2016 Summer Internship Program
Acoustic Monitoring Analysis of Belugas in Bristol Bay, Alaska
Hi my name is Caroline Tribble; I am a senior Biology major from Virginia Polytechnic Institute and State University. During my JISAO internship I had the honor and privilege of working with Dr. Manuel Castellote in the Marine Mammal Laboratory (MML) at NOAA Alaska Fisheries Science Center on acoustic monitoring of belugas in Bristol Bay, Alaska. This project aims to study the feeding behavior of Bristol Bay belugas to better conservation and management of Cook Inlet beluga population. Cook Inlet watershed almost surrounds Anchorage, an area with high noise pollution and boat traffic. When the Cook Inlet beluga population became endangered, hunting of the animals was prohibited. However, the population is continuing to decrease.
During my stay in Washington, I analyzed spectrogram data on MATLAB while listening to DTAG deployments to locate intense click train packets. These clicks become a terminal buzz, as the click train transitions to a buzz there can be a clear jerk in acceleration, indicating prey chasing. Whales were tagged with acoustic DTAGs, satellite tags, and given stomach temperature drop pills (STPs) during summer months of 2014 to 2016. The DTAG has two hydrophones facing the whale’s head, which record acoustic behavior and the surrounding environment. The satellite tag locates the whale throughout the deployment, while the STP locates points of temperature drops in the stomach, indicating ingestion of prey.
After spectrogram analysis, I compared times of temperature drops in the STP to echolocation activity in spectrograms to confirm feeding. From here I identified locations of the whale closest to these drop times using satellite tag data. We found the whales were concentrating around and up into the Snake River to feed. By determining where the whales in Bristol Bay are feeding, this information can be applied to Cook Inlet. Acoustic signals indicative of feeding can be used to monitor Cook Inlet river mouths and better describe critical habitat for the endangered Cook Inlet beluga.
Being a part of this internship at JISAO has greatly benefited me, preparing me for future research experiences. I have become a better marine science researcher and learned so much about acoustics, whales, and MATLAB software. Not only this, but I met some really incredible people and had the opportunity to explore the many beautiful hiking spots Washington has to offer. Thank you JISAO for this amazing experience!