Behavioral Analysis and Distribution of Marine Mammals in Southern California
Authors:Tanya Camper, Georgina Stone
Mentor:Lei Lani Stelle, Associate Professor of Biology, University of Redlands
In the summer months, the Southern California bight serves as feeding grounds for many species of marine mammals. Prey is concentrated along the continental shelf due to seasonal upwelling increasing nutrients. We hypothesized we would observe migratory whales feeding on the edge of the Continental Shelf, while resident species would be observed throughout the study area engaged in an equal mix of behaviors. We conducted surveys via boat transects and shore stations to monitor distribution of all marine mammals species, as well as boat traffic. Animals were photographed for identification, and behaviors and respiration data were recorded. GIS mapping was used to visualize the distribution and habitat use of each species, along with the locations and interactions of boats with marine mammals. The most commonly observed species (most frequent to least) were California Sea Lions (Zalophus californianus), Long Beaked Common Dolphins (Delphinus capensis), Blue Whales (Balaenoptera musculus), Bottlenose Dolphins (Tursiops truncatus), and Short Beaked Common Dolphins (Delphinus delphis). Twenty-one individual Blue Whales were identified and five individuals were resighted multiple times. Feeding was the most commonly observed activity in Blue Whales. Blue whales spent significantly more time feeding than traveling, resting, socializing, mating, milling, or unknown (χ2 = 36.57, p < 0.05, df = 6, N = 37). . GIS analysis is ongoing but the majority of sightings are on the edge of the continental shelf, as hypothesized. This research provides important data on marine mammal abundance, distribution, and habitat use.