Feeding regime of Persian sturgeon (Acipenser persicus) in the south Caspian Sea

Abstract

Feeding regime of the Persian sturgeon in the southern basins of the Caspian Sea was studied in summer and winter 2006 in three provinces Guilan, Mazandaran and Golestan. We caught 52 fish specimens in 85 sampling sites varying in depths from 2-100 m using bottom trawls. The average weight and length of fish specimens were 332.81+1 g and 37.69±1 cm, respectively. The alimentary tract of fishes were analyzed and 11 food items including Gobiidae, Gammaridae, Mysidae, Nereidae, Ampharetidae, Pseudocumidae, Clupeidae, Syngnathidae, Scrobicularidae, insects and Cardiidae were identified. The highest feed diversity was observed in Mazandaran province (9 items) and the lowest in the Golestan province (4 items). Although Nereids showed the highest percentage of benthic organisms (49%) but they were of secondary and tertiary importance in the fish diet qualitatively. Comparison of Fulton's condition factor of fishes in the three provinces showed a similar pattern (0.3<1(<0.4). A Tukey test revealed that there were no statistically significant differences between condition factor and gastro-somatic index in the three provinces while Vacuity index (CV) showed significant statistical differences among the provinces.