ICES Journal of Marine Science: Journal du Conseil

Heino, Mikko; Baulier, Loїc; Boukal, David S.; Ernande, Bruno; Johnston, Fiona D.; Mollet, Fabian M.; Pardoe, Heidi; Therkildsen, Nina O.; Uusi-Heikkilä, Silva; Vainikka, Anssi; Arlinghaus, Robert; Dankel, Dorothy J.; Dunlop, Erin S.; Eikeset, Anne Maria; Enberg, Katja; Engelhard, Georg H.; Jørgensen, Christian; Laugen, Ane T.; Matsumura, Shuichi; Nusslé, Sébastien; Urbach, Davnah; Whitlock, Rebecca; Rijnsdorp, Adriaan D.; Dieckmann, Ulf

doi: 10.1093/icesjms/fst077pmid: N/A

Heino, M., Baulier, L., Boukal, D. S., Ernande, B., Johnston, F. D., Mollet, F. M., Pardoe, H., Therkildsen, N. O., Uusi-Heikkilä, S., Vainikka, A., Arlinghaus, R., Dankel, D. J., Dunlop, E. S., Eikeset, A. M., Enberg, K., Engelhard G. H., Jørgensen, C., Laugen, A. T., Matsumura, S., Nusslé, S., Urbach, D., Whitlock, R., Rijnsdorp, A. D., and Dieckmann, U. 2013. Can fisheries-induced evolution shift reference points for fisheries management? – ICES Journal of Marine Science, 70: 707721.Biological reference points are important tools for fisheries management. Reference points are not static, but may change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to “shifting” reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in “true” reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in more perilous directions, such that actual risks are greater than anticipated. Our qualitative analysis suggests that all commonly used reference points are susceptible to shifting through fisheries-induced evolution, including the limit and “precautionary” reference points for spawning-stock biomass, Blim and Bpa, and the target reference point for fishing mortality, F0.1. Our findings call for increased awareness of fisheries-induced changes and highlight the value of always basing reference points on adequately updated information, to capture all changes in the biological processes that drive fish population dynamics.

