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This is the VOA Special English Environment Report.
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Scientists in Canada say big oceanfish have almost disappeared from the world since the start ofindustrial fishing in the nineteen-fifties. The scientists foundthat populations of large fish like tuna, swordfish and cod havedropped by ninety percent in the past fifty years.
The study took ten years. The researchers gathered records fromfishing businesses and governments around the world. The magazineNature published the findings.
The scientists say the common method called longline fishing isespecially damaging to populations of large fish. This methodinvolves many fishing lines connected to one boat. These wires canbe close to one-hundred kilometers long. They hold thousands ofsharp metal hooks to catch fish.
Longline fishing is especially common in the Japanese fishingindustry. Records showed that Japanese boats used to catch about tenfish for every one-hundred hooks. The study says longline fishingboats now might catch one fish per hundred hooks.
Modern methods also include the use of satellites and underwaterradar to find fish.
The scientists say industrial fishing can destroy groups of fishmuch faster than in the past. The study suggests that wholepopulations can disappear almost completely from new fishing areaswithin ten to fifteen years.
Ransom Myers of Dalhousie University in Nova Scotia led the studywith Boris Worm of Dalhousie and the University of Kiel in Germany.Mister Worm says the destruction could lead to a completere-organization of ocean life systems. Mister Meyers says thedecreased numbers of large fish is not the only worry. He says evenpopulations that are able to reproduce do not get the chance to livelong enough to grow as big as their ancestors. He says not only arethere fewer big fish, they are smaller than those of the past.
American government scientists say even with the best efforts toprotect fish populations, decreases are to be expected. Fishingindustry groups say the study makes the situation seem worse than itis. They say programs are in place to help repopulate big fish wherenumbers are low. And they say there have already been someimprovements.
Last year, many countries signed a declaration in South Africa towork toward the recovery of fishing areas by two-thousand-fifteen.
This VOA Special English Environment Report was written by CatyWeaver.