aquaculture

SEAFDEC Aquaculture Department (2005) has published a Code of Practice for Sustainable Use of Mangrove Ecosystems for Aquaculture in Southeast Asia.

Objectives of the Code of Practice
• To define principles, guidelines, and best practices for responsible aquaculture in mangrove ecosystems in Southeast Asia
• To provide a tool to guide States, non-government organizations, research and academic institutions, aquaculture practitioners, mangrove managers, local communities, global and regional aid and financial institutions, and other stakeholders concerned with both responsible aquaculture and the conservation and sustainable use of mangrove ecosystems
• To recommend key legislation and enforcement mechanisms to ensure both responsible aquaculture and the conservation and sustainable use of mangroves.

From the introduction:

Mangrove ecosystems (or simply ‘mangroves’) are the tide-influenced wetland complex consisting of mangrove forests, estuaries, lagoons, and associated habitats along the coasts and around islands in the tropics and subtropics. The mangrove forest consists of seawater-adapted flowering trees and shrubs, and the many associated ferns, fungi, and algae, including many epiphytes. The ‘true mangrove’ plants are members of the genera Rhizophora, Bruguiera, Ceriops, Avicennia, Sonneratia, Xylocarpus, Heritiera, and Excoecaria.

Mangroves support microscopic to large, terrestrial and aquatic (marine and freshwater), transient and resident wildlife. The mangrove physical environment includes waterways, mudflats, salt pans, and islands, with a wide ranges of salinities, daily tidal flood and ebb, and anaerobic mud bottoms.

The proceedings of a workshop held at Nong Nuch Village, Pattaya, Thailand, 27-31 May 1985, sponsored by the United Nations University and the National Research Council of Thailand have been edited by Peter Kunstadter, Eric C. F. Bird, and Sanga Sabhasri; and are available as an online book.

Subtitled The Socio-economic Situation of Human Settlements in Mangrove Forests, the introduction has this to say:

More than half the world’s people live in coastal regions, utilizing such resources as salt, minerals, fish, and crustaceans, the products of mangroves, salt marsh, seagrass, and kelp, energy from wind, waves, and tides, and such materials as sand, gravel, clay, and limestone, all obtained from the coast or the adjacent sea. Moreover, the coast provides sites for settlement, agriculture and aquaculture, ports and harbours, industry, commerce, and recreation. The management of coastal environments and their resources has raised many problems in both developed and developing countries, and it was felt appropriate that the United Nations University should give emphasis to this field of study.

The Coastal Resources Management Project was initiated as part of the University’s Natural Resources Programme. It was decided that the coastal environment – comprising the foreshore (between high and low tide lines), backshore (above high tide line to the landward limit of marine influences), and nearshore (from low tide line out to a depth of 20 metres) zones was a distinctive field for research and training that merited its own project within the programme.

A number of research studies and workshops were commissioned under this theme. Man in the Mangroves contains papers presented at a UNU-sponsored workshop. Three of the papers result from UNU research. The remainder were submitted by independent researchers. They focus on the socio-economic aspects of the use, development, and management of mangrove areas in relation to environmental and ecological factors.

Although the Coastal Resources Management Project has now been concluded, the University’s new programme on Resource Policy and Management has undertaken to maintain an international dimension in research, training, and dissemination, stressing the interaction of resource management, conservation, and development.

In Weeds to Wealth, the Equator Initiative reports on case studies of growing red seaweeds in Brazil. The Equator Initiative is a partnership bringing together the United Nations, civil society, business, governments and communities to help build the capacity and raise the profile of grassroots efforts to reduce poverty through the conservation and sustainable use of biodiversity.

From the report:

In Flecheiras, seaweed cultivators adopt the following method. A rope structure is attached to the sea bed and to buoys near the beach, and seaweed plants are cultivated in the rope. Planting is therefore carried out in shallow waters, and caring for the crop is done through frequent visits by boat. After approximately 3½ months, the plants can be harvested, cleaned and dried for retail. In general, seaweed loses about 80 per cent of its weight after drying. It is possible to cultivate several tonnes of seaweed in each location and studies have been made into the possibility of reducing the growing period. This would have the combined benefit of increasing income and reducing the seasonality of production. In areas such as Flecheiras and Guajiru, harvest periods as low as two months have been achieved.

There has been other research into the non-edible qualities of Brazilian seaweeds – the Brazilian Journal of Biology, vol.63 no.4 São Carlos Nov. 2003, has published research findings by Pereira, da Gama, Teixeira, and Yoneshigue-Valentin. The researchers noted that the Brazilian red seaweed Laurencia obtusa inhibited feeding by herbivores, and conducted research to discover what compounds were present in the plant. From the abstract:

Laboratory and field experiments were performed to assess the ecological roles of natural products produced by the Brazilian red seaweed Laurencia obtusa. Laboratory assays revealed that the natural concentration of the crude organic extract of L. obtusa significantly inhibited feeding by two herbivores: the crab Pachygrapsus transversus and the sea urchin Lytechinus variegatus. It was verified that this chemically defensive action was due to halogenated sesquiterpenoid elatol, found to be the major natural product of this red seaweed. In addition, it was verified that the antifouling property of the chemicals produced by L. obtusa could make this red alga less attractive for fish grazing. Direct protection against two herbivore species and indirect protection against herbivory by fouling inibition constitute evidence that the major natural product from Brazilian L. obtusa plays multiple environmental roles, thereby increasing the adaptive value of these metabolites. On the other hand, the evidence reinforces the idea that marine natural products may have different functions in the sea.

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.

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.