BACTERIAL DISEASES AFFECTING BROODSTOCK OF AFRICAN CATFISH (CLARIAS GARIEPINUS) AND THEIR REFLECTION ON THE REPRODUCTIVE PERFORMANCE

Walaa T. El-Ekiaby1;

Mohamed E. Abou El Atta1 and Adel M. Akar2

1Fish Health and Management Department. 2Fish Physiology and hatching Department. Central Laboratory for Aquaculture Research, Agricultural Research Center, Egypt.

Received 2/ 10/ 2018

Accepted 6/ 11/ 2018

Abstract

Growth, mortality and yield per recruit of the shrimp scad (Alepes djedaba)) from Mediterranean coast of Sinai Egypt. 780 specimens (11.1 to 25.3 cm total Length and 15.3 to 172.2 g total weight), were collected from January to December, 2016 (one fishing season). The relationship between length and weight was W= 0.0064*L 3.134. The Age groups were 0 to 5 years. Growths in length and weight at the end of each year were calculated as11.87, 15.94, 18.40, 20.40 and 22.37 cm for the 1, II, III, IV, and V  year of life respectively and the growth in weight were 14.9 ,37.6 ,58.9 ,81.4 and 108.6  g for the 1, II, III, IV, and V  year of life respectively. The growth parameters of von Bertalanffy equation were calculated as (L∞= 26.94 cm, K = 0.2946 year-1 and t0 = -1.0408 year). Growth performance index (φ′ = 2.33). Mortality rates were 0.91957 yr−1, 0.43654 yr−1and 0.48303 yr−1 for total, natural and fishing mortality respectively. The currently exploitation rate E = 0.53. The length at first capture (Lc) as 17.0cm, (2.34 year)). The results of age at first capture and the current exploitation rate indicated that the small fish are caught at higher fishing effort level. Since these fish represent a percentage of the total catch  in the Mediterranean Sea  coast of Sinai and  low price of  this fish    to some extent is an alternative to fish such as sea bream and sea bass, which are very high prices and also there is no previous studies on these fish,

So you should do the following studies on this type of fish to know in the Spawning season  and the length at first maturity  of these fish and distribution and feed habitat     so that fish can be managed catch and work to increase the production of these fish while preserving the stock of fish