Fish fecundity and maximum catch length: an additional tool for fishing management

Abstract

The relationships between fecundity (F) and body size, and between the relative fecundity to the gonad weight (Frg) and F, are described for 17 teleost species of the families Clupeidae, Ariidae, Mugilidae, Stromateidae, Centropomidae, Carangidae, Sciaenidae and Paralichthyidae. Adult females were obtained from artisanal fisheries in Parana coast, Southern Brazil. From each specimen data on total length and ovary weight were taken, and on stereoscopic microscopic vitellogenic oocytes were counted. Results have showed that F increases with the individual size in 15 from 17 species. Differences between F maximum and F minimum have varied from 56.9% to 98.2% of F maximum, depending on species, being represented by F(máx-mí­­n) = 8405 + 0.7587 Fmáx (n = 17; r = 0.96). Frg was commonly proportional to F: Frg = 1.15 F^0.7603 (r = 0.74; n = 228). Species with larger F values have usually presented oocytes smaller than those with small F values. Strategic sizes for conservation are recommended for the 17 species studied, corresponding to the total lengths in which the F maximum was found. Efficacy of using the maximum size in management rules requires studies on gillnets selectivity, addressed to professional fishing, and educative actions, to recreational one.