Misund, Ole Arve; Olsen, Erik

doi: 10.1093/icesjms/fst086pmid: N/A

Abstract Misund, O. A., and Olsen, E. 2013. .Lofoten–Vesterålen: for cod and cod fisheries, but not for oil? – ICES Journal of Marine Science, 70: 722–725. Over the last decade, the most controversial issue regarding the management of Norwegian marine waters has been about opening the Lofoten–Vesterålen areas for offshore oil and gas exploration. This paper outlines the political and management processes and reviews the arguments for and against. Our conclusion is that these valuable areas should not be opened for such activity because of their high biological significance as the main spawning grounds for northeast Arctic cod (Gadus morhua) and other important fish stocks in the northeast Arctic waters. Introduction In a recent interview with the Norwegian business newspaper, the chief executive officer (CEO) of TOTAL (a French multinational integrated oil and gas company and one of the world's five or six largest publicly owned oil and gas companies: http://en.wikipedia.org/wiki/Supermajor - cite_note-reut1808-1) expressed scepticism about offshore oil exploration in areas off Lofoten–Vesterålen on the Norwegian continental shelf (Dagens Næringsliv, Norway, 1 December 2012). “There is no such thing as zero risk,” he argued. “Macondo happened,” he added, referring to the accident in the Gulf of Mexico in May 2010. Therefore, he advocated caution when considering new areas for oil exploration. In an interview with the Financial Times in November 2012, he had also said “no” to oil exploration in the ice-covered areas of the Arctic. A few days after the article in Dagens Næringsliv, the managing director of TOTAL, E&P Norway A/S explained that the CEO's astonishing statements “were given in a global context” and added that TOTAL shared the viewpoint of other companies active in Norway—that there is a need for access to new areas for the offshore oil industry on the Norwegian continental shelf (Dagens Næringsliv, Norway, 5 December 2012). Along with other leaders in the oil industry, he further argued that the time had come for an impact assessment of future petroleum activities in the Lofoten–Vesterålen areas. In the Norwegian petroleum management system, an impact assessment is the first step towards opening new areas for petroleum activities. Political debate In light of the political debate in Norway regarding the development of the offshore oil industry in the last decade, the statements by the CEO of TOTAL are remarkable. Until now, representatives of the oil industry have argued unanimously for access to new areas farther north on the Norwegian continental shelf, including the subareas Nordland VI, Nordland VII, and Tromsø II off Lofoten–Vesterålen (Figure 1). Representatives from the fisheries sector, from non-governmental environmental organizations, and some local interest groups have argued strongly against opening the Lofoten–Vesterålen areas for offshore oil exploration. Conversely, other local and regional interest groups are in favour of opening the areas. Figure 1. Open in new tabDownload slide Spawning grounds for cod, herring, haddock, and saithe off the Lofoten–Vesterålen regions in northern Norway, vulnerable areas with fragile bottom fauna (deepwater coral reefs etc.), and subareas for allocation of petroleum licenses (depth contours in metres). Figure 1. Open in new tabDownload slide Spawning grounds for cod, herring, haddock, and saithe off the Lofoten–Vesterålen regions in northern Norway, vulnerable areas with fragile bottom fauna (deepwater coral reefs etc.), and subareas for allocation of petroleum licenses (depth contours in metres). Norwegian political parties have divergent views on the issue as well. During 2002–2005, Norway was governed by a minority coalition of Christian democrats, conservatives, and liberals. Since 2005, Norway has had a majority “red–green” coalition in power, led by social democrats, with participation from the centre and socialist parties. Both coalitions include parties with different opinions on whether the Lofoten–Vesterålen areas should be opened for oil prospecting. To handle this rather delicate political issue in a balanced manner, based on the best possible knowledge, the Christian democrat Prime Minister launched the concept of integrated ocean area management plans in his televised New Year's address on 1 January 2002. The first ocean area management plan was to be developed for the Lofoten–Barents Sea area; by 1 October 2003, a report on the living marine resources and ocean environment of the area was completed (Føyn et al., 2002). The management plan process was led by the Ministry of the Environment, with participation by the ministries of Fisheries, Trade, Justice, and Foreign Affairs. About 30 directorates, agencies, and research institutes were involved. Underlying documents for Fisheries, Shipping, Oil Industry, Marine Environment, and Vulnerable Areas had been developed by 2005 (Olsen et al., 2007; Winsnes and Skjoldal, 2008). The first Lofoten–Barents Sea management plan was presented as a white paper to the Norwegian Parliament and ratified in June 2006. Through a similar process, an area management plan was developed in 2009 for the Norwegian portion of the Norwegian Sea (Ottersen et al., 2011), and a plan for the Norwegian zone of the North Sea is scheduled for 2013. When the red–green coalition assumed leadership in Norway after winning the parliamentary elections in 2005 and 2009, their policy declarations stated that Lofoten–Vesterålen would not be opened for offshore oil exploration in the coming term. Still, the Lofoten–Barents Sea management plan was revised in 2011 as a new white paper ratified by the Parliament. The revised plan stated that the vulnerable areas off Lofoten–Vesterålen should remain closed for offshore oil exploration for the next four years. But the government immediately initiated further data collection on the impact of offshore oil exploration on fisheries, tourism, the marine environment, and coastal societies at local and regional scales. Apparently, the conclusions reached when the revised management plan was ratified were difficult for some parties and stakeholders to accept, and a conciliatory process had to be launched. A recent report from the Ministry