Showing papers in "Ices Journal of Marine Science in 2014"

BOFFFFs: on the importance of conserving old-growth age structure in fishery populations

Abstract: Mark A. Hixon1*, Darren W. Johnson2, and Susan M. Sogard3 Department of Biology, University of Hawai’i at Mānoa, Hawai’i, HI, USA Department of Biology, California State University, Long Beach, CA, USA Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Santa Cruz, CA, USA *Corresponding Author: tel: +1 808 956 6437; e-mail: hixonm@hawaii.edu

Ecological value of coastal habitats for commercially and ecologically important species

Abstract: Many exploited fish and macroinvertebrates that utilize the coastal zone have declined, and the causes of these declines, apart from overfishing, remain largely unresolved. Degradation of essential habitats has resulted in habitats that are no longer adequate to fulfil nursery, feeding, or reproductive functions, yet the degree to which coastal habitats are important for exploited species has not been quantified. Thus, we reviewed and synthesized literature on the ecological value of coastal habitats (i.e. seagrass beds, shallow subtidal and intertidal habitats, kelp beds, shallow open water habitats, saltmarshes, mussel beds, macroalgal beds, rocky bottom, and mariculture beds) as feeding grounds, nursery areas, spawning areas, and migration routes of 59 taxa, for which the International Council for the Exploration of the Sea (ICES) gives management advice, and another 12 commercially or ecologically important species. In addition, we provide detailed information on coastal habitat use for plaice (Pleuronectes platessa), cod (Gadus morhua), brown shrimp (Crangon crangon), and European lobster (Homarus gammarus). Collectively, 44% of all ICES species utilized coastal habitats, and these stocks contributed 77% of the commercial landings of ICES-advice species, indicating that coastal habitats are critical to population persistence and fishery yield of ICES species. These findings will aid in defining key habitats for protection and restoration and provide baseline information needed to define knowledge gaps for quantifying the habitat value for exploited fish and invertebrates.

Reflections on the success of traditional fisheries management

Abstract: The argument persists that the continued overexploitation by many fisheries around the world is evidence that current approaches to fisheries management are failing, and that more precautionary management approaches are needed. We review the available estimates of the status of fish stocks from three sources: the FAO’s “State of Marine Resources”, a database on scientific stock assessments, and recent estimates from statistical models designed to determine the status of unassessed fish stocks. The two key results are (i) that stocks that are scientifically assessed are in better shape and indeed are not typically declining but rebuilding, and (ii) that large stocks appear to be in better shape than small stocks. These results support the view that stocks that are managed are improving, while stocks that are not managed are not. Large stocks receive far more management attention than small stocks in jurisdictions that have active fisheries management systems, and most unassessed stocks are simply not managed. We assert that fisheries management as currently practised can (and often does) lead to sustainable fisheries, and what is needed is to actively manage the unassessed fisheries of the world. More precautionary management is not necessarily needed to ensure the sustainability of managed fisheries.

Fisheries management under climate and environmental uncertainty: control rules and performance simulation

Abstract: Andre E. Punt1,2*, Teresa A’mar3, Nicholas A. Bond4, Douglas S. Butterworth5, Carryn L. de Moor5, Jose A. A. De Oliveira6, Melissa A. Haltuch7, Anne B. Hollowed3, and Cody Szuwalski1 School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA CSIRO Wealth from Oceans Flagship, GPO Box 1538, Hobart, TAS 7001, Australia Alaska Fisheries Science Center, National Marine Fisheries Service, 7600 Sand Point Way NE, Seattle, WA 98115, USA Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, WA 98105, USA Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, South Africa CEFAS Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard East, Seattle, WA 98112, USA *Corresponding author: tel +1 206 2216319; fax +1 206 6857471; e-mail: aepunt@uw.edu

Mediterranean fishery discards: review of the existing knowledge

Abstract: A considerable amount of the existing knowledge of discards in the Mediterranean Sea is presented. Discarding highly varies along the basin both geographically and among the different fishing gears with bottom trawls being responsible for the bulk of discards, since they are characterized by high discards ratios. Midwater trawls, purse-seines, and small-scale fisheries, despite their less proportion of discards per se, produce overall high discards quantities, since they are responsible for the majority of the landings. Based on the collected information, a rough Mediterranean-wide estimate of discards around 230 000 t or 18.6% (13.3 –26.8%) of the catch is produced. Discarding in the Mediterranean is regulated by market demands rather than by legal constraints, and marketable bycatch may constitute an important supplemental source of income. A pattern in resource use related to socio-cultural characteristics is apparent, with welfare communities discarding more in terms of percentages. Natural conditions (e.g. environmental gradients) and fishers’ strategies also substantially affect discarding. Mitigation tools mainly comprise selectivity improvement and spatio-temporal closures. Despite the progress in studying discards, needs are evident to expand monitoring schemes, apply analytical techniques, and establish objectives of the discards issue under the framework of ecosystem approach to fisheries.

