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The nature and impact of fishing on predators that share a fished resource is an important consideration in ecosystem-based fisheries management. Krill (Euphausia superba) is a keystone species in the Antarctic, serving as a fundamental forage source for predators and simultaneously being subject to fishing. We developed a spatial multispecies operating model (SMOM) of krill-predator fishery dynamics to help advise on allocation of the total krill catch among 15 small-scale management units (SSMUs) in the Scotia Sea, with a goal to reduce the potential impact of fishing on krill predators. The operating model describes the underlying population dynamics and is used in simulations to compare different management options for adjusting fishing activities (e.g., a different spatial distribution of catches). The numerous uncertainties regarding the choice of parameter values pose a major impediment to constructing reliable ecosystem models. The pragmatic solution proposed here involves the use of operating models that are composed of alternative combinations of parameters that essentially try to bound the uncertainty in, for example, the choice of survival rate estimates as well as the functional relationships between predators and prey. Despite the large uncertainties, it is possible to discriminate the ecosystem impacts of different spatial fishing allocations. The spatial structure of the model is fundamental to addressing concerns of localized depletion of prey in the vicinity of land-based predator breeding colonies. Results of the model have been considered in recent management deliberations for spatial allocations of krill catches in the Scotia Sea and their associated impacts on dependent predator species.

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Perspectives on the South African experience with Marine Stewardship Council (MSC) certification, specifically that of the valuable hake trawl fishery which is as yet the only MSC certified fishery in Africa, are summarised based on discussions with local scientists and fishing industry members. On the positive side, the greatest benefit has been the resultant enhanced attention given to science. However, the fact that some MSC requirements relate to government rather than industry responsibilities raises the issue of the extent to which government omissions should result in penalties to industry. At a broader level, the question of whether raising or lowering of MSC standards would be in the best interests of promoting and achieving fisheries sustainability globally is discussed. [ABSTRACT FROM AUTHOR]

Management strategy evaluation ( MSE) involves using simulation to compare the relative effectiveness for achieving management objectives of different combinations of data collection schemes, methods of analysis and subsequent processes leading to management actions. MSE can be used to identify a 'best' management strategy among a set of candidate strategies, or to determine how well an existing strategy performs. The ability of MSE to facilitate fisheries management achieving its aims depends on how well uncertainty is represented, and how effectively the results of simulations are summarized and presented to the decision-makers. Key challenges for effective use of MSE therefore include characterizing objectives and uncertainty, assigning plausibility ranks to the trials considered, and working with decision-makers to interpret and implement the results of the MSE. This paper explores how MSEs are conducted and characterizes current 'best practice' guidelines, while also indicating whether and how these best practices were applied to two case-studies: the Bering- Chukchi- Beaufort Seas bowhead whales ( Balaena mysticetus; Balaenidae) and the northern subpopulation of Pacific sardine ( Sardinops sagax caerulea; Clupeidae). [ABSTRACT FROM AUTHOR]

Abstract: The authors’ experiences in relation to the estimation of selectivity and its impact on the formulation of management advice are summarised for 14 different resources. These include instances where advice (generally in the form of a catch limit) is based on an assessment, as well as cases where a Management Procedure is developed (applying MSE) for this purpose. Relative paucity of older fish in either or both of catches or surveys is a frequent occurrence which has a number of alternative explanations, including doming in selectivity, and estimates of many biological reference points are not robust to this uncertainty. However, when the impacts of uncertainties in estimating selectivities are considered relative to those of the other uncertainties which also influence the calculation of catch limits, the former usually (although not always) seem to be of somewhat lesser importance. [Copyright &y& Elsevier]

Rademeyer, R. A., Plagányi, É. E., and Butterworth, D. S. 2007. Tips and tricks in designing management procedures. – ICES Journal of Marine Science, 64: 618–625. Management procedures (MPs) are becoming widely used in fisheries management, but guidelines to assist in their construction, evaluation, and implementation are few. We provide simple guidelines by drawing on experience from developing and applying MPs in southern Africa and internationally. Suggestions are provided on how to choose between candidate MPs and on key trade-offs in selecting between data-based (empirical) and model-based formulations. Assistance is also provided in dealing with different sources of uncertainty, such as deciding which operating models should be included in a reference set used for primary simulation testing and tuning (in contrast to robustness or sensitivity tests), and on how weights for the associated alternative hypotheses are most practically assigned. Finally, some guidelines are given for presenting the results effectively, which is one of the key challenges of a successful implementation process. [ABSTRACT FROM PUBLISHER]