of Petroleum and Energy concluded that the prospects for oil and gas in the Lofoten–Vesterålen areas are quite good (Ministry of Oil and Energy, 2012). Estimates based on geological models, with input from seismic surveys carried out in 2007–2009, indicate a 95% probability for 76 million Sm3 oil equivalents and a 5% probability for >370 million Sm3 oil equivalents (Anon., 2010a). Regionally, this would give 400–1100 new jobs in the oil sector and 800–2300 new jobs in the nation as a whole (Ministry of Oil and Energy, 2012). The value creation would be of the order of 26–56 billion NOK (Ministry of Oil and Energy, 2012). But despite such good prospects for value creation and new jobs, the issue of opening the Lofoten–Vesterålen areas is so controversial that the Minister of Petroleum and Energy concluded that the areas would not be opened for offshore oil exploration by the present government. Intrinsic values So why is it so difficult for the offshore oil industry to gain access to the Lofoten–Vesterålen areas? The foremost reason is that the areas represent the main spawning grounds for several economically and ecologically important fish stocks, particularly the large northeast Arctic (NEA) cod (Gadus morhua) stock. Other commercially important species, such as NEA haddock (Melanogrammus aeglefinus), Norwegian spring-spawning herring (Clupea harengus), and NEA saithe (Pollachius virens), spawn in the areas. In addition, the areas harbour large seabird colonies, sensitive benthic habitats, and populations of marine mammals. Every winter, the NEA cod migrate from the Barents Sea and the waters around Svalbard to the banks and fjords of Lofoten–Vesterålen (Figure 1) to spawn (Olsen et al., 2010; Yaragina et al., 2011). The fish gather on the spawning grounds in February–March, with peak spawning around 1 April (Pedersen, 1984). The fish can be caught with jigs, handlines, gillnets, and Danish seine, and the fisheries have traditionally been conducted from small coastal vessels. The Lofoten winter fishery can be documented back about 1000 years to the time of the Vikings and has been a foundation for settlements in most of the coastal communities of northern and northwestern Norway. For centuries, trading of stockfish (dried cod) from this fishery was the main activity of the Hanseatic merchants in Bergen, at that time the largest city in Norway. Up to 33 000 fishers participated in the Lofoten winter fishery, landing about 81 000 t of cod (Anderssen-Strand, 1933; digitized reports in Norwegian from the Lofoten fishery from 1859 to the present available at http://www.fiskeridir.no/fiske-og-fangst/rapporter-utredninger/lofoten/rapporter-fra-lofotfisket). Now, most of the Norwegian quota of NEA cod is taken by larger seiners, gillnetters, and trawlers in the southern Barents Sea and off the coast of northern Norway. But, the Lofoten winter fishery is still important for the smaller vessels, and about 3200 fishers participated in the landing of about 37 000 t of cod in 2006 (Anon., 2006). Arguments As a central advisor to Norwegian fisheries and marine environment authorities, the Institute of Marine Research (IMR) has argued that the Lofoten–Vesterålen areas should not be opened to offshore oil exploration. The NEA cod is the basis for the main commercial fishery in the Barents Sea, with yields varying between about 400 000 and 700 000 t in recent years. The stock is managed jointly by Norway and Russia through the Norwegian–Russian Fisheries Commission (Hammer and Hoel, 2012). The annual TAC is shared equally between Norway and Russia, with about 43% to each, and 14% to third parties (EU, Iceland and Greenland). ICES has assessed the stock and determined it to be in very good condition (ICES, 2012), and the quota for 2013 is set at 1 million t by the Norwegian–Russian Fisheries Commission. Every year, the spawning stock migrates from the waters around Svalbard, in the northeastern and central Barents Sea, to the coast of northern Norway to spawn. The spawning areas vary slightly depending on weather patterns, but about 60% of the stock migrates to Lofoten–Vesterålen regardless of conditions (Sundby and Nakken, 2008). So, the Lofoten–Vesterålen area is undoubtedly of crucial importance to the largest cod stock in the world—and, therefore, to Norwegian, Russian, and EU fisheries. The risk to an offshore oil industry in a vulnerable area like Lofoten–Vesterålen is a large accidental oil spill. The probability of such an accident is very low, but accidents happen, and when they do, the environmental impact can be severe, as in the case of the “Deepwater Horizon” platform at the Macondo well in the Gulf of Mexico in May 2010 (Norwegian Research Council, 2012; Bakke et al., 2012; Mearns et al., 2012). Granted, analysis of fisheries data for the affected coastal area in the Gulf of Mexico shows that the 2010 year-classes of commercially important species were not lost (Fodrie and Hech, 2011). Although large fish may be able to swim away from an oil spill area, the effects on free-floating eggs and larvae and less-mobile juveniles can be substantial, particularly if the spill occurs in late winter/spring/early summer. A large fraction of a recruiting year-class of cod at the Lofoten–Vesterålen spawning grounds could be lost, and the impact on spawning habitats and nursery areas may last for decades. In addition, seabird colonies, e.g. the Atlantic puffins (Fratercula arctica) at the Røst nesting sites, would be severely affected by an accidental oil spill. Likewise, the picturesque Lofoten Islands, where the tourist industry constitutes an increasingly important economic activity, could become heavily soiled. In addition to IMR, other advisory bodies to the Norwegian government—the Norwegian Polar Institute, the Climate and Pollution Agency, and the directorates of Nature Management and Fisheries—all argue against opening the Lofoten–Vesterålen areas to offshore oil exploration. Where science comes into play Thus far, scientific advice, fisheries interests, and environmental protection arguments appear to have prevented the opening of the Lofoten–Vesterålen areas to the offshore oil industry. A future government might decide otherwise, however. Innovative technological development may also substantially reduce the risk of accidental