(Hamilton-Buchanan, 1822)
1. Distinctive characters of early developmental stages
(a) Eggs
No information available
(b) Larvae (Description based on 60-65 mm specimens)
Muraenesox bagio 1
Body transparent, ribbon-like, elongated and laterally compressed; dorsal and anal fins joined to caudal fin; caudal fin non-bifurcated; total myomeres vary between 127 and 134 in number with 78 to 80 pre-anal myomeres and 49 to 54 post anal myomeres (corresponding to 128 to 141 vertebrae in adults).
2. Distinguishing characters of larval stages of similar species occurring in the adjacent marine environment
(a) Muraenesox cinereus
Greater number of total myomeres found in the leptocephalus stage of 60 mm in size, corresponding to the vertebral count in adults.
3. Distinguishing characters of larval stages of similar families occurring in the adjacent brackish water and marine environment
(a) Ophichthidae
Ophichthidae
Upper jaw of the leptocephalus stage shorter than the lower jaw; upper and lower jaws with elongated and anteriorly protruding teeth; larvae with pre-anal and at times post-anal pigment groups on the ventral side of body; pre-anal pigment groups located on the dorsal side of alimentary canal; post-anal pigment groups, if present, are less in number than pre-anal pigment groups. Post-anal myomeres are compactly arranged and gradually increase in number from newly hatched larva to post larva (after Delsman, 1933a; Deraniyagala, 1934; Nair and Bhimachar, 1950; Nair and Dharmamba, 1960; Thangaraja, 1982).
4. Distinctive characters of juveniles and adults
33 to 39 lateral line pores before the anus, 47 to 59 dorsal fin rays before anus level; inter-orbital width 9 to 10% of head length; three longitudinal rows of teeth in both jaws; teeth present also in vomer; teeth in middle row of lower jaw and in vomer triangular, laterally compressed and with basal cusp in front and behind (Fischer and Bianchi, 1984).
5. Salient biological characteristics
(a) Maximum size
2 metres in length.
(b) Food and feeding habits
Carnivore, feeding on fishes living in the bottom marine environment (Fischer and Whitehead, 1974). In the mangroves, juveniles feed principally on bottom living shrimps and occasionally on small fishes (Jeyaseelan, 1981).
6. Salient ecological information
(a) Habitat
Adults are marine; leptocephalus stages occur sporadically in the mangroves, as well as in the lower reaches. Elvers not yet recorded from the mangroves. Juveniles use the mangroves as nursery ground, especially for feeding on small shrimps. Specimens of a size ranging from 15 to 50 cm are common in the shallow mangrove waterways of less than 2 m in depth.
(b) Geographic distribution
Throughout the Indo-Pacific region.
7. Capture fishes and utilization
Adults are caught by long lines from the sea. It is an important food fish. The airbladders are used in the preparation of isinglass. Undersized juveniles are caught in the mangroves of southeast India by cast-net, drag-net and stake-net.