Culture of fish in rice fields

Rice is presently grown in 113 countries. Rice farming also offers a suitable environment for the culture of fish and other aquatic organism. This publication synthesizes the available information on the role that aquaculture can play in rice-based farming systems towards food security and poverty alleviation.

Participatory research boosts catfish egg, fry production in Cameroon

The omnivorous African sharptooth catfish is a valuable species suitable for culture by smallholder farmers in Cameroon. A five-year research project that brought farmers together with research interests established simple, but effective approaches to increasing catfish fingerling production through improved egg handling, antipredation measures, and higher-density stocking options.

Hatchability of African catfish clarias gariepinus eggs in hapas and in basins: a diagnostic study of frequent inhibition by rainfall and water stagnation

To diagnose inhibition of egg hatchability by rainfall and water stagnation, some incubating eggs were protected against the physical impact of raindrops, some were subjected to various turbidity levels and others, to various incubation densities (number of eggs/litre of water) in flowing vs stagnant water. Data analyses showed that, unaffected by raindrop (P> 0.05), hatchability was inversely proportional to both turbidity (coefficient=-0.971) and incubation density (coefficient= -0.973). Only the properly constructed ponds (i.e.

Influence of symbiont strain on early growth of tridacnids.

Symbiotic algae (zooxanthellae) from the mantles of fast- and slow-growing Tridacna gigas, from T. maxima, T. crocea and Hippopus hippopus were isolated and supplied to larvae of T. gigas grown under hatchery conditions. Significant differences in growth rates of the larvae and juveniles were seen between these various treatments. The larvae and juveniles which had been supplied with zooxanthellae taken from fast-growing T. gigas grew faster than those supplied with zooxanthellae taken from slow-growers. No preference was noted inT.

Factors affecting early growth of Nile tilapia fry in hapa-in-pond environments

Hapas, usually suspended in fertilized ponds, have long been used for tilapia fry production (Santiago et al., 1985; Bhujel, 1997) and recently for fry rearing. In fish breeding programs, members of a full-sib family usually share a common tank or hapa prior to tagging and communal testing. This tends to increase resemblance between family members which may reduce the efficiency of breeding programs. For convenience of monitoring and identification of families, hapas are often arranged in rows over the pond.

Towards the maximum profitability of smallholder catfish nurseries: predator defense and feeding-adapted stocking of Clarias gariepinus

To determine how best smallholders could maximize the profitability of their catfish hatcheries, the cost/benefit analyses of using fences, hapas and bird nets to exclude predators; as well as over-stocking to create food shortage, were conducted. As compared to the typical production system (fertilized unfenced ponds) and at a stocking density of 10 two-day old fry/m2, survival increased by 28% in fenced ponds, 34% in open hapas and 55% in bird-netted hapas.

Intensity and profitability of Clarias nursing systems in periurban Yaoundé, Cameroon

To target development efforts, the technological options for investments in Clarias gariepinus hatchery systems were compared for cost, average weight, number of fingerlings harvested, survival and profitability in periurban Yaoundé, Cameroon. Costs were proportional to the level of intensity of production, with labour accounting for about 70% of the total. Profitability was similar among systems, with highly variable survival being a key constraint.


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