Study of some biological characteristics of Neogobius melanostomus (Pisces: Gobiidae) (Pallas,1814) along Noshahr and Chalus coasts, Southern Caspian Sea

A total of 191 specimens of Round goby (Neogobius melanostomus) were collectedon a monthly basis from 14 sites with sandy, gravel, natural rocky and artificial rockyshores in Noshahr and Chalus coasts at the southern Caspian Sea from March 2012to September 2013. Fish specimens were caught by angling for 2 hours andimmediately preserved in 10% formaldehyde. The highest catch rate were recordedin April 2012 from artificial rocky shores. The result of age determination recognized4 age classes ranging from 0+ year fish to 3+ year fish with 1+ year fishes as the mostabundant age class in both males and females. Sex ratio was nearly equal and themaximum and minimum total lengths were 112mm and 54mm for males and 89mmand 63mm for females, respectively. The maximum and minimum body weights were22.98g and 2.5g for males and 9.2g and 3.3g for females, respectively. The meanlength and weight for males (82.93mm, 7.99gr) were more than that for females(73.11mm, 5.2gr). In the stomach contents of all fishes, 10 food items were appearedconsisting of crab, shrimp, fish, barnacle, Nereis worm, gammarus, bivalve, ostracod,foraminifer and fish egg of which ostracods were the most abundant food item andthe barnacles were consumed by majority of gobiid fishes.

Keywords:

Gobiid fish , Food habit , Sex ratio , Age class , Substrate type