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The USGS Alaska Science Center conducts long-term research on the Pacific walrus to provide scientific information to Department of Interior management agencies and Alaska Native co-management partners. In addition, the USGS Pacific walrus research program collaborates with the U.S. Fish and Wildlife Service (USFWS) and the State of Alaska’s Department of Fish and Game and Alaska Native co-management partners to deliver scientific products that advance knowledge of walrus ecology and the importance of walrus in northern ecosystems. Because addressing population-level questions requires collaboration between U.S. and Russian scientists, many USGS studies have relied on Russian partnership.
Return to Ecosystems >> Marine Ecosystems
Department of Interior partner agencies require information on Pacific walrus survival, reproduction, population abundance, and population trend to inform management decisions and address statutory responsibilities.
US and Russian partners conducted aerial surveys in 1975, 1976, 1980, 1985, and 1990 to estimate population abundance. In 2006, USGS collaborated with US Fish and Wildlife Service (USFWS) and Russian partners to estimate population abundance from an offshore aerial survey that accounted for the proportion of walruses that were in-water and therefore unavailable to be counted, and was the first to rigorously account for uncertainty in the population abundance estimate.
Because these offshore survey efforts resulted in large uncertainty in the estimated population size, development began on alternative abundance estimation methods. The USFWS has led an effort, with USGS support, to estimate Pacific walrus population abundance using genetic mark-recapture methods. USGS efforts developing methods to determine sex and age of walruses from remotely collected biopsies support this effort.
USGS developed methods to estimate regional population size at a large coastal haulout and has refined these methods through use of unoccupied aerial systems (UAS or survey drones) through support of the USGS National Uncrewed Systems Office to estimate the regional walrus abundance in the U.S. Chukchi Sea autumn waters during 2018 and 2019.
Age structure surveys provide information on population demographics required by USFWS statutory responsibilities under the Marine Mammal Protection Act (MMPA). In the 1950’s, F.H. Fay pioneered methods for collecting walrus sex and age structure data by observing facial and tusk characteristics. These methods were applied to collect age structure data on offshore surveys from 1981-1999 with Department of the Interior support. The State of Alaska’s Department of Fish and Game evaluated these methods and found them to provide invaluable information on population demographics.
USGS developed integrated population models that estimated Pacific walrus survival, reproduction, and population trend. These models used all available age structure and population survey data to estimate population parameters required by the MMPA. These models found the age structure data to strongly influence estimated population trends, prompting USGS and FWS with support from the Alaska Department of Fish and Game to collect additional age structure data during 2013 - 2017.
USGS is pursuing further age structure data collection beginning in 2023. Development of integrated population models has allowed USGS and collaborators to evaluate threats posed to the Pacific walrus population from climate related changes in the Arctic. For example, an increase in deaths of young walruses resulting from disturbances at large coastal haulouts can affect population trend.
Pacific walruses primarily consume invertebrates that live in bottom sediments of the shallow continental shelf waters that extend across the Bering and Chukchi seas. In response to the understanding that sea ice loss causes walruses to change their movement and foraging behavior in ways that may affect survival and reproduction, USGS has developed minimally invasive methods to track walruses with small satellite-linked tags and has collected behavior and movement data from walruses across the Bering and Chukchi seas in support of numerous studies.
These studies include correcting aerial survey estimates for walruses in-water and therefore unavailable to be counted; understanding how walruses move within their habitat relative to sea ice movement in the northern Bering Sea; identifying how they move relative to sea ice and benthic biomass distributions in the Bering, and Chukchi Seas; and understanding how their resting and foraging efforts change when summer sea ice disappears.
The tracking data have also revealed walrus foraging areas within the Chukchi Sea and contributed to a broader understanding of marine mammal seasonal distributions in the Pacific Arctic. The tracking data are currently being analyzed to better understand how Pacific walruses utilize the largest coastal haulout in northwestern Alaska.
Walruses haul out of the water and rest between foraging bouts. They rest on sea ice when it is available but use land when waters are ice free.
USGS has developed methods to monitor walruses resting on shore through use of Earth observing satellite imagery. USGS is supporting local management of haulouts by providing satellite imagery analysis to local managers during the haulout season. USGS has worked with Russian partners to extend these methods at haulout sites with complex substrates and terrain and plans to continue this work at Alaskan study sites with State of Alaska, FWS and academic partners.
To support that effort, the USGS Advanced Research Computing center is using trail camera ground-truth imagery collected by partner agencies to teach deep neural networks to recognize walruses so they can more rapidly detect walruses remotely. USGS is also collaborating to automate interpretation of the walrus haulouts apparent in optical Earth observing imagery so that information can be transferred to management partners in real-time, and USGS has supported harmonization of aerial survey imagery collection efforts conducted in the U.S. and Russia so that haulout monitoring studies and results may be unified range-wide.
