Tenualosa

Tenualosa is a genus of fish in the family Clupeidae, commonly known as shads. Members of this genus are found in the Indo-Pacific region, with occurrences in coastal waters, estuaries, and river systems that connect to the sea. The best-known species is Tenualosa ilisha, commonly called hilsa or ilish, a highly valued fish in South Asia.

Description and biology have common traits shared with other clupeids: a slender, laterally compressed body, a small mouth positioned toward the front of the head, and a silvery to bluish sheen. Size varies by species, with hilsa among the larger representatives. Tenualosa species are typically filter or plankton feeders in the marine and brackish zones, and many exhibit anadromous life cycles, migrating from the sea into rivers to spawn. Juveniles often inhabit estuarine and freshwater environments before returning to saltwater as adults.

Distribution and significance: Hilsa ilisha ranges along the coasts and river systems of the Bay of Bengal, the Arabian Sea region, and adjacent waters, extending into India, Bangladesh, parts of Southeast Asia, and neighboring countries. Hilsa supports substantial artisanal and commercial fisheries and holds cultural importance in several communities, with seasonal runs and traditional processing methods.

Conservation and management: Some Tenualosa populations face overfishing, habitat modification, and barriers to migration such as dams. Management responses in various countries include seasonal fishing bans, protected spawning runs, gear restrictions, and restocking or habitat improvement programs to sustain stocks.

Taxonomy: Tenualosa belongs to Clupeidae, and its relationship to related genera such as Alosa has been revised by taxonomists. The genus is defined by a combination of morphological features and its distinctive ecological and fisheries role within its range.