Thursday, November 02, 2006

On The Depletion Of Marine Species By 2048 Due To Overfishing, Pollution, And Other Environmental Factors

"The world will run out of seafood by 2048 if steep declines in marine species continue at current rates, according to a study released today by an international group of ecologists and economists.

The paper, published in the journal Science, concludes that overfishing, pollution, and other environmental factors are wiping out important species across the globe, hampering the ocean's ability to produce seafood, filter nutrients and resist the spread of disease.

"We really see the end of the line now," said lead author Boris Worm, a marine biologist at Canada's Dalhousie University. "It's within our lifetime. Our children will see a world without seafood if we don't change things."

The 14 researchers from Canada, Panama, Sweden and the United States spent four years analyzing all the available data on fish populations and ocean ecosystems to reach their conclusion. They found that by 2003 -- the last year for which data on global commercial fish catches is available -- 29 percent of all fished species had collapsed, and that the rate of population collapses has accelerated in recent years.

As of 1980, just 13.5 percent of fished species had collapsed, even though fishing vessels were pursuing 1,736 fewer species back then. Today, the fishing industry harvests 7,784 species commercially." ...

Juliet Eilperin "Seafood Population Depleted by 2048, Study Finds" Washington Post November 2, 2006


Monterey Bay Aquarium Seafood Watch: Make Choices for Healthy Oceans

Pacific bluefin tuna
Thunnus orientalis

"Bluefin tuna are some of the largest and fastest fish in the ocean—they’re powerful swimmers, built for endurance and speed. To help conserve energy on its long-distance journeys, a tuna’s body is almost perfectly streamlined, reducing drag around its fins. And a tuna can retract those fins so water flows more smoothly over its body. This makes the tuna super-streamlined.

Unlike most fish, tuna are warm-blooded and can heat their bodies up to 20° C (36° F) warmer than the surrounding water. This added warmth helps a tuna’s muscles work faster and more efficiently. Tuna consume as much as 5% of their body weight daily and must continually swim with their mouths open to force water over their gills, supercharging their blood-rich muscles with oxygen.

Pacific bluefin tuna spawn midway between Okinawa and the Philippines and possibly in the Sea of Japan, then migrate over 6,000 nautical miles (11,112 km) to the eastern Pacific, eventually returning to their birth waters to spawn.

Diet fish, krill, pelagic red crab, squid

Size to 10 feet (3 m), 1,200 pounds (555 kg)

Range northern Pacific Ocean

Relatives yellowfin and albacore tuna, mackerel, bonito; Family: Scombridae

Conservation Notes Avoid eating bluefin tuna; they’re severely overfished throughout the world. They’re caught nearly everywhere they swim, and many young bluefins are caught before they have the chance to reproduce. Visit the Seafood Watch section on our web site to learn about choosing seafood wisely.

Creating effective fishing policies for bluefin tuna is difficult since they’re highly mobile and swim through the territorial waters of many different nations. Data about their movements and high levels of international cooperation are needed to ensure sustainable bluefin tuna populations.

To help provide some of this data, staff at the Tuna Research and Conservation Center have been tagging both Atlantic and Pacific bluefin tunas in the wild as well as studying them in their facility, next door to the aquarium. This research is helping inform fishing policies for bluefin tuna worldwide.

Cool Facts A Pacific bluefin tuna is capable of swimming at speeds of 12 to 18 miles (20-30 km) per hour for brief periods.

Magnetite, a mineral found in neural pits in the tuna’s snout, may be used by the tuna to detect the earth’s magnetic field for navigation."

Photo and text credit: (c) Monterey Bay Aquarium. With thanks.


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