Codend mesh size of beach seine nets influences fish species and size composition in Lamu, north coast, Kenya

Abstract

Beach seine nets are commonly used in reef lagoons in Kenya, with potentially destructive impacts on reefs and other habitats. The species composition and size frequency of catches made by nets with codend mesh sizes of 25 mm, 38 mm and 44 mm were evaluated for samples collected during three sampling trips in the Lamu area between 2014 and 2016. A total of 98 fish species belonging to 41 families were recorded. Most species with highest diversity (D = 10.67) were caught by the 25 mm codend mesh, followed by the 38 mm (D = 6.69) and 44 mm meshes (D = 3.04), respectively. Size frequencies of dominant species Leptoscarus vaigiensis, Siganus sutor and Lethrinus lentjan depended on the codend mesh size sampled, with the 25 mm mesh retaining more immature individuals than the other two meshes. It is concluded that codend mesh size influences catch properties of beach seine nets used in Lamu, and that introducing a minimum mesh size would reduce the proportions of juvenile fishes landed.