Integrating what? Levels of marine ecosystem-based assessment and management

Abstract: Integrated assessment requires examination of factors across biological hierarchies, taxonomic groups, ocean-use sectors, management objectives, and scientific disciplines. The articles in this theme set represent attempts to clarify and elaborate upon what integrated assessments are, with a particular emphasis on how they are being implemented. The aim of this themed article set is to clarify the use of integratedassessment terminology and demonstrate, by presenting case studies, examples in which integrated ecosystem assessments serve as useful tools to implement ecosystem-based management (EBM) while also identifying challenges that must be overcome for this to succeed. In theory, EBM seeks to address the various natural and anthropogenic pressures faced by the key components of marine systems simultaneously. EBM also attempts to account for “cumulative impacts” that might otherwise be overlooked. Nascent attempts to implement EBM highlight the need—in practice—to address trade-offs across multiple objectives for a given system, in a coordinated and comprehensive manner. During the past decade, the discussion over EBM has shifted from “what is it and why should we do it” (Link, 2002; Browman and Stergiou, 2004, 2005) to “how can we do it and when can we operationalize it” (Arkema et al., 2006; Link, 2010; Berkes, 2012). Marine EBM (e.g. Levin and Lubchenco, 2008; McLeod and Leslie, 2009) and similar ecosystem-based efforts for more specific ocean-use sectors, such as ecosystem-based fisheries management (EBFM; e.g. Pikitch et al., 2004; Link, 2010) or integrated coastal-zone management (e.g. Cicin-Sain and Knecht, 1998; Moksness et al., 2013), have become the mandated approach to managing ocean resources. EBM is a major policy objective of many marine-oriented organizations—as is clear from a perusal of the strategic plans of organizations such as ICES, PICES, FAO, UNEP, and NOAA. The need for integrated assessments frequently arises in the context of discussions over implementing EBM. The term “integrated assessments” is perceived as mysterious and ultimately unhelpful because it suffers from a plurality of definitions and it is used in a multitude of contexts—i.e. it has high linguistic uncertainty. That is why we pose the question in the title of this introduction: what are we integrating and, hence, what are we assessing? Returning to the EBM context for sustainably managing marine resources, we note that there are, in fact, multiple levels at which an “ecosystem approach” can be adopted in practice. To illustrate, we focus on the fisheries sector. There are levels of application for EBM that focus solely on fish stocks, levels that focus on fish stocks but with ecosystem considerations incorporated, ecosystem levels that focus solely on the fisheries sector but for the full system of fisheries and stocks, and the full set of ocean-use sectors impacted by and impacting the fisheries sector (Table 1). For example, consider forage stocks such as small pelagic fish. For an ecosystem approach to fisheries (EAF) that takes a stock focus, one would need to consider the effects of environmental factors (e.g. temperature changes or NAO events) and ecological factors (e.g. predator removals or models of multispecies interactions) in addition to targeted fisheries removals to truly grasp what is driving the population dynamics of such stocks. Using the same type of focal species as an example, for EBFM that takes a system focus in the fisheries sector, one would have to consider not only the impacts of other factors on these forage stocks, but also the dynamics of these forage stocks on other parts of the ecosystem. For instance, there are seabirds or marine mammals that have some form of protected or conservation status and that are highly dependent on small pelagic forage fish. There are commercially targeted groundfish that are also major predators of these small pelagic forage fish. There are also multiple fisheries operating on both the groundfish and the small pelagic species. In such a case, clearly a more integrated, “bigger picture” evaluation of the

Forage fish, their fisheries, and their predators: who drives whom?

Abstract: The North Sea has a diverse forage fish assemblage, including herring, targeted for human consumption; sandeel, sprat, and Norway pout, exploited by industrial fisheries; and some sardine and anchovy, supporting small-scale fisheries. All show large abundance fluctuations, impacting on fisheries and predators. We review field, laboratory, and modelling studies to investigate the drivers of this complex system of forage fish. Climate clearly influences forage fish productivity; however, any single-species considerations of the influence of climate might fail if strong interactions between forage fish exist, as in the North Sea. Sandeel appears to be the most important prey forage fish. Seabirds are most dependent on forage fish, due to specialized diet and distributional constraints (breeding colonies). Other than fisheries, key predators of forage fish are a few piscivorous fish species including saithe, whiting, mackerel, and horse-mackerel, exploited in turn by fisheries; seabirds and seals have a more modest impact. Size-based foodweb modelling suggests that reducing fishing mortality may not necessarily lead to larger stocks of piscivorous fish, especially if their early life stages compete with forage fish for zooplankton resources. In complex systems, changes in the impact of fisheries on forage fish may have potentially complex (and perhaps unanticipated) consequences on other commercially and/or ecologically important species.