The loss of sea ice has caused shifts in walrus space use, is forecasted to increase the energetic demands for lactating walruses and may cause changes to walrus prey. By coupling walrus behavior models with an understanding of the energy demands throughout the reproductive life of female walruses, USGS evaluated the energetic consequences of forecasted sea ice loss over the next century.
This study found that continued sea ice loss will increase walrus energetic demands, but there was uncertainty about the impact increased energetic demands might have on body condition and how that may affect reproduction rates. To understand how the walrus population may respond to the increased energetic demands, USGS is evaluating methods to monitor possible changes in walrus reproductive success over time as environmental conditions change.
Using information collected by Native Alaskan communities in the Bering Strait region, from captive walruses in zoos and aquaria, and from aerial imagery from drones at coastal haulouts, USGS is investigating different methods to monitor walrus body condition and how variation in body condition may affect female reproductive success.
In support of this study USGS has:
(1) Collaborated to determine how to reliably measure fat stores from harvested walruses
(2) Evaluated the condition and composition of walrus fat stores
(3) Collaborated to evaluate energetic costs for resting walruses across the range of reproductive conditions and across juvenile age-classes
(4) Collaborated to evaluate energetic cost of swimming, diving, and resting in water
(5) Explored the development of diving capabilities in young walruses.
Finally, the loss of sea ice may cause changes to walrus prey and understanding the consequences of a shift in the prey base requires methods to understand walrus diet. So, USGS developed non-invasive methods to monitor walrus diet.
Arctic marine mammals have historically had low exposure to vessel traffic and noise, but sea ice loss has increased accessibility of Arctic waters to vessels. Thus, Arctic vessel traffic is expected to increase, yet its effect on walruses is unknown.
Vessel exposure has the potential to change walrus population dynamics by altering how much time walruses use to rest, travel, and forage. Such changes may require walruses to consume more calories or reduce their energy stores which are needed to support growth, reproduction, and maintenance.
The Marine Mammal Protection Act requires an understanding of whether there are distinct stocks within the Pacific walrus sub-species. Pacific walruses range across the shallow waters of the continental shelf that extends between Alaska and the Russian Far East.
Three distinct breeding areas are known to develop during the sea ice maximum season each spring:
USGS investigated whether these distinct breeding regions may result in distinct stocks that may merit separate management efforts.
Investigations based on signatures from heavy metal isotopes characteristic of the two western breeding regions suggested that walruses in these regions had distinct isotopic signatures, suggesting that each region hosted walruses that habitually returned to that region.
However, genetic characterization of walruses from the three breeding regions determined that walruses freely moved amongst breeding regions, indicating that the Pacific walrus sub-species may be considered as a single stock.
Below are multimedia items associated with this project.
Adult female walrus on ice floe photographed shortly after receiving a behavior monitoring satellite-linked radio tag from USGS researchers.
Data acquired from such radio-tags are providing insights on the distribution and behavior of Pacific walruses during a time when their summer sea ice habitat is rapidly changing.
Adult female walrus on ice floe photographed shortly after receiving a behavior monitoring satellite-linked radio tag from USGS researchers.
Data acquired from such radio-tags are providing insights on the distribution and behavior of Pacific walruses during a time when their summer sea ice habitat is rapidly changing.
Female walruses and their young must haul out of the water to rest between foraging bouts.
Female walruses and their young must haul out of the water to rest between foraging bouts.
Adult female walruses on ice floe with young. Notice the radio tag borne on her her upper mid back.
This tag will monitor resting and foraging behavior and convey the information back to USGS scientists.
Adult female walruses on ice floe with young. Notice the radio tag borne on her her upper mid back.
This tag will monitor resting and foraging behavior and convey the information back to USGS scientists.
Scientists radio-tag walruses in the Chukchi and Bering seas to better understand their movements and foraging behavior.
Scientists radio-tag walruses in the Chukchi and Bering seas to better understand their movements and foraging behavior.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Nearly 200 male walruses resting on shore at Cape Seniavin along the shores of southern Bristol Bay
Nearly 200 male walruses resting on shore at Cape Seniavin along the shores of southern Bristol Bay
More than 150 male walruses resting on shore at Cape Peirce in northern Bristol Bay
More than 150 male walruses resting on shore at Cape Peirce in northern Bristol Bay
The USGS Alaska Science Center conducts long-term research on the Pacific walrus to provide scientific information to Department of Interior management agencies and Alaska Native co-management partners. In addition, the USGS Pacific walrus research program collaborates with the U.S. Fish and Wildlife Service (USFWS) and the State of Alaska’s Department of Fish and Game and Alaska Native co-management partners to deliver scientific products that advance knowledge of walrus ecology and the importance of walrus in northern ecosystems. Because addressing population-level questions requires collaboration between U.S. and Russian scientists, many USGS studies have relied on Russian partnership.
