aquaculture

Brian Coad has published a substantial work in the Freshwater Fishes of Iran.

From the introduction:

This work is meant to provide a guide to the freshwater fishes of Iran. There are no modern keys to this fauna, some available books are incomplete or cursory treatments or outdated, and the detailed and diverse scientific literature is widely scattered in time, languages and journals. Iran lies at a region of major zoogeographical interchange and has a diverse and interesting ichthyofauna about which comparatively little is known. An accurate identification is a pre-requisite for further scientific studies and this website aims to serve that purpose and to be an introductory guide to the fishes. The guide is aimed at a mixed audience, including scientists familiar with ichthyology to whom some introductory sections of this work will be superfluous, and those whose knowledge of fishes is embryonic or who may have limited access to literature sources.

This work has been carried out over a period of over 30 years from my first arrival in Iran in January 1976. In that year, 7 articles were published strictly on Iranian fishes (3 on parasites, 1 on pesticides, 1 on fisheries, 1 describing the blind white fish and 1 a summary of the latter; 2 were in Farsi). In 2006, 160 articles on Iranian fishes appeared, along with many relevant works from neighbouring countries, works on the aquatic environment in Iran and works on taxonomy and systematics relevant to Iran. The study of fishes is now a very active field within Iran and the Middle East. Accordingly, 2006 is the last year that this work was updated although some systematic and taxonomic studies may still be incorporated.

The potential of duckweed as a high-protein feed resource has been reported here previously.

Bui Xuan Men, Brian Ogle, and T R Preston have published research findings entitled Use of restricted broken rice in duckweed based diets for fattening Common and Muscovy ducks (Livestock Research for Rural Development, Volume 8, Number 3, September 1996). From the abstract:

A feeding system of restricted levels of broken rice (60 to 80 g/day) with free access to fresh duckweed appears to be appropriate for the Common type of duck typically used for foraging on rice fields throughout Vietnam. More research is needed in order to ascertain if the apparent capacity of Common ducks to eat large quantities of duckweed really is a comparative advantage and, if so, how this can best be used to improve the economic benefits to small scale poor farmers.

The authors have also published Duckweed (Lemna spp) as replacement for roasted soya beans in diets of broken rice for fattening ducks on a small scale farm in the Mekong delta (Livestock Research for Rural Development, Volume 8, Number 3, September 1996). From the abstract:

There was a slight indication (P=0.1 for females and 0.34 for males) that carcass yield was reduced on the duckweed treatments but differences were small. There were no differences in weights of chest and thigh muscle nor in heart and liver weights.

For farmers growing the duckweed there were economic benefits on all duckweed diets with best results from the complete substitution of the soya beans.

Paul Skillicorn, William Spira, and William Journey have published an extensive report entitled Duckweed Aquaculture – A new aquatic system for developing countries (The World Bank – Emena Technical Department, Agricultural Division). From the foreword:

Although duckweed species are familiar to most people who have seen the tiny aquatic plants covering stagnant water bodies, few people realize their potential. Until a few years ago, man made little use of duckweed species. Their unique properties, such as their phenomenal growth rate, high protein content, ability to clean wastewater and thrive in fresh as well as brackish water, were only recognized by a few scientists.

Prior to 1988 duckweed had been used only in commercial applications to treat wastewater in North America. In 1989 staff of a non-governmental organization based in Columbia, Maryland, The PRISM Group, initiated a pilot project in Bangladesh to develop farming systems for duckweed and to test its value as a fish feed. An earlier project in Peru investigated the nutritional value of dried duckweed meal in poultry rations.

The results of the pilot operations were extremely promising; production of duckweed-fed carp far exceeded expectations, and dried duckweed meal provided an excellent substitute for soy and fish meals in poultry feeds. Duckweed could be grown using wastewater for nutrients, or alternatively using commercial fertilizers.

During start-up of the pilot operations it also became apparent how little is known about the agronomic aspects of producing various species of the duckweed family, and exactly why it is so effective as a single nutritional input for carp and other fish.

