among different areas, and between male and female crabs, were found. Positive correlations were found between carapace length and mercury, methylmercury and cadmium concentrations, and between fat and arsenic and inorganic arsenic concentrations.

The aim of this study was to explore the effect of sex, size, region, and density on dispersal rate of the introduced red king crab (Paralithodes camtschaticus) in Norwegian waters. We examined the effect of these factors using logistic regression analysis. Tag-recapture data corrected for fishing effort enabled us to estimate dispersal rates from four main regions along the Norwegian coast: Varangerfjorden, Tanafjorden, Laksefjorden, and Porsangerfjorden. The probability of dispersal was independent of sex and size, but both the logistic regression and the evaluation of corrected tag-recapture data revealed differences in dispersal between region and with increasing duration. The recapture data indicated a relationship between population density and dispersal within research regions but not between population density and dispersal between research regions. Our main conclusion is that there are large individual differences in dispersal ability and the range expansion of red king crab is a result of (i) the presence of long-distance dispersers and (ii) time-dependent slow migration by short distance dispersers. We also conclude that there appears less dispersal in Norwegian waters than in native waters, which might be caused by differences in geographical complexity.

Aim: Anticipated changes in the global ocean climate will affect the vulnerability of marine ecosystems to the negative effects of non-indigenous species (NIS). In the Arctic, there is a need to better characterize present and future marine biological introduction patterns and processes. We use a vector-based assessment to estimate changes in the vulnerability of a high-Arctic archipelago to marine NIS introduction and establishment. Location: Global, with a case study of Svalbard, Norway. Methods: We base our assessment on the level of connectedness to global NIS pools through the regional shipping network and predicted changes in ocean climates. Environmental match of ports connected to Svalbard was evaluated under present and future environmental conditions (2050 and 2100 predicted under the RCP8.5 emissions scenario). Risk of NIS introduction was then estimated based on the potential for known NIS to be transported (in ballast water or as biofouling), environmental match, and a qualitative estimate of propagule pressure. Results: We show that Svalbard will become increasingly vulnerable to marine NIS introduction and establishment. Over the coming century, sea surface warming at high latitudes is estimated to increase the level of environmental match to nearly one-third of ports previously visited by vessels travelling to Svalbard in 2011 (n = 136). The shipping network will then likely connect Svalbard to a much greater pool of known NIS, under conditions more favourable for their establishment. Research and fishing vessels were estimated to pose the highest risk of NIS introduction through biofouling, while ballast water discharge is estimated to pose an increased risk by the end of the century. Main conclusions: In the absence of focused preventative management, the risk of NIS introduction and establishment in Svalbard, and the wider Arctic, will increase over coming decades, prompting a need to respond in policy and action.

The introduced red king crab ( Paralithodes camtschaticus ) is abundant in the coastal waters off northern Norway. We developed Bayesian hierarchical models to estimate growth parameters of a von Bertalanffy growth function using tag–recapture data. Individual variability in L ∞ (asymptotic length) was incorporated in the analysis. The models successfully estimate female red king crab lengths at intervals where data were sufficient. The length of small males was overestimated. The results indicate a difference in growth rate of male and female juvenile red king crab. The importance of including individual variability was confirmed: Variability in L ∞ for individuals was high compared to population variability in L ∞ . The model that incorporated individual variation resulted in more plausible values for the growth parameters and increased the precision of length estimates compared to the model that estimate a common L ∞ .

The introduced red king crab (Paralithodes camtschaticus) in the Barents Sea is abundant in the coastal waters of eastern Finnmark and supports a valuable fishery. In this paper we look at the development in size span among ovigerous females in the period between 1995 and 2010. We identify variations in individual fecundity in three fjords in Finnmark from 2000 to 2007. All the analyses were performed using regression and general linear models. We found that the size range decreased during this period. A decline in individual fecundity was observed. Individual egg weight (IEW) varied among fjords and years, and displayed a tendency to decline during the period of investigation, but the IEW was not affected by crab size. Increased fishing pressure on large males may have caused both a decline in size range of ovigerous females as well as a decline in fecundity. Reduced IEW however is likely to be due to limited available food. We attempted to compare individual fecundity in the invasive crab with fecundity results from populations in native areas. This comparison was inconclusive, due to differences in sampling season, size range and the methods employed.

The red king crab (Paralithodes camtschaticus) was introduced from the northern Pacific to the Russian Murman coast during the 1960s and 1970s. Over the subsequent decades, the crab has become established in northern Norwegian waters, where it continues spreading westward. The crab is an active predator on benthic fauna, especially feeding in deep soft-bottom environments. The present studies, carried out in the Varanger area close to the Russian border in 2007-2009, indicate that soft-bottom epifauna and infauna have become markedly reduced in crab-invaded areas. For infauna, quantitative data from 1994 were used as a basis to compare faunal composition before and after the crab became abundant in the area. It appeared that echinoderms, non-moving burrowing and tube-dwelling polychaetes, and most bivalves were reduced, whereas some small-sized polychaetes and small bivalves had increased. In situ sediment profile imagery (SPI) was used to examine sediment structure and biogenic activity. At several locations, the sediment habitat quality was degraded due to hypoxic conditions and low biological activity below surface layers. It is suggested that the crab has removed organisms performing important functions such as bio-irrigation and sediment reworking. Hence, it appears that the crab may reduce the functional diversity of the resident species assemblages, which may have overall implications for ecosystem function, production and responses to other environmental stressors.