Return to Ecosystems >> Marine Ecosystems
Department of Interior partner agencies require information on Pacific walrus survival, reproduction, population abundance, and population trend to inform management decisions and address statutory responsibilities.
US and Russian partners conducted aerial surveys in 1975, 1976, 1980, 1985, and 1990 to estimate population abundance. In 2006, USGS collaborated with US Fish and Wildlife Service (USFWS) and Russian partners to estimate population abundance from an offshore aerial survey that accounted for the proportion of walruses that were in-water and therefore unavailable to be counted, and was the first to rigorously account for uncertainty in the population abundance estimate.
Because these offshore survey efforts resulted in large uncertainty in the estimated population size, development began on alternative abundance estimation methods. The USFWS has led an effort, with USGS support, to estimate Pacific walrus population abundance using genetic mark-recapture methods. USGS efforts developing methods to determine sex and age of walruses from remotely collected biopsies support this effort.
USGS developed methods to estimate regional population size at a large coastal haulout and has refined these methods through use of unoccupied aerial systems (UAS or survey drones) through support of the USGS National Uncrewed Systems Office to estimate the regional walrus abundance in the U.S. Chukchi Sea autumn waters during 2018 and 2019.
Age structure surveys provide information on population demographics required by USFWS statutory responsibilities under the Marine Mammal Protection Act (MMPA). In the 1950’s, F.H. Fay pioneered methods for collecting walrus sex and age structure data by observing facial and tusk characteristics. These methods were applied to collect age structure data on offshore surveys from 1981-1999 with Department of the Interior support. The State of Alaska’s Department of Fish and Game evaluated these methods and found them to provide invaluable information on population demographics.
USGS developed integrated population models that estimated Pacific walrus survival, reproduction, and population trend. These models used all available age structure and population survey data to estimate population parameters required by the MMPA. These models found the age structure data to strongly influence estimated population trends, prompting USGS and FWS with support from the Alaska Department of Fish and Game to collect additional age structure data during 2013 - 2017.
USGS is pursuing further age structure data collection beginning in 2023. Development of integrated population models has allowed USGS and collaborators to evaluate threats posed to the Pacific walrus population from climate related changes in the Arctic. For example, an increase in deaths of young walruses resulting from disturbances at large coastal haulouts can affect population trend.
Pacific walruses primarily consume invertebrates that live in bottom sediments of the shallow continental shelf waters that extend across the Bering and Chukchi seas. In response to the understanding that sea ice loss causes walruses to change their movement and foraging behavior in ways that may affect survival and reproduction, USGS has developed minimally invasive methods to track walruses with small satellite-linked tags and has collected behavior and movement data from walruses across the Bering and Chukchi seas in support of numerous studies.
These studies include correcting aerial survey estimates for walruses in-water and therefore unavailable to be counted; understanding how walruses move within their habitat relative to sea ice movement in the northern Bering Sea; identifying how they move relative to sea ice and benthic biomass distributions in the Bering, and Chukchi Seas; and understanding how their resting and foraging efforts change when summer sea ice disappears.
The tracking data have also revealed walrus foraging areas within the Chukchi Sea and contributed to a broader understanding of marine mammal seasonal distributions in the Pacific Arctic. The tracking data are currently being analyzed to better understand how Pacific walruses utilize the largest coastal haulout in northwestern Alaska.
Walruses haul out of the water and rest between foraging bouts. They rest on sea ice when it is available but use land when waters are ice free.
USGS has developed methods to monitor walruses resting on shore through use of Earth observing satellite imagery. USGS is supporting local management of haulouts by providing satellite imagery analysis to local managers during the haulout season. USGS has worked with Russian partners to extend these methods at haulout sites with complex substrates and terrain and plans to continue this work at Alaskan study sites with State of Alaska, FWS and academic partners.
To support that effort, the USGS Advanced Research Computing center is using trail camera ground-truth imagery collected by partner agencies to teach deep neural networks to recognize walruses so they can more rapidly detect walruses remotely. USGS is also collaborating to automate interpretation of the walrus haulouts apparent in optical Earth observing imagery so that information can be transferred to management partners in real-time, and USGS has supported harmonization of aerial survey imagery collection efforts conducted in the U.S. and Russia so that haulout monitoring studies and results may be unified range-wide.