Guidance for implementation of integrated ecosystem assessments: a US perspective

Abstract: Ecosystem-based management (EBM) has emerged as a basic approach for managing human activities in marine ecosystems, with the aim of recovering and conserving marine ecosystems and the services they deliver. Integrated ecosystem assessments (IEAs) further the transition of EBM from principle to practice by providing an efficient, transparent means of summarizing the status of ecosystem components, screening and prioritizing potential risks, and evaluating alternative management strategies against a backdrop of environmental variability. In this paper, we draw upon lessons learned from the US National Oceanic and Atmospheric Administration’s IEA programme to outline steps required for IEA implementation. We provide an overview of the conceptual framework for IEAs, the practical constraints that shape the structure of individual IEAs, and the uses and outcomes of IEAs in support of EBM.

Ecological importance of sharks and rays in a structural foodweb analysis in southern Brazil

Abstract: Understanding the trophic interactions and the position of species within a foodweb is crucial if we want to understand the dynamics of marine communities and the impact individual components of the community have on trophic network compartments. Recent studies have indicated sharks and rays are important elements within foodwebs. In this study, we evaluated the ecological importance of sharks and rays in a subtropical ecosystem off the coast of southern Brazil by using topological analyses. We tested the hypotheses that some elasmobranchs can be considered key elements within the foodweb, and that large predators have topological importance (act as keystones), so that, when large predators are excluded, mesopredator elasmobranchs occupy higher topological positions. Our results indicate that Galeocerdo cuvier, Carcharhinus obscurus, Carcharias taurus, Sphyrna lewini and S. zygaena are species with large ecological function values and may exert a powerful influence over lower levels. These issues need to be considered by conservation and fishery management groups since it appears that ecosystem integrity may be compromised by reductions in the populations of large predators. Carcharhinus obscurus, S. zygaena and Zapteryx brevirostris were found to be the elasmobranchs with largest values of centrality, and can, therefore, be considered key elements in the topological structure.

Nursery habitat availability limits adult stock sizes of predatory coastal fish

Abstract: Habitat protection is a strategy often proposed in fisheries management to help maintain viable populations of exploited species. Yet, quantifying the importance of habitat availability for population sizes is difficult, as the precise distribution of essential habitats is poorly known. To quantify the contribution from coastal nursery habitats to exploited fish population sizes, we related adult density to the amount of nursery habitat available for 12 populations of the two dominant predatory fish species in a 40 000-km2 archipelago area of the Baltic Sea. Habitat distribution was mapped using three conceptually different techniques, Maxent, generalized additive models, and random forest, using spawning and 0-group point samples. Adult densities were estimated from gillnet surveys. Regressions demonstrated no evident effect from fishing, whereas habitat availability had a positive effect, explaining almost half of the variation in population sizes of both species. This result shows that a substantial proportion of the potential production of adult fish can be estimated by mapping essential nursery habitats distribution. Responses were non-linear, indicating that habitat protection has largest effects where there is little available habitat. By demonstrating the importance of habitat limitation of two exploited fish species, we provide quantitative support to the benefits of habitat protection for fisheries.

Implementing ecosystem-based fisheries management: from single-species to integrated ecosystem assessment and advice for Baltic Sea fish stocks

Abstract: Theory behind ecosystem-based management (EBM) and ecosystem-based fisheries management (EBFM) is now well developed. However, the implementation of EBFM exemplified by fisheries management in Europe is still largely based on single-species assessments and ignores the wider ecosystem context and impact. The reason for the lack or slow implementation of EBM and specifically EBFM is a lack of a coherent strategy. Such a strategy is offered by recently developed integrated ecosystem assessments (IEAs), a formal synthesis tool to quantitatively analyse information on relevant natural and socio-economic factors, in relation to specified management objectives. Here, we focus on implementing the IEA approach for Baltic Sea fish stocks. We combine both tactical and strategic management aspects into a single strategy that supports the present Baltic Sea fish stock advice, conducted by the International Council for the Exploration of the Sea (ICES). We first review the state of the art in the development of IEA within the current management framework. We then outline and discuss an approach that integrates fish stock advice and IEAs for the Baltic Sea. We intentionally focus on the central Baltic Sea and its three major fish stocks cod (Gadus morhua), herring (Clupea harengus), and sprat (Sprattus sprattus), but emphasize that our approach may be applied to other parts and stocks of the Baltic, as well as other ocean areas.

