This study will evaluate the nearshore marine feeding areas of breeding adult red-throated loons and assess the response of loon reproductive success to differences in the relative abundance, composition, and nutritional content of nearshore fish communities that vary in space and time.
Return to Ecosystems >> Terrestrial Ecosystems or Fish and Aquatic Ecology
Red-throated loon (Gavia stellata) populations have declined on the North Slope of Alaska, an area requiring ongoing and new management decisions related to oil and gas development. Given that adult red-throated loons have high survival rates, the declining population suggests that reproductive success is poor. Nesting red-throated loons forage in marine waters, unlike sympatric freshwater feeding loon species with stable or increasing populations. The USGS Alaska Science Center is conducting an integrative study of fish and loons at two locations along the Beaufort Sea coast over three field years (2021–2023). This study will not only evaluate possible drivers of the decline in loon numbers on the North Slope but inform the Bureau of Ocean Management (BOEM) about loon and fish habitats.
This work will necessitate two separate, coordinated field efforts (see study area map). One field effort will take place at loon nesting sites on small coastal lakes and include installing time-lapse cameras to estimate loon breeding success, loon captures to deploy GPS transmitters to record loon movements and foraging activities, and tissue collections to assess loon diet. A second field effort will take place in the nearshore and coastal marine areas where breeding loons forage. Boat based sampling in river plume and marine waters will quantify fish catch rates and community composition along beaches and in coastal waters up to 20 m deep. All fish sampling will include concurrent measurements of temperature and salinity. A subset of fish will be sacrificed for tissue collections to support loon diet assessment.
Specific study questions include:
- What is the reproductive success of red-throated loons nesting along the Beaufort Sea coastline?
- Where are the important Beaufort Sea nearshore and offshore feeding areas for red-throated loons?
- What is the diet of red-throated loons during the breeding season?
- What is the relative quality of common fish prey?
- Is loon reproductive success related to diet composition?
- Is loon diet composition similar to the fish community composition?
- Are there differences in loon foraging activity budgets between study sites?
Below are other science projects associated with this project.
Loon Research
Fish and Aquatic Ecology
- Overview
This study will evaluate the nearshore marine feeding areas of breeding adult red-throated loons and assess the response of loon reproductive success to differences in the relative abundance, composition, and nutritional content of nearshore fish communities that vary in space and time.
Return to Ecosystems >> Terrestrial Ecosystems or Fish and Aquatic Ecology
Remote image UrlSources/Usage: Public Domain. Visit Media to see details.Two red-throated loon eggs by the waterbank. Arctic Bird Fest 2019. Photo Credit: Lisa Hupp/USFWS, Public Domain Red-throated loon (Gavia stellata) populations have declined on the North Slope of Alaska, an area requiring ongoing and new management decisions related to oil and gas development. Given that adult red-throated loons have high survival rates, the declining population suggests that reproductive success is poor. Nesting red-throated loons forage in marine waters, unlike sympatric freshwater feeding loon species with stable or increasing populations. The USGS Alaska Science Center is conducting an integrative study of fish and loons at two locations along the Beaufort Sea coast over three field years (2021–2023). This study will not only evaluate possible drivers of the decline in loon numbers on the North Slope but inform the Bureau of Ocean Management (BOEM) about loon and fish habitats.
This work will necessitate two separate, coordinated field efforts (see study area map). One field effort will take place at loon nesting sites on small coastal lakes and include installing time-lapse cameras to estimate loon breeding success, loon captures to deploy GPS transmitters to record loon movements and foraging activities, and tissue collections to assess loon diet. A second field effort will take place in the nearshore and coastal marine areas where breeding loons forage. Boat based sampling in river plume and marine waters will quantify fish catch rates and community composition along beaches and in coastal waters up to 20 m deep. All fish sampling will include concurrent measurements of temperature and salinity. A subset of fish will be sacrificed for tissue collections to support loon diet assessment.
Sources/Usage: Public Domain.A Red-throated Loon swimming in a small lake on the Colville River Delta. Specific study questions include:
- What is the reproductive success of red-throated loons nesting along the Beaufort Sea coastline?
- Where are the important Beaufort Sea nearshore and offshore feeding areas for red-throated loons?
- What is the diet of red-throated loons during the breeding season?
- What is the relative quality of common fish prey?
- Is loon reproductive success related to diet composition?
- Is loon diet composition similar to the fish community composition?
- Are there differences in loon foraging activity budgets between study sites?
Sources/Usage: Public Domain. Visit Media to see details.A saffron cod (Eleginus gracilis) captured in the Beaufort Sea, Alaska. This study will evaluate the nearshore marine feeding areas of breeding adult red-throated loons and assess the response of loon reproductive success and nutritional content of nearshore fish communities. - Science
Below are other science projects associated with this project.
Loon Research
Scientists at the USGS Alaska Science Center have conducted research on Alaska’s three loon species since the late 1970s. Loons rely on freshwater lakes for nesting habitat and fish and invertebrates inhabiting lakes and marine ecosystems for food. All three loon species in Alaska occur within the National Petroleum Reserve-Alaska (NPR-A) on Alaska’s northern coast. Research by the USGS is...Fish and Aquatic Ecology
Fish and aquatic habitats in Alaska support important commercial, sport, and subsistence fisheries and provide forage fish that support wildlife populations. The USGS Alaska Science Center conducts interdisciplinary research to inform local, state, federal, and international policy makers regarding conservation of fish, aquatic species, and their habitats. We work collaboratively with hydrologists... - Data
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