عنوان مقاله [English]
We collected sturgeon specimens from seven fishing stations operating 30 to 35 Km away from each other in Guilan province over the years 1999- 2000. Trawl nets six meters long were drawn using motorboats at each station, repeated three times for each season. Among the studied premature sturgeons, 121 Acipenser persicus specimens with an average age of less than two years and a length of 10 to 49.9±0.77 cm showed full stomachs (57.17 % fullness). Among the mature specimens with an average age of 11 years and a length range of 90 to 194 cm, only three showed full stomachs (11.54 % fullness). The highest gut index in this study belonged to premature A. persicus.
A one-way analysis of variance showed no significant difference in condition factor and gastro-somatic index among the different length groups (P<0.05). We found that the food consumed by premature A. persicus was comprised of eight genera of benthic invertebrates Hypania sp., Hypaniola sp., Pterocuma sp., Stenocuma sp., Abra ovata, Paramysis sp., Gammarus sp. and Nereis sp. Adult sturgeons were found feeding mainly on fish species belonging to Gobidae, Atherinidae and Clupeidae families. The main preys of premature A. persicus were polychaet worms Hypania sp. and Hypaniola sp. belonging to the class Sedantaria. Crustaceans Stenocuma sp. and Pterocuma sp. of the class Cumacea were also seen in the diet of the premature sturgeons. The main preys of adult A. persicus were fishes belonging to the family Gobiidae and secondary prey were fishes of the family Atherinidae.