Fisheries Biology: A New Tool Kit for Dealing with New Problems

INTRODUCTION Fisheries biology was established as a discipline ofits own near the turn of the last century, when scientistS in Northern Europe and America began to ask . • I themselves seriously why fish stocks fl~ctuate and, more specifically, why exploited stocks become depleted. Was it tlie effect offishing or, as many argued, mainly the result of environmental fluctuations? . The Intemational Council for the Exploration ofthe Sea (ICES) was founded in 1902, mainly to address this question. Because the question was broad, the initial areas of emphasis of ICES scientists were also broad, e.g., the precise estimation of salinity (hence, the "Copenhagen standard"), the study of plankton distribution and other topics now generally considered to be part of marine and/or biological oceanographybut not necessarily of fisheries biology (Went 1972). The early attempt by Baranov to demonstrate that fisheries stocks react to fishing in a predictable fashion and that this reaction could be expressed in. mathematical terms was not widely accepted, perhapsbecauseit was published. too early and in Russian (Baranov 1918). In the 1930s, the problems were reformulated by Russell (1931), who identified the "overfishing problem" through bold reductions, i.e., byneglecting the effects on exploited fish stocks of factors other than growth and mortality (fishing and natural). Russell's concept was subsequently refined by M. Graham, but with the unscheduled "closed season" of the Second World War, it awaited Beverton and Holt (1957) to formulate a quantitative description of the dynamics of exploited fish population which inspired fisheries biologists throughout the world. The Beverton and Holt model not only provided a description of the impact of fishing on stocks but also, like any good paradigm, suggested what fisheries scientists should do: they should put their emphasis on estimating fish growth and mortality, and on quantifying the relationship between the size of captured fish and the mesh sizes of the gear that caught them.