ilish
- Kingdom: Animalia
- Phylum: Chordata
- Class: Actinopterygii
- Order: Clupeiformes
- Family: Clupeidae
- Genus: Tenualosa
What is ilish, and where is it found?
What is the life cycle of ilish?
What is the economic importance of ilish?
What is the cultural significance of ilish?
What are the threats to ilish populations?
ilish, (Tenualosa ilisha), species of saltwater herring of the Clupeidae family and a prized fish in South Asia. Native to the North Indian Ocean and most populous in the Bay of Bengal, ilish is the national fish of Bangladesh and the state fish of West Bengal, India.
Types and distribution
The distribution of ilish, which is also called the Indian shad or hilsa shad, ranges from the Persian Gulf to the Bay of Bengal. It lives in marine, brackish, and freshwater areas across 16 countries. Another species of this genus—Tenualosa toli, which is commonly called the toli shad or chandana ilish—is found in estuarine and coastal waters that extend from the Indian Ocean to the Java and South China seas. The kelee shad, or gurta ilish (Hilsa kelee), which is the only member of the genus Hilsa, occurs across the Indo-West Pacific. Ilish is known to take on the flavors of the rivers it travels along, and those from the Padma River of Bangladesh are especially widely sought after for their taste. In 2017 ilish of Bangladesh received the geographical indication tag, a designation that denotes an item’s specific geographic area and its reputed quality and regionally specific characteristics.
Biology
Description and diet
Adult fish have a streamlined and compressed body. They weigh about 2.5 kg (5.5 pounds) and can range from 30 to 40 cm (12 to 16 inches) in length, with some more than 50 cm (20 inches) long. Individual ilish measuring more than 60 cm (24 inches) in length have been reported in India, Bangladesh, and Iran, and one weighing more than 4 kg (8.8 pounds) has been reported in India. Females are bigger than males, and bigger females lay more eggs. Adults are silver, tinged with purple and gold, and have a black spot behind the gill openings. These fish lack dorsal and anal spines. They are plankton feeders, eating mainly zooplankton such as ostracods, copepods, and Daphnia species, small crustaceans, aquatic insects, and polyzoans. They also feed on phytoplankton such as diatoms, green algae, and blue-green algae.
Life cycle
Ilish is anadromous—it migrates from the ocean into freshwater rivers to spawn. Adults may migrate more than 1,000 km (620 miles) upriver to breed. Its major spawning season is October through November, though some level of spawning takes place throughout the year, with minor seasons in February through March and July through August. The spawning cycle follows the lunar cycle, and the most intense spawning occurs in the three days before and after both the new moon and the full moon. Ilish larvae hatch from fertilized eggs in 22 to 26 hours. They feed in nursery grounds of usually brackish waters in the downstream riparian environment as they grow into juveniles and, in about five or six months, reach the subadult, or jatka, stage. During this stage the jatka leave rivers and tributaries in favor of ocean water, where they live for one year before returning to rivers to breed. On average, ilish live for two to six years.
Economic and cultural importance
Bangladesh is the world’s largest supplier of ilish, providing 76 percent of the fish’s global production, followed by Myanmar (15 percent) and India (4 percent). In 2021, however, Bangladesh produced about 565,000 metric tons of ilish, accounting for 97.01 percent of the global catch that year. Ilish fishery provides livelihoods directly and indirectly to about three million people in the Bay of Bengal region. Bangladesh earns a revenue worth 1 percent of its gross domestic product (about $4.5 billion in 2024) from the commercial harvest of this fish. Moreover, the nonconsumptive value of ilish in Bangladesh—reflecting its cultural, ecological, and recreational importance—is also significant, estimated at between $167.5 million and $355.7 million annually.
Ilish holds a prominent place in the cultural and religious traditions of communities that prize it as food. Among Bengalis in India and Bangladesh, it has attained an almost iconic status—celebrated as the royalty of fish and featured in auspicious occasions such as the Bengali New Year, Durga Puja, Saraswati Puja, jamai shashthi (a day celebrating sons-in-law), and weddings. Countless recipes showcase ilish, with some of the most popular ones being shorshe ilish (fish in mustard gravy), bhapa ilish (steamed fish), ilish polao (fish pilaf), ilish paturi (fish smoked in banana leaves), bhaja ilish (fried fish), and panta ilish (fermented rice and fried fish).
The fish’s unique shape has been frequently used in Bengali art, both traditional and contemporary, as a symbol of culture and heritage. In the pattachitra tradition—a folk art form of India, particularly West Bengal—patua painters unroll painted scrolls while singing ballads, often featuring ilish as an important figure in the narrative. In Bengali literature, this expensive seasonal fish is often referenced as a sign of status, a metaphor for life, and a symbol of Bengali identity. Bengali writing and cinema, particularly the works referencing the partition of India, often employ it as a metaphor for nostalgia and the loss of a once resource-rich homeland in East Bengal (now Bangladesh) for more than a million displaced Bengalis. For this population who started anew in India following the partition, the upstream-swimming ilish came to symbolize resilience and resistance. The fish is also the unofficial mascot of East Bengal FC, one of India’s most prominent football (soccer) clubs and historically associated with the Bengalis displaced from East Bengal.
- Also called:
- hilsa
Notable mentions of the fish can be found in the poems “Ilshe Gunri” (“Drizzling Rain”; 1930) by Satyendranath Dutta and “Ilish” (1943) by Buddhadeb Basu; short stories “Abdul Majhir Golpo” (“The Tale of Ferryman Abdul”; 1941) by Rabindranath Tagore and “Gangar Ilish” (“Ilish of the Ganges”; 1944) by Pramathanath Bishi; and novels Kamalakanter Daptar (“From the Desks of Kamalakanta”; 1875) by Bankim Chandra Chatterjee and Padma Nadir Majhi (“Boatman of the River Padma”; 1936) by Manik Bandyopadhyay.
Threats and conservation efforts
In recent years, populations of ilish have been affected by environmental and human-made changes in the Bay of Bengal region. Reduced water discharge from upstream rivers, siltation of riverbeds, illegal harvesting of jatka, overfishing, disruption of migration routes because of the construction of dams and barrages on rivers, and the loss of spawning, nursery, and feeding grounds have affected ilish populations. Conservation measures adopted by the major ilish-harvesting countries in the Bay of Bengal region include seasonal fishing bans, regulations on net mesh size, and prohibitions on the capture and sale of juveniles. Experts also recommend creating protected areas, restoring habitats of ilish, and providing incentives to fishers to ensure the species is sustainably managed. Bangladesh proclaimed a Jatka Conservation Week in 2025 to raise awareness for the protection of jatka.