oil spills, thereby making a possible opening of the Lofoten–Vesterålen areas for offshore oil exploration a less divisive issue. In the meantime, the oil industry engaged on the Norwegian continental shelf can still enjoy an historically high activity level owing to the discovery of a large new reserve in the North Sea—the Johan Sverdrup field discovered off Stavanger—and by exploring less controversial areas in the southern Barents Sea. The issue boils down to the question of whether some areas have such a high biological value—regardless of the economic value of associated fisheries—that even low risks of accidental spills are unacceptable—regardless of the monetary benefits of petroleum development. The possibility of opening the Lofoten–Vesterålen areas to petroleum activities has become the focus issue of a united environmental lobby in Norway. The oil industry argues that the risk is minute and that even a large spill only affects a fraction of the stocks and might be remedied within 1–3 years. However, their underlying analyses are fraught with methodological errors and uncertainties related to the data used to run the risk models (Anon., 2010b). The uncertainties are seldom mentioned by the oil lobby, but as marine scientists—providers of the data—we are well aware of the shortcomings (Anon., 2010b). Conclusion The consequences of underestimating the environmental risk in a uniquely valuable and sensitive area such as Lofoten–Vesterålen would be much more serious than in any other part of the Norwegian marine environment. Faced with such uncertainty and dire potential consequences, the precautionary approach should come into play and the government should refrain from allowing potentially harmful petroleum activity until all problems are resolved. Acknowledgements We are indebted to Janet Holmén for advice, corrections, and suggestions on how to improve the English language in our paper. We are thankful to Editor Emory Anderson for suggestions on how to improve our paper, and to an anonymous reviewer for being supportive. The review given by Niels Daan was most valuable in giving our text a proper structure and conveying clear messages and statements. References Anderssen-Strand The Lofoten Fishery 1933. The Yearbook of the Norwegian Fisheries – 1993 – No. 2. J. Grieg, Bergen , In Norwegian , 1933 pg. 102 http://biblioteket.imr.no/e-tidsskrifter/lofotfisket/filer/lof_1933.pdf OpenURL Placeholder Text WorldCat Anon The Lofoten Fishery This Year , In Norwegian , 2006 http://www.fiskeridir.no/fiske-og-fangst/aktuelt/2006/aarets-lofotfisk OpenURL Placeholder Text WorldCat Anon Petroleum Resources in the Waters off Lofoten, Vesterålen and Senja , In Norwegian , 2010a Stavanger Norwegian Petroleum Directorate pg. 36 http://www.npd.no/no/Publikasjoner/Rapporter/Petroleumsressursene-i-havomradene-utenfor-Lofoten-Vesteralen-og-Senja/ Google Scholar Google Preview OpenURL Placeholder Text WorldCat COPAC Anon The scientific basis for updating the management plan for the Barents Sea and the waters off Lofoten. Report from the Scientific Forum, the Surveillance Group, and the Risk Assessment Group to the interdepartmental steering group for the management plan. Fisken og havet, særnummer 1a – 2010 , In Norwegian , 2010b Bergen Institute of Marine Research pg. 314 http://www.imr.no/publikasjoner/andre_publikasjoner/faglig_forums_rapport_2010/nb-no Google Scholar Google Preview OpenURL Placeholder Text WorldCat COPAC Bakke T. , Klungsøyr J. , Sanni S. . Long-term environmental impact of discharges from the Norwegian petroleum industry. Review of a 10-year research programme , 2012 (Submitted to Marine Ecology Progress Series.) OpenURL Placeholder Text WorldCat Fodrie F. J. , Hech K. L. . Response of the coastal fishes to the Gulf of Mexico oil disaster , PloS ONE , 2011 , vol. 6 e21609. doi.10.13717journal.pone.0021609 Google Scholar OpenURL Placeholder Text WorldCat Føyn L. , Quillfeldt C. H. , Olsen E. . Marine environment and living resources in the areas Lofoten – The Barents Sea. 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Cod, haddock, saithe, herring, and capelin in the Barents Sea and adjacent waters: a review of the biological value of the area , ICES Journal of Marine Science , 2010 , vol. 67 (pg. 87 - 101 ) Google Scholar Crossref Search ADS WorldCat Olsen E. , Gjøsæter H. , Røttingen I. , Dommasnes A. , Fossum P. , Sandberg P. . The Norwegian ecosystem-based management plan for the Barents Sea , ICES Journal of Marine Science , 2007 , vol. 64 (pg. 599 - 602 ) Google Scholar Crossref Search ADS WorldCat Ottersen G. , Olsen E. , Meehren G. I. , Dommasnes A. , Loeng H. O. . The Norwegian plan for integrated ecosystem-based management of the marine environment in the Norwegian Sea , Marine Policy , 2011 , vol. 25 (pg. 389 - 398 ) Google Scholar Crossref Search ADS WorldCat Pedersen T. . Dahl E. , Danielssen D. S. , Moksness E. , Solemdal P. . Variation in peak spawning of Arcto-Norwegian cod (Gadus morhua L.) during the time period 1929–1982 based on indices estimated from fishery statistics , In The Propagation of Cod Gadus morhua L , 1984 (pg. 301 - 316 ) Flødevigen Rapportser, 1 Google Scholar Google Preview OpenURL Placeholder Text WorldCat COPAC Sundby S. , Nakken O. . Spatial shifts in spawning habitats of Arcto-Norwegian cod related to multidecadal climate oscillations and climate change , ICES Journal of Marine Science , 2008 , vol. 65 (pg. 953 - 962 ) Google Scholar Crossref Search ADS WorldCat Winsnes I. , Skjoldal H. R. . Bianchi G. , Skjoldal H. R. . Management plan for the Norwegian part of the Barents Sea Ecosystem , In The Ecosystem Approach to Fisheries , 2008 FAO Rome (pg. 228 - 249 ) Google Scholar Google Preview OpenURL Placeholder Text WorldCat COPAC Yaragina N. A. , Aglen A. , Sokolov K. . Jakobsen T. , Ozhigin V. K. . Cod , In The Barents Sea. Ecosystem, Resources, Management. Half a Century of Russian–Norwegian Cooperation , 2011 Trondheim Tapir Academic Press (pg. 225 - 270 ) Google Scholar Google Preview OpenURL Placeholder Text WorldCat COPAC Author notes Handling editor: Emory Anderson © 2013 International Council for the Exploration of the Sea. Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 International Council for the Exploration of the Sea. Published by Oxford University Press.

