FOOD AND FEEDING HABIT OF SPINY EEL Macrognathus aral (Bloch and Schneider) FROM UPPER ASSAM

Food and feeding habits of for M. aral were studied by examining a total of 421 digestive tracts during August, 2008 and July, 2010. It is very important to know the feeding habits of the fish in the natural environment in order to conduct stock enhancement by releasing the seedlings, because prevention of starvation, improvements of their growth and effective management can be conducted from this knowledge. The results reveals that the lowest value of relative length of gut (RLG) was found as 0.58(±0.09) in 27-32 cm whereas the highest values as 0.62(±0.12) in 7-12 cm group. Fullness of gut was recorded as18.38% (full); 9.18% (¾ full); 11.23% (½ full); 12.54% (¼ full); 19.77% (nearly empty) and 28.9% (empty). Gastro somatic index (GSI) was ranged from 0.55±0.13 (Feb) to 3.72±1.84 (Jun) for males and that of female from 0.45±0.12 (Feb) to 1.85±0.61 (Aug). In juveniles, a strong positive selection was observed for zooplanktonic organism (46.44%), insect larvae (27%), miscellaneous includes unidentified matter, algal & fish egg (17.16%), annelids (5.38%), sand & mud (2.05%) and crustaceans (1.97%). In adults, the most dominant food item was insect larvae (34.45%) and followed by zooplankton (19.56%); miscellaneous includes unidentified matter, algal & fish egg (15.04%); annelids (11.75%), crustaceans (8.02%), sand & mud (6.02%) and molluscs (5.16%). The index of pre-ponderance values showed that insect larvae were the most preferred food item (63.1%) for this species followed by zooplankton (20.02%) miscellaneous includes unidentified matter, algal & fish egg (10.59%), sand & mud (4.37%), crustaceans (1.30%), annelids (0.52%) and molluscs (0.10%). [PUBLICATION ABSTRACT]