Potential of Fish Gamete Cryopreservation in Conservation Programs in Bangladesh

Abstract

Bangladesh is enriched with aquatic biodiversity and ranked third in Asia after China and India. It has highly potential fisheries resources comprising 260 freshwater fish, 475 marine fish, 24 freshwater prawn, and 36 marine shrimp species. The country produced 4.134 million metric tons fish in the year 2017, in which open water capture fishery contributed 28.14% and aquaculture contributed 56.44%. Presently, Bangladesh ranked fifth in aquaculture production and third in open water capture fisheries in the world. Earlier, the lion share of the production came from open water capture fisheries, but the production has been reduced over the years due to environmental and human-created problems. As a result, natural recruitment of many fish species has been hampered and they became threatened. According to IUCN Bangladesh (2015), among the 260 fresh water fish species, 9 have been categorized as critically endangered, 30 as endangered, and 25 as vulnerable. Aquaculture production of the country is being increased day by day due to availability of seeds produced through hypophysation in the private and government hatcheries, but the quality of seeds has been deteriorated due to some genetics causes such as inbreeding, interspecific hybridization, and negative selection. Therefore, it is urgent to protect the endangered fish as well as to improve the quality of seeds of commercially important fish species. This can be done by applying cryopreservation techniques associated with genetic improvement program. Considering the potential of fish cryopreservation, research on sperm cryopreservation began in the Department of Fisheries Biology and Genetics, Bangladesh Agricultural University in 2002, and protocols have been developed for a number of fish species such as Indian major carps, exotic carps, catfishes, indigenous endangered fish species, barb, and tilapia. Breeding of Indian major carps using cryopreserved sperm in private hatcheries demonstrated excellent performance of cryopreserved sperm-originated seeds and broods that urged to establish cryogenic sperm bank of commercially important fish as well as endangered fish species in Bangladesh.