Steve Connor The Independent 18 Feb 12;
The indiscriminate slaughter of vast numbers of turtles, sharks, albatrosses and other endangered marine animals that get unintentionally caught by fishermen as "by-catch" could be prevented by a radical proposal of mobile marine reserves, scientists said yesterday.
Protected areas of the ocean where commercial fishing is banned would work far better if they were not static conservation areas, as they are at present, but moveable reserves that take into account the mobile nature of sea life, they said.
The proposed new conservation zones would not impose fishing restrictions in one place, but shift location according to where threatened species are expected to be found. The idea has resulted from a revolution in satellite and tagging technology that has allowed scientists routinely to monitor the seasonal movements of marine creatures, which would have been impossible a decade ago.
Scientists said existing marine protection areas (MPAs), where fishing is controlled to enable wildlife to recover, frequently fail to do their job because the endangered animals simply migrate to unprotected regions where they get caught accidentally.
This is believed to be the main reason why populations of loggerhead and leatherback turtles, both critically endangered, have slumped dramatically in recent years as commercial fishing with nets and extremely long fishing lines has become more intense.
Leatherback turtles have suffered particularly badly in the Pacific Ocean where populations have fallen by more than 90 per cent in just 20 years. Sharks and albatrosses have also declined significantly as a result of being caught accidentally by fishermen.
Creating mobile protection areas monitored by satellite would enable some of the world's most endangered species to recover, as well as allowing fishermen to ply their trade in other parts of the ocean where by-catch is less likely, said Larry Crowder, professor of marine biology at Stanford University in California.
"Small, stationary reserves do little to protect highly mobile animals, like most fish, like the turtles and sharks and seabirds. You might say that the only way to achieve conservation of these kinds of organisms is to protect them everywhere in the ocean," he said.
"But we don't need to close the entire ocean; we only need to close the place where they are concentrated," he told the American Association for the Advancement of Science in Vancouver.
Satellite tagging and other ways of monitoring the movements of marine creatures have shown that sea life tends to congregate near oceanographic features such as "upwellings", where rising currents bring minerals to the sea surface, and "convergence zones", where ocean currents collide. "Those are where everything in the ocean goes to feed, and the fishermen understand that," Professor Crowder said. These features tend to move, taking sea life with them.
"Satellite technology, tagging and acoustic technology allows us to look into the ocean and figure out who is going where," he added. "The time is ripe for the idea of mobile marine protection areas and a good candidate to consider is the North Pacific convergence zone. We know it moves seasonally. In the summer it's about 1,000 miles north of Hawaii and in the winter, it is further south."
Caught in the net: Threatened species
Turtles
The number of leatherback turtles in the Pacific have declined by 90 per cent in 20 years with by-catch a main cause. The loggerhead turtle has been hit particularly hard by shrimp trawling.
Albatrosses
They can become caught on fishing lines and drown. The northern royal albatross is an endangered species.
Sharks
An estimated 50 million sharks are caught unintentionally every year. The angel shark, vulnerable to by-catch, is now one of the five most endangered shark species.
Charlie Cooper
Protection zones 'should go mobile'
(UKPA) Google news 18 Feb 12;
Mobile protection areas that follow the movements of fish, turtles and sea birds may be the best way to safeguard creatures in the oceans, a leading expert claims.
The "pelagic" conservation zones would not impose fishing restrictions in one place, but shift location according to where threatened species are expected to be.
US marine biologist Professor Larry Crowder believes advances in satellite tagging and oceanography has made the change from static Marine Protected Areas (MPAs) feasible. He points out that such a system could actually benefit fishermen by allowing for more flexibility.
Once an endangered species moved out of a zone they wanted to fish in, they would no longer be restricted in that area.
Speaking at the annual meeting of the American Association for the Advancement of Science in Vancouver, Canada, Prof Crowder said: "We think of protected areas as being a place and we think of that place as being locked down to a map but places in oceans aren't locked down to maps, they move.
"Now the science is in place both in terms of tagging technology for the organisms that you're concerned about and the underlying oceanography."
Animals migrate across the oceans in search of food and to find mates. But such behaviour can be influenced by factors such as ocean floor geology and currents, said Prof Crowder.
The North Atlantic Convergent Zone, for instance, was a massive front where two current systems meet, causing a concentration of food and marine species. Its location changed with the seasons.
"That moves 1,000 miles north and south seasonally," said Prof Crowder. "In the summer it's 1,000 miles further north than in the winter. If you decide to protect something there it makes no sense to protect in that dimension, in latitude, because the feature moves."
International agreements might be needed to make mobile marine protection areas workable in the open ocean, Prof Crowder acknowledged. But he pointed out that there were already international agreements for mining the ocean floor.
