aquaculture

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.

Paul Adler examines young lettuce seedlings which are grown for about 3 weeks in a separate hydroponic system before they are set in the “conveyor production system” to remove nutrients from the rainbow trout effluent. (Photo by Keith Weller, USDA-ARS).

Adler, P.R. 1998. Phytoremediation of aquaculture effluents. Aquaponics J. 4(4):10-15. From the abstract:

The study is on an integrated system for rainbow trout production, effluent treatment and production of lettuce. The objective was to reuse water by removal of the nutrients in a vegetable product. The microscreen filter removes about 80% of the P excreted by the fish with the biosolids, leaving about 20% of the P in the effluent. A mass balance of system nutrients was conducted and it was determined that it takes 7.5 – 10 heads of lettuce to remove the P excreted in the effluent by the production of 1 pound of trout or 13 – 18 lettuce heads for each kg of feed consumed. Greenhouse studies demonstrated that by using the conveyor production strategy (CPS), phosphorus could be removed to <0.01 mg/L by lettuce without an apparent reduction in production or quality.

Conventional thinking regarding the use of food crops to clean aquaculture effluents has been that plants cannot remove nutrients in water to low levels without a reduction in productivity and quality. If water is distributed in a horizontal plug-flow pattern, all nutrients will be luxury consumed at the inlet, making nutrients limiting at the outlet and significant greenhouse space will be dedicated to growing plants that have no market value.

Because greenhouse space is expensive, productivity is critical for a profitable operation. A unique production system for lettuce, called the conveyor production strategy (CPS), was developed using thin-film technology for plant production in dilute aquaculture effluents. With the CPS, young plants are positioned near the solution inlet and are moved progressively, like along a conveyor belt, towards the outlet as they grow. Luxury consumption by lettuce (Lactuca sativa L.cv. Ostinata) enabled them to store P in their tissues early in their growth cycle for use later as water P levels decreased and influx could no longer meet current demands.

According to a speech presented at Aquavision 2002, the profile of the salmon industry in Chile is extensive:

• Modern salmon aquaculture first appeared in Chile around 1980 and has been developed in the southern Regions.

• Today, aquaculture is Chile’s fourth largest exporter, making Chile the world’s leading trout farming country and world number two in salmon farming. In 2001, the Chilean salmon industry exports were worth close to US $964 millions.

• Chile offers optimal environmental conditions: the temperature of the water, the quality of the water, geography, availability of fishmeal, and availability of suitable production sites.

• Aquaculture has a huge potential for development in Chile and investigations are progressing with several new species.

• The success of salmon farming has led to a number of social and economic effects. The southern regions now have some of the highest levels of employment in the country; currently 40,000 direct and indirect jobs result from the industry. These developments have also led to cultural changes as aquaculture requires trained people, at all levels.

The School of Aquaculture of the Catholic University of Temuco has hatchery and fish farming facilities, and offers aquaculture technician and degree courses. The web site offers content in spanish and english.

The FAO has published a profile of fisheries in Chile, (2000) which includes aquaculture. The FOA observe:

In Chile, this sector has been characterized for being one with bigger dynamics and importance of the national fishing sector, and for having reached a high development which began in the 80’s, mainly based in the culture of salmonoids and, at a lower level, molluscs, clams and seaweeds.

APFIC have published a number of reports available as free downloads about the rehabilitation of fisheries and aquaculture in coastal communities in those countries affected by the 1994 tsunami.

Strategic framework – Rehabilitation of fisheries and aquaculture in tsunami affected countries represents a regional strategic framework that has been developed in support of recovery and rehabilitation efforts following the earthquake and subsequent tsunami waves that originated off the west coast of northern Sumatra on the 26 December 2004 and that caused extensive damage to coastal communities in the region.

The framework presented consists of a vision for the rehabilitation of the fishery and aquaculture sectors which reflects an “ideal state” towards which all strategies and activities contribute and which avoids the mistakes of the past.

In response to the disaster, a consortium (CONSRN) of key regional agencies was formed with the objective of supporting coordination and harmonization of rehabilitation efforts in fisheries and aquaculture. In particular, it was agreed that activities were to focus on collating and disseminating information, carrying out assessments and supporting partners and governments to build a common vision for post-tsunami rehabilitation of the sector.

Other documents available as free downloads include: the report of the FAO/MOAC Joint tsunami assessment mission – Thailand. This is a report of a joint FAO/Ministry of Agriculture and Cooperatives (MOAC) detailed technical damage and needs assessment mission in the fisheries and agriculture sectors.

This is the final report of the Regional Workshop on Rehabilitation of Fisheries and Aquaculture in Coastal Communities of Tsunami Affected Countries in Asia held in Bangkok, Thailand from 28 February to 1 March 2005 is also available as a free download. Major topics discussed were: introduction to workshop and regional strategic framework; country priorities for rehabilitation; the rehabilitation vision and guiding principles; rehabilitation strategies; aligning donors/agencies/ countries to strategies and the workshop recommendations.

APFIC (The Asia-Pacific Fishery Commission) established by the Food and Agriculture Organization of the United Nations publish a range of research documents, including research into Myanmar aquaculture and inland fisheries (note: 6.84 MB) available as a free download.

This report is the outcome of two concurrent missions, one to coastal areas and one to inland areas, fielded by FAO-RAP, the Network of Aquaculture Centres in Asia-Pacific (NACA) and the Australian Centre for International Agricultural Research (ACIAR). The purpose was to review the status of aquaculture and small-scale inland fisheries, identify areas for technical assistance related to sustainable development of coastal and inland aquaculture and management of aquatic resources, and identify immediate assistance opportunities. The report includes the findings of the missions as well as conclusions and recommendations in support of the long term sustainability of fishery resources in Myanmar.

Fish and fish products are crucial in the nutrition and livelihoods of the Myanmar people. Whilst it is certainly recognized that fish is second only to rice in the diet of Myanmarians, little information is available on their patterns of consumption, inter-regional differences, availability and types of fish consumed. In this respect Myanmar is similar to many south-east Asian countries where emphasis is paid to rice production as a crucial element of food security, with little or no recognition of the fish component, which gives the rice-based diet much of its nutritional value outside of calories and crude protein.

Myanmar has impressive freshwater capture fisheries. The aquatic resource area of the river systems within Myanmar encompass a total of 8.2 million ha of permanent and seasonal water bodies. There were 29000 ha of freshwater fishponds and a further 40716 ha of shrimp ponds in 2001. These resources support, in many ways, the livelihoods of the people of Myanmar. Myanmar has a long coastline of nearly 3000 km and coastal aquaculture contributes significant export earnings and shows potential for future development and diversification. Of the total aquaculture production, an estimated 18794 tonnes comes from coastal aquaculture. Shrimp farming in particular has grown significantly in the past ten years, and small amounts of marine fish and crabs are also produced.

The FAO have also published this 1997 report on Support to Special Plan for Prawn and Shrimp Farming which gives some interesting insights into backyard scale shrimp hatcheries in Myanmar.

Neither intensive nor semi-intensive culture of shrimps has developed in Myanmar. Farming of marine shrimps has spread rapidly in South-east and South Asia, with exception of a few countries, including Myanmar. Myanmar’s neighbors Bangladesh to the north and Thailand to the south are both major producers of cultured marine shrimps. Culture of marine shrimps is now spreading rapidly in India. In all these countries export of cultured marine shrimps is a major earner of foreign exchange. There are about 30,00 acres (12,000 hectares) of traditional shrimp farms in operation which are mainly located in Rakhine State which borders with Bangladesh. The yield from the ponds are very low – 100 kgs/ha/year.