Selectivity of Gill Nets Used in the Commercial Spanish Mackerel Fishery of Florida

Abstract

Selection curves of encircling (run-around) and drifting (stab) gill nets used in the winter fishery for Spanish mackerel Scomberomorus maculatus off southern Florida were estimated by use of cumulative probability distributions of retention girth at length. Selection curves corresponded well with observed size frequencies obtained from each mesh size, Increasing differences between maximum and head girth perimeters as fish grew resulted in selection curves indicating increased selection range and efficiency. Selectivity of Spanish mackerel gill nets will change as the condition of the fish changes with the onset of the spawning season. Apparently, selectivity also changes with twine size.