Wednesday, June 27, 2018

28/06/2018: Farmed crayfish

by Vaughn Entwistle, Features Editor, International AquaFeed

Crayfish are low on the food chain, which makes them very easy to look after and stock in small aquaculture systems. They can be easily grown at low densities. There is a long history of freshwater crayfish farming worldwide, particularly in the United States and Europe with more recent industrial development in Australia.

American crayfish species
In America, the most commonly farmed species are the red swamp crayfish (Procambarus clarkii) and the white swamp crayfish (P. acutus). These are both indigenous species to these areas but they have been exported (alive) to many other continents, where they are now produced. The crayfish industry is the largest commercial crustacean aquaculture industry in the United States with an annual harvest exceeding 45 million kg. The predominant commercial species is the red swamp crayfish.

In the southern USA, red swamp crawfish and the white swamp crawfish are cultured in shallow ponds with a water depth of 300 to 600mm. Deeper ponds are sometimes used in very hot areas.

Although total production remains quite small Redclaw aquaculture has been established for more than 25 years. This despite many projections that it would become a significant aquaculture species worldwide, and possibly a rival of the giant freshwater prawn (Macrobrachium rosenbergii).

There is no hatchery production. Redclaws are reared directly in juvenile ponds where it obtains the bulk of its food from decaying matter and associated microbes contained in the pond bottom mud. Commercial crayfish pellets are available and have proven to be effective. A feeding frequency of once per day is adequate, preferably at dusk when crayfish are active.

UK crayfish farming

There are about 80 crayfish producers in the UK and supplies are available from July to October, the crayfish "season". Several types of production system exist, the most popular being extensive ranching or semi-intensive systems.

Ranching is favoured if crayfish farming is only an addition to a mainline enterprise. The ponds only need to be stocked and the crayfish breed and multiply naturally with the surplus crayfish harvested. Semi-intensive or intensive production systems exercise more control over the aquatic environment, feeding, etc. and the labour requirements are higher (much higher construction and management costs).

The enterprise is more suited to southern England than most of Scotland and has yet to be proved to be a viable commercial enterprise on a long-term basis.

Read the full article, HERE.

The Aquaculturists
This blog is maintained by The Aquaculturists staff and is supported by the
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