a1 LEI (Agricultural Economics Research Institute), Fisheries Unit, PO Box 29703, 2502 LS The Hague, The Netherlands
a2 Wageningen IMARES, Wageningen UR, PO Box 68, 1970 AB IJmuiden, The Netherlands
Catchability is crucial for the economic performance of fisheries and their management. However, in many bio-economic simulation models it is assumed to be either constant or it is largely ignored, despite the fact that it is known to vary due to technical, environmental and behavioral factors. Such variation can cause the relationship between effort and fishing mortality to be nonlinear. This paper provides evidence for the possibility of nonlinear optimizing behavior from the Dutch beam trawl fishery, provides a methodology for estimating the curvature of the resulting relation, and a simple way of implementing these processes within a bio-economic model. Moreover, it shows the influence of a nonlinear relationship between effort and fishing mortality in a model of effort management (EU long-term flatfish management plan).
(Received September 13 2007)
(Accepted March 13 2008)
(Online publication July 26 2008)