News

Reducing discards in a temperate prawn trawl fishery: a collaborative approach to bycatch research in South Australia

We present the outcomes of a collaborative research programme tasked with reducing bycatch, and thus discards in a temperate Australian prawn trawl fishery. Sea trials in the Gulf of St Vincent, South Australia, assessed the performance of a modified trawlnet that incorporated a rigid polyethylene grid and a T90-mesh codend. Compared with conventional designs, the modified net yielded marked reductions in bycatch (cumulatively >81% by weight), with pronounced decreases in sponge (92%), elasmobranchs (80%), teleost fish (71%), molluscs (61%), and crustaceans (78%). Using commercial logbook data, we estimate that the use of modified nets could reduce discards by ∼240 tons per year. This outcome was achieved with moderate declines in the catch rate (kg h−1) of the target species, Western King Prawn (mean ∼15%), of which almost all were small adults of low commercial value. Adoption of the modified net by industry was realized in March 2012, because it met environmental objectives (i.e. reducing bycatch and improving public perceptions of sustainability), reduced prawn damage, demonstrated commensurate financial returns, and engaged stakeholders throughout the development process. Overall, the project provides a useful example of bycatch research with demonstrable outcomes of improving the ecological and economic sustainability of prawn harvests.

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Shifting gears: assessing collateral impacts of fishing methods in US waters

Problems with fisheries are usually associated with overfishing; in other words, with the deployment of “too many” fishing gears. However, overfishing is not the only problem. Collateral impacts of fishing methods on incidental take (bycatch) and on habitats are also cause for concern. Assessing collateral impacts, through integrating the knowledge of a wide range of fisheries stakeholders, is an important element of ecosystem management, especially when consensual results are obtained. This can be demonstrated using the “damage schedule approach” to elicit judgments from fishers, scientists, and managers on the severity of fishing gear impacts on marine ecosystems. The consistent ranking of fishing gears obtained from various respondents can serve as a basis for formulating fisheries policies that will minimize ecosystem impacts. Such policies include a shift to less damaging gears and establishing closed areas to limit collateral impacts.

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Entrenching environmental obligation in marine regulation

The institutional frameworks addressing issues in connection with the marine commons agreed by States are set out in the 1982 UN Convention on the Law of the Sea, which is the basis of the European Union’s common fisheries policy. Despite a substantial body of environmental legislation, provisions concerning the protection of ecosystems and bioversity have not been incorporated into any international measure or EU to control fishing, leading to ecosystem degradation. Regulation should impose the responsibility for rectifying damage to fish stocks and ecosystems as a result of fishing activity on the fishing industry.

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An alternative reference point in the context of ecosystem-based fisheries management: maximum sustainable dead biomass

Under the 2013 Reform of the European Union's Common Fisheries Policy (CFP), fisheries management aims to ensure that, within a reasonable time frame, the exploitation of marine biological resources restores and maintains populations of harvested stocks above levels that can produce the maximum sustainable yield (MSY). The CFP also calls for the implementation of an ecosystem-based approach to fisheries management (EBFM). In this paper, we present the concept of maximum sustainable dead biomass (MSDB) and its associated management reference points for fishing mortality and spawning-stock biomass as alternatives to those associated with MSY. The concept of MSDB is illustrated by a dynamic pool production model of a virtual fish stock which takes into account variations in natural mortality (M), fishing mortality (F), and exploitation pattern. Our approach implies a compensatory mechanism whereby survivors may benefit from compensatory density dependence and is implemented through progressive substitution of M with F for varying rates of total mortality (Z). We demonstrate that the reference points for fishing mortality and spawning-stock biomass associated with MSDB are less sensitive to increasing compensation of M with F than those associated with MSY and more sensitive to changes in selection pattern. MSDB-based reference points, which are consistent with maximum stock productivity, are also associated with lower fishing mortality rates and higher stock biomasses than their MSY-based counterparts. Given that selection pattern can be influenced through fishery input measures (e.g. technical gear measures, decisions on areas, and/or times of fishing), whereas variations of M in response toF are not controllable (indeed poorly understood), that the results of many fish stock assessments are imprecise, that maximum stock productivity corresponds to MSDB and that MSY-based reference points may best be considered as limits, we propose that MSDB-based reference points provide a more appropriate basis for management under an EBFM.

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Is Europe ready for a results-based a pproach to fisheries management? The voice of stakeholders

The reformed Common Fisheries Policy (CFP), adopted by the European Union in 2013, aims to achieve sustainable exploitation of marine resources. Beyond the mainstream of stakeholders׳ engagement, the literature increasingly calls for shared accountability in fisheries management. In such scenarios, identifying stakeholders׳ insights becomes critical for a successful design of innovative management approaches. This paper analyses how the stakeholders perceive a results-based management system for four fisheries in different European sea-basins as well as at a pan-European level. The results indicate a need for adaptive and participatory management approaches, building on regional adaptations within transparent and plural frameworks for fisheries. To succeed, the system should explicitly address its associated public and private costs; neither participation nor accountability comes for free.

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Designed for failure: A critique of the Common Fisheries Policy of the European Union

The Common Fisheries Policy(CFP) is the European Union’s (EU’s) instrument for the management of fisheries, aimed at enhancing the sustainability of fish stocks and the economic competitiveness of the fishing industry. However, neither the living aquatic resources, nor the profits of the fishing industry have benefited from it, with 88% of the stocks being overfished and profit margins of fishermen continuously in decline [1].

