PSG 2012 Hawaii abstracts - Pacific Seabird Group

OR; 3 Moss Landing Marine Laboratories, Moss Landing, CA; 4 U. S. Geological Survey, Western
Ecological Research Center, Dixon, CA; 5 Bureau of Ocean Energy Management, Pacific Outer
Continental Shelf Region, Camarillo, CA; 6 U. S. Geological Survey, Western Ecological Research
Center, Vallejo CA.
Interest has increased for developing renewable energy sources to reduce U. S. dependence on oil. Some
policy makers include power generation along the continental shelf of the U. S. Pacific coast, beyond
state waters. This region supports abundant populations of seabirds and marine mammals, but
comprehensive, multi-seasonal aerial surveys were conducted two decades ago. Marine spatial planning,
including potential site selection for offshore energy development, requires the description and
quantification of recent species-specific and community patterns in distribution. To relate patterns of
seabird abundance to physical and biological characteristics of ocean habitats, we conducted lowelevation
aerial seabird surveys during January, June, and October 2011 (and continuing in 2012) along
parallel strip-transects spanning continental shelf and slope waters from Fort Bragg, CA to Grays Harbor
WA. Although effort focuses on Federal Waters outside of the 3-nautical mile state boundary, surveys
include inshore waters to allow comparisons both within and adjacent to potential renewable energy
developments. In the past, environmental analyses of aerial seabird surveys have relied on satellitederived
products of ocean optical properties that are coarse in scale or temporally-averaged to produce
better spatial coverage. Therefore, in addition to aerial pyrometry to measure sea-surface temperature, we
installed an on-board hyperspectral radiometer to collect remotely-sensed reflectance simultaneously with
species observations. Herein, we discuss survey methods and describe inter-seasonal trends in abundance
and distribution for marine birds and variability in the ocean environment, and introduce aerial
hyperspectral radiometry as a potential tool for delineating fine-scale ocean habitat features (fronts and
watermasses) based on ocean color.
CASPIAN TERN (HYDROPROGNE CASPIA) FORAGING ECOLOGY AND PREDATION ON JUVENILE
SALMONIDS IN SAN FRANCISCO BAY, CALIFORNIA
Lindsay J. Adrean *1 , Daniel D. Roby 1 , Donald E. Lyons 1 , Ken Collis 2 , and Allen F. Evans 2 , 1 U.S. Geological
Survey – Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, 104 Nash
Hall, Oregon State University, Corvallis, Oregon 97331, USA, lindsay.j.adrean@state.or.us; 2 Real Time
Research, Inc., 52 S.W. Roosevelt Ave., Bend, Oregon 97702, USA.
Brooks Island in San Francisco Bay is a proposed relocation site for some Caspian Terns (Hydroprogne caspia)
currently nesting in the Columbia River estuary. A bioenergetics modeling approach and radio-tracking of
Caspian Terns nesting on Brooks Island in 2008 and 2009 were used to estimate consumption of Endangered
Species Act–listed juvenile salmonids (Oncorhynchus spp.) and examine availability of other forage fish
resources. Estimated salmonid consumption was ca. 205,000 smolts in 2008 and ca. 167,000 smolts in 2009.
Estimated predation rates on threatened Central Valley spring-run Chinook (0.1%) were lower than those on
unlisted fall-run Chinook (1.0%). Assuming mortality from Caspian Tern predation is 100% additive, the
proposed enhancement of the colony to 3,000 individuals would at most cause declines in annual population
growth rates (λ) of 0.02% for spring-run Chinook and 0.28% for fall-run Chinook. The median foraging distance
from the colony was greater in 2009 compared to 2008 (20.6 km vs. 14.0 km), average number of foraging trips
per day was higher (4.4 vs. 3.4 foraging trips), and average adult colony attendance was lower (43% vs. 52% of