Upcoming Events
Brown-Bag Lunch Hour Seminar: Internal Tides and Mixing on the Oregon Continental Slope Kim Martini
Environmental gradients and prey availability relative to glacial features in Kittlitz's murrelet foraging habitat
Tuesday, 20 October, 8:30 amMayumi Arimitsu, M.S. Fisheries Candidate
Juneau Center, School of Fisheries and Ocean Sciences
Faculty Advisor: Dr. Nicola Hillgruber
Juneau—101 Lena Point • Fairbanks—Vera Alexa O'Neill • Anchorage—Bragaw Off Anchorage MAP Office
The goal of this study was to characterize Kittlitz’s murrelet (Brachyramphus brevirostris) foraging habitat relative to prey availability and oceanography in Kenai Fjords National Park, a glacial-marine system. I conducted oceanographic, hydroacoustic, trawl, and beach seine surveys in conjunction with marine bird surveys monthly from June-August in 2007 and 2008. High sediment load from glacial river runoff shaped the marine ecosystem in Kenai Fjords, and this appeared critically important to Kittlitz’s murrelets at sea. Submerged glacial moraine characteristics including sill depth and passage width created inner fjord habitat that was characterized by cool, fresh, stratified, and silt-laden waters. Glacial runoff limited light availability and chlorophyll a near tidewater glaciers but secondary production was enhanced in the surface waters, perhaps due to the absence of a photic cue for vertical migration. Zooplankton community structure was influenced by glacial features and varied along an increasing temperature gradient over the summer. Acoustic measurements suggested that low density fish and zooplankton were available in the surface waters near glacial river outflows where murrelets occur. Dense fish aggregations moved into the fjords later in the summer. Kittlitz’s murrelets were more likely to occur in areas with higher acoustic biomass near glaciers, making these birds more susceptible to climate change than the congeneric marbled murrelet (B. marmoratus).