aquaculture

In 1998-1999 the Nefisco Foundation implemented the Homestead Magur (catfish) Culture Programme, also known as the Chari in the Bari programme in the Compartmentalization Pilot Project in Bangladesh. With this programme they tried to reach the poorest of the poor, and wanted to show this group that it is possible to grow high-value fish with limited resources.

The main idea behind the programme was that while magur (African catfish, Clarias gariepinus) is a good fish to be grown, because of its high growth rate, disease resistance, ability to take up oxygen from the air, etc., most local people were not aware of the potential of this fish. A few households in the CPP area had already been growing magur on their homesteads. This method proved to be successful, so CPP has taken up the task to spread this local knowledge among other households with emphasis on professional fishermen, landless, and other poor people. Initially 200 households joined the Chari in the Bari programme.

According to tve.org the African catfish Clarias gariepinus is one of the most suitable species for aquaculture in Africa. Since the 1970s it has been considered to hold great promise for fish farming in Africa. The African catfish has a high growth rate, is very resistant to handling and stress, and is very well appreciated in a wide number of African countries, including Nigeria (where it is often referred to as lungfish).

The FAO have produced a free document Artificial Reproduction and Pond Rearing of the African Catfish Clarias Gariepinus in Sub-Saharan Africa – A Handbook, edited by Gertjan de Graaf and Hans Janssen, from the Nefisco Foundation mentioned above.

Research has also been conducted in Brazil – Dietary canitine maintains energy reserves and delays fatigue of exercised african catfish (Clarias gariepinus) fed high fat diets effectively exploring better diets – which should lead to better growth patterns.

Rhodes University offer a free, online Clarias husbandry manual. They observe:

The African sharptooth catfish, Clarias gariepinus, is undoubtedly a remarkable and fascinating beast. Biologically it has all the attributes of a premier aquaculture species. Its biology, ecology and life history is well known and documented. From a teaching point of view this makes it an ideal species, allowing students to obtain an insight into how natural history information can be used for the development of culture technologies. Despite the technological know-how, total production of clariid catfish in Africa in 1993 has been estimated at a mere ca. 4500 tons. Despite the fact that there may be a considerable margin of error in the reported production figures, the farming of catfish in Africa is still a marginal activity. The reasons for this are manifold and can be primarily pinned on market forces, inadequate regional infrastructures, production costs, the socio-economics of fish farming and the underlying philosophy upon which aquaculture development in Africa is still largely based. Nevertheless the future potential for the farming of Clarias gariepinus throughout its distributional range is immense.

The Australian Fish Names Committee have recently launched a web site to support consumers and industry with fish names. The Australian Fish Names List is also available in csv and .pdf (which is the most recently approved (official) version of the lists). It is also possible to search the CSIRO’s CAAB (Codes for Australian Aquatic Biota) database.

A Fremantle (West Australia) restaurant has had a $A15,000 fine imposed on it after the restaurant proprietors pleaded guilty to cooking less expensive varieties of fish and serving them as more expensive varieties. This should serve as a valuable reminder to industry of the importance of using the correct names for seafood whenever it was sold. The Australian seafood industry had been concerned that consumers were not receiving adequate information regarding fish names in order to make informed choices.

Sena S. De Silva, Rohana P. Subasinghe, Devin M. Bartley, and Alan Lowther; from the Food and Agriculture Organisation of the United Nations (FAO) authored a review (FAO Fisheries Technical Paper. No. 453. Rome, FAO. 2004. 65p.) on tilapia as an alien aquatic species, available online.

The abstract:

Tilapias are not native to Asia but have been a significant component of inland fisheries and aquaculture in the region for over half a century. They have been introduced into over 90 countries worldwide, with a global distribution second only to common carp. The contribution of tilapias to global aquaculture production has increased over the past three decades with production in 2002 exceeding 1.5 million tonnes with an estimated value of US$1.8 billion. The average annual growth rate in aquaculture and capture fisheries production of tilapias from 1970 to 2002 has been 13.2 percent and 3.5 percent, respectively. In the present context of development, success of a species is determined not only by its contribution to production per se, but also by its social, cultural, economic and environmental impacts. Although tilapia has been associated with adverse environmental impacts, detailed analysis of the literature suggested that other factors, such as overfishing, environmental degradation from land-based activities, and changes in hydrological regime have probably been more responsible for adverse impacts. It is clear that numerous factors working together can impact biodiversity. It is also clear that tilapias, as a group of alien species, have made a significant contribution to food production, poverty alleviation and livelihoods support in Asia and the Pacific. In spite of the wide-scale introduction into Asian waters, there is scant explicit evidence to indicate that tilapias have been overly destructive environmentally.

