Sediment mobilisation by bottom trawls : a model approach applied to the Dutch North Sea beam trawl fishery

Acknowledgements A. Lokker (Cooperatie Westvoorn), H. Klein-Woolthuis (HFK engineering), A. van Wijk (van Wijk, BV), M. Drijver and a number of individual skippers are gratefully acknowledged for providing information on gear dimensions. We tank Niels T. Hintzen for providing an updated data set with swept area ratios by grid cell for conventional tickler chain and chain mat beam trawl. Funding This study was funded by the European Maritime and Fisheries Fund (EMFF) and the Netherlands Ministry of Agriculture Nature and Food Quality (LNV) (Grand/Award Number: 1300021172), the Netherlands Ministry of Agriculture Nature and Food Quality (BO-code), the Belgian EMFF project “Benthisnationaal” and by the FP7-project BENTHIS (312088). The article does not necessarily reflect the views of the European Commission and does not anticipate the Commission’s future policy in this area.Peer reviewedPublisher PD

Consumption of discards by herring gulls Larus argentatus and lesser black-backed gulls Larus fuscus off the Belgian coast in the breeding season

Fishery discards in the Belgian part of the North Sea are a source of food for Herring Gulls Larus argentatus and Lesser Black-backed Gulls L. fuscus. To understand the importance of discards for local L. argentatus and L. fuscus populations, single-item discard experiments were performed at four offshore distances from the gullery of the Port of Zeebrugge, at four different stages of the breeding season (May to August 2011). We compared flock composition during discarding with the distribution of Herring and Lesser Black-backed Gulls, with respect to offshore distance from the colony as reflected by an 11-year (2002-2013) dataset of standardised ship-based surveys. Consumption of discards depended on the type of fish that was discarded, but prey selectivity by adults was reduced during the chick rearing stage. A generalised linear mixed model identified the number of scavengers following the vessel, the proportion of adults and of Herring Gulls in the flock and the frequency of food robbery events interacting with the stage of the breeding season as affecting the variation in flatfish consumption. Shifts in scavenger flock composition and discard consumption between stages of the breeding season are likely linked to variation in food requirements of the gull population along the season and to dispersal patterns towards the end of summer. Nutrient requirements of breeding adults peak during the chick rearing stage, making this a key period in terms of dependence of the breeding parents on discarded fish as food source

Key Elements in a Framework for Land Use Impact Assessment Within LCA (11 pp)

Background, Aim and Scope: Land use by agriculture, forestry, mining, house-building or industry leads to substantial impacts, particularly on biodiversity and on soil quality as a supplier of life support functions. Unfortunately there is no widely accepted assessment method so far for land use impacts. This paper presents an attempt, within the UNEP-SETAC Life Cycle Initiative, to provide a framework for the Life Cycle Impact Assessment (LCIA) of land use. Materials and Methods: This framework builds from previous documents, particularly the SETAC book on LCIA (Lindeijer et al. 2002), developing essential issues such as the reference for occupation impacts; the impact pathways to be included in the analysis; the units of measure in the impact mechanism (land use interventions to impacts); the ways to deal with impacts in the future; and bio-geographical differentiation. Results: The paper describes the selected impact pathways, linking the land use elementary flows (occupation; transformation) and parameters (intensity) registered in the inventory (LCI) to the midpoint impact indicators and to the relevant damage categories (natural environment and natural resources). An impact occurs when the land properties are modified (transformation) and also when the current man-made properties are maintained (occupation). Discussion: The size of impact is the difference between the effect on land quality from the studied case of land use and a suitable reference land use on the same area (dynamic reference situation). The impact depends not only on the type of land use (including coverage and intensity) but is also heavily influenced by the bio-geographical conditions of the area. The time lag between the land use intervention and the impact may be large; thus land use impacts should be calculated over a reasonable time period after the actual land use finishes, at least until a new steady state in land quality is reached. Conclusions: Guidance is provided on the definition of the dynamic reference situation and on methods and time frame to assess the impacts occurring after the actual land use. Including the occupation impacts acknowledges that humans are not the sole users of land. Recommendations and Perspectives: The main damages affected by land use that should be considered by any method to assess land use impacts in LCIA are: biodiversity (existence value); biotic production potential (including soil fertility and use value of biodiversity); ecological soil quality (including life support functions of soil other than biotic production potential). Bio-geographical differentiation is required for land use impacts, because the same intervention may have different consequences depending on the sensitivity and inherent land quality of the environment where it occurs. For the moment, an indication of how such task could be done and likely bio-geographical parameters to be considered are suggested. The recommendation of indicators for the suggested impact categories is a matter of future researc

