Lethal Gene Danger from Unplanned Fish Breeding

The existing unplanned fish inbreeding may cause a genetic deterioration into the aquaculture production and open water fisheries resources in terms of hatchery stock breed seeds in floodplain and other open waters, reports New Nation of Bangladesh.

"Unconscious negative selection of broodstock, mating of female and male spawns from a finite population and unplanned hybridization in hatchery stocks especially carps has created the widespread concern," said Dr Golam Hossain, Director General of Bangladesh Fisheries Research Institute (BFRI).

Dr Hossain said fish seed production through artificial propagation or induced breeding is a common practice in the country.

Around 1,000 hatcheries are engaged in the breeding purposes contributing more than 95 per cent of the total spawn production at present. However, he said, genetic deterioration has frequently been reported in hatchery populations in a number of recent past research findings. In this context, he defined that poor brood stock management and close mating of breeders possibly brother and sister or parent and offspring resulting in inbreeding causing adverse effect on the fisheries populations. Due to their ignorance, most commercial hatchery owners and employees use low quality brood fish for breeding purposes producing less health and weight offspring leading to an excessive death rate.

Many hatchery owners were also found unplanned and uncontrolled hybridisation between carp and ruhi, rui and mrigel, and carp and mirror carp frequently creating a horrible situation.

They do the malpractice only to catch the highly demanded markets of fish fry and fingerling as the government has been implementing fish releasing programme in the country's flood-plain during every monsoon in addition to large-scale promotion of fish farming for the last couple of years.

"If the unplanned trend persists there will be an acute trouble in the gene mixing of the indigenous major carp species - ruhi, carp and mrigel," Dr Hossain cautioned.

He said the BFRI has been providing necessary training for the hatchery owners and others concerned but unfortunately they do not follow the guidelines to earn more money through selling the low quality fish seed.

New Nation reports that the major threat with the inbreeding problem is lethal gene action that causes production loss, breeding inequality, disability and disease infection.

Meanwhile, Divisional Deputy Director of the Department of Fisheries, Abu Baker Siddiqui, said that there are 28 big and five small state level hatcheries, 233 private hatcheries and 2,065 nurseries in Rajshahi division.

To overcome the crisis, Dr Hossain put forward a number of recommendations which included use of suitable age and weight brood fish and proper exchange of those among the hatcheries, creation and collection of more brood fish from high-growing fingerlings and more harvesting from river sources, preventing inbreeding between close relations along with inter-specific hybridisation and substantial improvement of overall hatchery management.

In this context, he suggested bringing the hatcheries and nurseries under a close monitoring and supervision so that they could be enforced following the prescribed guidelines.

To this end, he said all the government and non-government organisations concerned should be more effective to make the grassroots fish artificial and induced breeding activities ethical and planned, concludes the New Nation report.