Assessing the anthropogenic impacts, long-term health, and welfare of elasmobranch species within San Francisco Bay, California
Grantee: Meghan Holst
Institution: University of California, Davis, United States
Grant amount: $19,200
Grant type: Small grants
Focal species: Shark (Selachimorpha sp.)
Conservation status: Near threatened
Disciplines: Animal welfare science, population ecology, community ecology, marine biology, ichthyology
Research location: United States
Project summary
Individuals belonging to several elasmobranch populations use the San Francisco Bay Estuary during critical periods of their life history. For example, the broadnose sevengill shark (Notorynchus cepedianus) is an apex predator that visits seasonally to pup. Pups then appear to reside in the estuary for several years before they join the adult population that migrates from Alaska to Baja, California. The San Francisco Bay also serves as a major harbor for container and cruise ships. To allow these large vessels to enter the bay, dredging occurs continuously within San Francisco Bay in the primary channel where many of the adult elasmobranchs also reside, potentially increasing contaminant exposure. Additionally, both commercial and recreational fishing occurs on shark species and their preferred prey, posing direct physiological impacts on elasmobranchs and constraints to their prey availability. Little has been done to evaluate potential unrecognized consequences of these activities on the health and welfare of elasmobranch species and the San Francisco Bay ecosystem. To address this gap in knowledge, this project will measure stress physiology and blood contaminants to evaluate whether the health and welfare of elasmobranchs is threatened within San Francisco Bay, and evaluate dietary needs of elasmobranch species within San Francisco Bay to determine whether individuals are threatened with hunger/starvation due to fishing of their preferred prey. Stable isotope analysis of the sharks and potential prey will also be used to more precisely identify their dietary needs and sensitivities, and ultimately map ecological relationships within the ecosystem.
Why we funded this project
We funded this project primarily because it addresses our interest in understanding the welfare implications of ecological system dynamics. The project also focuses on lifestage-specific ecological differences within the focal species, focusing on juveniles, which are the most numerous and often neglected. Additionally, the lead researcher is a PhD student who has an interest in wild animal welfare and has already demonstrated an aptitude for coordinating scientific research projects. The ability to write a compelling proposal at such an early research stage is very promising for their future career prospects.
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