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Tuesday, May 5, 2015

05/05/2015: Fish and finance: How China dictates the size of your carp farm

by Malachi Stone, International Aquafeed 

First published in International Aquafeed, March-April 2015

A bureau de change? What's that got to do with the price of fish? Quite a lot, actually. Well over two thirds of the world's farmed common carp is produced in China. As a result, it is believed that the strength of the Chinese yuan can have a significant effect on the market price of this fish worldwide. 

     
http://issuu.com/international_aquafeed/docs/iaf1502_w1/46
Image: L Church
Now, imagine you are a carp-farmer in India. You are well aware that the cheaper carp is for the consumer, the less lucrative it is for you, the producer. And therefore, the fewer production costs you can meet. Production costs such as the price of specially-formulated fish feeds. 


Without such feeds, you are forced to rely on whatever protein sources you can gather from the surrounding countryside: snails, worms, clams and insects. But even if you had all day free to gather it, such a supply has its limits. There's only so many bugs and slugs an area can produce every twenty-four hours. 


http://issuu.com/international_aquafeed/docs/iaf1502_w1/46
Image: Tristram Brelstaff
And so, you are caught in a classic catch-22 situation: you will only be able to feed, and thus produce, more carp per unit area of your pondage should the price of carp go up significantly, providing you with a comfortable profit-margin from which to spend on specialised feeds. But such a price-hike will tend to happen only if fewer carp are being produced. 


Unless, of course, the Chinese oblige you by doing something to significantly strengthen their own currency and so drive carp prices up that way. Which isn’t terribly likely. Small wonder, then, that only about 3 percent of carp are currently farmed intensively in tanks or cages. 

Nevertheless, the common carp is still one of the most widely cultured freshwater fish in the world, accounting for about eight or nine percent of global aquaculture production. This percentage has remained constant over the last few years: carp aquaculture has increased in direct proportion to the growth in aquaculture of all species worldwide. 


Most carp are farmed on a less intensive scale, in ponds in polyculture with a variety of other fish species. The ratio of carp to other fish can vary hugely, from a few percent to almost all the individuals in a pond. 


When it comes to breeding, the farmer can let the fish just 'do their thing' and spawn when they feel the urge, depositing their fertilised eggs on artificial substrates which are then removed to another pond before the forgetful parents eat their own offspring (alternatively it is the adult fish who are transferred). 


But to maximise production, a little ingenuity is called for. The following 'recipe' gives a general outline of the usual practice: 


1. Take a female fish - the bigger the better.
2. Inject her with hormones to induce ovulation artificially and on a larger scale than would occur naturally (Alternatively, the hormone can be administered in little balls put into the water).
3. When she's fat with eggs, scoop her out of the water, hold her over a bucket and give her belly a gentle squeeze.
4. Take the eggs thus collected, mix them with sperm (likewise produced by injecting hormones into one or more males) and allow fertilisation to take place.
5. Incubate the fertilised eggs for 3 to 5 days at at least 20 degrees Celsius. 


Being poikilotherms (ie, 'cold-blooded'), carp do best in warmer climes. The eggs hatch quicker, the juveniles and adults feed more actively, food is converted more efficiently to body-mass and, as a result, the fish grow more rapidly.


Optimum growth and propagation seem to occur between 20 and 25 degrees Celsius. Widely distributed across the globe, this is nonetheless a fish that does best in and around the tropics.


Source: FAO

Read the magazine HERE.

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This blog is maintained by The Aquaculturists staff and is supported by the
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1 comment:

  1. Catchy title, though slightly misleading. there is just a disincentive for producing carp in an intensive set-up with maximise production. If people can do it in a cheap way, eg with technology advancements being economically feasible, then people will.

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