Comparative stock assessment of two sciaenid species, Pseudotolithus typus (Bleeker, 1863) and Pseudotolithus senegalensis (Valenciennes, 1833) off Cameroon

Abstract

Commercially-exploited stocks of two sciaenid species, Pseudotolithus typus and Pseudotolithus senegalensis off Cameroon were compared. Length-frequency data collected in 1984 from the catch of two commercial fishing companies at Douala, Cameroon, were adjusted for relative fishing effort to reflect the natural population structure, and were subsequently analysed to estimate growth and mortality. Averages of stock parameters estimated using 3 different methods were used for yield prediction. P. typus grows larger than P. senegalensis, but since both species have similar instantaneous growth and mortality, they can be managed on the same basis. P. typus is currently exploited at a small size. Yield assessment suggests that a larger mesh size (67-mm stretched mesh) should increase the average long-term yield by over 60%. This policy seems appropriate in a country where small-sized fish have low economic value.