Discarded fish in European waters: general patterns and contrasts

Abstract: To reduce the practice of discarding commercially fished organisms, several measures such as a discard ban and extra allowances on top of landings quotas (“catch quota”) have been proposed by the European Commission. However, for their development and successful implementation, an understanding of discard patterns on a European scale is needed. In this study, we present an inter-national synthesis of discard data collected on board commercial, towed-gear equipped vessels operating under six different national flags spanning from the Baltic to the Mediterranean Seas mainly between 2003 and 2008. We considered discarded species of commercial value such as Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), European hake (Merluccius merluccius), and European plaice (Pleuronectes platessa). Comparisons of discard per unit effort rates expressed as numbers per hour of fishing revealed that in the Mediterranean Sea minimum size-regulated species such as hake are generally discarded in much lower numbers than elsewhere. For most species examined, variability in discard rates across regions was greater than across fisheries, suggesting that a region-by-region approach to discard reduction would be more relevant. The high uncertainty in discard rate estimates suggests that current sampling regimes should be either expanded or complemented by other data sources, if they are to be used for setting catch quotas.

Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013

Abstract: Antarctic krill (Euphausia superba) are a key species in Southern Ocean ecosystems, maintaining very large numbers of predators, and fluctuations in their abundance can affect the overall structure and functioning of the ecosystems. The interannual variability in the abundance and biomass of krill was examined using a 17-year time-series of acoustic observations undertaken in the Western Core Box (WCB) survey area to the northwest of South Georgia, Southern Ocean. Krill targets were identified in acoustic data using a multifrequency identification window and converted to krill density using the Stochastic Distorted-Wave Born Approximation target strength model. Krill density ranged over several orders of magnitude (0–10 000 g m−2) and its distribution was highly skewed with many zero observations. Within each survey, the mean krill density was significantly correlated with the top 7% of the maximum krill densities observed. Hence, only the densest krill swarms detected in any one year drove the mean krill density estimates for the WCB in that year. WCB krill density (µ, mean density for the area) showed several years (1997/1998, 2001–2003, 2005–2007) of high values (µ > 30 g m−2) interspersed with years (1999/2000, 2004, 2009/2010) of low density (µ < 30 g m−2). This pattern showed three different periods, with fluctuations every 4–5 years. Cross correlation analyses of variability in krill density with current and lagged indices of ocean (sea surface temperature, SST and El Nino/Southern Oscillation) and atmospheric variability (Southern Annular Mode) found the highest correlation between krill density and winter SST (August SST) from the preceding year. A quadratic regression (r2 = 0.42, p < 0.05) provides a potentially valuable index for forecasting change in this ecosystem.

Krill, climate, and contrasting future scenarios for Arctic and Antarctic fisheries

Abstract: Arctic and Antarctic marine systems have in common high latitudes, large seasonal changes in light levels, cold air and sea temperatures, and sea ice. In other ways, however, they are strikingly different, including their: age, extent, geological structure, ice stability, and foodweb structure. Both regions contain very rapidly warming areas and climate impacts have been reported, as have dramatic future projections. However, the combined effects of a changing climate on oceanographic processes and foodweb dynamics are likely to influence their future fisheries in very different ways. Differences in the life-history strategies of the key zooplankton species (Antarctic krill in the Southern Ocean and Calanus copepods in the Arctic) will likely affect future productivity of fishery species and fisheries. To explore future scenarios for each region, this paper: (i) considers differing characteristics (including geographic, physical, and biological) that define polar marine ecosystems and reviews known and projected impacts of climate change on key zooplankton species that may impact fished species; (ii) summarizes existing fishery resources; (iii) synthesizes this information to generate future scenarios for fisheries; and (iv) considers the implications for future fisheries management. Published studies suggest that if an increase in open water during summer in Arctic and Subarctic seas results in increased primary and secondary production, biomass may increase for some important commercial fish stocks and new mixes of species may become targeted. In contrast, published studies suggest that in the Southern Ocean the potential for existing species to adapt is mixed and that the potential for the invasion of large and highly productive pelagic finfish species appears low. Thus, future Southern Ocean fisheries may largely be dependent on existing species. It is clear from this review that new management approaches will be needed that account for the changing dynamics in these regions under climate change.

