BIOLOGICAL AND DYNAMICAL STUDIES ON LETHRINUS NEBULOSUS, FORSSKAL, 1775 (FAMILY: LETHRINIDAE) IN THE GULF OF SUEZ, EGYPT

Abstract

The Gulf of Suez is the most productive fishing ground i11 the Egyptian sector of the Red Sea. - The present study was carried out to throw some light on the biological and the dynamical aspects of L. nebulosus ( Family Lethrinidae ) from the Gulf of Suez taken by the artisanal fishery. -The total catch ofLethrinids from the Gulf of Suez in comparison with the total artisanal fishery were recorded for 17 years from the fishing season1979/1980 to 1995/1996. the corresponding fishing effort were recorded for the same period. - The fishing effort were represented by the total number oflandings and the total number of boats. - The fish production from the total artisanal catch was 671.4 ton during

1979/1980 and 293.6 ton dw•ing 1994/1995. The allllual catch of Lethrinids fishes ranged from ti1e maximum 200.0 ton 1981/1982 to tile minimum 17.2 ton 199 J/1992. - Age detennination of L. nebulosus was done by means of scale readings. The

scales of L. nebulosus proved to be the most suitable hard structure for agemg. - The total-lengti1 scale-radius relationship has the following equations:

males L = 1.19241 + 5.72566 S females L = 1.48964 + 5.54212 S combined sexes L = 1.38375 + 5.61127 S -Lee's equation (1920) was used in ti1e back-calculation of ti1e body length at ti1e end of the different years of life. Males reached 13 years, while females attained 18 years oflife.