The vulnerability of fish to capture by commercial beach-seine nets in False Bay, South Africa

Abstract

An experimental net was set behind a commercial beach-seine net to estimate the number of fish that escape from the latter. Escapement was high, 95% of the combined catch being caught in the cover net. Escapees were numerically dominated by the baitfish species Engraulis capensis (52%) and Atherina breviceps (36%). A relatively low proportion of angling species was lost from the commercial net. These species, namely Lithognathus lithognathus, Rhabdosargus globiceps, Pomatomus saltatrix and Diplodus sargus capensis, become vulnerable to capture by commercial beach-seines well before they reach two years of age and long before maturity. It is argued that the substantial increase in mesh size needed to reduce the by-catch of these juvenile angling species would drastically lower the total catch of Liza richardsonii, the principal target species of the commercial beach-seine fishery.