Aquarium of the Bay Research Project

Tracking Sevengill Sharks In San Francisco Bay

Sevengill sharks, Notorhychus cepedianus, live and reproduce in San Francisco Bay, but little is know about their behavior and ecology. Working with UC-Davis’ Biotelemetry Lab, Aquarium of the Bay staff are implanting two different types of transmitters into sevengills to track and detect the movements of sevengills in the bay.   Click here to see a mini-documentary about our sevengill shark tagging program.

During the 2008 project season, the Aquarium actively tracked four adult sevengills using ultrasonic transmitter tags implanted in the shark’s body. After tagging the shark, it is released back into the bay. Then, the transmitter sends a continuous record of the shark’s swimming direction, depth, and geographic coordinates. On the Aquarium’s research vessel, the Blue Shark, staff follow the tagged shark continuously for one to three days. The data collected will reveal valuable information about sevengill movements and activities in the San Francisco Bay. 

In addition to the ultrasonic transmitters, the Aquarium Team implanted coded signature beacons in twenty sevengills. These beacons have a lifespan of five years, and transmit a signal every 45 to 95 seconds. Monitors positioned throughout the bay detect and record these signals, collecting information that will provide a long-term perspective on the sharks’ life patterns and basic ecology.