Jennings, S.

doi: 10.1093/icesjms/fst044pmid: N/A

Jennings, S. 2013. When can “principles” support advice on fisheries and environmental management? – ICES Journal of Marine Science, 70: 726733.Demands for advice on fisheries and environmental management often outstrip scientists' capacity to supply it. The imbalance would be smaller if some of the advice could be based on principles rather than tailored case-by-case analyses, where I define principles as “evidence-based rules that underpin scientific advice on management options and reduce uncertainty about decisions and outcomes with fewer resources than tailored case-by-case analyses”. I consider the role, development, existing and potential uses, strengths and weaknesses of principles in underpinning advice, and how principles might complement methodological innovations and risk assessment. The extent to which principles might replace case-by-case analyses is expected to depend on structures and processes in the management system, particularly the treatment of uncertainty and risk. If advice based on principles is seen as less salient, credible, and legitimate than advice developed from case-by-case analyses then this could lead to political push-back or non-compliance with management measures, transferring costs from the advisory process to other parts of the management system. In general, I propose that principles provide the greatest benefits in a management system when they address complex advisory issues that lead to advice on management measures with relatively small social and economic consequences or when they simplify parts of an advisory process leading to management measures with a range of consequences. Notwithstanding limits on their application, further development and uptake of principles could reduce demands for case-by-case advice on fisheries and environmental management. A formalized challenge, testing, and updating process for principles, supported by an audit trail, would encourage and increase their use. The development of principles would provide a new focus for the targeting, review, and uptake of research. Spatial planning initiatives, the emergence of marine protected area networks, and other changes in management measures can be treated as experiments to inform development and testing of principles.

