In North America (where ilish is not always readily available) other shad fish are sometimes used as an ilish substitute, especially in Bengali cuisine. This typically occurs near the East coast of North America, where fresh shad fish having similar taste can be found. In Bangladesh, fish are caught in the Padma-Meghna-Jamuna delta, which flows into the Bay of Bengal and Meghna (lower Brahmaputra), and Jamuna rivers. In India, the Rupnarayan (which has the Kolaghater Ilish), Ganges, Mahanadi, Chilka Lake, Narmada and Godavari rivers are also famous. They are also caught in the sea, but some consider the marine stage of the fish as not so tasty. The fish has very sharp and tough bones, making it problematic to eat for some. Ilish is an oily fish rich in omega 3 fatty acids. Recent experiments have shown its beneficial effects in decreasing cholesterol level in rats and insulin level. In Bengal, ilish can be smoked, fried, steamed, baked in young plantain leaves, prepared with mustard seed paste, curd, Begun (eggplant), different condiments like jira and so on. It is said that people can cook ilish in more than 50 ways. Ilish roe is also popular as a side dish. Ilish can be cooked in very little oil since the fish itself is very oily.