Size Selection of Channel Catfish in Slat Traps of Different Interslat Space Widths

Abstract

Slat traps are a passive gear used in freshwaters of the southeastern United States, primarily for catfishes (family Ictaluridae) in commercial fisheries. They are particularly selective for channel catfish Ictalurus punctatus. Slat traps have four interslat spaces of defined width that are designed to allow undersized individuals to escape. We conducted two experiments to assess the relationship between the width of the interslat spaces and the length of the channel catfish retained in the trap. Slat traps having interslat spaces of 1 and 2 cm retained all fish larger than 250 mm. Increasing the width of the interslat spaces from 2 cm to 3, 3.8, and 5 cm resulted in the escape of progressively larger fish from the trap. Traps having interslat spaces of more than 5 cm retained no channel catfish. Size selectivity did not differ between traps with 1-cm and 3-cm interslat spaces for channel catfish larger than 250 mm. The 3.8-cm trap selected for larger fish and showed a 50% probability of retaining an individual 392 mm in length. The mean total length of channel catfish retained in the 3.8-cm trap was also greater than that in traps with smaller interslat spaces. These results suggest that the current legal minimum interslat space width in Mississippi (3.8 cm) leads to the release of most channel catfish at or below the current statewide minimum length limit of 300 mm.