elsayed farrag
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The life history parameters, including age, growth, mortality and recruitment of Yellowfin hind, Cephalopholis hemistiktos were studied in monthly collected samples from January to December 2018. Otolith was used for age determination. Mean size by the end of each year of life was estimated and showed that, the highest annual increment was identified at the end of the first year of life then gradually decreased with increase of fish age. The estimated von Bertalanffy growth parameters were L∞=43.51 cm, K=0.26 per year, t0=-0.74 year. Asymptotic weight W∞ was estimated as 1375.23 g. The length-weight relationship was W=0.0126 L3.0746 with R2=0.94 for both sexes. The instantaneous rates of total mortality and natural mortality were estimated as 0.77 and 0.49 per year, respectively. The gonado-somatic index showed increasing from April to August with a peak in June for both sexes. Size at first capture (Lc)was estimated as 24.30 cm, which was smaller than the mean size at first sexual maturity 25.31 cm. The value of fishing mortality (F=0.28y-1) was slightly higher than the optimum (Fopt=0.25y-1) and smaller than the limit (Flimit=0.33y-1) biological reference point, indicating that species was exploited within sustainable limit. Estimated parameters and the relative yield-per-recruit analysis showed that this species is not over-exploited.
Keywords: Age, Growth, Mortality, Recruitment, Exploitation rate
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