Fishery, growth and mortality of coral grouper, Plectropomus maculates Bloch, 1790 (Teleostei: Serranidae), in the coral reefs, Red Sea, Sudan

Abstract

The fishery, growth and mortality of coral grouper (najil), Plectropomusmaculates Bloch, 1790 from deep water coral reef and the coastal fringingreef, Arakiyai, Sudanese Red Sea was described. A total of 451,861 kg frommore than 48 fish species, in addition to 24,465 kg from sharks and 2,048 kgfrom lobster were landed during 2007 in the central fish market, Port Sudan.P. maculates formed 5.2% from the total fish landing and the lowest landing(860kg) was in January and the highest landing (4195kg) was in August 2007.Samples of P. maculates were collected during 2003-2004 by cast and gillnets and hook and lines. Mean total length was ranged from 31 cm to 63.9 cmand mean weight from 827.5 to 4550.0g. Length-weight relationship wasobtained as W= 0.0251L3.003. The relative condition factor value ranged from0.944 to 1.060, with mean value of 0.999. The lengths of fish were 31, 41, 48,54, 59 and 64 cm for the ages 1-6 years respectively. The growth model wasLt= 83 [1-e-0.192 (t + 1.492)]. The growth performance index (ø) of the species wascomputed as 3.12.Total mortality rate (Z) was computed as 0.568, naturalmortality rate (M) as 0.441, fishing mortality rate (F) as 0.127 and theexploitation ratio was 0.224, indicating that the coral grouper stock inSudanese Red Sea is under exploitation.