A Study On Biology And Ecology Of Epinephelus Polyphekadion Along Sudanese Red Sea Coast

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Shaaban, Abasher Bashir Eisa
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The present study was conducted during the period of September 2003 to August 2004 to investigate some aspects of biology and ecology of Epinephelus polyphekadion fish from Sudanese Red Sea. Water samples were obtained from the study area during January, May, July and October of the sampling period and analysed to provide insight to water characteristics. Analysis of water characteristics of the samples obtained from the study area (Hiadoub) showed that the nutrients concentrations were relatively higher during the rainy season compared with the rest of year. The temperature, evaporation rate, winds speed and direction, dissolved oxygen and salinity showed seasonal variation Random samples comprising 207 specimens of E. polyphekadion ranging in total length from 26 to 60 cm and from 275 to 4000 g in weight were collected from the artisanal landings and the study area. The growth rate of E. polyphekadion is maximum at the first two year of life; the annual length increment percentage during the first two years of life is 53.9%, 52.7%, for males and females respectively. Operculum readings of E. polyphekadion showed formation of both annual and spawning rings. The annual rings laid down during February to June while spawning rings were deposited during the rest of the year. The studied sample ranged between 2 to 7 years for both sexes. Results of investigations of the food habits indicated that E. polyphekadion feeds mainly on Decapods crustacean (crabs) and small fishes (sardine), while cephalopods were considered less important food items. The sex-ratio of E. polyphekadion in the samples was 1:1.4 males to females. The spawning season extends from June to July. Obviously the species spawns once a year. The onset of sexual maturity was reported to occur in the fourth year for males at an average total length of 36.5cm and in the third year for females at an average total length of 34.1cm. The females attained sexual maturity earlier than males. The absolute fecundity of E. polyphekadion females ranged between 86000 to 748000 eggs. The study recommends prohibition of E. polyphekadion landing during the breeding season (June- July), assessment of biology and ecology of important fish (for fishery regulation
Study,Biology,Ecology,Epinephelus,Polyphekadion,Sudanese,Red Sea,Coast