In a complementary study to our work on kelp forests, the BREACH lab is also studying sea otter feeding behavior in Sitka Sound. Below is a summary the work we did last summer (2015), written by BREACH graduate student Coralie (Coco) Delorme. Thanks, Coco!
Hello everyone, my name is Coralie Delorme and I am a Msc student in Animal Behavior and Ecology at the University Jean-Monnet in France. Because of my passion for marine biology I came to Alaska as an exchange student and had the chance to study Sea Otters for my Master's project thanks to Heidi.
During the summer 2014 we went to Sitka and observed sea otter behavior from Allen Marine boats. Because of their history, the reintroduction of sea otters in Alaska led to an important conflict between them and Alaska fisheries, which depends economically on the same prey species that sea otters are targeting. Our main goal was thus to identify what otters were preying on in Sitka Sound. We were also interested in knowing if the macro nutrient composition of prey items had an influence on the prey choice, and if mothers with pups are more likely to eat bigger sized prey items with a higher content in macro nutrient.
Sea otter activity was determined by scanning the ocean's surface through a camera Nikon D7000 with a 500mm lens and through laser range-finder binocular which allowed us to obtain the distance of sea otters to the boat. Before an otter was disturbed by the presence of the boat, we recorded for each sighting of otters, their behavior classified as foraging, grooming, traveling or interacting, as well as the time of arrival and departure, the presence of a pup and other environmental factors such as visibility, cloud coverage and wind intensity determined by using the Beaufort chart. Then, when we approached a raft or single otters we determined their location using a global positioning system (GPS Garmin) and also indicated any change in behavior due to the presence of the boat and finally pictures were taken in order to verify the number of otters counted, the presence of pups and to identify the prey eaten when they were foraging.
Here are some photos I took from the boat. Enjoy!