Monster Seminar JAM - Retrospective analysis of a century of fishing and oceanographic variability on seabird diets in the California Current System
Dr. Steven R. Beissinger, Professor, Environmental Science, Policy & Management, University of California, Berkeley
Overfishing has changed marine community structure, species dominance and ecosystem characteristics. Subsequently, trophic interactions observed today might be artifacts of recent structural changes to marine communities. However, the relative impacts of overfishing are often difficult to distinguish from natural variability in fish stocks due in part to fluctuations in ocean climate that affects community composition. I investigate how the trophic level of five marine avian predators (Cassins Auklet, Common Murre, Marbled Murrelet, Pelagic Cormorant and Tufted Puffin), which differ in contemporary food habits (ranging from planktivorous to piscivorous to omnivorous), has varied over the past century in the California Current by reconstrucint their diets from changes in their stable isotopic signatures, and whether diet variation can be attributed to the overfishing of prey or cyclic changes in ocean temperature.
Date and Time:
March 31, 2011,
11:00 am - 12:00 pm