Broadening the horizon of size selectivity in trawl gears

Abstract

The discussion of alternative harvest patterns in commercial fisheries has been raised by stock assessment and fishery modelers, especially in the wider context of balanced harvesting. But often, these theoretical approaches propose alternative exploitation patterns that are difficult to achieve within the current limitations in the selectivity characteristics of fishing gears, such as trawl gears. The aim of the present study is to broaden the horizon for size selectivity in trawl gears by demonstrating the feasibility of alternative selectivity patterns for trawls. As a case study, we combined two well-known selection devices to obtain a bell-shaped selectivity curve in trawls with low catch ability of both small and large individuals from the target species. We have successfully tested this gear in the Baltic Sea cod fishery. The results revealed that completely different exploitation patterns for trawl gears can be achieved by means of gear technology.