By Mary Hearty

With the increasing demand for fish protein coupled with capture fisheries decline, the Kenya Marine and Fisheries Research Institute (KMFRI) is committed to implement fish genetic improvement program to help increase fish production at minimal cost.

The KMFRI recently stated in their 2021 report titled: State of Aquaculture in Kenya that genetic improvement can increase farm income either through increased production, cost reduction or a combination of both.

This biological trait improvement will be achieved through selection of traits from parent stock that confer an advantage to the fish, producer, marketer, and consumer.

Though, unlike Asia and Europe, Africa, Kenya included has largely depended on unimproved fish strains as their brood stock. This is with the reason that infrastructure for preferred traits selection in aquaculture is yet to be advanced.

These genetic improvement efforts have been successfully demonstrated in Atlantic salmon, Gift Nile tilapia in Egypt and South East Asian countries and Common carp in India, according to the government research institute.

In Kenya, the prominence of Nile tilapia has intensified and diversified efforts to improve the genetic baseline of these species and significant development have been seen, KMFRI noted.

Similarly, there has been increased demand by hatcheries and grow-out farms for importation of super YY males, GIFT and Abbassa strains. Moreover, Dutch and Indonesian strains of African catfish have been imported to enhance the species productivity.

Nevertheless, KMFRI stated that this comes with little knowledge by the value chain actors on the genetic improvement impacts on the environment associated with any fish breeding program, thus the need for demand driven local breeding program.

Other than the traditional and science-based quantitative genetic approaches in Nile tilapia breeding, chromosomal manipulations, physiological alteration of sex determination, gender transfer, and genetic marker-assisted breeding are also in practice globally.

Although, KMFRI noted that traditional tilapia breeding approaches that take advantage of additive and non-additive gene effects are still the most practical means of improving brood stock for small scale breeders across the globe.

At the moment, KMFRI is engaged in Nile tilapia and African catfish selective breeding and mass breeding respectively.

For instance, Nile tilapia involving two sires and one dam per ha has seen 200 sires and 100 dams used as filial generation, which are screened from Sagana and Lake Victoria strains.

KMFRI revealed in the report that the Nile tilapia breeding program initiated in 2012 is in the 8th generation, and part of its mixed sex population have been distributed to over 12 multiplication centres across the country for seed production and supply to grow-out farms.

They further pointed out that the main challenge in genetic improvement programs is the cost implication, with these breeding programs mainly operated by private firms with minimal involvement from government as observed in developing and developed countries.

Notably, the KMFRI explained that successful fish genetic improvement will require personnel with skills and knowledge in population genetics, molecular genetics and biotechnology.

Again, it will need reliable capacity in terms of infrastructure and human capacity that closely monitor fish during the breeding procedures meaning, “Continuous funding for sustainability and structure systems to ensure that different generations are closely monitored will be required.”

Other factors that the KMFRI mentioned include market demand for production and survival traits, adding that demand of a particular trait in the market determines the improvement to be done in a particular fish species.

For instance, high fillet yields has been the driving force towards selective breeding for fast growth and high yields; disease outbreak has also led to selection for disease resistance in tilapia, rainbow trout; flesh colour for selection in Salmon; and tolerance to a given climatic condition like cold tolerance for tilapia and high temperature tolerance to rainbow trout.

The KMFRI also noted that if far reaching societal gains from a genetic improvement program are to be realized, like providing safer fish or environment protection, then the program may depart from economic gain concept.

Also, the report notes that genetic improvement in aquaculture is occasioned by a series of experimentation with plentiful and efficient record keeping for years and thus the desired results may take long to be realized.