Forage fish are small pelagic schooling fish that play a key role in transferring energy between plankton and top marine predators. Many seabirds, marine mammals, and commercial fish species depend on forage fish to grow and survive.
Return to Ecosystems >> Marine Ecosystems >> Seabirds and Forage Fish Ecology
Project Overview
As part of the Gulf Watch Alaska long-term ecological monitoring program, we are collecting data on forage fish abundance and condition in order to better understand how the abundance and nutritional quality of key prey species changes over time. This information is helpful for understanding predator-prey interactions, especially in light of recent seabird die-offs in Alaska.
Why are we studying forage fish?
Forage fish are the link between plankton and predators. In this way they are a key to healthy marine bird populations. As the U.S. Department of Interior (DOI) has Trust responsibility for monitoring and conservation of all seabirds, our studies on forage fish and impacts of environmental change on seabird prey populations are vital to our research role in USGS and DOI.
Where are we working?
Northern Gulf of Alaska, including Prince William Sound, Cook Inlet, and the continental shelf region.
How do we monitor forage fish?
Since we define forage fish as a group of species that play a functional role in ecosystems, and because each species has a different seasonality and habitat due to differing life history strategies, we use a variety of methods to count, catch, and measure forage fish populations. For example:
- Collect forage fish in seabird diets: Seabird diets provide some of the longest timeseries data on forage fish in the Northern Gulf of Alaska. Middleton Island is located at the continental shelf break in the Gulf of Alaska. Seabirds catch their food in the ocean around their colony and bring it back to their nests, making it easy to collect information on their food.
- Sample fish from a boat during aerial surveys: We sample forage fish that are surveyed by airplanes in coastal areas of Prince William Sound. Skilled observers in the plane have a better view than we do in the boat and they can direct us to the fish schools so we can find them more easily.
- Measure fish density in the water column with hydroacoustics: From our research vessel USGS R/V Alaskan Gyre we conduct acoustic-trawl surveys in summer and fall. This method uses sonar technology that transmits and recieves sound in the water. When we find acoustic fish sign in the water column we send a net down to the correct depth to identify the fish species and size.
- Sample forage fish habitat: We also collect information on the type of habitat forage fish occur in by measuring ocean temperature, salinity, turbidity, light availability, nutrients, phytoplankton, and the abundance of zooplankton (forage fish food) in the water.
WhaleFest 2019 Podcast
To learn more, listen to USGS Research Ecologist Mayumi Arimitsu's interview for a podcast about whale prey, forage fish, and seabird die-offs. Arimitsu talked about research on changes in forage fish populations that were first signaled by large die-offs of seabirds during the 2014-2016 North Pacific marine heatwave – aka “The Blob.”
Below are other science projects associated with this project.
Seabirds and Forage Fish Ecology
Seabird Die-offs in Alaska
Cook Inlet Seabird and Forage Fish Study
Terrestrial Influence on Glacial-Marine Food Webs
Below are publications associated with this project.
Monitoring Long-Term Changes in Forage Fish Distribution, Abundance and Body Condition
Exxon Valdez Oil Spill Trustee Council Project 16120114-O Final Report
Age-0 sablefish size and growth indices from seabird diets at Middleton Island, Gulf of Alaska
Extreme mortality and reproductive failure of common murres resulting from the northeast Pacific marine heatwave of 2014-2016
Spatial and temporal dynamics of Pacific capelin Mallotus catervarius in the Gulf of Alaska: Implications for ecosystem-based fisheries management
Algal toxins in Alaskan seabirds: Evaluating the role of saxitoxin and domoic acid in a large-scale die-off of Common Murres
Effects of ocean climate on the length and condition of forage fish in the Gulf of Alaska
Extreme reduction in nutritional value of a key forage fish during the Pacific marine heatwave of 2014–2016
Seasonal distribution of Dall's porpoise in Prince William Sound, Alaska
Biogeography of pelagic food webs in the North Pacific
Tracing biogeochemical subsidies from glacier runoff into Alaska's coastal marine food webs
Influence of glacier runoff on ecosystem structure in Gulf of Alaska fjords
- Overview
Forage fish are small pelagic schooling fish that play a key role in transferring energy between plankton and top marine predators. Many seabirds, marine mammals, and commercial fish species depend on forage fish to grow and survive.
