family Acipenseridae

Body elongate, its axis turned upto support upper lobe of tail; snoutprojecting beyond mouth, somewhatsub-conical to flat and elongate; jawsprotractile, without teeth; mouth transverse or crescentic; lips fleshy, 4 barbels in a row in front. A single dorsalfin, set far back on body, as also pelvic fins, first pectoral finray spinous;anal fin below hind part of dorsal fin;caudal fin heterocercal. Five rows ofbody scutes or bucklers along body (dorsal and paired lateral and ventrals) andusually minute grains, or sometimessmall bony plates, between rows of scutes; head covered with bony shields.

Freshwater and anadromous, when insea mainly in brackish waters and nearshores; bottom-living or midwater pelagic; mostly solitary, but in smallswarms during spawning runs or at placesof hibernation.

Feeding on bottom invertebrates(molluscs, crustaceans, polychaeteworms) and small fishes.

Spawning usually in spring or earlysummer in gravel, to which the eggs adhere.