Incidental mortality (bycatch) of seabirds in pelagic longline fisheries remains a major threat to many populations. The design and implementation of technical innovations aimed at reducing seabird bycatch rates have long been a focus of research. However, it has historically been difficult to extrapolate the efficacy of a particular mitigation measure to the scale of seabird populations or oceanic basins. Here, we develop an ecological risk assessment for five populations of threatened albatross and petrel species that forage in the south Atlantic Ocean. Since seabird bycatch rates are likely under-reported to fisheries regulatory bodies, we adopted a risk-based approach to predict differences in bycatch rates between different combinations and specifications of mitigation measures, comparing those currently specified by the International Commission for the Conservation of Atlantic Tunas (ICCAT) against best practice guidelines recommended by the Seabird Bycatch Working Group of the Agreement on the Conservation of Albatrosses and Petrels (ACAP). We conclude that updating existing mitigation measure specifications for pelagic longlining in the South Atlantic to reflect current best practice guidelines would potentially reduce seabird mortality by 41-86 %, compared to use of any two of the three options by vessels. Simultaneous application of all three mitigation measures recommended as current ACAP best practice was predicted to reduce seabird mortality by 72-93 % and therefore should be considered by ICCAT as the most appropriate management measure for seabirds until further data are available to undertake more rigorous analyses.

Climate change is already affecting the distributions of marine fish, and future change is expected to have a particularly large impact on small islands that are reliant on the sea for much of their income. This study aims to develop an understanding of how climate change may affect the distribution of commercially important tuna in the waters around the United Kingdom’s Overseas Territories in the South Atlantic. The future suitable habitat of southern bluefin, albacore, bigeye, yellowfin and skipjack tunas were modelled under two future climate change scenarios. Of all the tunas, the waters of Tristan da Cunha are the most suitable for southern bluefin, and overall, the environmental conditions will remain so in the future. Tristan da Cunha is not projected to become more suitable for any of the other tuna species in the future. For the other tuna species, Ascension Island and Saint Helena will become more suitable in the future, particularly so for skipjack tuna around Ascension Island, as the temperature and salinity conditions change in these areas. Large marine protected areas have been designated around the territories, with those in Ascension and Tristan da Cunha closed to tuna fishing. Although these areas are small relative to the whole Atlantic, these model projections could be useful in understanding whether this protection will benefit tuna populations into the future, particularly where there is high site fidelity.

Demands for management advice on mixed and multispecies fisheries pose many challenges, further complicated by corresponding requests for advice on the environmental impacts of alternate management options. Here, we develop, and apply to North Sea fisheries, a method for collectively assessing the effects of, and interplay between, technical interactions, multispecies interactions, and the environmental effects of fishing. Ecological interactions involving 21 species are characterized with an ensemble of 188 plausible parameterizations of size-based multispecies models, and four fleets (beam trawl, otter trawl, industrial, and pelagic) characterized with catch composition data. We use the method to evaluate biomass and economic yields, alongside the risk of stock depletion and changes in the value of community indicators, for 10 000 alternate fishing scenarios (combinations of rates of fishing mortality F and fleet configuration) and present the risk vs. reward trade-offs. Technical and multispecies interactions linked to the beam and otter trawl fleets were predicted to have the strongest effects on fisheries yield and value, risk of stock collapse and fish community indicators. Increasing beam trawl effort led to greater increases in beam trawl yield when otter trawl effort was low. If otter trawl effort was high, increases in beam trawl effort led to reduced overall yield. Given the high value of demersal species, permutations of fleet effort leading to high total yield (generated primarily by pelagic species) were not the same as permutations leading to high catch values. A transition from F for 1990 to 2010 to F-MSY, but without changes in fleet configuration, reduced risk of stock collapse without affecting long-term weight or value of yield. Our approach directly addresses the need for assessment methods that treat mixed and multispecies issues collectively, address uncertainty, and take account of trade-offs between weight and value of yield, state of stocks and state of the environment.

The report describes a framework that can be used to identify the most important trade-offs in ecosystem based fisheries management. The framework contains a description of how to identify the bord ...

