Longer is not always better: the influence of beach seine net haul distance on fish catchability

Abstract

The aim of this study was to compare the influence of different haul distances of a codend beach seine on the catchability of fish in a surf zone. Two different surf zone sites (A and B) at the Cassino Beach (Rio Grande do Sul, Brazil) were sampled at three different distances, parallel to the beach (30, 60, and 90 m). Starting 40 m from the beach line, diagonal distances of approximately 50, 70, and 100 m were swept. The total CPUE and CPUA haul distances are compatible with a declining trend in catch rates with increased haul distance at both sites. However, statistically significant differences were observed only for the short distance CPUA (50 m) in relation to the other haul distances at one of the sites sampled. Two fish size groups were observed (TL 40 and > 40 mm), but only small individuals ( 40 mm) captured in the shorter haul distance at site B showed significant differences in CPUA. This result indicates that size structure for hauls at different distances was equal and that smaller individuals determined the pattern of fish abundance. The net performance indicates that a short haul ( 50 m) is the best strategy to reduce net avoidance and fish escape when using this type of sampling gear.