Some Consideration on Overexploitation of Coral Reef Fish in Relation to Coral Reef Degradation in El-Tour, South Sinai, Egyptian Red Sea Coast

摘要

This study was carried out to throw light on the expected negative effect of fish overexploitation on the Red Sea coral reef healthy. Lethrinus nebulosus is represented the most important coral reef fishes commercially and economically. Age, growth, mortality of L. nebulosus was estimated using the fish otoliths reading as well as the feeding behavior was analyzed. Estimated life span was ten years. Estimated growth parameters were, asymptotic length (L∞) = 81.6 and growth co-efficient (K) = 0.161 year-1. Total, natural and fishing mortality rates were Z = 0.722, M = 0.237 and F = 0.485, respectively. Exploitation ratio was estimated as E = 0.67. Analysis of stomach contents revealed that L. nebulosus is a heavily carnivores fish, feed on Crustaceans, Fish, Echinoderms and Mollusks. Small fish =35.0 cm while the lengths >=55.0 cm, Echinoderms dominate as the fish gets larger. Results raveled that large individuals of L. nebulosus feeding mainly on Echinoderms are exposed to a heavily overexploitation. The decline of large individuals lead to the over spreading of acanthasters which has a feeding ability to attack coral polyps affecting coral reefs healthy. Results expected that the depletion of functionally important consumers by over-exploitation can indirectly influence coral reef ecosystem.