USC Wrigley Institute – wrigley.usc.edu
By Yukun Lin
As a Wrigley Marine Science Center Summer Fellow, my project this summer is to track leopard sharks with AUVs (Autonomous Underwater Vehicles) in Big Fisherman Cove on Catalina island.
Why track leopard sharks? They are model systems for Elasmobranchii (a subclass of fish that includes sharks), and by studying and understanding the behavior of leopard sharks, we can make inferences about other species of sharks.
To track the leopard sharks, we first tag them with an acoustic tag, which sends out a “ping” every 2 seconds. These pings are picked up by stereo hydrophones mounted below our AUVs, and are used to determine the location of the tagged shark. With the location of the sharks known, the AUV is able to follow the shark autonomously. Of course, we don’t want to end up chasing the shark around, so we program the AUVs to always keep a standoff distance from the tagged shark.
This summer, we will also be tagging leopard sharks with a new tag that clamps onto the fins of the shark. In addition to an acoustic pinger, the tag will also have a video camera, a MARG (Magnetic Angular Rate and Gravitational) sensor, and a VHF transmitter. The tags are programmed to release from the shark after a certain period of time by unclamping, allowing us to recover the tag to download data from it and also to reuse it.
The technologies that allow marine biologists to tag and track sharks were only developed in the last few decades; we hope to further develop these technologies to help marine biologists gain an even better understanding of the behavior of these animals.
Yukun is a student at Harvey Mudd College in the Department of Computer Science, working in collaboration with Cal State University Long Beach’s Shark Lab.