Map of locations within the Alaska Forage Fish Database where forage species were encountered (color). Grey points represent sites where sampling occurred, but the specific forage species was not encountered.
Mayumi L Arimitsu, Ph.D.
Forage fish, seabirds, predator-prey interactions, glacier-marine ecosystems, marine heatwaves, climate change
I lead research to identify factors influencing the status and trends of rare or threatened species on DOI lands, to understand the effects of glacier dynamics on coastal fjord ecosystems, and to document impacts of novel ocean climate patterns on the functioning of marine food webs. As the Pelagic Lead for the Gulf Watch Alaska long-term monitoring program I coordinate research integration across sampling programs for forage fish, marine birds, humpback whale, and killer whales.
Science and Products
Alaska Forage Fish Database
The Alaska Forage Fish Database is a consolidation of survey catch data and predator diets from multiple partners including USGS Alaska Science Center, NOAA National Marine Fisheries Service Alaska Fisheries Science Center, USFWS Alaska Maritime National Wildlife Refuge, Alaska Department of Fish and Game, and others. The spatial coverage of the database encompasses the coastal and offshore...
North Pacific Pelagic Seabird Database
The North Pacific Pelagic Seabird Database (NPPSD) contains survey transect data designed and conducted by numerous partners primarily to census seabirds at sea. The NPPSD includes more than 486,000 transect segments and includes observations of over 20 million birds of 258 species collected over the span of 50 years (from 1973 to 2022).
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.
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...
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.
Tidewater Glacier Influence on Marine Ecosystems
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.
Harmful Algal Bloom Toxins in Alaska Seabirds
Elevated ocean temperatures are linked to the development of harmful algal blooms (HABs). Toxins from these blooms may pose health threats to marine organisms, including seabirds. Since 2015, the USGS has worked with a variety of stakeholders to develop testing methods and research projects to better understand the geographic extent, timing and impacts of algal toxins in Alaska marine ecosystems...
Detecting Long-term Changes in Forage Fish Populations in Prince William Sound, Alaska
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.
Condition of Forage Fish in Prince William Sound During the Marine Heatwave
Changes in the body condition of a key forage fish species, Pacific sand lance ( Ammodytes personatus ), are examined to understand how energy transfer to predators may have been disrupted during the recent marine heatwave in the North Pacific (late 2013 to mid 2016).
Forage fish occurrence map
Map of locations within the Alaska Forage Fish Database where forage species were encountered (color). Grey points represent sites where sampling occurred, but the specific forage species was not encountered.
Map of data contributors and primary sampling methods
This map is showing data contributors and primary sampling methods for Alaska Forage Fish Database (AFFD).
This map is showing data contributors and primary sampling methods for Alaska Forage Fish Database (AFFD).
Bird Survey Map Matthew Island, Alaska
This map shows all available marine bird survey data from the North Pacific Pelagic Seabird Database (NPPSD) around St.
This map shows all available marine bird survey data from the North Pacific Pelagic Seabird Database (NPPSD) around St.
Capelin flyer
Capelin, a small forage fish, are spawning on beaches around Alaska and your observations can contribute to our understanding of beach spawning behavior and the health of marine ecosystems.
Capelin, a small forage fish, are spawning on beaches around Alaska and your observations can contribute to our understanding of beach spawning behavior and the health of marine ecosystems.
Effects of the North Pacific Marine Heatwave on Ocean Food Webs infographic
Infograph describing the effects of North Pacific marine heatwave on ocean food webs.
Infograph describing the effects of North Pacific marine heatwave on ocean food webs.
How do Marine Heatwaves Impact Seabirds
An infographic that highlights a study describing four main mechanisms by which marine heatwaves affect seabirds and marine ecosystems, i.e., (1) habitat modification, (2) physiological forcing, (3) behavioral responses, and (4) ecological processes or species interactions. Study findings indicate that marine heatwaves can affect seabirds directly by creating
An infographic that highlights a study describing four main mechanisms by which marine heatwaves affect seabirds and marine ecosystems, i.e., (1) habitat modification, (2) physiological forcing, (3) behavioral responses, and (4) ecological processes or species interactions. Study findings indicate that marine heatwaves can affect seabirds directly by creating
Pacific capelin trawl catch
Photo of Pacific capelin trawl catch in Cook Inlet Alaska. Capelin are cold water forage fish that play a key role in transferring energy between plankton and top marine predators. Seabirds, and their forage fish prey, serve as practical indicators of change in the marine environment— natural or human induced— and can be readily monitored at sea.
Photo of Pacific capelin trawl catch in Cook Inlet Alaska. Capelin are cold water forage fish that play a key role in transferring energy between plankton and top marine predators. Seabirds, and their forage fish prey, serve as practical indicators of change in the marine environment— natural or human induced— and can be readily monitored at sea.