Evaluating effectiveness of time/area closures, quotas/caps, and fleet communications to reduce fisheries bycatch

Abstract: Designing effective bycatch mitigation programmes requires an understanding of the life histories of target and non-target species, interactions of fish and fishing gear, effects of spatial and temporal shifts in fishing effort, socio-economic impacts to the fishery, and incentives of fishery participants. The effects of mitigation measures (including fishing gear modification, time/area closures, bycatch quotas and caps, incentive programs, and fleet communication programs) have been evaluated with respect to reducing bycatch and discards. Less attention has been focused on evaluating unanticipated results related to shifts in fishing effort, changes in the size of non-target species caught, reduced catch of target species, and economic viability to fishing fleets. Time/area closures, bycatch quotas/caps, and fleet communication programmes were evaluated against a set of criteria to assess overall effectiveness in reducing bycatch without causing unintended biological and socio-economic impacts. The results suggest that wide-ranging studies of species’ life histories, potential changes in fleet behaviour, and individual incentives are important for developing and implementing mitigation programmes. Combining a suite of mitigation techniques has been successful in meeting biological and socio-economic fisheries goals. Additionally, collaborative programmes that utilize the skill sets of fishers, scientists, and managers have increased effectiveness in meeting bycatch reduction objectives.

Lessons learned from developing integrated ecosystem assessments to inform marine ecosystem-based management in the USA

Abstract: Jameal F. Samhouri1*, Alison J. Haupt2, Phillip S. Levin1, Jason S. Link3, and Rebecca Shuford4 Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA 98112, USA West Coast Governors Alliance, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA 98112, USA National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 166 Water St., Woods Hole, MA 02543, USA Marine Ecosystems Division, Office of Science and Technology, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Silver Spring, MD 20910, USA

Are Calanus spp. shifting poleward in the North Atlantic? A habitat modelling approach

Abstract: This research was funded by the European Commission (Contract No. 264933, EURO-BASIN: European Union Basin-scale Analysis, Synthesis and Integration). We acknowledge CliSAP-Integrated Climate Data Center and NOAA for providing climate and bathymetry data, respectively. We are grateful to present and past staff of SAHFOS who have contributed to the maintenance of the CPR time-series. We acknowledge Mireia Valle for technical support in model cross-validation. This is contribution 653 from AZTI-Tecnalia Marine Research Division.

Spatial management of Indian Ocean tropical tuna fisheries: potential and perspectives

Abstract: Effective use of spatial management in the pelagic realm presents special challenges due to high fish and fisher mobility, limited knowledge and significant governance challenges. The tropical Indian Ocean provides an ideal case study for testing our ability to apply existing data sources to assessing impacts of spatial management on tuna fisheries because of several recent controversial spatial closures. We review the scientific underpinnings of pelagic MPA effects, spatio-temporal patterns of Indian Ocean tuna catch, bycatch and fish movements, and the consequences of these for the efficacy of spatial management for Indian Ocean tropical tuna fisheries. The tropical Indian Ocean is characterized by strong environmental fluctuations, regular seasonal variability in catch, large observed tuna displacement distances, relatively uniform catch-per-unit-effort and bycatch rates over space, and high fisher mobility, all of which suggest significant variability and movement in tropical tuna fisheries that are simply not well adapted to static spatial closures. One possible exception to this overall conclusion would be a large time/area closure east of Somalia. If closed for a significant fraction of the year it could reduce purse-seine bycatch and juvenile tuna catch. Dynamic closures following fish migratory patterns are possible, but more focused information on fish movements will be needed for effective implementation. Fortunately, several recent improvements in conventional fishery management and reporting will likely enhance our ability to evaluate spatial and non-spatial management options in the near future, particularly as pertaining to bycatch species.

A review of early life history dynamics of Barents Sea cod (Gadus morhua)

Abstract: Geir Ottersen1,2*, Bjarte Bogstad3, Natalia A. Yaragina4, Leif Christian Stige2, Frode B. Vikebo3, and Padmini Dalpadado3 Institute of Marine Research, Gaustadalleen 21, N-0349 Oslo, Norway Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway Institute of Marine Research, PO Box 1870 Nordnes, N-5817 Bergen, Norway Polar Research Institute of Marine Fisheries and Oceanography, 6 Knipovich Street, Murmansk 183038, Russia *Corresponding author: tel: +47 2285 7288; fax: +47 22854001; e-mail: geir.ottersen@imr.no

Modelling larval fish navigation: the way forward

Abstract: Recent advances in high-resolution ocean circulationmodels, coupled with a greater understanding of larval behaviour, have increased the sophistication of individual-based, biophysical models used to study the dispersal of larvae in the sea. Fish larvae, in particular, have the ability to swim directionally and increasingly fast during ontogeny, indicating that they may not only disperse, but also migrate using environmental signals. How and when larvae use local and large-scale cues remains a mystery. Including three-dimensional swimming schemes into biophysical models is becoming essential to address these questions. Here, we highlight state-of-the-art modelling of vertical andhorizontalmigrations of fish larvae, aswell as current challenges inmoving towardsmore realistic larvalmovements in response to cues. Improvedunderstanding of causes fororientationwill provide insight into the evolutionary drivers of dispersal strategies for fish andmarine organisms in general.