Return to Ecosystems >> Marine Ecosystems >> Seabirds and Forage Fish Ecology
Project Overview
Key forage fish in Alaska (from top to bottom): Pacific capelin, Pacific herring, Pacific sand lance, and juvenile walleye pollock. Cook Inlet, Alaska.(Credit: Mayumi Arimitsu, USGS. Public domain.) As part of the Gulf Watch Alaska long-term ecological monitoring program, we are collecting data on forage fish abundance and condition in order to better understand how the abundance and nutritional quality of key prey species changes over time. This information is helpful for understanding predator-prey interactions, especially in light of recent seabird die-offs in Alaska.
Why are we studying forage fish?
Forage fish are the link between plankton and predators. In this way they are a key to healthy marine bird populations. As the U.S. Department of Interior (DOI) has Trust responsibility for monitoring and conservation of all seabirds, our studies on forage fish and impacts of environmental change on seabird prey populations are vital to our research role in USGS and DOI.
Where are we working?
Northern Gulf of Alaska, including Prince William Sound, Cook Inlet, and the continental shelf region.
How do we monitor forage fish?
Since we define forage fish as a group of species that play a functional role in ecosystems, and because each species has a different seasonality and habitat due to differing life history strategies, we use a variety of methods to count, catch, and measure forage fish populations. For example:
Black-legged Kittiwakes foraging for fish in Cook Inlet, Alaska.(Credit: Sarah Schoen, USGS. Public domain.) - Collect forage fish in seabird diets: Seabird diets provide some of the longest timeseries data on forage fish in the Northern Gulf of Alaska. Middleton Island is located at the continental shelf break in the Gulf of Alaska. Seabirds catch their food in the ocean around their colony and bring it back to their nests, making it easy to collect information on their food.
- Sample fish from a boat during aerial surveys: We sample forage fish that are surveyed by airplanes in coastal areas of Prince William Sound. Skilled observers in the plane have a better view than we do in the boat and they can direct us to the fish schools so we can find them more easily.
- Measure fish density in the water column with hydroacoustics: From our research vessel USGS R/V Alaskan Gyre we conduct acoustic-trawl surveys in summer and fall. This method uses sonar technology that transmits and recieves sound in the water. When we find acoustic fish sign in the water column we send a net down to the correct depth to identify the fish species and size.
- Sample forage fish habitat: We also collect information on the type of habitat forage fish occur in by measuring ocean temperature, salinity, turbidity, light availability, nutrients, phytoplankton, and the abundance of zooplankton (forage fish food) in the water.
Mayumi Arimitsu lowering the CTD equipment into the water.(Public domain.) WhaleFest 2019 Podcast
To learn more, listen to USGS Research Ecologist Mayumi Arimitsu's interview for a podcast about whale prey, forage fish, and seabird die-offs. Arimitsu talked about research on changes in forage fish populations that were first signaled by large die-offs of seabirds during the 2014-2016 North Pacific marine heatwave – aka “The Blob.”
- Collect forage fish in seabird diets: Seabird diets provide some of the longest timeseries data on forage fish in the Northern Gulf of Alaska. Middleton Island is located at the continental shelf break in the Gulf of Alaska. Seabirds catch their food in the ocean around their colony and bring it back to their nests, making it easy to collect information on their food.
- Science
Below are other science projects associated with this project.
