Integrated Multi-Trophic Aquaculture

Integrated Multi-Trophic Aquaculture
Neither monoculture nor polyculture, IMTA is a technique that involves utilizing the waste from a fed species to feed other species kept in the same environment. This creates a balanced ecosystem with enhanced profitability and stability as well as better environmental sustainability. While monoculture is the farming of a single species, and polyculture is the farming of multiple similar species, IMTA incorporates multiple species from different nutritional or "trophic" levels in the same system. For example, a farm could incorporate shrimp, which are fed by the farmers, with seaweed and shellfish, which would make use of any waste nutrients from the shrimp.

Concerns
Some issues have been raised concerning the potential for contaminants being passed from one species to another. However, there has so far been no noticeable levels of heavy metals, pesticides, or other toxins. Worries that mussels grown near salmon farms could have a fishy taste have also been allayed. In fact, their meat yield is significantly higher as a direct result of the increased nutrients from the salmon pens.

Canada
There are two major IMTA projects in Canada.The Bay of Fundy project is a collaborative effort involving industry, academics, and government. It incorporates Atlantic salmon, blue mussels, and kelp working together in a self-contained ecosystem. The Pacific SEA-lab research initiative propogates sablefish, scallops, oysters, blue mussels, urchins, and kelp in a more complex system.

More Info:
http://www.dfo-mpo.gc.ca/aquaculture/sheet_feuillet/polyculture_e.htm
http://www.springerlink.com/content/j416160726015891/
http://www.aquaculture.ca/files/species-multi-trophic.php

http://brinkgamenews.com/
http://diablo3releasenews.com/

Catfish Farming - Overview of Methods

There are three main systems for farming channel catfish: levee, watershed, and cages.

Levee Ponds
Levee ponds are built on a flat area with earthen levees on all four sides, between 4 to 6 feet high. Water is often supplied from a well. If sufficient aeration equipment is used, as many as 4,500 fish per acre can be supported.

Watershed Ponds
Watershed ponds are built on slopes, often in a series of stepped ponds. They are formed by building dams to catch runoff water. Like levee ponds, they are generally 4 to 6 feet deep, since making them shallower allows weeds to grow, and making them deeper can cause low oxygen problems.

Cages
Cages can be used to let a catfish farmer grow fish in a lake or pond where harvesting and monitoring fish would normally be extremely difficult. Care must be taken to ensure that the cages do not become clogged with algae, and that there are no more than 1,000 fish per acre of surface area.

http://brinkgamenews.com/
http://diablo3releasenews.com/