Publication Abstract

The ICES Multispecies Assessment Working Group: evolution, insights and future problems

J.G. Pope

An overview of the work of the ICES Multispecies Assessment Working Group is presented. This Working Group has been a powerful engine for developing practical multispecies assessment methods in the ICES area. Methods for multispecies virtual population analysis (MSVPA) have been developed and implemented in such a way as to utilize the available data sets. The results of these analyses have caused a profound rethinking of our picture of the North Sea, with predation mortality emerging as a major factor. Prospective models have also been developed which attempt to predict the future behaviour of the system under changing exploitation patterns. These predictions produce results which contradict single-species assessment and indicate that long-term advice has to be based upon multispecies models. Sensitivity analysis of such models indicates that recruitment is a major determinant of these predictions. This suggests that multispecies effects need to be investigated from early life history stages onwards. MSVPA techniques do not seem appropriate for these investigations and fresh modelling initiatives need to be considered. A further area needing urgent modelling investigations is concerned with the interactions between fisheries. These determine the feasible directions of change in exploitation patterns and thus indicate how and in which directions the exploitation of the system can be modified.

Reference:

J.G. Pope, 1991. The ICES Multispecies Assessment Working Group: evolution, insights and future problems. ICES Marine Science Symposium, 193: 22-33.