Forage species caught in trawl net, Prince William Sound, Alaska
Squid, adult walleye pollock, herring, eulachon, northern smoothtongue, capelin, juvenile walleye pollock, krill, and shrimp are forage species that are caught by a modified-herring trawl in Prince William Sound, Alaska during the Fall Integrated Predator-Prey Survey.
Squid, adult walleye pollock, herring, eulachon, northern smoothtongue, capelin, juvenile walleye pollock, krill, and shrimp are forage species that are caught by a modified-herring trawl in Prince William Sound, Alaska during the Fall Integrated Predator-Prey Survey.
young of the year walleye pollock
Photo of young of the year walleye pollock, Prince William Sound, Alaska. Although adults are targeted in one of the largest commercial fisheries in the world, young of the year walleye pollock are important in diets of many marine predators.
Photo of young of the year walleye pollock, Prince William Sound, Alaska. Although adults are targeted in one of the largest commercial fisheries in the world, young of the year walleye pollock are important in diets of many marine predators.
Pacific herring in Prince William Sound, Alaska
Pacific herring in Prince William Sound, Alaska
Pacific herring in Prince William Sound, Alaska
ANSEP student Tatiana Korthuis recording data on USGS research vessel
Alaska Native Science and Engineering Program (ANSEP) student Tatiana Korthuis recording fish catch data on board the USGS research vessel Alaskan Gyre in Herring Bay, Alaska. This was part of a USGS study to monitor forage fish and seabirds in Prince William Sound, Alaska.
Alaska Native Science and Engineering Program (ANSEP) student Tatiana Korthuis recording fish catch data on board the USGS research vessel Alaskan Gyre in Herring Bay, Alaska. This was part of a USGS study to monitor forage fish and seabirds in Prince William Sound, Alaska.
Key forage fish, Cook Inlet, Alaska
Key forage fish in Alaska (from top to bottom): Pacific capelin, Pacific herring, Pacific sand lance, and juvenile walleye pollock. Cook Inlet, Alaska
Key forage fish in Alaska (from top to bottom): Pacific capelin, Pacific herring, Pacific sand lance, and juvenile walleye pollock. Cook Inlet, Alaska
Common Murres with visibly protruding keels
Common Murres with visibly protruding keels flush from Gull Island, Kachemak Bay, Alaska.
Common Murres with visibly protruding keels flush from Gull Island, Kachemak Bay, Alaska.
ASC biologists necropsy Common Murres
ASC biologists John Piatt, Sarah Schoen, Gary Drew, and Brielle Heflin necropsy Common Murres recovered in Prince William Sound following the massive die-off of murres in 2015/2016.
ASC biologists John Piatt, Sarah Schoen, Gary Drew, and Brielle Heflin necropsy Common Murres recovered in Prince William Sound following the massive die-off of murres in 2015/2016.
Emaciated Common Murre lays on the laboratory table
An emaciated Common Murre lays on the laboratory table during a necropsy to determine the cause of death for a massive die-off of murres in 2015/2016.
An emaciated Common Murre lays on the laboratory table during a necropsy to determine the cause of death for a massive die-off of murres in 2015/2016.
Catch of forage fish from a trawl in Cook Inlet, Alaska
Catch of forage fish from a trawl in Cook Inlet, Alaska. Trawling was part of an assessment of abundance, distribution and species composition of forage fish in marine waters in lower Cook Inlet.
Catch of forage fish from a trawl in Cook Inlet, Alaska. Trawling was part of an assessment of abundance, distribution and species composition of forage fish in marine waters in lower Cook Inlet.
Catch of forage fish from a trawl in Prince William Sound, Alaska
Catch of forage fish from a trawl in Prince William Sound, Alaska. Trawling was part of detecting long-term changes in forage fish populations.
Catch of forage fish from a trawl in Prince William Sound, Alaska. Trawling was part of detecting long-term changes in forage fish populations.
R/V Alaskan Gyre near a glacier in Prince William Sound, Alaska
The research vessel Alaskan Gyre is near a glacier in Prince William Sound, Alaska.
The research vessel Alaskan Gyre is near a glacier in Prince William Sound, Alaska.
The R/V Alaskan Gyre with a mountain backdrop, Alaska
The R/V Alaskan Gyre in Prince William Sound, Alaska with a mountain background
The R/V Alaskan Gyre in Prince William Sound, Alaska with a mountain background
Kittlitz’s Murrelet takes flight
Kittlitz’s Murrelet takes flight at Kenai Fjords National Park, Alaska. The Kittlitz’s murrelet is a rare seabird that appears to be specialized for life in glacially influenced environments.
Kittlitz’s Murrelet takes flight at Kenai Fjords National Park, Alaska. The Kittlitz’s murrelet is a rare seabird that appears to be specialized for life in glacially influenced environments.
