Kittlitz’s and Marbled Murrelets in Kenai Fjords National Park, Alaska: At-sea Distribution and Abundance, and Foraging Habitat
Arimitsu ML, Piatt JF, Romano MD, Conaway J. 2008. Kittlitz’s and Marbled Murrelets in Kenai Fjords National Park, Alaska: At-sea Distribution and Abundance, and Foraging Habitat. U.S. Geological Survey. Anchorage, AK
During summer 2007, the second year of a 3-year study, we conducted research focusing on distribution and abundance of Kittlitz’s Murrelets (Brachyramphus brevirostris) and Marbled Murrelets (Brachyramphus marmoratus) in the nearshore waters adjacent to Kenai Fjords National Park, Alaska. Using a systematic design, we conducted a coastwide survey of marine birds and mammals, June 25-29, 2007, to determine broad-scale distribution and abundance of murrelets and other species. We also conducted additional surveys in selected bays in June and August. We estimated there were 346 (95% CI: 132-908) Kittlitz’s Murrelets and 3229 (95% CI: 2123-4912) Marbled Murrelets in the nearshore waters we surveyed during mid-summer. Kittlitz’s Murrelets had a clumped distribution and were found only in the upper ends of glacial fjords. Marbled Murrelets were more widely distributed. Based on our nearshore fish sampling and observations of birds eating and carrying fish, we found Pacific herring, Pacific sand lance, and spawning capelin are important forage species for both Kittlitz’s and Marbled Murrelets in Kenai Fjords. We found acoustic backscatter (a proxy for biomass) was higher in glacial areas of Northwestern Lagoon compared to glacial areas in Aialik Bay. Euphausiid density in trawls was negatively associated with distance to tidewater glaciers, but we found no significant differences in zooplankton abundance between or within fjords. Primary productivity was higher at glacial stations in Northwestern compared to those in Aialik. Distal areas (seaward of the moraines) had higher temperature and salinity than glacial areas. We also detected differences in marine nutrients between fjords, and ammonium was higher in close proximity to tidewater glaciers.
- Type
- Unpublished Report
- Authors
- Arimitsu, M; Piatt, J; Romano, M; Conaway, J
- Date of Issue
- 2008-04
- Publisher
- U.S. Geological Survey
- Units
- KEFJ
- Keywords
- Abundance (Biodiversity), Alaska, at-sea surveys, Brachyramphus brevirostris, Brachyramphus marmoratus, Currents, Distribution (Biodiversity), foraging habitat, Kenai Fjords National Park, Kittlitz's Murrelet, Marbled Murrelet, Marine Birds, Marine Mammals, Nutrients, Oceanography