The role of fisheries and the environment in driving the decline of elasmobranchs in the northern Adriatic Sea

Abstract: Elasmobranch populations are declining worldwide, calling for urgent assessment of fishery exploitation and application of effective conservation strategies. Here, we applied a novel approach, integrating long-term time-series of landings (1945 –2012) and extensive surveys at the fish market of Chioggia, Italy, home of the major fishing fleet of the northern Adriatic Sea, to evaluate the status of elasmobranch populations and fisheries in the one of the most fished Mediterranean basins. The time-series highlight a dramatic decline in elasmobranch landings, particularly for skates and catsharks (Scyliorhinus spp.), whose current catch rates are 2.4 and 10.6% of the average 1940s levels, respectively. These data likely reflect similar large reductions in abundance, as indicated by the analysis of catch-per unit-effort timeseries. The biomass of landed skates and catsharks showed regular fluctuations that disappeared after the collapse of the landings. Elasmobranch market composition, assessed through the sampling of 11 900 specimens from 2006 to 2013, included 14 species, but was dominated by just two: Mustelus mustelus and M. punctulatus, which represented more than 60% of the catch. The proportion of sexually immature individuals was generally very high, up to 83% of landed females and 71% of landed males, depending on the species. Although some correlations were detected between landings and local hydrography or climatic indices, the analyses of landings and surveys at the fish market identified fishery exploitation as the main driver of the striking, long-term elasmobranch decline in the northern Adriatic Sea, calling for urgent management actions to improve the conservation status of these fish.

Conservation and fisheries effects of spawning aggregation marine protected areas: What we know, where we should go, and what we need to get there

Abstract: There is a global trend in the depletion of transient reef fish spawning aggregations (“FSAs”), making them a primary target for management with marine protected areas (MPAs). Here, we review the observed and likely effectiveness of FSA MPAs, discuss how future studies could fill knowledge gaps, and provide recommendations for MPA design based on species’ life history and behaviour, enforcement potential, and management goals. Modelling studies indicate that FSA MPAs can increase spawning-stock biomass and normalize sex ratio in protogynous fish populations, unless fishing mortality remains high outside protected FSA sites and spawning times. In the field, observations of no change or continued decline in spawning biomass are more common than population recovery. When empirical studies suggest that FSA MPAs may not benefit fish productivity or recovery, extenuating factors such as insufficient time since MPA creation, poor or lack of enforcement, inadequate design, and poorly defined management objectives are generally blamed rather than failure of the MPA concept. Results from both the empirical and modelling literature indicate that FSA MPAs may not improve exploitable biomass and fisheries yields; however, investigations are currently too limited to draw conclusions on this point. To implement effective FSA MPAs, additional modelling work, long-term monitoring programmes at FSA sites, and collections of fisheries-dependent data are required, with greater attention paid to the design and enforcement of area closures. We recommend a harmonized, adaptive approach that combines FSA MPA design with additional management measures to achieve explicitly stated objectives. Conservation objectives and, therefore, an overall reduction in mortality rates should be targeted first. Fisheries objectives build on conservation objectives, in that they require an overall reduction in mortality rates while maintaining sufficient access to exploitable biomass. Communication among researchers, regulatory agencies, park authorities, and fishers will be paramount for effective action, along with significant funds for implementation and enforcement.

Selecting relative abundance proxies for BMSY and BMEY

Abstract: The objectives for many commercial fisheries include maximizing either yield or profit. Clearly specified management targets are a key element of effective fisheries management. Biomass targets are often specified for major commercial fisheries that are managed using quantitative stock assessments where biomass is calculated and tracked over time. BMSY, the biomass corresponding to Maximum Sustainable Yield, is often used as a target when maximizing yield is important, while BMEY is the biomass target to maximize profit. There are difficulties in estimating both quantities accurately, and this paper explores default proxies for each target biomass, expressed as biomass levels relative to carrying capacity, which are more easily estimated. Integration across a range of uncertainties about stock dynamics and the costs of fishing suggests that a proxy for BMSY in the range of 35-40% of carrying capacity minimizes the potential loss in yield compared with that which would arise if BMSY was known exactly, while a proxy for BMEY of 50-60% of carrying capacity minimizes the corresponding potential loss in profit. These estimates can be refined given stock-specific information regarding productivity (particularly the parameter which defines the resilience of recruitment to changes in spawning stock size) and costs and prices. It is more difficult to find a biomass level that achieves a high expected profit than a biomass level that achieves a high expected catch, because the former is sensitive to uncertainties related to costs and prices, as well as parameters which determine productivity.