Sand lance catch from a beach seine in the Aleutian Islands
Pacific sand lance catch from a beach seine in the Aleutian Islands.
Pacific sand lance catch from a beach seine in the Aleutian Islands.
Science and Products
Alaska Forage Fish Database
The Alaska Forage Fish Database is a consolidation of survey catch data and predator diets from multiple partners including USGS Alaska Science Center, NOAA National Marine Fisheries Service Alaska Fisheries Science Center, USFWS Alaska Maritime National Wildlife Refuge, Alaska Department of Fish and Game, and others. The spatial coverage of the database encompasses the coastal and offshore...
North Pacific Pelagic Seabird Database
The North Pacific Pelagic Seabird Database (NPPSD) contains survey transect data designed and conducted by numerous partners primarily to census seabirds at sea. The NPPSD includes more than 486,000 transect segments and includes observations of over 20 million birds of 258 species collected over the span of 50 years (from 1973 to 2022).
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.
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...
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.
Tidewater Glacier Influence on Marine Ecosystems
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.
Harmful Algal Bloom Toxins in Alaska Seabirds
Elevated ocean temperatures are linked to the development of harmful algal blooms (HABs). Toxins from these blooms may pose health threats to marine organisms, including seabirds. Since 2015, the USGS has worked with a variety of stakeholders to develop testing methods and research projects to better understand the geographic extent, timing and impacts of algal toxins in Alaska marine ecosystems...
Detecting Long-term Changes in Forage Fish Populations in Prince William Sound, Alaska
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.
Condition of Forage Fish in Prince William Sound During the Marine Heatwave
Changes in the body condition of a key forage fish species, Pacific sand lance ( Ammodytes personatus ), are examined to understand how energy transfer to predators may have been disrupted during the recent marine heatwave in the North Pacific (late 2013 to mid 2016).
Forage fish occurrence map
Map of locations within the Alaska Forage Fish Database where forage species were encountered (color). Grey points represent sites where sampling occurred, but the specific forage species was not encountered.
Map of locations within the Alaska Forage Fish Database where forage species were encountered (color). Grey points represent sites where sampling occurred, but the specific forage species was not encountered.
Map of data contributors and primary sampling methods
This map is showing data contributors and primary sampling methods for Alaska Forage Fish Database (AFFD).
This map is showing data contributors and primary sampling methods for Alaska Forage Fish Database (AFFD).
Bird Survey Map Matthew Island, Alaska
This map shows all available marine bird survey data from the North Pacific Pelagic Seabird Database (NPPSD) around St.
This map shows all available marine bird survey data from the North Pacific Pelagic Seabird Database (NPPSD) around St.
Capelin flyer
Capelin, a small forage fish, are spawning on beaches around Alaska and your observations can contribute to our understanding of beach spawning behavior and the health of marine ecosystems.
Capelin, a small forage fish, are spawning on beaches around Alaska and your observations can contribute to our understanding of beach spawning behavior and the health of marine ecosystems.
Effects of the North Pacific Marine Heatwave on Ocean Food Webs infographic
Infograph describing the effects of North Pacific marine heatwave on ocean food webs.
Infograph describing the effects of North Pacific marine heatwave on ocean food webs.
How do Marine Heatwaves Impact Seabirds
An infographic that highlights a study describing four main mechanisms by which marine heatwaves affect seabirds and marine ecosystems, i.e., (1) habitat modification, (2) physiological forcing, (3) behavioral responses, and (4) ecological processes or species interactions. Study findings indicate that marine heatwaves can affect seabirds directly by creating
An infographic that highlights a study describing four main mechanisms by which marine heatwaves affect seabirds and marine ecosystems, i.e., (1) habitat modification, (2) physiological forcing, (3) behavioral responses, and (4) ecological processes or species interactions. Study findings indicate that marine heatwaves can affect seabirds directly by creating
Pacific capelin trawl catch
Photo of Pacific capelin trawl catch in Cook Inlet Alaska. Capelin are cold water forage fish that play a key role in transferring energy between plankton and top marine predators. Seabirds, and their forage fish prey, serve as practical indicators of change in the marine environment— natural or human induced— and can be readily monitored at sea.
Photo of Pacific capelin trawl catch in Cook Inlet Alaska. Capelin are cold water forage fish that play a key role in transferring energy between plankton and top marine predators. Seabirds, and their forage fish prey, serve as practical indicators of change in the marine environment— natural or human induced— and can be readily monitored at sea.
Forage species caught in trawl net, Prince William Sound, Alaska
Squid, adult walleye pollock, herring, eulachon, northern smoothtongue, capelin, juvenile walleye pollock, krill, and shrimp are forage species that are caught by a modified-herring trawl in Prince William Sound, Alaska during the Fall Integrated Predator-Prey Survey.
