Fisheries and marine conservation : how to proceed in a knowledge-poor environment? On the need of interaction between ecological research and marine management

Concepts as ‘integrative’ and ‘ecosystem approach’ are often mentioned as key concepts to manage renewable marine resources sustainably. The existing amount of information on how to manage marine ecosystems in a sustainable way, however, is often perceived as insufficient. Combining the aim of putting a halt to ecosystem deterioration with an efficient and sustainable fishery seems to be a major challenge. In areas where the use of bottom gear is common, both overexploitation and the direct damage to bottom life prove to be concerns that need to be addressed urgently. This chapter presents a strategy to gather scientific information to support ecosystem management, taking into account the complexity of the system. The Belgian part of the North Sea (BPNS) was used as a model to apply this strategy. The strategy focuses on small-scale, short-term studies on a limited set of organisms in order to provide ready-to-use scientific information on a short term basis. Organisms investigated are chosen because of their horizontal and vertical links with other (groups of) organisms and because of their (direct or indirect) economic value. For the application in the BPNS, the bio-engineering polychaete Lanice conchilega (Sandmason) has been used. As it enabled specific research to quantify both the importance for commercial fish species as well as the impact of beam trawl fisheries on the benthic environment, this reef builder was proven to be a good proxy for the quality of the benthic environment The strategy of using small scale, short term studies on a limited number of species makes it possible to study a well defined area in a cost-efficient way; the information gathered in the case of L. conchilega is an example of ready-to-use information for the marine renewable resource management of the soft-bottom area of concern, taking the ecosystem approach into account