Rice, Jake; Daan, Niels; Gislason, Henrik; Pope, John

doi: 10.1093/icesjms/fst071pmid: N/A

Rice, J., Daan, N., Gislason, H., and Pope, J. Does functional redundancy stabilize fish communities? – ICES Journal of Marine Science, 70: 734742.Functional redundancy of species sharing a feeding strategy and/or maximum size has been hypothesized to contribute to increased resilience of marine fish communities (the “portfolio effect”). A consistent time-series of survey data of fish in the North Sea was used to examine if trophic functional groups or maximum length of species (Lmax) groups with larger numbers of species had lower coefficients of variation in abundance and biomass over time than did groupings with fewer species. Results supported this hypothesis. However, the stabilizing effect of numbers of species in a group on variation in abundance or biomass could be accounted for by the Law of Large Numbers, providing no evidence that specific ecological processes or co-adaptations are necessary to produce this effect. This implies that successful conservation policies to maintain the resilience of a marine fish community could be based on strategies to maintain the number of species in functional groups, without having to know the detailed ecological interactions between the species.

Skagen, Dankert W.; Skern-Mauritzen, Mette; Dankel, Dorothy; Enberg, Katja; Kjesbu, Olav S.; Nash, Richard D. M.

doi: 10.1093/icesjms/fst043pmid: N/A

Skagen, D. W., Skern-Mauritzen, M., Dankel, D., Enberg, K., Kjesbu, O. S., and Nash, R. D. M. 2013. A simulation framework for evaluating fisheries management decisions using environmental information. – ICES Journal of Marine Science, 70: 743754.The population dynamics of marine fish stocks are influenced by both physical and biological conditions. Yet, such environmental impacts on stock dynamics, and hence stock production, are rarely included in applied fisheries management. To test the utility of taking ecosystem information into account in management decisions requires efficient tools. We propose a simulation framework for evaluating fisheries management schemes that use environmental information as part of the decision basis. A key feature is to link environmental signals to parameters in functions that define the population dynamics. This allows a direct incorporation of environmental drivers into models of population dynamic processes and emphasizes the need for a quantitative understanding of the influence of environmental drivers on such processes. The utility of the simulation framework is demonstrated through a worked example with different management scenarios, where decisions to increase or decrease the exploitation rely on environmental indicators only, or also on information on stock abundance. In this example, a management that was based on indicators only, without updated measures of the state of the stock itself, failed to respond adequately to changes in stock productivity.

Large, Scott I.; Fay, Gavin; Friedland, Kevin D.; Link, Jason S.

doi: 10.1093/icesjms/fst067pmid: N/A

Large, S. I., Fay, G., Friedland, K. D., and Link, J. S. 2013. Defining trends and thresholds in responses of ecological indicators to fishing and environmental pressures. – ICES Journal of Marine Science, 70: 755767.Both fishing and environmental forces can influence the structure of marine ecosystems. To further understand marine ecosystems and to implement ecosystem-based fisheries management (EBFM), an evaluation of ecosystem indicators is warranted. In this context, it is particularly important to identify thresholds where fishing and environmental pressures significantly influence ecological indicators. We empirically determined numerical values of environmental forces and fishing pressure that significantly altered the response of ecological indicators for the Northeast Shelf Large Marine Ecosystem. Generalized additive models predicted a non-linear relationship for each pressure–response pairing. With this smoother, 95% confidence intervals (CI) for estimated first and second derivatives for each relationship were determined via parametric bootstrap. A significant trend or threshold was noted when the CI for the first or second derivative was greater or less than zero, delineating the level at which pressure variables influence the rate and direction of ecosystem indicator responses. We identify reference levels where environmental forces and fishing pressure result in ecosystem change by collectively examining the responses of multiple ecological indicators. Individual indicators showed unique responses to pressures, however, similar values for the pressures were associated with significant changes for multiple indicators. These reference levels establish a foundation for implementation of EBFM.