Squid, adult walleye pollock, herring, eulachon, northern smoothtongue, capelin, juvenile walleye pollock, krill, and shrimp are forage species that are caught by a modified-herring trawl in Prince William Sound, Alaska during the Fall Integrated Predator-Prey Survey.
young of the year walleye pollock
Photo of young of the year walleye pollock, Prince William Sound, Alaska. Although adults are targeted in one of the largest commercial fisheries in the world, young of the year walleye pollock are important in diets of many marine predators.
Photo of young of the year walleye pollock, Prince William Sound, Alaska. Although adults are targeted in one of the largest commercial fisheries in the world, young of the year walleye pollock are important in diets of many marine predators.
Pacific herring in Prince William Sound, Alaska
Pacific herring in Prince William Sound, Alaska
Pacific herring in Prince William Sound, Alaska
ANSEP student Tatiana Korthuis recording data on USGS research vessel
Alaska Native Science and Engineering Program (ANSEP) student Tatiana Korthuis recording fish catch data on board the USGS research vessel Alaskan Gyre in Herring Bay, Alaska. This was part of a USGS study to monitor forage fish and seabirds in Prince William Sound, Alaska.
Alaska Native Science and Engineering Program (ANSEP) student Tatiana Korthuis recording fish catch data on board the USGS research vessel Alaskan Gyre in Herring Bay, Alaska. This was part of a USGS study to monitor forage fish and seabirds in Prince William Sound, Alaska.
Key forage fish, Cook Inlet, Alaska
Key forage fish in Alaska (from top to bottom): Pacific capelin, Pacific herring, Pacific sand lance, and juvenile walleye pollock. Cook Inlet, Alaska
Key forage fish in Alaska (from top to bottom): Pacific capelin, Pacific herring, Pacific sand lance, and juvenile walleye pollock. Cook Inlet, Alaska
Common Murres with visibly protruding keels
Common Murres with visibly protruding keels flush from Gull Island, Kachemak Bay, Alaska.
Common Murres with visibly protruding keels flush from Gull Island, Kachemak Bay, Alaska.
ASC biologists necropsy Common Murres
ASC biologists John Piatt, Sarah Schoen, Gary Drew, and Brielle Heflin necropsy Common Murres recovered in Prince William Sound following the massive die-off of murres in 2015/2016.
ASC biologists John Piatt, Sarah Schoen, Gary Drew, and Brielle Heflin necropsy Common Murres recovered in Prince William Sound following the massive die-off of murres in 2015/2016.
Emaciated Common Murre lays on the laboratory table
An emaciated Common Murre lays on the laboratory table during a necropsy to determine the cause of death for a massive die-off of murres in 2015/2016.
An emaciated Common Murre lays on the laboratory table during a necropsy to determine the cause of death for a massive die-off of murres in 2015/2016.
Catch of forage fish from a trawl in Cook Inlet, Alaska
Catch of forage fish from a trawl in Cook Inlet, Alaska. Trawling was part of an assessment of abundance, distribution and species composition of forage fish in marine waters in lower Cook Inlet.
Catch of forage fish from a trawl in Cook Inlet, Alaska. Trawling was part of an assessment of abundance, distribution and species composition of forage fish in marine waters in lower Cook Inlet.
Catch of forage fish from a trawl in Prince William Sound, Alaska
Catch of forage fish from a trawl in Prince William Sound, Alaska. Trawling was part of detecting long-term changes in forage fish populations.
Catch of forage fish from a trawl in Prince William Sound, Alaska. Trawling was part of detecting long-term changes in forage fish populations.
R/V Alaskan Gyre near a glacier in Prince William Sound, Alaska
The research vessel Alaskan Gyre is near a glacier in Prince William Sound, Alaska.
The research vessel Alaskan Gyre is near a glacier in Prince William Sound, Alaska.
The R/V Alaskan Gyre with a mountain backdrop, Alaska
The R/V Alaskan Gyre in Prince William Sound, Alaska with a mountain background
The R/V Alaskan Gyre in Prince William Sound, Alaska with a mountain background
Kittlitz’s Murrelet takes flight
Kittlitz’s Murrelet takes flight at Kenai Fjords National Park, Alaska. The Kittlitz’s murrelet is a rare seabird that appears to be specialized for life in glacially influenced environments.
Kittlitz’s Murrelet takes flight at Kenai Fjords National Park, Alaska. The Kittlitz’s murrelet is a rare seabird that appears to be specialized for life in glacially influenced environments.
Sand lance catch from a beach seine in the Aleutian Islands
Pacific sand lance catch from a beach seine in the Aleutian Islands.
Pacific sand lance catch from a beach seine in the Aleutian Islands.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government