The rapidly changing Arctic marine ecosystems face new challenges and opportunities that are increasing and shifting governance needs in the region. A group of economists, ecologists, biologists, political scientists and resource managers met in Stockholm, SE, Sept 4–6, 2014 to discuss the governance of Arctic marine resources in a spatial context. We report on the findings here. The rapidly changing Arctic marine ecosystems face new challenges and opportunities that are increasing and shifting governance needs in the region. A group of economists, ecologists, biologists, political scientists and resource managers met in Stockholm, SE, Sept 4–6, 2014 to discuss the governance of Arctic marine resources in a spatial context. We report on the findings here.

Russian scientists introduced the red king crab (Paralithodes camtschaticus) to the Barents Sea during the 1960s and 1970s, and the crab has now become abundant in the coastal waters of Finnmark, North Norway. The growing stock size of this introduced species raises increasing demands for management of the stock. Therefore, basic knowledge of general biology and ecology is required. This paper presents analyses of the moulting increment and moulting frequency results based on tag and recapture experiments. The mean increments in carapace length per moult of males (immature and mature) are estimated to be 17.0 mm for all premoult carapace lengths between 67 and 172 mm, while the increment decreased from 14.4 to 5.1 mm for females as they became ovigerous. The results show that the growth increments of the red king crab in Varanger are within the ranges reported in the eastern Bering Sea. A model relating probability of moulting as a function of carapace length is developed based on tag-recapture and qualitative carapace age judgement.

The snow crab, Chionoecetes opilio (Fabricius, 1788), is recorded from the North Pacific, Arctic and Northwest Atlantic. In 1996 however, Russian fishing vessels captured five snow crabs in the Barents Sea and since then, fishing vessels operating in the area have occasionally reported this spider crab in the by-catch. Annual bottom-trawl surveys conducted jointly by Russia and Norway since 2004 have confirmed the presence of C. opilio in the northern region of the Barents Sea. Furthermore, in 2008 an increase in abundance and distribution range was found with a significant number of crabs being recorded in the central region of the Barents Sea, mainly between 180 and 350 m deep, in depths and temperatures similar to the species natural habitat in the Northwest Atlantic and North Pacific. The carapace width (CW) of the captured snow crabs typically range from 14 to 130 mm. About 40% of the crabs were juveniles (CW smaller than 50 mm), providing evidence for successful recruitment. These small-sized crabs were exclusively found on Goose Bank, identifying it as the main recruiting area. Ovigerous crabs have been collected since 2004, and the smallest female with extruded eggs measured 65 mm CW. Females larger than 80 mm CW were all egg carrying. Minimum size at maturity in male snow crab, based on presence of spermatophores, was estimated to be 43 mm CW. All males larger than 45 mm CW were mature and can potentially engage in mating. Their diet consisted of benthic organisms such as crustaceans (mainly decapods), polychaetes, molluscs, echinoderms and fish. The Barents Sea population of the snow crab seems to possess similar biological characteristic as those occurring in its natural distribution areas. Chionoecetes opilio was unintentionally introduced to the Barents Sea and as yet the processes that might limit recruitment and distribution are unknown as are its origins. Genetic methods based on new microsatellite markers have been developed and applied to several Northwestern Atlantic crab populations. It is hoped that these markers will allow identification of the origins of the snow crab population in the Barents Sea.

In a warmer Arctic, living conditions will change at all trophic levels of the marine ecosystem. Increased air and water temperatures will likely substantially reduce ice coverage. Trophic interactions might change and increased competition between resident Arctic species and invasive species seems likely. A theme session on “Marine harvesting in the Arctic” was held at the international Arctic Frontiers Conference in Tromsø, Norway, in January 2013. The theme session partitioned the topic into two sub-sessions: (i) introduced species, immigration and fate of resident species and (ii) prospective harvesting of marine biological resources in the Arctic. The four articles that follow this introduction are based on presentations made at the Arctic Frontiers theme session. These articles cover topics such as: how ice breeding seals (Pagophilus groenlandicus) can cope with ice retention in the Northwest Atlantic, how planktonic stages of the resident polar cod (Boreogadus saida) and the pole-ward expanding Pacific sand lance (Ammodytes hexapterus) may compete for food in the warming Beaufort Sea, and how the introduced red king crab (Paralithodes camtschaticus) disperse in the Barents Sea. The fourth article shows how differences in the life-history strategies of keystone zooplankton species will likely affect future productivity of commercial fisheries in polar regions.

In 1961–1969 the red king crab (Paralithodes camtschaticus), brought from the Far East, was introduced into some inlets of the Kola Bay and in the open areas of the Barents Sea. The first red king crab was caught in the Barents Sea in 1974. The crab is now common in all fjords along the northern coast of Norway and coastal areas reaching about 25°E. Total catch for Russia and Norway amounted 200,000 crabs in 2001. Even if 1,500 tons of the north Pacific pink salmon Oncorhynchus gorbusha were caught in the Barents and White Sea basins in 1999, it is considered that a stable self-reproducing population has not been established yet in the Barents Sea; it is still necessary to transport eggs of the pink salmon area periodically.