A don, Prof. Paul Bolorunduro, of the Ahmadu Bello University, Zaria, has called for caution in the cross-breeding of different species of fish due to its adverse impact on human health.
Cross-breeding is the mating of genetically differentiated fish species or crossing-breeding fishes within a particular specie.
The Cross-Breeding technique is used by aqua-culturists in the hope of producing aquatic organisms with desired traits.
Bolorunduro, a professor of fisheries at ABU, said although cross-breeding is a new practice in the Nigerian fisheries sector, local fish farmers must exercise caution in its adoption.
“We have had several cross-breeding of fish species in Nigeria that have been successful.
“We cross-bred catfish from different species and they produced an offspring we call Heteroclarias.
“But the only caution in cross-breeding fish is that these hybrid fish can result in ecological disasters.
“It has happened in the United States, where a particular hybrid fish of the catfish family eventually caused major obstructions in their waterways,” he told NAN.
The academician also warned against the use of excessive chemical additives to fish feeds, which he said, were harmful when consumed by man.
“Just like in organic crop agriculture, it is better to feed fish without excess chemical additives in the fish feed.
“There is a huge difference between the naturally-bred fish and the chemically-bred fish in the colour of the fish skin and even in their taste.
“There are chemical deposits in the chemically-bred fish, and when humans consume the fish without knowing, what is called biological modification occurs which is more terrible on the consumers than on the fish,”
The expert said an advocacy for low chemical-based feed is being encouraged among local fish farmers but the use of chemical additives to fish feeds cannot be overruled.
“We are promoting low-based chemical application because we cannot do without some of these chemical ingredients but for bio-security reasons and for human health, we try to de-emphasise it.
“We suggest integrated farming whereby the manure from poultry or ruminants can be used to fertilize fish ponds as natural food for their growth,”