Seasonality, labor and integration of aquaculture into southern African smallhold farming systems

Fish production on Malawian smallholdings is generally limited by the quantity and quality of inputs to the pond (Brummett and Noble 1995). The timing of labor availability and other farm activities limit the amount farmers put into their ponds resulting in lower growth rates and yields. There is potential for improving production and yields through modifications of production schedules to accommodate other farming activities. Limited material and labor inputs among farming system enterprises can be better allocated by considering seasonal availability of inputs and adapting the pond and fish farming technology to the farming system. This case from Malawi demonstrates that aquaculture technology that neglects the annual cycle of events and constraints on the farm will not be easily integrated into the farming system. Focusing on technology that maximizes fish production rather than facilitation of adoption and integration has been a feature of the majority of African smallholder agriculture/aquaculture projects. Farming Systems Research (FSR) must identify niches and opportunities for system improvement for it to be worth supporting as a development intervention.

River-based artificial propagation of the African catfish Clarias gariepinus: an option for the small fish farmer

A cheap method of propagating the African catfish, Clarias gariepinus, by incubating the fertilized eggs in a cage placed directly in a flowing river is described. Hatching ranged between 39 and 70%. This is not significantly different from the commonly used water recirculating flow through system. The economic advantages of the river hatching method are discussed with special emphasis on the rural fish farmers.

Investing in Africa: the WorldFish Center's African strategy in summary

Across much of Africa, freshwater and coastal fisheries provide an important source of food and livelihood for many millions of people. In addition, the aquaculture potential of the continent has only recently begun to be developed. To help sustain these capture fisheries, support the emergence of aquaculture and foster the contribution of both to sustainable livelihoods and improved food security, the WorldFish Center is increasing its investment in Africa. The framework for this investment is provided by a new Strategy for Africa and West Asia 2002-2006 that identifies priorities for the Center’s work in rivers and floodplains, lakes and reservoirs, coastal fisheries, aquaculture, policy research and capacity building. The present article summarizes the issues being addressed by the Center and describes initial research priorities.

African freshwater fisheries: what needs to be managed?

The management of African freshwater fisheries in Southern African Development Coordination (SADC) countries is discussed. Changes in catch and fishing effort in the SADC freshwater fisheries in the past 50 years, the main causes behind the patterns of change in fishing effort, the effects of fishing effort and environment on the regeneration of fish stocks, as well as existing and proposed fisheries management regulations are investigated.

Comparative study of hatching rates of African catfish (Clarias gariepinus Burchell 1822) eggs on different substrates

The hatching rates of African catfish (Clarias gariepinus) eggs on four natural substrates: the roots of Nile cabbage (Pistia stratiotes), water hyacinth (Eichhornia crassipes), pond weed (Ceratophyllum dermasum) and green grass leaves (Commelina sp.), and four artificial substrates: sisal mats, nylon mats, papyrus mats and kakaban mats, was assessed. Concrete slabs were used as control. The natural substrates performed better than the artificial ones. Pistia roots gave the best mean hatching rate of 66.2 ± 3.62%. Green grass leaves were second with a mean rate of 54.0 ± 3.46%, water hyacinth was third with 49.7 ± 3.16% and Ceratophyllum fourth with a mean of 13.0 ± 2.37%. Concrete slabs gave a mean rate of 18.6 ± 2.8%, sisal mats 18.6 ± 2.0%, papyrus 12.2 ± 1.2% and kakaban 11.8 ± 1.9%. Nylon mats were the last, with a mean rate of 4.0 ± 0.7%. The best performing natural substrates were those with the ability to float and thin fibrous roots that seemed to allow higher aeration of the eggs during incubation. The cost of using natural substrates was minimal.

The evolution of body muscle composition of the African catfish (Clarias gariepinus) (Burchell 1822)

Changes in body muscle composition of Clarias gariepinus were studied in fish reared from 1.08 g to 383 g mean body weight in a 201-day culture period. Changes in the amount of protein content, dry matter and ash free dry matter in the muscle tissue can be described as a function of body weight. The percentage of protein content was observed to be higher in bigger fish. Fat content was low throughout the fingerling stage. Specific growth rate decreased significantly at 400 g mean body weight (P<0.05) while feed conversion rate increased. The conclusion, based on the culture conditions in this study, is that the optimal weight for harvesting C. gariepinus is 400 g.

Production of fingerlings and marketable size African catfish (Clarias gariepinus) in ponds in northern Cameroon

A simple running water method of catfish (Clarias gariepinus) fingerling production in ponds in Northern Cameroon is outlined.

Training in fisheries planning and management: the case of the Southern African Development Community nations

This paper presents an evaluation of the 15-week course on Training in Fisheries Planning and Management being offered at the University of Namibia since 1991. This course includes instruction in fisheries technology, fisheries biology, fisheries law and law of the sea, fisheries economics, fisheries sociology, environment impact assessment, planning and management, the logical framework approach to planning and computer literacy. The participats in the course have rated the various elements in a range of 2.9 to 4.7 out of a maximum of 5 points.

European Union supports project to strengthen fisheries and biodiversity management in African, Caribbean, and Pacific (ACP) countries

Proper resource management implies a better understanding of ecosystems and the conservation of biodiversity. Scientists from developing countries often have limited information on their aquatic resources because of many difficulties in accessing and exchanging information on a national and international level. The project described not only aims to strengthen the scientific capacity of fisheries scientists in ACP institutions but it is also expected to create an awareness among fisheries researchers and managers of the importance of conserving biodiversity for the sustainable use of living aquatic resources. This will be achieved through training, building a network of regional and transregional cooperation using modern communication facilities, the promotion of research and the distribution and improvement of fisheries management tools. It is hoped that these capabilities will enable fisheries scientists in ACP countries to actively contribute towards a discussion to solve common problems originating from the endangering of the ecological basis of their fisheries.

Influence of music on the growth of koi carp, Cyprinus carpio (Pisces: Cyprindae)

An experiment was carried out to investigate the influence of music on the growth of Koi Carp (Cyprinus carpio) by subjecting the fish to music. Weekly growth in weight was recorded and used to calculate the growth rate and specific growth rate. The difference in growth between the control and experiment groups of fishes was statistically tested for significance. It was observed that the growth of fish subjected to music was significantly higher.

Trawling Operations and South African (Cape) Fur Seals, Arctocephalus pusillus pusillus

South African (Cape) fur seals, Arctocephalus pusillus pusillus, interact with the South African trawl fisheries-offshore demersal, inshore demersal, and midwater fisheries. These interactions take thef ollowing forms: Seals take or damage netted fish, on particular vessels they become caught in the propeller, seals drown in the nets, live seals come aboard and may be killed. Except in specific cases of seals damaging particular trawler propellers, interactions result in little cost to the offshore and midwater trawl fisheries. For the inshore fishery, seals damage fish in the net at an estimated cost in excess of R69, 728 (US$18,827) per year, but this is negligible (0.3%) in terms ofthe value of the fishery. Seal mortality is mainly caused by drowning in trawl nets and ranges from 2,524 to 3,636 seals of both sexes per year. Between 312 and 567 seals are deliberately killed annually, but this most likely takes place only when caught and they enter the area below deck, where they are difficult to remove, and pose a potential threat to crew safety. Overall, seal mortality during trawling operations is negligible (0.4-0.6%) in terms of the feeding population of seals in South Africa.