Chapter 22 - Sustainable fisheries/aquaculture of hilsa, Tenualosa ilisha in changing and dynamic riverine ecosystem of India and its neighborhood

Abstract

Hilsa (Tenualosa ilisha) is commonly known as the Indian shad and belongs to the family of Clupeidae. This fish is spread over Indo-Pacific province from the Arabian Gulf (Pakistan, India, Bangladesh, and Burma) to South Vietnam. Hilsa is a euryhaline and anadromous fish. This fish naturally attains the growth and maturation in the sea water and later migrates to freshwater rivers for spawning. After spawning, embryonic and larval development take place in freshwater. Larvae migrate to lower regions of rivers (downstream rivers), which is nursery ground and finally to near shore coastal waters. Larvae grow to juveniles hilsa (locally called as jatka in Bangladesh and West Bengal) remain in the nursery grounds for 5–6 months. The juveniles are euryhaline in nature and move to seawater for feeding, growth, and sexual maturation and when the fishes are sexually matured (adult fish, 1.5 years old) migrates toward freshwater rivers for spawning. Different life stages of T. ilisha pass through diverse habitats due to migratory nature, which have different ecosystem and food available. It is an important commercial fish of the Indo-Pacific region, especially Bangladesh, India, and Myanmar where its fishery generates employment and income for millions of people. Now a days, catch of hilsa has dropped because of overfishing and changes in the dynamics of riverine ecosystem. The main causes of the ecological changes are pollution, obstruction of natural migration, and river sedimentation. In our current research, we have refined the artificial breeding of hilsa through dry stripping form wild mature broodstock. We also developed the nursery rearing protocol in pond ecosystem. Further, domesticated F1 broodstock of hilsa is developed in pond and recirculatory aquaculture system (RAS). We also aim to complete the breeding cycle of hilsa in captivity, which will help in development of conservation strategies and aquaculture of hilsa.