An ideal fisheries policy should foster the sustainable use of fish stocks, provide for coherent laws and regulations that yield adequate economic incentives, and guarantee consistent enforcement of the legal framework. Furthermore, the regulation scheme ought to be based on transparent rules rather than a discretionary political decision-making process, which may be blurred by short- term interests. None of these principles is met by the CFP. In this article we explore the biological, economical, legal and political shortcomings that have led to its failure. We then evaluate how these shortcomings are addressed in the recent Green Paper [1] which aims at promoting the reform of the CFP after 2013.

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Balanced harvesting in fisheries: a preliminary analysis of management implications

Balanced harvest (BH) proposes to distribute a moderate mortality from fishing across the widest possible range of species, stocks, and sizes in an ecosystem, in proportion to their natural productivity so that the relative size and species composition are maintained, in line with the CBD requirement for sustainable use. This proposal has many and not always intuitive implications for fisheries management, e.g. in relation to selectivity, protection of juveniles and spawning sites, models of harvesting strategies, a focus on size and species, the impacts of discarding, aspects of emblematic species and ecosystem services, operational complexity, partial implementation, ecosystem rebuilding, and relations with broader management frameworks. The paper closes with a discussion ofBHimplementation, concluding that a logical stepwould be to integrate several separate initiatives to move fisheries into a more ecosystem-conscious context. Implementation challenges will be encountered, but there are lessons to be drawnfrom fishery ecosystems already close to BH, as in some tropical multispecies fisheries, and further, the implementation challenges are already being taken on in many well-managed fisheries and areas as management begins to address the realities of what ecosystem-based fishery management actually entails.

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MARES Conference dissemination

The MARES Consortium and EuroMarine Network are pleased to announce that the Call for Abstracts for the Mares Conference on Marine Ecosystems Health and Conservation 2016 has been extended until the 9th October 2015.
The abstract submission deadline has been extended for the reason that authors now have the option to publish accepted abstracts in the Open Access Mares Conference 2016 Collection via the publisher PeerJ ‘Collections’.
All accepted abstracts can be published in the PeerJ PrePrints (a preprint server incurring no cost) in the Mares Conference on Marine Ecosystems Health and Conservation 2016 Collection. We also invite full length journal articles of accepted abstracts to be submitted for publication in PeerJ (the peer-reviewed journal), with the best 10 oral presentations and 10 posters being subsidised for the publication costs of the first author. PeerJ has an impact factor of 2.1 for publications, and PeerJ PrePrint publications are also traceable via ResearchGate and Google Scholar.
The second Mares Conference on Marine Ecosystems Health and Conservation will be held from the 1st to 5th February 2016 in Olhão, Portugal. Throughout the conference scientific sessions and exhibitions six thematic subjects will be explored, with the following keynote speakers presenting on each theme:

- Future oceans: temperature changes - hypoxia – acidification - Professor Jean-Pierre Gattuso

- Understanding biodiversity effects on the functioning of marine ecosystems - Professor Steve Widdicombe

- Biological invasions - Professor Anna Occhipinti Ambrogi

- Natural resources: overexploitation, fisheries and aquaculture - Dr Jake Rice

- Ocean noise pollution - René Dekeling

Habitat loss, urban development, coastal infrastructures and marine spatial planning - Dr Tundi Agardy

Further details on the conference themes, keynote speakers, programme and training workshops can be found at www.maresconference.eu or visit www.facebook.com/maresconference

 

Balanced harvesting in fisheries: economic considerations

This paper explores economic aspects of a recent proposal to shift fisheries to a “Balanced Harvesting” (BH) strategy, as a means to achieve the goal, set by the Convention on Biological iversity and related to the Ecosystem Approach to Fisheries, of “conservation of ecosystem structure and functioning” within fishery ecosystems. Studies indicate that a BH strategy—broadening the range of species and sizes caught in the aquatic ecosystem, and lowering exploitation rates for some conventionally targeted species—may provide improved ecological performance relative to conventional harvesting strategies. However, the potential economic implications have received little attention to date. This paper provides a preliminary economic assessment of BH, focusing on six main themes: (i) assessing benefits and costs, (ii) factors affecting the economics of BH, (iii) economic issues in implementing the ingredients of BH, (iv) effects of incremental and/or partial implementation of BH, (v) transition options within the harvesting sector of the fishery, and (vi) distributional impacts arising across fisheries, fleet sectors, and fishing gears, and between the present and the future.

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A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries

Due to global declines, skates and sharks have become a focus of marine conservation in recent years. Despite protective measures, they remain vulnerable to bycatch by fisheries, especially bottom-trawls and pose a problem for fisheries management measures that aim to eliminate discards in the future. In the mixed-species bottom-trawl fisheries of the North Atlantic catches can be increased by fitting a length of chain known as a “tickler” in front of the groundgear of the trawl. It was hypothesized that the tickler is especially effective at catching skates and rays that may otherwise escape beneath the net. A trial was undertaken with paired tows with and without the tickler chain. The trial demonstrated that the catch rate of skates and sharks can be significantly lowered by removing the tickler. A set of secondary nets (groundgear bags) attached behind the groundgear of the main net allowed the number of fish escaping under the net to be estimated and showed that the reduction of skates and sharks in the main net was accompanied by an increase in number in the groundgear bags. This suggests that prohibition of the use of tickler chains in areas that are known to be especially important to skates and sharks could have conservation benefits. The removal of the tickler chain had little effect on catch rates of haddock, whiting, and flatfish, but caused a marked decrease in the catch rate of commercially valuable anglerfish.

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