Co-feeding strategy promising survival and growth of Hilsa (Tenualosa ilisha) larvae

Hilsa, Tenualosa ilisha , is a commercially important high valued food fish in South Asian countries. Recently, much attention of this species has been paid for its conservation through captive culture due to its declining trend of population. Insufficient number of Hilsa seeds is the major bottleneck for its captive culture. This study aimed at developing a larval rearing protocol through co-feeding combined with planktons and formulated diet to facilitate its seed production that can support its culture. Hilsa larvae (3.67 ± 0.21mm/0.36 ± 0.00mg) were reared for 80 days in fiberglass-reinforced plastic tanks at 250 nos m − 3 in triplicates. They were fed with three different formulated diets as FI, F2, and F3 having 35.5%, 40.5%, and 45.3% crude protein (CP), along with Chlorella sp., Brachionus sp. and mixed zooplanktons as a co-feeding strategy. F2 diet feeding larvae showed significantly (P < 0.05) higher survival (88.5%), final body-length (36.21mm), final body-weight (0.43g), daily body-length gain (0.41mm), daily body-weight gain (0.01g) and SGR (8.96% day − 1 ) than that of other two diets: survival, F169.33% & F3 40.33%; final body-length, F1 32.1mm & F3 30.03mm; final body-weight, F1 0.31g & F3 0.2g; daily body-length gain, F1 0.36 mm & F3 0.33mm; daily body-weight gain, F1 0.004g & F3 0.003g; and SGR, F1 8.55% day − 1 & F3 8.02% day − 1 , respectively). Hilsa larval growth and survival achieved optimal while fed F2 diet with 40.5% dietary CP along with plankton as co-feeding. The finding may facilitate Hilsa culture in captivity through co-feeding strategy.