از مرحله بچه ماهي نورس تا انگشت قد در استخر خاكي )Acipenser guldenstaedti( و چالباش )Husohuso( بررسي عادات غذايي فيل ماهي

Investigation on the feeding habits of Huso huso and Acipenser guldenstaedti from stage of fry to fingerling in earthen pond

In order to study of feeding habits of Huso huso and Acipenser guldenstaedti, three earthen ponds with 2 hectars (two ponds for Acipenser guldenstaedti & one pond for Huso huso) were selected randomly. Culture period was prolonged to 31 days. The fullness index, feeding habits, condition factor (K) and growth rate (G) of the fingerlings were measured in the rearing period. Regarding of the percentage of prey abundance in the guts content of Huso huso fingerling, Cladocera (Daphnia sp.) was the primary prey (Fp>50%), Chironomidae larvae and Ostracoda were secondary prey (10 %< Fp<50%) and Copepoda (Cyclops sp.) was the occasional prey (Fp<10%). In A. guldenstaedti fingerlings at the first group: Cladocera, Copepoda and Chironomidae larvae were secondary prey degree of first to third importance respectively and Ostracoda was occasional prey. In the second group: all of the feeding organisms were as a secondary prey and on the basis of the statical analysis conducted significant differences were observed in Cladocera, Copepoda and Ostracoda in guts content. The result of observation also indicated a decrease in the growth rate and condition factor with increase of weight and length of fingerlings. Result showed the growth performance of Huso huso and A. guldenstaedti fingerlins were positive allometric (b>3) and negative allometric (b<3) respctively.