Aquaculture for all

Ecologists fear huge rise in krill catch

Industrial fishing companies are gearing up for the rush to exploit a great untapped seafood resource, Antarctic krill.

After decades of trying, the puzzle of krill exploitation has been solved and super trawlers are being equipped for the giant polar fishery.

Plans to take up 746,000 tonnes a year were disclosed at the weekend in Hobart after an international meeting agreed on new measures to control krill fishing. For years the catch had hovered around 100,000 tonnes.

In for the krill - a food source for aquaculture?

But concerns remain about potential ecological costs of the fishing effort, particularly by pair trawlers, which are banned in some seas because their giant nets can snare mammals.

Scientists are still trying to calculate the amount of krill in the Antarctic. The best estimate is half a billion tonnes, said Steve Nicol, a senior scientist at the Australian Antarctic Division.

In an area of the Southern Ocean off the far reaches of the Australian Antarctic Territory a catch limit of 2.6 million tonnes has been set, out of an estimated biomass of 15.9 million tonnes.

"Our concern is that we have catch limits set in fairly large areas," Dr Nicol said. "Despite the size of these catch limits, it is possible to take them out of a very small area, meaning there could be strong local effects."

Krill is at the centre of the polar food web, providing the main food for most Antarctic birds and marine mammals. There is escalating demand for krill, particularly in the aquaculture and pharmaceutical industries and as a source of food additives.

A Norwegian company, Aker, appears to have cracked the processing puzzle by using a giant hose to pump the catch from nets directly into the factory on its trawler, Saga Sea. Able to catch about 50,000 tonnes of krill a year, it will be eclipsed by a new Aker ship, the 121-metre Atlantic Navigator, which the company is converting in a $100 million investment in krill fishing.

In for the krill - the many uses of a crustacean

Fishermen have been replaced by food chemists in the high-tech pursuit of uses for the vast potential supply of krill. Among the uses is aquaculture feed .
Krill stimulates growth and encourages immunity to disease, and replaces artificial colouring used to redden farmed fish flesh with a natural pink; krill oil.
The oil is less than 5 per cent of krill by weight, but its uses are multiplying. High in omega-3 fatty acids, it can be used in aquaculture or for human nutrition. The French dairy giant Yoplait is working to develop krill oil products.
Even the shell of krill can be used as a base material for contact lenses and artificial skin.

Source: Sydney Morning Herald
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