Some biological and fisheries studies on the Lessepsian migrant shrimp scad Alepes djedaba from the Eastern Mediterranean coast of Egypt

The Lessepsian migrant shrimp scad Alepes djedaba is an important component of the purse seine fishery in the Egyptian Mediterranean Sea. This study aimed to investigate the state of the fishery of A. djedaba. A total of 1391 specimens were collected from two landing sites in the Eastern Mediterranean (Damietta and Port Said) from January to December 2019. The estimated length-weight relationship (W= 0.003 L 3.419 ) showed positive allometric growth. Aging by otolith readings was corroborated by length-frequency analysis and the results revealed three age groups with the second age group is dominant in the catch. The von Bertlanffy growth parameters estimated at L ∞ = 29.21 cm, K= 0.301, W ∞ = 307.4 g and t o = 1.2. The growth performance index was ɸ=2.41. The yield and biomass per recruit analysis showed that the current rate of fishing mortality (F curr = 0.872) was higher than the estimated biological reference points (F max , F 0.1 and F 0.5 ). The percentage of the current biomass per recruit to the unexploited level was 20.76% which implied recruitment overfishing. The management measures should include reduction of fishing effort and controlling fishing gear.