UC Davis

The northeastern Pacific population of the broadnose sevengill shark, Notorynchus cepedianus, is a large apex predator found ranging from Alaska, USA to Mexico. Like other large shark species, sevengill sharks face threats of overfishing and climate change. Threats to sevengill sharks may be exacerbated in areas considered essential for aspects of their life history, such as breeding or feeding. The northeastern Pacific population of sevengill sharks is known to frequent bays and estuaries along their range, but the only suggested nursery areas have been Humboldt and San Francisco Bays, California, USA. California has an open targeted fishery that is not restricted to size, sex, season, or location. This dissertation 1) tests whether San Francisco Bay is a nursery habitat based on published criteria, 2) evaluates sevengill physiological response to catch-and-release fishing, and 3) investigates attitudes and opinions of current sevengill management and explores the ecological knowledge of key stakeholders (charter captains and California Fish and Wildlife (CDFW)). Results demonstrate that San Francisco Bay is a shark nursery area for sevengill sharks as previously suggested. Significant physiological effects were observed during 30-minute catch-and-release stress events. Stakeholder interviews revealed positive attitudes of charter captains towards informed conservation management, with captains proactively implementing fishing restrictions more strictly than what is required of them by CDFW. Results suggest that if the population is at risk in the future, San Francisco Bay is an essential fish habitat worth exploring for protections, and would be well supported in San Francisco Bay, California, where they are frequently targeted by recreational anglers.