The loss of sea ice has caused shifts in walrus space use, is forecasted to increase the energetic demands for lactating walruses and may cause changes to walrus prey. By coupling walrus behavior models with an understanding of the energy demands throughout the reproductive life of female walruses, USGS evaluated the energetic consequences of forecasted sea ice loss over the next century.
This study found that continued sea ice loss will increase walrus energetic demands, but there was uncertainty about the impact increased energetic demands might have on body condition and how that may affect reproduction rates. To understand how the walrus population may respond to the increased energetic demands, USGS is evaluating methods to monitor possible changes in walrus reproductive success over time as environmental conditions change.
Using information collected by Native Alaskan communities in the Bering Strait region, from captive walruses in zoos and aquaria, and from aerial imagery from drones at coastal haulouts, USGS is investigating different methods to monitor walrus body condition and how variation in body condition may affect female reproductive success.
In support of this study USGS has:
(1) Collaborated to determine how to reliably measure fat stores from harvested walruses
(2) Evaluated the condition and composition of walrus fat stores
(3) Collaborated to evaluate energetic costs for resting walruses across the range of reproductive conditions and across juvenile age-classes
(4) Collaborated to evaluate energetic cost of swimming, diving, and resting in water
(5) Explored the development of diving capabilities in young walruses.
Finally, the loss of sea ice may cause changes to walrus prey and understanding the consequences of a shift in the prey base requires methods to understand walrus diet. So, USGS developed non-invasive methods to monitor walrus diet.
Arctic marine mammals have historically had low exposure to vessel traffic and noise, but sea ice loss has increased accessibility of Arctic waters to vessels. Thus, Arctic vessel traffic is expected to increase, yet its effect on walruses is unknown.
Vessel exposure has the potential to change walrus population dynamics by altering how much time walruses use to rest, travel, and forage. Such changes may require walruses to consume more calories or reduce their energy stores which are needed to support growth, reproduction, and maintenance.
The Marine Mammal Protection Act requires an understanding of whether there are distinct stocks within the Pacific walrus sub-species. Pacific walruses range across the shallow waters of the continental shelf that extends between Alaska and the Russian Far East.
Three distinct breeding areas are known to develop during the sea ice maximum season each spring:
USGS investigated whether these distinct breeding regions may result in distinct stocks that may merit separate management efforts.
Investigations based on signatures from heavy metal isotopes characteristic of the two western breeding regions suggested that walruses in these regions had distinct isotopic signatures, suggesting that each region hosted walruses that habitually returned to that region.
However, genetic characterization of walruses from the three breeding regions determined that walruses freely moved amongst breeding regions, indicating that the Pacific walrus sub-species may be considered as a single stock.
Below are multimedia items associated with this project.
Adult female walrus on ice floe photographed shortly after receiving a behavior monitoring satellite-linked radio tag from USGS researchers.
Data acquired from such radio-tags are providing insights on the distribution and behavior of Pacific walruses during a time when their summer sea ice habitat is rapidly changing.
Adult female walrus on ice floe photographed shortly after receiving a behavior monitoring satellite-linked radio tag from USGS researchers.
Data acquired from such radio-tags are providing insights on the distribution and behavior of Pacific walruses during a time when their summer sea ice habitat is rapidly changing.
Female walruses and their young must haul out of the water to rest between foraging bouts.
Female walruses and their young must haul out of the water to rest between foraging bouts.
Adult female walruses on ice floe with young. Notice the radio tag borne on her her upper mid back.
This tag will monitor resting and foraging behavior and convey the information back to USGS scientists.
Adult female walruses on ice floe with young. Notice the radio tag borne on her her upper mid back.
This tag will monitor resting and foraging behavior and convey the information back to USGS scientists.
Scientists radio-tag walruses in the Chukchi and Bering seas to better understand their movements and foraging behavior.
Scientists radio-tag walruses in the Chukchi and Bering seas to better understand their movements and foraging behavior.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses gathered on Alaskan shores of the Chukchi Sea by the tens of thousands in late August and September of 2010 after the last of the sea ice dissipated.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Walruses in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010.
Nearly 200 male walruses resting on shore at Cape Seniavin along the shores of southern Bristol Bay
Nearly 200 male walruses resting on shore at Cape Seniavin along the shores of southern Bristol Bay
More than 150 male walruses resting on shore at Cape Peirce in northern Bristol Bay
More than 150 male walruses resting on shore at Cape Peirce in northern Bristol Bay
