WASHINGTON (AFP) - Improved fishing nets have saved tens of thousands of endangered sea turtles in recent years, but 4,600 are still dying annually, mainly in Gulf of Mexico shrimp trawls, said a US study on Wednesday. Turtle-excluder devices (TEDs), or large holes that allow the creatures to escape from nets that nab smaller marine creatures, have helped cut back on sea turtle deaths up to 94 percent since the 1990s, said the report in the journal Biological Conservation. The current annual death rate is a dramatic reduction from the estimated peak of about 71,000 before protective measures were put in place, said the Duke University-led study which examined data from the US National Marine Fisheries Service on 20 US coastal fisheries.