Many of the turtles appear to have propeller wounds from boats or have become entangled in fishing nets or lines, Howell says. Others have parasites or are emaciated. The increase in deaths comes as the turtles swim closer to shore to nest and shrimping season gets into full swing along the upper Texas coast, said Roger Zimmerman, lab director of the NOAA marine fishery laboratory in Galveston. "Historically, they increase about this time of year. ... This is a few more than we would normally expect," Zimmerman said. "We are concerned and we'll keep an eye on it." Researchers are also watching the massive oil spill off the coast of Louisiana. If the oil were to begin moving in the direction of the Texas Gulf — which isn't predicted at the moment — many Kemp's ridleys swimming in to nest would be right in its path. In 1979, after an oil spill off the coast of Mexico, Kemp's ridleys were airlifted to cleaner waters.