Fishery, growth and mortality of the threadfin bream, Nemipterus japonicus (Bloch, 1791) (Pisces: Nemipteridae) from the southern Sudanese waters, Red Sea

Abstract

The fishery, growth and mortality of the threadfin bream, Nemipterusjaponicus (Nemipteridae) from the southern region of the Sudanese Red Seawas assessed. Fishes were collected from the Tawkar fishing region, southSawakin, by trawl net during 2003-2004. The total fish caught during theexperiment period was 33,000 kg, of this 3,586 kg where threadfin bream.The species constituted 10.8% of the total catch. The average total catch perunit of effort was 83.3 kg/hr and for the threadfin bream was 9.0 kg/hr.Length-weight relationship was calculated and yields the followingequation: W=0.021 L 2.85 for fish ranged from 12-19 cm. The relativecondition factor of the species ranged from 0.90 to 1.04 (mean ± S.D 0.976± 0.0468). The population parameters estimated for the threadfin breamwere L∞= 22.8cm, K= 0.36 and to= 1.374. The growth performance index(ø) of the species was computed as 2.27.Total mortality rate (Z) wascomputed as 0.939, natural mortality rate (M) as 0.763, fishing mortality rate(F) as 0.176 and the exploitation ratio was 0.187, indicating that thethreadfin bream stock in Sudanese Red Sea is under exploitation.