GOLDEN GATE CETACEAN RESEARCH
Field Studies of Porpoises, Dolphins & Whales
in San Francisco Bay and on the Coast of Northern California
Goals and Methods: Using techniques developed with minke whales in the San Juan Islands and Monterey Bay, our project will collect the following data to use as values for parameters in the Mass-Balance Model --
Population Size: Photographic identification techniques are used to estimate minimum population size.
Individual Residency Patterns: We look for patterns that suggest whether individuals seasonally migrate or are year round residents.
Feeding Rates: The number of feeding events per hour is calculated to gauge individual foraging success rates. This can be used to compare over time and between areas. Changes in feeding rates within an area may indicate an environmental shift. Feeding represents a transfer of energy and material from one trophic level to another, “higher” one.
Foraging Behavior: We have identified two distinct feeding strategies employed by minke whales. Each strategy has its own costs and benefits (Hoelzel et al. 1989). What strategy do Bay Area minke whales use? Check back here, when we figure that out, you’ll be the first to know!! And we are also interested in search behavior.
Top-Down Effects: The impacts of top level predators on lower trophic levels. We are using computer models to estimate energy flow rates between trophic “compartments” in the the local marine ecosystem. Parameter values will be derived from the results of our field work.
This research is authorized by a Letter of Confirmation issued by the National Marine Fisheries Service.