Study on the growth status of mullets with Viral Nervous Necrosis disease in the southern Caspian Sea

Abstract

Mullet and mullet products have considerable economic importance at a regional level, especially around the Caspian Sea. The leaping mullet constitutes an important part of their production. This study is the first detailed work on the age and growth of the leaping mullet (Liza saliens) from September 2012 to March 2013 in theSouthern coast of the Caspian Sea.Age and growth determinations were based upon thescale samples taken from 102 fish. Marginal increment analysis was used to validate agedetermination. The back-calculated lengths stage estimated from the scale showed no differences between in this study. The maximum age of leaping mullet in the Southern coast of the Caspian Sea was 5 years for males and 6 years for females.The von Bertalanffy growth functions were Lt=30.415(1-e-0.275(t+0.645)) for males and Lt=34.832(1-e0.211(t+1.009)) for females. A large spread and length overlapcharacterized the age groups. The estimated LengthWeight relationships were common for the two sexes(W=0.079L3 ). The slope (b) values of the length-weight relationship showed that weight of leaping grey mullet in Mazandaran increased associated with length in isometric. The mean condition factor for males, females and all specimens were determined as 0.908, 0.900 and 0.897, respectively. According to sex groups, the mean condition factor of males was slightlyhigher than that of females. The total length for leaping grey mullet was determined as 23.3 cm.