Backyard Aquaculture in Hawaii: A Practical Manual by James Szyper, Ph.D., is available as a free .pdf download.

This large document (93 pages), is written for the beginning aquaculturist. It focuses which plants and animals to grow, and how to grow them with a minimum investment in land and equipment. The basics are covered, and then there’s added value with information on such subjects as pond management and water recycling. The manual has numerous valuable tables and drawings. While this manual is written to be an effective guide to backyard aquaculture for Hawaii, the principles hold true anywhere.

In this book, the terms “backyard” and “small-scale” generally refer to systems larger than home aquariums, but no larger than ponds of about one acre, a size range that takes in many possibilities. Many excellent books on aquarium-keeping are available for people with that interest, and a great number of works have been written on large-scale commercial aquaculture.

This book will provide a starting point and information source for individuals interested in learning more about backyard aquaculture, or in starting up a small-scale culture system. It will present information to help you decide whether this kind of activity will be possible and enjoyable for you; suggest an orderly approach to maximize your chances for success; present some detail on how to accomplish necessary tasks and start up some specific culture systems; and serve as a source of reference materials for further or more detailed reading.

Water Hyacinth (Eichhornia crassipes) usually floats free in large masses but may be rooted in the mud. The plants may range from a few inches to as much as 90cm (3 feet) in height. They have slender rootstocks with rosettes of leaves and dark, fibrous, branching roots dangling beneath the plant. Flowers may be blue, violet, or white and are usually quite showy.

In many regions Water Hyacinth is regarded as being amongst the worst of aquatic weeds. However, there is a continued theme from some researchers that there is significant benefit to be obtained from seeing the Hyacinth a resource rather than a rogue.

In an abstract from 1985, Ricardo B. Jacquez and Walter H. Zachritz II report on Combining nutrient removal with protein synthesis using a water hyacinth-freshwater prawn polyculture wastewater treatment system. They report overall performance of the polyculture system for the removal of total COD, TSS, total coliforms (MPN), and turbidity (NTU) indicated removals of 58, 98, 99.9, and 94 percent, respectively. Other parameters for the two stage system were monitored including temperature, Ortho-P, biomass, productivity, alkalinity, pH, and specific conductance.

F. Shoeb and H. J. Singh (2000) have published Kinetic Studies of Biogas Evolved from Water Hyacinth. The paper deals with the kinetics of gas produced from Water Hyacinth. The study was done in a batch fed digester. Attempts have been made to reach an optimum condition for the production of maximum amount of gas by the addition of lower volatile fatty acids, cow dung and inoculums etc. The conclusions that were drawn from the study is that biogas plants can be run even on the cold winter nights by using certain additives. After digestion, Water Hyacinth inoculums can be used as good manure for soil fertility. They are free from harmful chemicals – a boon for sustainable agriculture practices.

permaculture@lists.ibiblio.org have captured information about Uses for water hyacinth – Las Gaviotas project from August 2002. The information lists two links which are now invalid. Sad, because it would be interesting to see how the information had updated over time. This focus of this research has taken a rather different approach:

Oyster Mushrooms:
Scientific research initiated by Margaret Tagwira for ZERI Foundation demonstrated that dried water hyacinth is the best substrate for farming mushrooms. This program directed by Prof. S. T. Chang, an authority on the matter, confirmed that the water hyacinth is a blessing in disguise. Sociological studies confirmed that nearly all African cultures had mushrooms as a part of their diet. The spent substrate after fungi harvesting is rich in protein from the mycelia of the mushrooms and are excellent feed for earthworms, which convert it all into humus and can be fed to chickens, ducks and pigs.

After only 30 days, the dried substrate from water hyacinth produced a variety of mushrooms. Once harvested, it did not take more than ten days to harvest a second and even a third flush. One hundred kilograms of dried water hyacinth generates more than 100 kilograms of mushrooms. The water hyacinth outperforms traditional substrate materials such as sawdust. In addition, since the substrate of water hyacinth is rich in minerals and nutrients, the oyster and straw mushrooms cultivated ended up enriched with potassium, magnesium, iodine and calcium, along with numerous other components that are critical to a healthy food diet. Much of what was lost in the form of washed away topsoil can be recovered in the mushroom. The water hyacinth can also recover harmful metals such as cadmium and lead and store them in their roots if these metals are found in the rivers or lakes.