( Selective curve of gill-nets utilized in catching acará, Geophagus brasiliensis Quoy & Gaimard, 1824 ( Osteichthyes, Cichlidae ) and his reproduction period in Ponte Nova Reser- voir, Tietê River, São Paulo State, Brazil )

Abstract

The selectivity curve of gill-nets utilized in the catching of the fresh water fish "acara" Geophagus brasiliensis, was determined according to Gulland (1969). The observed results are:

c*(L)= e^{-0.3104(L í  1.3283 m)2}

Where:

c*(L)= relative frequency of retention

L = total length of the fish

m = perimeter of the mesh.

The relationships between total lengths (and body weights) and the internal perimeter of meshes the annual reproductive period (Spring) were also determined.