On 6 August 2017, Department of Patents, Designs and Trademarks under the Ministry of Industries declared ilish as a Geographical Indication of Bangladesh.

[10] The fish schools in coastal waters and ascends up the rivers (anadromous) for around 50 – 100 km to spawn during the southwest monsoons (June to September and January to April).

[11] After spawning, they return to the sea which are known as Jatka in Bangladesh (fish size up to 9 cm), although some stocks remain resident in rivers.

[14] The fish is found in 11 countries: Bangladesh, India, Myanmar, Pakistan, Iran, Iraq, Kuwait, Bahrain, Indonesia, Malaysia and Thailand.

[15] The fish is popular food amongst the people of South Asia and in the Middle East, but especially with Bengalis, Odias and Telugus of Coastal Andhra.

This typically occurs near the East coast of North America, where fresh shad fish, which tastes similar to ilish, can be found.

[citation needed] In Bangladesh, fish are caught in the Meghna-Jamuna delta,[17] which flows into the Bay of Bengal and Meghna (lower Brahmaputra), and Jamuna rivers.

In India, Rupnarayan (which has the Kolaghater hilsa), Hooghly, Mahanadi,[18] Narmada and Godavari rivers and the Chilika Lake are famous for their fish yields.

This migratory journey is crucial, as it's believed that the Godavari's unique muddy waters contribute to the development of a richer flavour and firmer texture in the fish, compared to hilsa caught elsewhere.

It is considered a rich delicacy, often referred to as the "king of fish" in Godavari Areas and features in celebratory meals and as a prized gift.

[21] In Bengal and Odisha, ilish can be smoked, fried, steamed or baked in young plantain leaves, prepared with mustard seed paste, curd, aubergine, different condiments like jira (cumin) and so on.

In the past ilish were not harvested between Vijaya Dashami and Saraswati Puja due to some informal customs of Odia and Bengali Hindus as it is the breeding period of the fish.

[33] The advent of finer fishing nets and advanced trawling techniques, and environmental degradation of the rivers, has worsened the situation.

[34] Furthermore, the changes brought about by global warming have led to a gradual depletion of the ilish's breeding grounds, reducing populations of the fish even further.

Despite this, former Prime Minister Sheikh Hasina periodically lifted the ban to allow the annual export and gifted of 3,000-5,000 tonnes of fish to India during the Durga Puja, popularly known as "Hilsa Diplomacy".