All About Nigerian Catfish Culture
Catfishes of the family Claridae comprise the most commonly cultivated fishes in Nigeria. The growth of aquaculture in Nigeria now is largely becoming boosted by a steady rise in catfish culture. Considering that the culture of Clarias gariepinus by means of hypophysation was initiated in Western Nigeria in 1973, the procedure has been widely practiced all through Nigeria therefore leading to boost of farm-raised catfishes from the 80’s to date. The favored catfish species in Nigeria aquaculture incorporate: Clarias gariepinus, Heterobranchus bidorsalis, Clarias X Heterobranchus hybrid (Heteroclarias) and Clarias nigrodigitatus. Heterobranchus sp is the much more generally cultured fish in the South Eastern parts of Nigeria.
Regardless of the popularity of the African catfish and its great market potentials, the production is still basically at subsistence level due majorly to inadequate availability of seed for stocking and feed difficulties. In Europe, about 75% of Clarias fingerling demands are supplied by a few producers. In Nigeria however, the fingerlings supplied from both the government and privately owned hatcheries are not enough to meet the catfish farmers’ fingerling demands.
Artificial propagation of C gariepinus is now carried out in hatcheries with hormonal induction. Farmers have found the homoplastic pituitary gland suspension cheaper, practical and far more highly reliable than the imported synthetic hormonal analogues. The C gariepinus broodstock weight utilized for artificial breeding ranges between 3kg and 2kg (Olaleye, 2005). Despite the breakthrough with use of hormone in induced spawning fry survival is still beset with a number of biotic and abiotic factors. The biotic elements include cannibalism, heavy predation by frogs/aquatic insects and the abiotic factors incorporate water temperature, dissolved oxygen (>4.5mg/L-1), levels of ammonia.
In the course of the very first week after stocking, the most crucial factor for the successful nursing of the catfish larvae is the availability of zooplankton. Feeds and feeding of the larvae, fry and fingerlings of the catfishes have been most studied and shown to influence the growth and survival of the fish. Studies have revealed that live zooplankton is the preferred larval food. A lot of smallholdings merely rear larvae to fingerling size in organically fertilized ponds at a density of between 30-1000 larvae/m2 (Olaleye, 2005). Fingerlings are stocked into rearing ponds at a rate of 50-75 fish/m3 under great management.
Simply because of the cannibalistic nature of Clarias gariepinus, several sorting is vital. For outdoor fry/fingerlings rearing, screening of the tanks with mosquito nets is suggested to prevent dragonfly and other predatory insects from breeding in the ponds. Poly-culture of Clarias gariepinus and Tilapia species is practiced. A poly-culture of Clarias gariepinus and Oreochromis niloticus, integrated with poultry with some supplementary feeding had been shown to be viable.
Feed and feeding of catfishes in grow outs ponds are maybe the most documented in literature. A variety of efforts have been made to establish the crude protein and amino acid requirement of C gariepinus. Ayinla (1988) recommended 35% and 40% crude protein (Cp) for raising table size and brood stock respectively. Of the 10 essential amino acids (EAA) needed by warm water fish species, only 3 EAAs studied have been documented and these are arginnie, methionine and lysine. In order to formulate and compound aqua feeds that will meet the nutrient requirements of the catfish at reasonably priced cost, several conventional and non-conventional animal by-goods and plant residues have been tested to substitute or replace fishmeal (Table 1). Feeding development has moved from the use of single ingredient, broadcasting un-pelleted meal to pelleting and in truth the use of pelleted floating feed which has created a big distinction to aquaculture development in Nigeria as C gariepinus is being raised to maturity within 6 months.
The yearnings of farmers and scientists to have a farmed catfish that combines the quick growth traits of Heterobranchus spp and early maturing traits of C gariepinus led to the development of a hybrid ‘Heteroclarias’ spp. The technology was widely accepted as it gave 58% internal rate of return (IRR) on investment (Adeogun et al, 1999).
In the review of Oresegun et al (2007), it was stated that early fish farmers in Nigeria raised their fish in burrow pits, abandoned minefields and in earthen ponds on extensive production method. The introduction of concrete tanks permits for manageable pond size and modification of the environment through a water flow-by way of method and supplementary feeding therefore permitting for higher fish yield. The advent of the indoor water re-circulatory method (WRS) has ushered in a new prospect for aquaculture. The introduction of WRS has developed a turning point in the production of catfish in Nigeria.
The story of aquaculture in Nigeria is essentially the story of catfish culture and the hope of fish supply in Nigeria hangs on its development and culture. Recent trends all over the world, point to a decline in landing from capture fisheries, an indicator that fish stocks have approached or even exceeded the point of maximum sustainable yield. Aquaculture therefore remains the only viable option for increasing fish production in order to meet the protein will need of the men and women.
It was observed that of the over 30,000MT of numerous freshwater and brackish water fish species caught in the year 2000, catfishes were more abundant next to Tilapines (Table 2). FAO (1993) reported that 27,488MT of catfishes produced in 1990 were consumed locally. This implies that there is still fantastic require for higher production for both nearby and international markets.