Description: Climate-mediated oceanographic changes have led to protracted periods of above- or below-average water temperatures over the eastern Bering Sea shelf since the early 2000s. Ecosystem components, from phytoplankton to marine birds, have shown dichotomous responses to these temperature stanzas. Understanding within-stanza responses is fundamental to modelling efforts that project ecosystem responses under future climate scenarios. This study describes fish communities associated with Walleye Pollock during the age-0 period and also examines within-stanza homogeneity of assemblages. Spatial patterns of assemblage structure are compared with pre-defined ecoregions and environmental indices are assessed to determine potential mechanisms that delineate species assemblages. Walleye Pollock, rockfishes, Sand Lance, and Northern Rock Sole contributed to spring assemblages in every year. Assemblages were delineated by across-shelf gradients in 2008 and 2010 while 2009 assemblages showed less spatial structure. In summer, the diversity of fish assemblages increased across years but early-stage juvenile Walleye Pollock represented a small portion of the total abundance in 2009. Environmental gradients were related to fish assemblages, but patterns were along-shelf in 2008 and across-shelf in 2010. In fall, late-stage juvenile Walleye Pollock dominated the catch in 2008, but did not typify any assemblage in 2009. Overall, patterns of assemblage structure were not consistent with pre-defined ecoregions. Assemblage structure in 2009 was unique and indicates that within-stanza variability may complicate modelling projections based on ecosystem-level responses to climate changes.

Description: The Natura 2000 network forms the cornerstone of the biodiversity conservation strategy of the European Union and is the largest coordinated network of protected areas (PAs) in the world. Here, we demonstrated that the network fails to adequately cover the marine environment and meet the conservation target of 10% set by the Convention on Biological Diversity. The relative percentage of marine surface cover varies significantly among member states. Interestingly, the relative cover of protected seascape was significantly lower for member states with larger exclusive economic zones. Our analyses demonstrated that the vast majority (93%) of the Natura 2000 sites that cover marine waters include both a terrestrial and a marine component. As a result, the majority of the protected surfaces is adjacent to the coastline, and decreases offshore; only 20% of Natura marine PAs is at depths 〉200 m. The lack of systematic planning processes is further reflected by the great variability in the distances among protected sites and the limited number of shared Natura sites among member states. Moreover, 〈40% of the marine sites have management plans, indicating the absence of active, or limited management in most sites. This work highlights the gaps in coverage and spatial design of the European conservation network in the marine environment, and raises questions on the unevenly treatment of marine vs. terrestrial areas.

Description: Indices of annual growth variation are not routinely incorporated into fisheries stock assessment models, due to a lack of a general framework for deciding when to include these indices, and of a mechanistic understanding about growth drivers. Such incorporation may also not necessarily lead to improved estimation or management performance. We demonstrate a way to incorporate such an index into an assessment model (Stock Synthesis), and use risk analysis to evaluate its management-related advantages and shortcomings. We applied this method to splitnose rockfish ( Sebastes diploproa ), where a previously developed growth index is highly correlated with decadal-scale climate indices. We find that including a similar index in the simulated assessment increases precision and reduces bias of parameter estimates. However, not including an index or including a completely erroneous index led to highly imprecise estimates when growth was strongly climate-driven. Including this growth index when individual growth was actually constant did not lead to poorer estimation performance. The risk analysis approach can be applied to other stocks to evaluate the consequences of including an index of growth variation.

Description: As with many other regions in the world, more complete information on the distribution of marine habitats in the Gulf is required to inform environmental policy, and spatial management of fisheries resources will require better understanding of the relationships between habitat and fish communities. Towed cameras and sediment grabs were used to investigate benthic habitats and associated epifauna, infauna and fish communities in the central Gulf, offshore from the east coast of Qatar, in water depths of between 12 and 52 m. Six different habitats were identified: (i) soft sediment habitats of mud and (ii) sand, and structured habitats of (iii) macro-algal reef, (iv) coral reef, (v) mixed reef, and (vi) oyster bed. The epibenthic community assemblage of the mud habitat was significantly different to that of sand, which in turn differed from the structured habitats of coral reef, mixed reef and oyster bed, with the macroalgal assemblage having similarities to both sand and the other structured habitats. Fish assemblages derived from video data did not differ between habitats, although certain species were only associated with particular habitats. Epibenthic diversity indices were significantly lower in mud, sand and macro-algal habitats, with no differences recorded for fish diversity. Soft sediment grab samples indicated that mud habitats had the highest benthic diversity, with Shannon-Weiner values of 〉4, and were more diverse than sand with values of 3.3. The study demonstrates high biodiversity in benthic habitats in the central and southwestern Gulf, which may in part be due to the absence of trawling activity in Qatari waters. There is a strong influence of depth on benthic habitat type, so that depth can be used to predict habitat distribution with a high level of accuracy. The presence of outcrops of hard substrata creates a mosaic of patchy shallow structured benthic habitat across extensive areas of the offshore seabed. Such heterogeneity, and the association of commercially exploited fish species with specific habitats, indicates that this region is well suited to a spatial approach to fisheries management.