Once upon a larva: revisiting the relationship between feeding success and growth in fish larvae

Abstract: P.P.andD.R.contributedequallytothisstudyandothershavecontributedequally.Authorshavebeenlistedinalphabeticalorderforeachcontributionlevel.Pepin, P., Robert, D., Bouchard, C., Dower, J. F., Falardeau, M., Fortier, L., Jenkins, G. P., Leclerc, V., Levesque, K., Llopiz, J. K.Meekan, M. G., Murphy, H. M., Ringuette, M., Sirois, P., and Sponaugle, S. Once upon a larva: revisiting the relationshipbetween feeding success and growth in fish larvae. – ICES Journal of Marine Science, doi: 10.1093/icesjms/fsu201.Received7 July 2014; revised 29 September 2014; accepted 18 October 2014.Variationsinlarvalfishgrowthratesarelargelytheresultofvariabilityinbioticandabioticcharacteristicsofthefeedingenvironmentexperiencedbyeachindividual.Anassessmentofanindividual’soverallfeedingsuccess(i.e.accumulationofutilizableorganicmatter)canbestbeachievedatthe time of capture when the relationships among environment, short-term feeding success as defined by gut content and long-term feedingsuccess as defined by accumulated growth can be contrasted. Here, we investigated the relationships between average growth, feeding success,and variability in individual growth and feeding rates across a range of taxa based on a synthesis of studies in which stomach content andotolithgrowthweremeasuredinthesameindividuals.Instantaneousmeasuresoffeedingsuccesswerehighlyvariableanddemonstratedapositiveyetsomewhatlimitedassociationwithgrowthratesacrossalltaxa.Thestrengthofthefeeding-growthrelationshipsamongtaxa,andcohortswithintaxa,wasreflectedintheautocorrelationofindividualgrowthrates,suggestingthatstablegrowthwasachievedthroughconsistentfeedingsuccess.However, when viewed atthe individual level, fastergrowth was achieved in individuals with morevariable growth rates, and by inference morevariablepastfeedingsuccess.Thedichotomyintheseunderlyingrelationshipsmaypointtotheimportanceofstochasticeventsinthedevelop-mentofexceptionalindividualsinapopulation,andmaybelinkedtohowsurplusenergyisallocatedtoindividualgrowthrates.Thepositivecor-relationfoundbetweenfeedingsuccessandgrowthinalltaxaisconsistentwiththegrowth-survivalparadigmforthelarvalstageoffish.However,boththecorrelationbetweenfeedingsuccessandgrowthandtheserialcorrelationofgrowthtime-serieswasgreatestinfast-growingspecies,sug-gesting thatthe potential foran early “critical period” regulatingsurvival varies amongspecies, reaching a maximumin fast-growing fish.Keywords: early life history, gut content, otolith microstructure, recruitment, survival, trophodynamics.

The future of fisheries oceanography lies in the pursuit of multiple hypotheses

Abstract: Fisheries oceanography is largely an applieddisciplinewith amajor goal of improving fisheriesmanagement andmarine conservation. Johan Hjort’s critical period hypothesis, and its decedents, remain a dominant theme and focuses on year-class success asmediated by prey availability and feeding. Bottom-up forcing, a related hypothesis, focuses on the sequential transfer of energy through the pelagic foodweb from primary productivity to fishery productivity. Another approach assumes that trophic interactions of adults determine abundance. Fisheries assessment andmanagement, however, is based on the hypothesis that fishery abundance is determined by time-varying fishing and yearclass success related to spawning-stock biomass. These approaches, their basic hypotheses, and underlying processes and mechanisms suggest very different dynamics for fishery populations. Other hypotheses challenge these traditional views: predation of early life stages, parental condition, shifting migration pathways, and physiological limits. Support for these other hypotheses is reviewed and the research needs are described to apply these hypotheses to fisheries assessment andmanagement. Some of these hypotheses were identified by Hjort (e.g. parental condition hypothesis) and others are relative new (e.g. early life stage predation hypothesis). Moving into the future, we should focus on Hjort’s approach: multi-hypothesis, integrative, and interdisciplinary. A range of hypotheses should be pursued with an emphasis on comparing and linkingmultiple hypotheses. The results thenmust be incorporated into fishery assessments andmanagement decisions to support the long-term sustainability of exploited species and the conservationof threatened and endangered species.

