Catch and effort of night purse seine with emphasize to Age and Growth of lessepsian Etrumeus teres (Dekay, 1842), Mediterranean Sea, Egypt

Catch and effort (CPUE) of the purse-seine using light, age and growth of lessepsian fish “Etrumeus teres” from the Egyptian Mediterranean waters were studied in the period 2008. It was found that, the average annual catch (CPUE) was 1.7 (ton/boat/night). The catch diversity was composed of seventeen different species. Clupeids were the dominant 74.1% of the total catch. Seven lessepsian species were involved and constituted 41.18% and 19.01% of the total number and weight of the catch, respectively. Round herring E. teres was the highest one of these immigrants, accounting for 10.93% of the total catch; it exhibited the highest average values of the catch during winter and autumn (19.7% and 19.2%, respectively). The exponent “b” of length-weight was 3.052 revealing positive allometric mode of growth. The length range was 9–25 cm for combined sexes with an average of 17.22 ± 3.29 cm while the smallest lengths were recorded during the summer season. The highest condition factor (k) was recorded in July, while the lowest one was in February, this factor increased with the increase in fish length. Round herring, E. teres reached to five years that was determined by otolith. Growth parameters; L∞ were 31.71, 29.058 and 30.26 cm for males, females and combined sexes, respectively. Growth coefficients (K) were 0.214, 0.246 and 0.225 year−1 for males, females and combined sexes, respectively; values of to were −0.776, −0.686 and −0.744 year−1 for males, females and combined sexes. Growth performance indexes (Ø) were 2.33, 2.31 and 2.31 for males, females and combined sexes, respectively. This study reflected the importance of such fishing gear in the Egyptian marine fisheries. Round herring “E. teres” as lessepsian species is predicted to be of economic value in the marine fisheries and give the positive impact of the lessepsian migration. The age of E. teres was five age groups that were higher than those from the Red Sea reflecting the good establishment of such immigrants in the new habitat. This may be ascribed to the environmental variations between different localities and due to the low exploitation rate of such new immigrant species in the Egyptian Mediterranean waters.