Friday, February 4, 2011

San Diego Bay Sea Turtle, Recovering at SeaWorld

The Power Plant is Closed - and the Turtles are Still Here!

December 31st, 2010, was the last day of operation for the South Bay Power Plant. For over 50 years, this massive plant has produced energy for San Diego businesses and residents, and now the four-unit energy-generator is silent. This was no surprise (read some past blog posts to learn more!). Regulators, residents and researchers all knew the power plant's days were numbered, it was just a matter of time. The plant used old technology, called once-through-cooling (OTC), and pulled in water in from the San Diego bay to cool and condense the steam used for the plant's operation, and the warmed water was then discharged back into the bay.

For several decades, the population of green sea turtles (Chelonia mydas) which forage (or eat) in the south part of the bay have been monitored by graduate students and researchers from NOAA's protected resources division at the Southwestern Fisheries Science Center. Since the power plant's closure, researchers have conducted two monitoring days, and each time turtles have been found. The first day yielded a remarkable 6 turtles found. And last week, while conducting a regular monitoring session, NOAA researchers, whom I've assisted for the past three seasons, found one sea turtle. This turtle, however, wasn't looking very good.

The large male green sea turtle (Chelonia mydas)
found in the San Diego Bay, and was later taken to Sea World
for rehabilitation.

The large male green turtle had been found in past years, as well as earlier this monitoring season. When I first met this particular turtle, two things were immediately noticeable: 1) a large portion of his tail is missing, 2) one of his rear flippers was quite mangled and injured. Neither of these injuries were recent, and were each likely due to entanglement and or interaction with a boat.

The left rear flipper and tail showed past injuries. The white bar is a
sonic tag used to monitor the turtle's location locally within the San Diego Bay.

Floating debris, such as discarded fishing line and plastic pollution, and boat strikes are common causes of injuries to turtles around the world. But the other thing that researchers noticed about this turtle, which was different from the past years, was that he was more lethargic than usual, and he had lost a considerable amount of weight. (Weighing and measuring turtles, in addition to tagging and photographing them, is part of the monitoring program for this endangered species.)

Images from SeaTurtle.org Image Library

The turtle found in the San Diego Bay last week is part of a population of green turtles that breed and nest at beaches in Mexico and off-shore islands and are an endangered species that is protected by the US Endangered Species Act and additional international agreements, such as CITES. Genetic research by NOAA's scientists is helping to identify where exactly the sea turtles in the San Diego Bay nest and breed.

Standard protocol for when a turtle is deemed to need immediate medical attention, is to transport the animal to the veterinarians at Sea World. NOAA scientists determined that this large male turtle needed help, and so we took him to Sea World for diagnosis and rehabilitation. This was the first such animal that I have encountered during my time helping NOAA which was is poor enough condition to warrant intervention. A goal of endangered species research is to be as minimally intrusive into their normal behaviors as possible.

Later in the week, I heard the news that x-rays had shown this turtle to have been shot. I couldn't believe the news. After thinking about it some more, I really wasn't all that surprised that some people might do this - after all - I've heard plenty of stories about sea lions being shot by people who view them as an annoyance, despite the animals being a protected species. And it seems there will always be a few people out there who give humans an especially bad image.

The doctors at Sea World said that the wounds from the four shots did not look new, so the shooting was not a recent incident. It is likely that a combination of factors, including being entangled when he sustained his tail/flipper injuries, cool winter temperatures, and any number of threats (trash, pollution, boats & etc.) were the cause of this turtle's lethargic state.

But the good news is that the large green turtle has received a good prognosis from the veterinarians treating him, and he should be released, perhaps later this summer, so that he can continue his life-journey as one of San Diego's sea turtles.