Habitat, biology, and fisheries: Clupeids are typically marine coastal and schooling fishes that feed on
small planktonic animals (mainly crustaceans). They form large schools and scatter large numbers of
pelagic eggs that hatch planktonic larvae. There is great range in the biology and ecology of clupeids.
Some enter fresh water to feed, some are anadromous, and some live permanently in fresh water, some
are partial or full-time filter-feeders, some are predators on fishes (and probably form only loose and small
schools as adults), and some produce only 200 eggs or less (pygmy species) or attach their eggs to the
substrate. It is mainly the cool water genera that dominate the clupeid catches. Individually, few
warm-water species dominate clupeid catches (exceptions are Sardinella lemuru and S. longiceps), but
multispecies clupeid fisheries may account for as much as 1/3 of the total fish catch in some areas. Found
in all seas from 70°N to about 60°S. Usually adults range in size from 10 to 20 cm in standard length.
However, great variation is found in size, from the shad Tenualosa ilisha (to about 60 cm) to riverine pygmy
species (Sierrathrissa leonensis and Thrattidion noctivagus), which may be mature at less than 2 cm.