Temporal changes in the phytoplankton community along the French coast of the eastern English Channel and the southern Bight of the North Sea

Abstract: Long-term trends in the phytoplankton community along the French coast of the English Channel and southern Bight of the North Sea were studied and related to physico-chemical factors and large-climatic indices. Phytoplankton and hydrological data were acquired through three transects. Sampling took place between 1992 and 2011 as part of the French Phytoplankton Monitoring Network (REPHY) and the Regional Nutrients Monitoring Network (SRN). Trends in time-series were identified with dynamic linear models tailored to environmental monitoring data characteristics (e.g. irregular sampling frequency, missing data). Temporal and spatial patterns in the phytoplankton community were explained with a partial triadic analysis. Relationships between the phytoplankton community composition, environmental factors, and climatic indices were assessed using a redundancy analysis (RDA). The analyses revealed long-term changes in the community composition, characterized by a temporal structure that remained common to all transects. The abundance of some groups of taxa such as the one composed by Gymnodinium and Gyrodinium, as well as the group of Pseudo-nitzschia increased during the study period, whereas the abundance of other taxa as for example Guinardia and the group of Coscinodiscus and Stellarima globally decreased. More generally, the proportion of dinoflagellates relative to diatoms increased. Trends in environmental variables were also observed in most sites and related to decreases in nutrient concentrations and an increasing trend in salinity. The RDA indicated that the Atlantic Multidecadal Oscillation index and salinity were the main factors defining the temporal structure of the phytoplankton community. This suggests that variations observed in the phytoplankton community are linked to hydro-climatic changes in the coastal environment.

Why the complex nature of integrated ecosystem assessments requires a flexible and adaptive approach

Abstract: This article considers the approach taken by the ICES to integrated ecosystem assessments (IEAs) in the context of the wider evolution of IEAs and the science/policy landscape within the ICES region. It looks forward and considers the challenges facing the development of IEAs, specifically those of scoping for objectives, participatory engagement, developing indicators and targets, risk analysis, and creating tools to evaluate management measures for marine anthropogenic activities. It concludes that expectations that the implementation of IEAs will take an ordered, stepwise approach will lead to disappointment and frustration. This is a consequence of the need to operate in an adaptive manner in a complex system. The ecosystem, the science support infrastructure, and the governance systems are all complex. Plus when engaged in a debate about societal objectives, we expect to encounter a complex and changing landscape. As a community, the challenge is to find leverage mechanisms to encourage IEA efforts to provide insights and tools within resources. We will need to innovate and be responsive to the complexity of the ecosystem and governance structures encountered when performing IEA.

Changing attitudes 1970–2012: evolution of the Norwegian management framework to prevent overfishing and to secure long-term sustainability

Abstract: Fisheries have for centuries been an important part of life along the Norwegian coast. The development of new fishing technology and increasing fishing capacity posed challenges for the sustainability of the fisheries. The Norwegian spring-spawning herring was overfished in the 1960-ies with dire consequences. This event, an d the successive efforts to rebuild the stock, was paramount to the gradual development of a coherent Norwegian policy to prevent overfishing and to secure long-term sustainability. Nevertheless, overfishing continued the next transitional decades when a range of new management tools were developed and made effective. Internationally the extension to 200 mil es economic zones and agreement on the sharing and management of joint stocks were important elements. At the national level the development of measures to curb overcapacity, improvement of exploitation patterns through technical regulations and ban on discard, and the d evelopment of procedures for rational decision-making on the setting of TACs through sust ainable harvest control rules, were all decisive elements. Besides, the creation of a whol e new profession of fishery inspection has been necessary.We describe a system of close collab oration, but distinct roles between scientists, fishery managers, and stakeholders in b uilding a solid framework to prevent overfishing and secure long-term sustainability.

Fine-scale diel and gender-based patterns in behaviour of Atlantic cod (Gadus morhua) on a spawning ground in the Western Gulf of Maine

Abstract: Understanding the influence of spawning behaviour on the fine-scale distribution of Atlantic cod is essential to the design of effective conservation measures. Laboratory studies suggest that spawning activity occurs primarily at night, yet no field studies have evaluated the influence of diel period on the behaviour of individual wild spawning cod. Using an acoustic telemetry positioning system, the fine-scale movements of spawning cod were observed in situ as they returned to the same spawning location over consecutive seasons. The resulting data identify clear gender-based diel patterns in space use and aggregation behaviour among cod on a spawning ground. During the day, females remained aggregated in one small location that varied little within and between years. Males also aggregated during the day, but occupied a much larger adjacent area. At night, individual males sought out separate small territories while females generally remained near their daytime aggregation site, making periodic excursions into the surrounding area. These patterns were surprisingly stable over the 2 years of observation, indicating little interannual variability in spawning behaviour. This study provides an unprecedented examination of the natural spawning behaviour of Atlantic cod, and makes connections between earlier laboratory studies and field observations.