Comparison of mechanical disturbance in soft sediments due to tickler-chain SumWing trawl versus electro-fitted PulseWing trawl

This study was part-funded by the EU FP 7 project BENTHIS (grant no. 312088). It does not necessarily reflect the views of the European Commission and does not anticipate the Commission’s future policy in this area. We are grateful for the logistic support of VLIZ, the fishermen of TX43 and TX29 and crew members of RV ISIS and RV Simon Stevin during the sea trials and NIOZ for the use of their box corer. ADR and LRT were partly supported by the project “Impact assessment pulsvisserij”. We are indebted to the skippers and Eddy Buyvoets for drawing the net plans of the trawls. We thank John Aldridge for his insights in sediment transport in relation to natural dynamics; Bavo De Witte for conducting the particle size analysis; Daniel Benden for assisting SPI analyses; Miriam Levenson for English-language editing and Julie Bremner and Stefan Bolam for their critical review. We also wish to thank 3 anonymous reviewers for their constructive comments on earlier drafts of this manuscript.Peer reviewedPostprin

Ten lessons on the resilience of the EU common fisheries policy towards climate change and fuel efficiency - A call for adaptive, flexible and well-informed fisheries management

To effectively future-proof the management of the European Union fishing fleets we have explored a suite of case studies encompassing the northeast and tropical Atlantic, the Mediterranean, Baltic and Black Seas. This study shows that European Union (EU) fisheries are likely resilient to climate-driven short-term stresses, but may be negatively impacted by long-term trends in climate change. However, fisheries' long-term stock resilience can be improved (and therefore be more resilient to increasing changes in climate) by adopting robust and adaptive fisheries management, provided such measures are based on sound scientific advice which includes uncertainty. Such management requires regular updates of biological reference points. Such updates will delineate safe biological limits for exploitation, providing both high long-term yields with reduced risk of stock collapse when affected by short-term stresses, and enhanced compliance with advice to avoid higher than intended fishing mortality. However, high resilience of the exploited ecosystem does not necessarily lead to the resilience of the economy of EU fisheries from suffering shocks associated with reduced yields, neither to a reduced carbon footprint if fuel use increases from lower stock abundances. Fuel consumption is impacted by stock development, but also by changes in vessel and gear technologies, as well as fishing techniques. In this respect, energy-efficient fishing technologies already exist within the EU, though implementing them would require improving the uptake of innovations and demonstrating to stakeholders the potential for both reduced fuel costs and increased catch rates. A transition towards reducing fuel consumption and costs would need to be supported by the setup of EU regulatory instruments. Overall, to effectively manage EU fisheries within a changing climate, flexible, adaptive, well-informed and well-enforced management is needed, with incentives provided for innovations and ocean literacy to cope with the changing conditions, while also reducing the dependency of the capture fishing industry on fossil fuels. To support such management, we provide 10 lessons to characterize 'win-win' fishing strategies for the European Union, which develop leverages in which fishing effort deployed corresponds to Maximum Sustainable Yield targets and Common Fisheries Policy minimal effects objectives. In these strategies, higher catch is obtained in the long run, less fuel is spent to attain the catch, and the fisheries have a higher resistance and resilience to shock and long-term factors to face climate-induced stresses