Marchal, Paul; Vermard, Youen

doi: 10.1093/icesjms/fst073pmid: N/A

Marchal, P., and Vermard, Y. 2013. Evaluating deepwater fisheries management strategies using a mixed-fisheries and spatially explicit modelling framework. – ICES Journal of Marine Science, 70: 768781.We have used in this study a spatially explicit bioeconomic modelling framework to evaluate management strategies, building in both data-rich and data-limited harvest control rules (HCRs), for a mix of deepwater fleets and species, on which information is variable. The main focus was on blue ling (Molva dypterygia). For that species, both data-rich and data-limited HCRs were tested, while catch per unit effort (CPUE) was used either to tune stock assessments, or to directly trigger management action. There were only limited differences between the performances of both HCRs when blue ling biomass was initialized at the current level, but blue ling recovered more quickly with the data-rich HCR when its initial biomass was severely depleted. Both types of HCR lead, on average, to a long-term recovery of both blue ling and saithe (Pollachius virens) stocks, and some increase in overall profit. However, that improvement is not sufficient to guarantee sustainable exploitation with a high probability. Blue ling CPUE did not always adequately reflect trends in biomass, which mainly resulted from fleet dynamics, possibly in combination with density-dependence. The stock dynamics of roundnose grenadier (Coryphaenoides rupestris), black scabbardfish (Aphanopus carbo) and deepwater sharks (Centrophorus squamosus and Centroscymnus coelolepis) were little affected by the type of HCR chosen to manage blue ling.

Homrum, Eydna í; Hansen, Bogi; Jónsson, Sigurður Þór; Michalsen, Kathrine; Burgos, Julian; Righton, David; Steingrund, Petur; Jakobsen, Tore; Mouritsen, Rógvi; Hátún, Hjálmar; Armannsson, Hlynur; Joensen, Jákup Sverri

Le Bris, Arnault; Fréchet, Alain; Galbraith, Peter S.; Wroblewski, Joseph S.

doi: 10.1093/icesjms/fst068pmid: N/A

Le Bris, A., Fréchet, A., Galbraith, P. S., and Wroblewski, J. S. 2013. Evidence for alternative migratory behaviours in the northern Gulf of St Lawrence population of Atlantic cod (Gadus morhua L.). – ICES Journal of Marine Science, 70: 793804.Inter-individual variation in migration propensity affects population dynamics and connectivity. The diversity of migratory behaviours of Atlantic cod (fork length >40 cm) in the northern Gulf of St Lawrence was studied using data-storage tags that record depth and temperature. Movement patterns of Atlantic cod equipped with data-storage tags were reconstructed using a geolocation model based on daily maximum depth and bottom temperature. Reconstructed migration routes revealed the previously undocumented coexistence of resident and migratory individuals in the population. Migratory cod overwintered in relatively deep (300–500 m) and warm (5°C) waters, while residents displayed a prolonged period of immobility in shallow (<100 m) and near-freezing (–1.5°C) coastal waters of western Newfoundland. In the spring, migratory cod displayed extensive diel vertical migration suggestive of spawning behaviour. The presence of alternative migratory behaviours should be considered in the spatiotemporal management of the collapsed population.

Pansch, Christian; Schlegel, Peter; Havenhand, Jonathan

doi: 10.1093/icesjms/fst092pmid: N/A

Pansch, C., Schlegel, P., and Havenhand, J. 2013. Larval development of the barnacle Amphibalanus improvisus responds variably but robustly to near-future ocean acidification. – ICES Journal of Marine Science, 70: 805811.Increasing atmospheric CO2 decreases seawater pH in a phenomenon known as ocean acidification. In two separate experiments we found that larval development of the barnacle Amphibalanus (Balanus) improvisus was not significantly affected by the level of reduced pH that has been projected for the next 150 years. After 3 and 6 days of incubation, we found no consistent effects of reduced pH on developmental speed or larval size at pH 7.8 compared with the control pH of 8.1. After 10 days of incubation, there were no net changes in survival or overall development of larvae raised at pH 7.8 or 7.6 compared with the control pH of 8.0. In all cases, however, there was significant variation in responses between replicate batches (parental genotypes) of larvae, with some batches responding positively to reduced pH. Our results suggest that the non-calcifying larval stages of A. improvisus are generally tolerant to near-future levels of ocean acidification. This result is in line with findings for other barnacle species and suggests that barnacles do not show the greater sensitivity to ocean acidification in early life history reported for other invertebrate species. Substantial genetic variability in response to low pH may confer adaptive benefits under future ocean acidification.