科学家降低墨西哥湾地区生态评级

Six months after the rig explosion that led to the largest offshore oil spill in U.S. history, damage to the Gulf of Mexico can be measured more in increments* than extinctions*, say scientists polled by The Associated Press.

In an informal survey, 35 researchers who study the Gulf lowered their rating of its ecological health by several points, compared to their assessment before the BP well gushed* millions of gallons of oil. But the drop in grade wasn't dramatic. On a scale of 0 to 100, the overall average grade for the oiled Gulf was 65 — down from 71 before the spill.

This reflects scientists' views that the spilled 172 million gallons of oil further eroded what was already a beleaguered* body of water — tainted for years by farm runoff from the Mississippi River, overfishing, and oil from smaller spills and natural seepage*.

Surprisingly, there are some wildlife winners from the oil spill. That's because there was a commercial fishing ban for months in parts of the northern Gulf, offering respite* to some overfished species. More than 90 percent of the Gulf's federal waters are now open to fishing.