Speaker: Dawn Barlow, Postdoctoral Scholar, Marine Mammal Institute, Oregon State University, Hatfield Marine Science Center

Topic: Three decades of nearshore surveys reveal habitat use, distribution, and abundance of gray whales and harbor porpoises in the Northern California Current

The coastal waters of the Northern California Current are home to abundant biological productivity. We use a 31-year dataset of standardized, nearshore surveys between San Francisco Bay and the Columbia River to examine the distribution and abundance of two marine predators with different life history strategies and prey requirements: gray whales and harbor porpoises. We investigate how coastal upwelling dynamics and biogeographic features influence their habitat use patterns, and how their abundance has fluctuated over time. Our findings reveal long-term, stable hotspots in gray whale distribution patterns, shedding light on how nearshore habitat characteristics shape foraging opportunities. The distribution of harbor porpoises overlaps with several different forage fish species throughout our study area, and we illustrate potential region-specific prey preference patterns. Finally, we consider our analysis of the past three decades in the context of how global climate change is influencing these coastal marine mammals, and what changing ocean conditions may mean for their future.