Poos, J. J., Bogaards, J. A., Quirijns, F. J., Gillis, D. M., and Rijnsdorp, A. D. 2010. Individual quotas, fishing effort allocation, and over-quota discarding in mixed fisheries. – ICES Journal of Marine Science, 67: 323–333. Many fisheries are managed by total allowable catches (TACs) and a substantial part by individual quotas. Such output management has not been successful in mixed fisheries when fishers continue to fish while discarding marketable fish. We analyse the effects of individual quotas on spatial and temporal effort allocation and over-quota discarding in a multispecies fishery. Using a spatially explicit dynamic-state variable model, the optimal fishing strategy of fishers constrained by annual individual quotas, facing uncertainty in catch rates, is studied. Individual fishers will move away from areas with high catches of the restricted quota species and, depending on the cost of fishing, will stop fishing in certain periods of the year. Individual vessels will discard marketable fish, but only after their individual quota for the species under consideration has been reached. These results are in line with observations on effort allocation and discarding of marketable fish, both over-quota discarding and highgrading, by the Dutch beam-trawl fleet. The models we present can be used to predict the outcomes of management and are therefore a useful tool for fisheries scientists and managers.

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The increasingly complex nature of marine resource management calls for stronger stakeholder participation in advancing knowledge and developing management approaches. Studies on stakeholder involvement in marine resource management have primarily focussed on participation in resource use negotiation and not on participation in science. Using fishers' knowledge research frameworks, we evaluate over 15 years of science‐industry research collaboration (SIRC) in Dutch demersal fisheries. Four key lessons emerge: (a) Capacity building in SIRC works multiple ways and triggers shifts in the fishers' knowledge research spectrum; (b) Successful SIRC depends on acceptance of industry collected data for scientific advice, which necessitates close involvement of end‐users from the outset to provide feedback and obtain support; (c) (Fisher) participation raises often‐overlooked equity questions and may result in selection bias; and (d) The governance context strongly influences structure of SIRC and integration of SIRC knowledge. To ensure a sustainable, continuous process of stakeholder participation and use of their knowledge in marine resources research, collaborative research should be embedded in the institutional frameworks for science and management. It demands continuous maintenance of the relationship between scientists and stakeholders in the context of management developments, calls for reflection about selection and equity considerations, and requires continuous attention for communication with all parties involved at different levels. The lessons learnt in science‐industry research collaboration in fisheries are also relevant for the wider field of marine science, where stakeholder participation is necessary but not yet common.

Piet, G. J., Quirijns, F. J., Robinson, L., and Greenstreet, S. P. R. 2007. Potential pressure indicators for fishing, and their data requirements. – ICES Journal of Marine Science, 64: 110–121. Indicators of fishing pressure are necessary to support an ecosystem approach to fisheries management (EAFM). We present a framework that distinguishes four levels of pressure indicators that move from being a simple description of anthropogenic activity to more precisely describing the actual pressure on the ecosystem and its components, but which require increasingly more information to be quantified. We use the example of the Dutch beam trawl fleet in the North Sea to compare these pressure indicators, as the level of information used is increased. The first level is that of fleet capacity (e.g. number of vessels), the second is fishing effort, usually expressed as the number of hours fishing or days at sea, the third incorporates fishing parameters such as the proportion of time actually spent fishing, fishing speed, or gear characteristics, e.g. the size of the beam trawl in order to determine the frequency with which an area is fished, and at the fourth level, the most informative measure of fishing pressure, annual fishing mortality, is available for a few commercial species from stock assessments. For other species, it can be calculated from the lower level pressure indicators through the incorporation of the chance of individuals of a species coming into contact with the fishing gear and the encounter mortality, which is the portion of mortality caused by the passing of the gear. Comparison of trends and absolute values shows that the pressure indicators at different levels differ considerably in their description of both present and historical fishing impact in the North Sea. Therefore, for an EAFM, we advise using the highest level pressure indicator that can be obtained with the data available.

The scope of this paper is to quantify, for a wide selection of European fisheries, fishing tactics and strategies and to evaluate the benefits of adjusting the definition of fishing effort using these elements. Fishing tactics and strategies were identified by métiers choices and a series of indices. These indices have been derived to reflect shifts in tactics (within a fishing trip) and in strategies (within a year). The Shannon-Wiener spatial diversity indices of fishing tactics (FT_SW) and strategies (YE_SW) had the greatest impact on catch rates. In particular, FT_SW was always negatively correlated to catch rates. One may anticipate that during a fishing trip, vessels with high FT_SW have been searching fish aggregations for a long time, while vessels with low FT_SW have been more efficient in finding these aggregations. The linkage between YE_SW and catch rates was of a more complex nature. Adjusting fishing effort by means of (i) the métier effect and (ii) the indices of tactics and strategies generally led to a substantial gain in the precision of the relationship between fishing mortality and fishing effort. Résumé : L'objectif de cette étude est de quantifier, pour une large sélection de pêcheries européennes, les tactiques et stratégies de pêche, et d'évaluer dans quelle mesure ces éléments peuvent être utilisés pour mieux ajuster l'effort de pêche. Les tactiques et stratégies de pêche ont été identifiées par les choix de métiers et une série d'indices. Ces indices ont été calculés pour quantifier les changements de tactique (au cours d'une marée) et de stratégie (au cours d'une année). Les indices de Shannon-Wiener décrivant la distribution spatiale de l'effort de pêche au cours d'une marée (FT_SW) et d'une année (YE_SW) ont eu l'effet le plus important sur les taux de capture. En particulier, FT_SW était négativement corrélé aux taux de capture pour tous les cas d'étude. Ce résultat était prévisible. Au cours d'une marée, les bateaux caractérisés par un FT_SW élevé ont vraisemblablement cherché les agrégations de poisson pendant une longue période, tandis que les bateaux caractérisés par un faible FT_SW auront été plus efficaces pour localiser ces agrégations. Le lien entre YE_SW et les taux de capture était d'une nature plus complexe. L'ajustement de l'effort au moyen, (i) de l'effet métier et, (ii) des indices de tactique et de stratégie, conduit généralement à un gain substantiel de précision de la relation entre effort de pêche et mortalité par la pêche. Marchal et al. 533