Image by spakattacks via Flickr

Something is killing endangered sea turtles in the Gulf of Mexico.

Last month’s explosion and blowout of the BP-Deepwater Horizon oil rig was immediately blamed for the deaths of sea turtles whose carcasses had washed ashore. But most of dead turtles had stranded (washed up) before the oil rig disaster.

As I reported for OnEarth, marine biologist and sea turtle expert Andre Landry, Jr., told me, “At this point, I can’t say if any turtles have died due to oil from the rig explosion. That doesn’t mean they haven’t. And it certainly does not mean that they won’t.”

On Wednesday, Barbara Schroeder, the national sea turtle coordinator for the National Oceanic and Atmospheric Administration (NOAA) issued this statement about an additional 38 sea turtles that had stranded after April 30.

Based on careful examination, NOAA scientists do not believe that these sea turtle strandings are related to the oil spill. NOAA and its partners have conducted 10 necropsies so far – none of ten turtles showed evidence of oil, externally or internally.

Did the shrimp trawls do it?

So, what killed these turtles?

Carol Allen seems pretty certain that she knows the culprit: Shrimp trawlers.

“It is highly likely that shrimpers are taking advantage of the oil crisis,” says Allen, who directs the Gulf office of the Sea Turtle Restoration Project (STRP). “Probably few law enforcement officers have the time to board their boats” to check on the TEDs.

Turtle Excluder Device in action. (Courtesy of NOAA)

TED, incidentally, is short for Turtle Excluder Device — a combination grate (to stop turtles but allow shrimp to pass to the back of the net) and a trap door that allows turtles to escape. The use of TEDs is mandated by law, but adequate enforcement of that law is difficult, even when there is no massive oil gusher commanding official attention.

And a 2002 study by NOAA estimated that 25,000 sea turtles die annually in the gulf due to shrimp trawls.

But how many of those deaths are attributable to shrimpers not using TEDs or rendering them ineffective? I’ve put that question to several experts recently and none have been able to provide an answer beyond: we don’t know.

This morning I received an angry email from an attorney representing the shrimp industry. He was upset about another piece I wrote in which I quoted STRP’s Allen on the possibility that shrimpers are contributing to sea turtle deaths by messing with TEDs.

(He called the article a “slanted, unsupported, and factually inaccurate hit job on a vulnerable industry.” I replied with the data and studies supporting the facts in the article and asked him to point out the specific flaws in the studies cited. I’ll post his response here, when it arrives.)

Fishing regulations gone mild

I received another email, this one more reflective and insightful. The writer, Marydele Donnelly, is the director of international policy for the original sea turtle conservation group, the Caribbean Conservation Corporation, founded in 1959. Here’s what she wrote:

Many sea turtles are expected to perish in the Gulf of Mexico as a result of the Deepwater Horizon oil spill, along with enormous numbers of fish and other marine and coastal species. We should try to be as accurate as possible when talking to the press or writing about this event because there is just too much misinformation in the media these days as people rush to meet deadlines, don’t make the time to do research, and want to be out there first with the “scoop.”

Yesterday a colleague reported that turtle carcasses recently found in the Gulf were very decomposed and therefore believed to be the result of the winter’s cold stunning event and not the oil spill. Similarly, earlier today the National Sea Turtle Coordinator for the National Marine Fisheries Service reported a number of Kemp’s ridleys without externally visible oil have washed up on northern Gulf shores. Some colleagues suggest the deaths of these ridleys can be attributed to shrimpers not using Turtle Excluder Devices (TEDs) during intense fishing. It’s entirely plausible shrimpers aren’t using TEDs, but it is also possible these turtles died after being caught and released multiple times by shrimp boats using TEDs. Either way, the result is bad for the turtles.

It’s time to replace intense and chaotic southeastern shrimp fishing with comprehensive Gulf-wide time and area closures. Each year from mid May thru mid-July shrimping is banned in Texas out to 200 miles to allow brown shrimp to grow to a larger, more marketable size. During this period, Texas shrimpers move to the eastern Gulf and into the Atlantic to fish, putting more pressure on those areas. When the Texas closure ends, shrimp boats from everywhere descend on the Western Gulf. If only boats registered in the Gulf are allowed to fish for shrimp there and only boats registered in the Atlantic are allowed to fish for shrimp along that coast, marine resources in both areas would benefit.

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Osha Gray Davidson is the author of Fire in the Turtle House: The Green Sea Turtle and the Fate of the Ocean (PublicAffairs, 2003)