Saturday, May 28, 2011
A young Gray Whale carcass that washed up on a beach south of Cambria was probably killed by Orcas, researchers who examined it say. I guess if you're involved with research, lying down next to the carcass makes sense. Thanks to Nicky Beaulieu of the National Marine Fisheries Service’s whale-stranding team for posing to help us get perspective on the size of the body.
The lower jaw and tongue were missing, which is typical of Orca kills. The body also showed 'rake' marks, that could have been made by Orca teeth.
In happier news, a female elephant seal with a GPS tracking device showed up at Piedras Blancas, so a team came down from Santa Cruz to retrieve the device. "The team, with a federal marine mammal research permit, notified the local docents on bluff duty and went down on the beach below the dunes south of the boardwalk with their equipment. They sedated the seal, removed the GPS unit, about the size of a wallet, glued to her head, weighed her, took blood, and did an ultrasound to determine the depth of her blubber (5 to 6 inches), an indication of how much weight she had added while foraging since her winter fast. They weighed her by putting her on a tarp attached to steel poles, winching it up and weighing it, then deducting the weight of the tarp. She weighed 900 pounds."
Dan Costas discussed the significance of retrieving the devices, how much more data can be extracted when the device itself is available. I look forward to learning more about where this animal traveled and what she was eating.
Friday, May 6, 2011
Dan Costa of UCSC presented his research on using elephant seals and other seals as data collectors. Their ability to dive deep makes them preferable to mechanical remote sensing vehicles -- they just dive where they want to go. By attaching electronic equipment to them, his team has been able to collect data from places that were previously inaccessible. "Technology is allowing us to do things we only dreamed of until recently," he said.
These animal oceanographers have provided data on ocean weather, the fronts that move through the ocean as storms move through the atmosphere. The devices they wear report back on changes in temperature, condition of ice, where krill are. Among elephant seals, usually females age six or seven are tagged. He told about the serendipitous mistake one team of students made, mis-reading a tag and attaching a device to a 17-year-old female. The amazing thing is, out of all the seals on the beach, she was one who had been tagged 11 years earlier as a six-year-old. The device recorded her journey across the Pacific, far west past the tip of the Aleutians, the same journey she made 11 years before. He said he's still kicking himself that he didn't ask the students to tag her again the next year. She was reported on the beach with a new pup through 2010. The devices are revealing more about elephant seal behavior, too. Females and males have different diving and feeding behavior. I'll post more on that next week.