The age and growth of two grouper fish species, Epinephelus summana (Forsskål, 1775) and Cephalopholis argus (Schneider, 1801) from Egyptian Red Sea off Hurghada, were studied based on the otolith readings. The maximum longevity of the two species was 10 and 6 years for E. summana and C. argus respectively. The age group II was the most dominant age group in the catch forming 46.09 % for E. summana and 22.33% for C. argus from the total collected samples. The asymptotic standard length (L∞) and the growth coefficient (K) were estimated as 63.39 cm and 0.13 year -1 for E. summana and 44.22 cm; and 0.26 year -1 and C. argus, respectively. The total mortality was computed as 0.82 and 1.31 year -1 for E. summana and C. argus, respectively. The mean values of natural mortality were 0.33 and 0.56 year -1 for E. summana and C. argus, respectively. Accordingly, the fishing mortality rates were estimated as 0.49 and 0.75 year -1 for E. summana and C. argus, respectively. The exploitation rates of E. summana (0.6) and C. argus (0.57) along with the fishing mortality rates reflect the overexploitation situation of the two serranid species in the Egyptian Red Sea.
Egyptian Red Sea Otolith morphology analysis is one of the main tools used for fish or stock identification. Moreover, it is used in the stomach content studies for the identification of prey fish and their size according to the relationship between fish and otolith sizes. In the present study, the relationships between fish length and otolith morphological dimensions were investigated for Epinephelus summana (Forsskål, 1775) and Cephalopholis argus (Schneider, 1801) (family: Serranidae). A total of 170 E. summana and 154 E. argus (i.e 340 and 308 sagittal otoliths for E. summana and E. argus respectively) were sampled from the coast of the Egyptian Red Sea off Shalateen fishing ground. The statistical analysis was done by generalized linear models for the relationship between body length and weight and otolith morphology descriptors (length, width, area and perimeter) and shape indices (Aspect ratio, Compactness, rectangularity, Sulcus and Ostium). The results revealed that there is significantly correlation between the TL of fish and the eleven morphology descriptors and shape indices, where the side effect was p<0.05. Also, this study added new information for the region because of lack of data for the relationships between otolith morphometric and fish length.
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