Report of the Benchmark Workshop on Baltic Multispecies Assessments (WKBALT) : 4–8 February 2013, Copenhagen, Denmark

The inconsistency of single-species objectives in a mixed-fisheries context has repeatedly been highlighted as a key issue in the current European Common Fishery Policy, and it has long been suggested that this issue would be better addressed through fleet (group of vessels) and m tier (type of activity) - based approaches. Since the late 1980s. when such approaches were first introduced, there have been substantial developments in this area of science, to the point where the concepts of fleet and m tier now underpin the whole EC Data Collection Framework. However, their implementation in the management system has been slow and difficult, being hampered by a number of intrinsic issues. Mixed fisheries are an ongoing "governance headache" combining management complexity, scientific uncertainty and political sensitivity.This paper summarises the current state of play for fleet-based approaches in EU fisheries management, and highlights our views on both their potential and the challenges they face in the context of the future CFP. As a convenient layer between the current single-stock level and the level of the individual vessel, fleet/metier- approaches could potentially address a wide range of issues, especially with regards to the policy emphasis on ecosystem-based fisheries management. However, the rigid categorisation they induce may not properly address the flexibility of individual vessels, and should therefore be supplemented by more detailed considerations at the local scale. (C) 2012 Elsevier Ltd. All rights reserved.

Single-species management is a cause of discarding in mixed fisheries, because individual management objectives may not be consistent with each other and the species are caught simultaneously in relatively unselective fishing operations. As such, the total allowable catch (TAC) of one species may be exhausted before the TAC of another, leading to catches of valuable fish that cannot be landed legally. This important issue is, however, usually not quantified and not accounted for in traditional management advice. A simple approach using traditional catch and effort information was developed, estimating catch potentials for distinct fleets (groups of vessels) and metiers (type of activity), and hence quantifying the risks of over- and underquota utilization for the various stocks. This method, named Fcube (Fleet and Fisheries Forecast), was applied successfully to international demersal fisheries in the North Sea and shaped into the advice framework. The substantial overquota catches of North Sea cod likely under the current fisheries regimes are quantified, and it is estimated that the single-species management targets for North Sea cod cannot be achieved unless substantial reductions in TACs of all other stocks and corresponding effort reductions are applied.

This chapter contains sections titled: Introduction Mixed Fisheries and COD Recovery The Science of Fisheries Current and Future Developments References

The scientific basis of fisheries management advice has traditionally focused on the individual fish stock as the unit to be managed. However, the management advice applies to the vessels fishing those stocks, rather than to the stocks themselves. Where previously annual total allowable catches (TACs) were the primary management measure for stocks in European waters, other measures, particularly restrictions on fishing effort, are now becoming similarly important. The advisory system has not kept pace with these changes; the existing stock assessments provide a means of giving advice on annual TACs, but not yet on fishing effort. Here, we describe the recent history of the North Sea cod (Gadus morhua) stock and how this has sparked interest in the development of approaches for using information on the activity of fishers in management advice, and review the existing research that could inform the development of such approaches. Finally, we discuss the possible development and application of such approaches against the background of the changing context for fisheries management advice.

Since 1974, annual assessments have constituted the core of the scientific advice underpinning management of the North Sea cod stock. Here, we base our evaluation of the assessments' performance on the quality of the advice and on the wider issue of how science is used to produce management advice. At the same time, we consider catch-at-age analyses and catch forecasts in the context of the amount of person-time and expertise available at the relevant working group meetings. The results indicate that, generally, the catch forecasts have been positively biased and that the bias has been driven by three main factors: (i) substantial overestimates of terminal stock size since the late 1990s, (ii) overestimates of incoming recruitment, and (iii) overestimates of growth. information for other North Sea stocks (haddock, plaice, and sole) suggests that bias is a problem generally, not one unique to cod. Our results include a discussion of ways to use science more effectively in supplying management advice.

Current ICES advice for fish stocks is based on single species stock assessments. As such they involve giving advice on individual species, across a large area, based on very detailed data. In contrast the requirements of the ecosystem approach involve advice on a much wider range of species and a much finer spatial scale, for which there is typically much more limited data. Assessment and management of mixed- species, multi-fleet fisheries represents an intermediate situation between single species fisheries management and the application of a full ecosystem approach, in terms of their complexity, data needs and spatial scale. As a result, recent developments in approaches to give advice on a fishery basis, rather than a stock basis, offer a way to bridge the gap between existing single species approaches and the needs of the ecosystem approach. Here we describe these approaches and discuss their possible extensions and applications to the ecosystem approach to fisheries management.

The EU project Policy and Knowledge in Fisheries Management investigated the use of biological knowledge in various parts of the fisheries system, using North Sea cod as a case study. The project examined the way scientific advice was generated from technical and institutional perspectives, as well as the way claims about science appeared in both policy-setting and in public debate through the press. The results suggested that many people involved in the system want a new way to reflect about science in management. People from all major stakeholder groups are calling for a more interactive system of producing a common knowledge base. Such a system could bring uncertainty from its current marginal role as the leftovers of certainty to the heart of the science process. It would require stakeholders to help address uncertainty and to negotiate a more realistic placement of burden of proof.