Project: Sevengill Shark movements within San Francisco Bay

Introduction:

Fig. 1. Sevengill shark. Photo by M. Buckhorn

Sevengill sharks (Fig. 1) are common inhabitants of estuaries and bays from southeastern Alaska to the southern end of Baja California. They are a top predator in this system feeding on fish and other elasmobranchs as adults. Very little is known about their movements or reproduction in this area. It hypothesized that San Francisco Bay is the primary pupping grounds for west coast sevengills.

Fig. 2. Golden Gate Bridge as seen from San Francisco Bay. Photo by M. Buckhorn

Objective:

To gain knowledge of sevengill movements within San Francisco Bay (Fig. 2), and to detect potential habitat preferences and migration patterns of sevengill sharks. This will provide much needed information for management and conservation of this large predatory species.

Methods:

Sevengill shark movements will be actively tracked using continuous Vemco transmitters implanted in the abdominal cavity of the sharks (Fig. 3). Tracks will be attempted on individual sharks for a period up to 72 hours. An additional 20 sharks will be implanted with coded Vemco transmitters and those sharks will be tracked using the monitor array in San Francisco Bay.

Progress:

The field portion of this study is complete and the data is being prepped for publication. There is also a mini-documentary produced by David McGuire called “City of the Shark” that will be used for research fundraising purposes. A second year of the study is being planned.

Personnel:

Fig. 3. Dr. Buckhorn surgically inserting ultrasonic tag into a sevengill shark. Photo by M. Buckhorn

Michele Buckhorn, Ph.D. (lead)

Pete Klimley, Ph.D. (P.I.)
Department of Wildlife, Fish, & Conservation Biology, University of California, Davis

Christina Slager
Director of Husbandry, Aquarium of the Bay

Mike McGill
Boat Captain & Senior Aquarist, Aquarium of the Bay

Funding Sources:

The Aquarium of the Bay Foundation. Results from this project will contribute to conservation efforts and also be used for the Aquarium’s educational programs.