ICES CM 2002/M:8 Challenges and problems in modelling seamount ecosystems and their fisheries

The ecological and oceanographic importance of seamounts for the status of marine food webs and biodiversity has recently been recognized. Seamounts have been intensively exploited in all world oceans, and serious stock depletion has been detected in every case. Resident seamount fish are mostly slow-growing and late-reproducing while transient migratory fish also rely on seamount food webs, so that the impact of overfishing raises serious concerns. Moreover, trawling threatens the integrity of benthic habitats. The prevention of further negative impacts on these sensitive ecosystems is now an important policy objective. Because of the extensive trophic links on seamounts, ecosystem-based modelling approaches are essential to understand the ecosystem functioning and to ensure an effective management. However, there have been few attempts to model seamount communities. This talk will discuss the problems associated with modelling seamount ecosystems using the Ecopath-with-Ecosim framework. We propose modelling approaches to seamount processes such as the influences of peculiar current patterns on the seamount system and complex food web structure depending on advective food supplies. The hypothesis that the aggregating fish stocks on seamounts are supported from external sources was supported by the Ecopath models