America's fish varieties declining
29/07/2005 - 07:18:25US scientists say the variety of tuna, marlin, swordfish and other big ocean predators has declined up to 50% over the past half-century because of overfishing.
For the first time, ecologists and oceanographers mapped the hotspots with the largest concentrations of many big fish species, then and now. Their findings are reported in the online edition of the journal Science.
The scientists found average declines of about 50% in diversity in the Atlantic and Indian oceans and an average decline of about 25% in the Pacific.
They also discovered a link between the sea surface temperature and level of oxygen in the water and where the big fish concentrated.
