Krill fishing threatens the Antarctic

Juliette Jowit

The Antarctic, one of the planet's last unspoilt ecosystems, is under threat from mankind's insatiable appetite for harvesting the seas. The population of krill, a tiny crustacean, is in danger from the growing demand for health supplements and food for fish farms.

The Antarctic, one of the planet’s last unspoilt ecosystems, is under threat from mankind’s insatiable appetite for harvesting the seas.

The population of krill, a tiny crustacean, is in danger from the growing demand for health supplements and food for fish farms.

Global warming has already been blamed for a dramatic fall in numbers because the ice that is home to the algae and plankton they feed on is melting. Now “suction” harvesting, which gathers up vast quantities, has been introduced to meet the increased demand. It threatens not just krill, but the entire ecosystem that depends on them, say environmental campaigners.

Krill are also believed to be important in removing the greenhouse gas carbon dioxide by eating carbon-rich food near the surface and excreting it when they sink to lower, colder water to escape predators.

“Whales, penguins, seals, albatrosses and petrels—all those creatures we think are absolute icons of Antarctica—depend on krill,” said Richard Page, a marine reserves expert with Greenpeace International. “It’s part of the global commons, and one of the most pristine environments on Earth. That’s why we should treat it with the greatest of respect.”

However, scientists say they are monitoring the fishing but so far the total catch is a small proportion of the population.

“We’re aware of this fishing effort gearing up and we’re not particularly concerned at the moment,” said Dr Geraint Tarling, head of ecosystem dynamics at the British Antarctic Survey (BAS). “When people get close to the allowable catches we’d be concerned, but at the moment it’s nowhere near.”

The eerie-looking Antarctic krill, with their translucent reddish bodies and black eyes, are thought to be one of the largest aggregations of marine life on the planet. Each creature weighs little more than a large paperclip; taken together, teeming shoals that can measure kilometres across are thought to weigh more than the human population.

Scientists believe krill have declined by 80% since the 1970s, and the most likely cause is global warming. There is uncertainty, though, about the remaining population: the BAS estimates 100-million tonnes; krill harvesting companies claim about 400-million to 500-million tonnes.

Under the Convention on the Conservation of Antarctic Marine Living Resources, the annual allowed krill catch in the Southern Ocean is four million tonnes. But until now there has been “huge under-fishing”, usually less than 20% of that quota, said Tarling.

However, there is growing interest and new products being developed. Most krill fished are used as fish-farm feed and to produce omega-3 oil and other health supplements. Last month alone, the Antarctic Krill Conservation Project reported four firms planning to expand operations. New on-board processing and fast-freezing technology are enabling ships to take bigger catches.

However, Helge Midttun, chief executive of Norwegian-based processor Aker BioMarine, said it is careful not to damage krill stocks, including developing a net around its suction system to stop other species being harvested. “It’s in our interests that these fisheries are taking place in a way that’s not destroying the environment,” said Midttun.

But Page warned: “What we don’t want to do is what we have done in pretty much every fishery in the world. We thought the natural resources of the sea were unlimited; we have proved time and time again that’s not the case.”

A crucial species

  • Krill live in all the world’s oceans, but Antarctic krill are the most numerous, with an estimated population of up to 500-million tonnes.

  • Antarctic krill grow to 6cm. If they were all put together, they could fill Wembley football stadium 1 500 times.

  • Krill eat algae and plankton and are eaten by predators such as whales. One whale can eat four tonnes of krill a day.

  • Krill are thought to “sequester” carbon equivalent to the emissions of 35-million cars a year.

  • Average Antarctic Peninsula temperatures have risen by 2,5 degrees Celsius in the past 50 years.
  • Sources: British Antarctic Survey; Antarctic Krill Conservation Project

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