Seabirds and Forage Fish Ecology
Alaska's coastal and offshore waters provide foraging habitat for an estimated 100 million birds comprising more than 90 different species; from loons and seaducks that nest inland, to petrels and puffins that breed on islands off shore. All these birds depend on the sea to provide a wide variety of food types— from clams, crabs and urchins nearshore— to krill, forage fish, and squid offshore. The...Seabird Die-offs in Alaska
Beginning in 2015, large numbers of dead seabirds have been appearing on beaches in most marine areas of Alaska. Although seabird die-offs are known to occur sporadically (e.g. 1970, 1989, 1993, 1997/1998, and 2004) in Alaska, these recent die-offs have been distinguished from past events by their increased frequency, duration, geographic extent, and number of different species involved.Cook Inlet Seabird and Forage Fish Study
A massive die-off of Common Murres was documented in the Gulf of Alaska (GOA) during the fall and winter of 2015-2016 in association with a record-breaking marine heat wave in the GOA.Terrestrial Influence on Glacial-Marine Food Webs
Where glaciers meet the sea in the Gulf of Alaska (GOA), they create unique and productive marine habitats. Ringed by the continent’s tallest coastal mountains, 20% of the GOA coastal watershed is covered by glacial ice and the annual freshwater discharge into the GOA from glacial melt is comparable to that of the Mississippi river. - Multimedia
- Publications
Below are publications associated with this project.
Monitoring Long-Term Changes in Forage Fish Distribution, Abundance and Body Condition
Exxon Valdez Oil Spill Trustee Council Project 16120114-O Final ReportAge-0 sablefish size and growth indices from seabird diets at Middleton Island, Gulf of Alaska
Sablefish (Anoplopoma fimbria) is a commercially valuable groundfish species in Alaska, with the population assessed annually by the National Oceanic and Atmospheric Administration Alaska Fisheries Science Center. Sablefish recruit into the commercially fished population at 2 years old and are poorly sampled by most surveys before that age. However, information on the abundance, distribution, andAuthorsMayumi L. Arimitsu, Scott A. HatchExtreme mortality and reproductive failure of common murres resulting from the northeast Pacific marine heatwave of 2014-2016
About 62,000 dead or dying common murres (Uria aalge), the trophically dominant fish-eating seabird of the North Pacific, washed ashore between summer 2015 and spring 2016 on beaches from California to Alaska. Most birds were severely emaciated and, so far, no evidence for anything other than starvation was found to explain this mass mortality. Three-quarters of murres were found in the Gulf of AlAuthorsJohn F. Piatt, Julia K. Parrish, Heather M. Renner, Sarah K. Schoen, Timothy Jones, Mayumi L. Arimitsu, Kathy J. Kuletz, Barbara Bodenstein, Marisol Garcia-Reyes, Rebecca Duerr, Robin Corcoran, Robb S.A. Kaler, Gerard J. McChesney, Richard T. Golightly, Heather A. Coletti, Robert M. Suryan, Hillary K. Burgess, Jackie Lindsey, Kirsten Lindquist, Peter Warzybok, Jaime Jahncke, Jan Roletto, William J. SydemanSpatial and temporal dynamics of Pacific capelin Mallotus catervarius in the Gulf of Alaska: Implications for ecosystem-based fisheries management
Pacific capelin Mallotus catervarius are planktivorous, small pelagic fish that serve an intermediate trophic role in marine food webs. Due to the lack of a directed fishery or monitoring of capelin in the Northeast Pacific, there is limited information on their distribution and abundance, and how spatio-temporal fluctuations in capelin density affects their availability as prey. To provide informAuthorsDavid W. McGowan, Esther Goldstein, Mayumi L. Arimitsu, Alison Dreary, Olav Ormseth, Alex DeRobertis, John Horne, Lauren Rogers, Matt Wilson, Kenneth Coyle, Kris Holderied, John F. Piatt, W.T. Stockhausen, Stephani ZadorAlgal toxins in Alaskan seabirds: Evaluating the role of saxitoxin and domoic acid in a large-scale die-off of Common Murres
