Age determination and feeding habits of Nemipterus japonicus (Bloch, 1791) in the northern Oman Sea


Age determination and feeding habits of the Japanese threadfin bream, Nemipterus japonicus, was carried out in the northern Oman Sea (Chabahar area), based on 212 specimens collected between September 2009 and May 2010. The minimum and maximum fork length and body weight were measured as 145, 258 mm and 55.31, 288.12 g. The relationship between Body Weight (BW) and Fork Length (FL) for all individuals was estimated as BW= 0.0001×FL2.83 (r2 = 0.9425, n= 212). The Vacuity Index (VI) was 55.2% that shows N. japonicus is a moderate feeder. The maximum and minimum Gastro-Somatic Index for males was in autumn and winter seasons and for females were in summer and spring. The Food Preference Indices were estimated as: crustacean (63.2%) as main food fishes (38.9%) and molluscs (36.8%) as minor food. Age determination was done by otolith sectioning. A total of 135 sagitta were sectioned. The maximum age was 5+ years old for a female with FL= 256 mm and the youngest one was 1 year old for a female with FL= 145 mm. Based on obtained results there is a significant relationship between feeding and age namely with increase of age, the feeding rate is decreased without any changes in type of feeding and food contents.