Determination of some reproduction characteristics of the whiting (Merlangius merlangus) and red mullet (Mullus barbatus) that captured in region Sinop

In this study which is carried out between June 2010 - May 2011 for whiting and between May 2010 - April 2011 for red mullet in offshore Sinop in Middle Black Sea Region with regard to population properties including size, weight and sex composition, length-weight relationship, condition factor and some reproduction properties including gonadosomatic index and first reproduction length have been examined, whiting (Merlangius merlangus) and red mullet (Mullus barbatus) among economic fish species. The average length and weight of whiting were 14.4±0.06 cm (8.3?23.3) and 22.53±0.25 g (5.7?82.9) respectively and the sex ratio was calculated as 1.4:1. Lenght?weight relationship was determined as W=0.0137L2.7504. Condition factor was found higher in winter months (November ? March). The first reproduction length of whiting was calculated as 13.9 cm and the fish was found to spawn mostly in January and in May and June. The average length and weight of red mullet were 13.0±0.03 cm (8.3?16.9) and 20.97±0.14 g respectively and the female fish was bigger than males. Sex ratio was observed as 2.44:1 and length-weight relationship was found as W= 0.384L2.448. Condition factor was calculated 0.9316±0.0125 for females and as 0.9265±0.0190 for males, and for males condition factor was found higher in summer months. When examined for monthly GSI values, red mullet was found to spawn in August and the first reproduction length was 13.5 cm. It was recommended to set a prohibition of 14 cm for whiting and red mullet. Keywords: Middle Black Sea, Red mullet, Whiting, Population parametres, Growth