Elevated seawater temperatures are linked to the development of harmful algal blooms (HABs), which pose a growing threat to marine birds and other wildlife. During late 2015 and early 2016, a massive die-off of Common Murres (Uria algae; hereafter, murres) was observed in the Gulf of Alaska coincident with a strong marine heat wave. Previous studies have documented illness and death among seabirdsAuthorsCaroline R. Van Hemert, Sarah K. Schoen, R. Wayne Litaker, Matthew M. Smith, Mayumi L. Arimitsu, John F. Piatt, William C. Holland, Ransom Hardison, John M. PearceEffects of ocean climate on the length and condition of forage fish in the Gulf of Alaska
Climatic drivers of the size and body condition of forage fish in the North Pacific are poorly known. We hypothesized that length and condition of forage fish in the Gulf of Alaska (GoA) should vary in relation to ocean temperature on multiple scales. To test this hypothesis, we analyzed morphometric data for capelin (Mallotus catervarius) and Pacific sand lance (PSL; Ammodytes personatus) samAuthorsSarah Ann Thompson, Marisol Garcia-Reyes, William Sydeman, Mayumi L. Arimitsu, Scott Hatch, John F. PiattExtreme reduction in nutritional value of a key forage fish during the Pacific marine heatwave of 2014–2016
Pacific sand lance Ammodytes personatus are a key forage fish in the North Pacific for many species of salmon, groundfish, seabirds, and marine mammals and have historically been important to predators in relatively warm years. However, extreme declines in the nutritional value of sand lance in Prince William Sound, Alaska, USA, during 2012-2016 indicate that energy transfer from lower trophic levAuthorsVanessa R. von Biela, Mayumi L. Arimitsu, John F. Piatt, Brielle Heflin, Sarah K. Schoen, Jannelle Trowbridge, Chelsea ClawsonSeasonal distribution of Dall's porpoise in Prince William Sound, Alaska
Dall's porpoise, Phocoenoides dalli, are a conspicuous predator in the Prince William Sound ecosystem, yet there has been little effort directed towards monitoring this species since the 1980s, prior to the Exxon Valdez oil spill. We used vessel-based surveys to examine the seasonal distribution of Dall's porpoise in the waters of Prince William Sound during eight years from 2007 to 2015. Over theAuthorsJ.R. Moran, M.B. O'Dell, Mayumi L. Arimitsu, Jan M Straley, D.M.S. DicksonBiogeography of pelagic food webs in the North Pacific
The tufted puffin (Fratercula cirrhata) is a generalist seabird that breeds throughout the North Pacific and eats more than 75 different prey species. Using puffins as samplers, we characterized the geographic variability in pelagic food webs across the subarctic North Pacific from the composition of ~10,000 tufted puffin meals (~56,000 prey items) collected at 35 colonies in the Gulf of Alaska (GAuthorsJohn F. Piatt, Mayumi L. Arimitsu, William J. Sydeman, Sarah Ann Thompson, Heather Renner, Stephani Zador, David C. Douglas, Scott A. Hatch, Arthur B. Kettle, Jeffrey C. WilliamsTracing biogeochemical subsidies from glacier runoff into Alaska's coastal marine food webs
Nearly half of the freshwater discharge into the Gulf of Alaska originates from landscapes draining glacier runoff, but the influence of the influx of riverine organic matter on the trophodynamics of coastal marine food webs is not well understood. We quantified the ecological impact of riverine organic matter subsidies to glacier-marine habitats by developing a multi-trophic level Bayesian three-AuthorsMayumi L. Arimitsu, Keith A. Hobson, D'Arcy N. Webber, John F. Piatt, Eran W. Hood, Jason B. FellmanInfluence of glacier runoff on ecosystem structure in Gulf of Alaska fjords
To better understand the influence of glacier runoff on fjord ecosystems, we sampled oceanographic conditions, nutrients, zooplankton, forage fish and seabirds within 4 fjords in coastal areas of the Gulf Alaska. We used generalized additive models and geostatistics to identify the range of glacier runoff influence into coastal waters within fjords of varying estuarine influence and topographic coAuthorsMayumi L. Arimitsu, John F. Piatt, Franz J. Mueter