HALIFAX, Nova Scotia, April 6 (UPI) -- Canadian scientists said unlimited fishing has slashed populations of large predator fish and those caught now are half the size of fish caught in the 1950s.
Researchers at Dalhousie University studied a 6,000-square mile area in the middle of the equatorial Pacific Ocean. There they found populations of sharks, tuna and other top-of-the-food-chain fish were 80 percent smaller than they were 50 years ago.
"The main consequence of many years of industrial fishing in the area is a reordering of the ecosystem, thus increasing the number of small fish that we don't like to eat," said researcher Ransom Myers. "Pelagic stingrays are becoming a major part of the ecosystem, replacing tunas and other desirable fish. Yellowfin tuna, for example, caught in recent years, on average weigh half of those caught in the 1950s."
Several smaller species, such as the stingray and snake mackerel, have increased in abundance, but they have not replaced the lost biomass resulting from over-fishing of the larger fish.
The study is published in the April issue of the journal Ecology.
