The Bay of Bengal is termed as the gold mine of fisheries resources. The BOB is a potential source of pelagic demarsal fishes and shellfishes. From the FAO survey report (1993, 1968, 1972) it was well known that 475 spp of fishes belonging to 138 families existed in the BoB.
Some commercially important pelagic fishes are herring (Hilsa ilisha), pomfret (Stomateus chinensis, Pampus argentus), tuna (Euthynus affinus), sardin (Sardinella fimbriata), ribbion fish (Trichiurus spp), bombay duck (Harpodon neherius), salmon (Polynemus indicus), Sea bass (Lates calcarifer) and jew fish (Johnius argenteus).
Besides 32 species of shrimps have been reported and standing stock of shrimps of BoB is 90,000 tons/year. Common species of shrimps are Penaeus monodon, P. indicus, P. merguiensis and Metapenaeus monoceros.
Moreover, dozen of species of crabs have been identified from the littoral system of BoB out of which Scylla serrata, Portunus pelagicus and P. sanguinolentus are commercially important.
Half dozen of lobsters have been identified. Among them Panulirus polyphagus (mud spiny lobster), Panulirus versicolor and Panulirus ornatus (Painted spiny lobster) are dominant.
Among cephalopods total species available 10 (Squids 7, Cuttle fish 2 and Octopus 1). Cuttle fish (Sepia officinalis), Squid (Loligo spp) and Octopus (Octopus lentus) are dominant species in the BoB.
Total available species of bivalves and gastropods are 50. Some commercial important species are Babilonia spp, Ostrea spp, Tonna spp, Oliva spp, Cypraea spp, Lambis spp, Umbonium spp, Mytilus spp, Placenta placenta, Crassostrea spp and Perna spp.
5 species of turtles are found among the St. Martin Island. But only green turtle Chelania mydas and Caretta caretta are to be significant.
Two species of crocodiles are found in BoB such as Crocodiles porosus and Crocodiles palustris.
Total marine algae species 165. Some important marine algae are Laminaria spp, Hypnea spp, Halimeda spp, Sargassum spp, Padina spp, Gelidium spp, Dictyota spp, Gracilaria spp, Caulerpa spp and Ulva spp.
Dr. Nurul Islam (1976) reported 160 species of phytoplankton from the BoB. Among them some species are Skeletonema, Ceracium, Coscinodiscus, Diatom, Nevicula, Dinoflagellates etc. Besides this BoB contains large amount of zooplankton including Sagitta, Syclops, Copepods, Dophnia etc. which are good for shrimp and fishes in both larval and adult stage. Average primary productivity during SW monsoon 1.06 gc/m3/day. Average primary productivity during NE monsoon 0.21 gc/m3/day.
Haidar and Mahmud (1992) described 13 genera of corals under 6 families from the water ground of St. Martin Island. Some commercial important species are Styliphora, Asteropora, Acropora, Goniastrea, Monastrea, Favia, Favites, Porites and Porona.