Description: Fisheries management is mainly conducted via single-stock assessment models assuming that fish stocks do not interact, except through assumed natural mortalities. Currently, the main alternative is complex ecosystem models which require extensive data, are difficult to calibrate, and have long run times. We propose a simple alternative. In three case studies each with two stocks, we improve the single-stock models, as measured by Akaike information criterion, by adding correlation in the cohort survival. To limit the number of parameters, the correlations are parameterized through the corresponding partial correlations. We consider six models where the partial correlation matrix between stocks follows a band structure ranging from independent assessments to complex correlation structures. Further, a simulation study illustrates the importance of handling correlated data sufficiently by investigating the coverage of confidence intervals for estimated fishing mortality. The results presented will allow managers to evaluate stock statuses based on a more accurate evaluation of model output uncertainty. The methods are directly implementable for stocks with an analytical assessment and do not require any new data sources.

Description: A new EU Common Fisheries Policy (CFP) came into force on 1 January 2014. Article 15 of the new CFP basic regulation introduced a discard ban or landing obligation (LO) in EU fisheries whereby the discarding of quota species is prohibited. There is an urgent need to understand the impact of this new regulation on the UK fishing industry and fishing industries elsewhere in Europe. This study conducted a discard ban trial to provide an opportunity for the fishing industry to demonstrate what a LO would mean for them. The results are mostly illustrative and qualitative, designed to inform policy decisions and identify areas of future work to assist in the implementation of the discard ban. Five recommendations are made, which if adopted, would significantly improve the prospects of a smooth transition to a largely discard-free EU fishery.

Description: Marine ecosystems have been heavily impacted by fishing pressure, which can cause major changes in the structure of communities. Fishing directly removes biomass and causes secondary effects such as changing predatory and competitive interactions and altering energy pathways, all of which affect the functional groups and size distributions of marine ecosystems. We conducted a meta-analysis of eighteen trawl surveys from around the world to identify if there have been consistent changes in size-structure and life history groups across ecosystems. Declining biomass trends for larger fish and invertebrates were present in nine systems, all in the North Atlantic, while seven ecosystems did not exhibit consistent declining trends in larger organisms. Two systems had alternative patterns. Smaller taxa, across all ecosystems, had biomass trends with time that were typically flat or slightly increasing. Changes in the ratio of pelagic taxa to demersal taxa were variable across the surveys. Pelagic species were not uniformly increasing, but did show periods of increase in certain regions. In the western Atlantic, the pelagic-to-demersal ratio increased across a number of surveys in the 1990s and declined in the mid 2000s. The trawl survey data suggest there have been considerable structural changes over time and region, but the patterns are not consistent across all ecosystems.

Description: Ecosystem-based fisheries-management (EBFM) is increasingly used in the United States (U.S.), including in the Gulf of Mexico (GOM). Producing distribution maps for marine organisms is a critical step in the implementation of EBFM. In particular, distribution maps are important inputs for many spatially-explicit ecosystem models, such as OSMOSE models, as well as for biophysical models used to predict annual recruitment anomalies due to oceanographic factors. In this study, we applied a recently proposed statistical modelling framework to produce distribution maps for: (i) younger juveniles (ages 0–1) of red snapper ( Lutjanus campechanus ), red grouper ( Epinephelus morio ), and gag ( Mycteroperca microlepis ), so as to be able to define the potential larval settlement areas of the three species in a biophysical model; and (ii) the functional groups and life stages represented in the OSMOSE model of the West Florida Shelf (“OSMOSE-WFS”). This statistical modelling framework consists of: (i) compiling a large database blending all of the encounter/non-encounter data of the GOM collected by the fisheries-independent and fisheries-dependent surveys using random sampling schemes, referred to as the “comprehensive survey database;” (ii) employing the comprehensive survey database to fit spatio-temporal binomial generalized linear mixed models (GLMMs) that integrate the confounding effects of survey and year; and (iii) using the predictions of the fitted spatio-temporal binomial GLMMs to generate distribution maps. This large endeavour allowed us to produce distribution maps for younger juveniles of red snapper, red grouper and gag and nearly all of the other functional groups and life stages represented in OSMOSE-WFS, at different seasons. Using Pearson residuals, the probabilities of encounter predicted by all spatio-temporal binomial GLMMs were demonstrated to be reasonable. Moreover, the results obtained for younger juvenile fish concur with the literature, provide additional insights into the spatial distribution patterns of these life stages, and highlight important future research avenues.

Description: In the deep sea trawl fishery targeting shrimp ( Pandalus borealis ) and other cold-water shrimp species, fishers often use a Nordmöre sorting grid ahead of a small mesh codend to avoid bycatch. However, small fish can pass through the grid and are subsequently retained in the codend. This makes shrimp size selection complex and the size-dependent curve for both the shrimp and the bycatch species often exhibits a bell-shaped signature. In this study we developed a new model and method to estimate size selection in this fishery, conducted fishing trials in the Northeast Barents Sea, and applied the new method to quantify the individual and combined size selection of the Nordmöre grid and codend for deep water shrimp and two bycatch species. The size selectivity for both bycatch species showed the expected bell-shaped signature with low retention probability of very small and larger fish. The Nordmöre grid had high passage probability for all sizes, although it decreased slightly for the largest shrimps. The smallest shrimps were released by the codend.

Description: States have acknowledged that the new internationally legally binding instrument (ILBI) for the conservation and sustainable use of marine biodiversity beyond national jurisdiction must take account of the interests of coastal states with continental shelves that extend beyond 200 nautical miles. This article argues that the ILBI should go beyond repeating the existing legal position as set out in international treaties and customary international law. In particular, the concept of sedentary species is unhelpful in the context of a legal regime governing the use of marine genetic resources. The article makes a number of suggestions for possible inclusions in the ILBI to clarify the relationship between the continental shelf regime and the regime for biodiversity beyond national jurisdiction.