Although these pilot operations were located in South Asia and Latin America, the results suggested that the plant would be important as a source of fish and poultry feed and simultaneously as a wastewater treatment process in selected areas of the Middle East, particularly in Egypt and Pakistan.

Technical and agronomic information about duckweed culture and feed use, and details of farming duckweed and fish in a single system, are not easily available to the general public, let alone to fish farmers in developing countries. The pilot operations in Bangladesh demonstrated that duckweed and fish culture can succeed commercially, although such ventures would initially require technical assistance and information. In many other areas of the world pilot operations linked to applied research may be required to review production parameters before commercial operations should be initiated. This Technical Study was therefore designed to bring together, in one publication, relevant information on duckweed culture and its uses to make people worldwide aware of the potential of this plant, to disseminate the currently available technical and agronomic information, and to list those aspects that require further research, such as duckweed agronomy, genetics and use in animal feeds.

This Technical Study is aimed at the following audiences: (a) established fish farmers who would like to experiment with duckweed as a fish feed, and staff of agricultural extension services involved in fish culture; (b) scientists of aquaculture research institutes who may initiate pilot operations and applied research on duckweed; (c) staff of bilateral and multilateral donor agencies who may promote funding for duckweed research and pilot operations; and (d) wastewater specialists in governments and donor agencies who may promote wastewater treatment plants based on duckweed in conjunction with fish culture.

According to William A. Wurts from the Kentucky State University, Cooperative Extension Program, Sustainable Aquaculture in the Twenty-First Century (a .pdf download – Reviews in Fisheries Science, 8(2): 141-150 (2000)) people have approached sustainability from three perspectives: environmental, economic, and sociological. Wurts notes in the abstract:

Ultimately, sustainability may be the aquaculture industry’s ability to adapt on a planet with an ever increasing human population which continues to consume its limited supply of non-renewable resources at an alarming rate.

Although ever increasing costs of resources such as oil and water continue to apply pressure to the development of sustainable models across all spectra of human endeavor, the discussion around sustainable aquaculture is not exactly new. Sustainable Aquaculture Development and the Code of Conduct for Responsible Fisheries was presented by William D. Dar to the FAO, Rome in March 1999.

Sustainability is also not just a concern of aquaculture – the broader concerns of ocean governance has also been considered by George Pararas-Carayannis in Ocean Governance and Sustainability – Present Trends – Future Challenges. From the abstract:

The ability of marine ecosystems to produce the economic and ecological goods and services that are desired and needed, have been substantially reduced. In some instances there has been a significant decline of ocean wildlife and even collapses of ocean ecosystems. It is clearly evident that what we once considered to be inexhaustible and resilient is, in fact, finite and fragile.

Patrick Sorgeloos offers comment regarding Technologies for Sustainable Aquaculture Development. From the introduction:

Risks of major environmental and human-health problems need to be weighed against achieving a more cautious rise in production that is, in the longer term, sustainable. We should all see this not only as a challenge to do it well and responsibly, but also as a commercial opportunity for the industry.

Aquaculture is clearly at a crossroads and can come, in fact, should come of age in the twenty-first century. However, this will require more responsible researchers and more integrated R&D approaches than we apply at present.

Denis Bailly and Rolf Willmann have provided research findings entitled Promoting Sustainable Aquaculture through Economic and other Incentives. From the abstract:

Economic incentives have been widely applied to encourage growth in aquaculture production, especially in the “infant” phase of development where risks are often high and scale economies cannot yet be realized. In recent years, increasing attention has been given to incentives that encourage the use of environmental and natural resources in a sustainable manner. This growing interest is not least due to the frequently disappointing performance of command and control measures. Different kinds of incentives can be developed in isolation or in combination, including tradable use/access rights, taxes/subsidies, codes of conduct, eco-labelling and others. While practical experiences are still very limited in aquaculture, these measures have proven effective in other sectors to induce producers to adopt better and more environmentally friendly production practices.