Nearshore Marine Ecosystem Research Active
Nearshore ecosystems include many resources that are of high ecological, recreational, subsistence, and economic value. They also are subject to influences from a wide variety of natural and human-caused perturbations, which can originate in terrestrial or oceanic environments. Our research is designed to evaluate sources of variation in the nearshore and how they influence resources of high conservation interest.
Return to Ecosystems >> Marine Ecosystems
Sea Otter Population Assessment
With the exception of 13 small remnant populations, sea otters were extirpated from their historic range in the north Pacific Ocean during the 18th and 19th centuries as a result of the commercial harvest for their fur. During most of the 20th century, through protection and reintroduction, sea otter populations generally increased in abundance and distribution such that most of their range in Alaska, with the exception of southeast Alaska, was occupied by 2000. Although population abundance data are incomplete, there is evidence of increasing, stable and declining sea otter populations in different areas within their range. The factors that ultimately regulate sea otter population abundance are not completely understood, but can include predation, human harvest, food limitation, disease and catastrophic events such as oil spill. There is good evidence that the recent declines in sea otters in SW Alaska are related to killer whale predation and the Exxon Valdez oil spill reduced the size of the western Prince William Sound population in 1989. Human harvest of sea otters can adversely affect sea otter abundance, evidenced by the commercial fur trade leading to near extirpation. Because sea otters occupy relatively small home ranges and do not migrate, sustainable harvest requires management at appropriate spatial scales. Recently, harvest of sea otters for subsistence have been increasing, although effects of the harvest at current levels on population trend are unknown. Because sea otter populations occur over vast and remote areas and may display divergent trends in abundance over relatively small spatial scales, determining population status and trends can be challenging.
Methods to assess sea otter population status and trends are important to evaluate the recovery of populations and the potential effects of human perturbations (e.g., harvest, contaminants, and habitat modifications) on populations. This information is important to resource managers in identifying potential conflicts, identifying mechanisms of change, and improving the ability to detect and respond to change from human induced sources.
Objectives of our sea otter population assessment studies include: 1) develop and test methods to identify the degree of population structuring among north Pacific sea otter populations, 2) develop and test techniques to accurately and precisely estimate the status of sea otter populations, 3) develop and test methods to identify cause(s) of change in the status and numeric trends of sea otter populations, 4) develop and test methods to determine the role of density dependent processes in affecting change in sea otter populations, and 5) evaluate the effects of population reductions and translocations on sea otter genetic variability.
Role of Sea Otters in Structuring Nearshore Communities
Sea otters provide one of the best documented examples of top-down forcing effects on the structure and function of nearshore marine ecosystems in the North Pacific Ocean. Much of our knowledge of the role of sea otters as a source of community variation resulted from the spatial and temporal pattern of sea otter population recovery since their near extirpation about 100 years ago. During most of the early 20th century sea otters were absent from large portions of their habitat in the north Pacific. During the absence of sea otters, many of their prey populations responded to reduced predation through increased densities and sizes. Since the middle of the 20th century sea otter populations have been recovering previous habitats, due to natural dispersal and translocations. Following the recovery of sea otters, scientists have continued to provide descriptions of nearshore marine communities and have been able to contrast those communities before and after the sea otters return. At least three distinct approaches have proven valuable in understanding the effects of sea otters. One is contrasting communities over time, before and after recolonization by sea otters. This approach, in concert with appropriate controls, provides an experimentally rigorous and powerful study design allowing inference to the cause of the observed changes in experimental areas. Another approach consists of contrasting different areas at the same time, those with, and those without the experimental treatment (in this case, sea otters). A third approach entails experimentally manipulating community attributes and observing community response, usually in both treatment and control areas. All these opportunities currently present themselves at various locations throughout the sea otters’ range.
One area of recent reoccupation is Glacier Bay in Southeast Alaska, where sea otters were absent until as recently as 1994, but currently number > 4000 individuals. We are using this situation in Glacier Bay as a laboratory to experimentally evaluate the role of sea otter in structuring coastal marine communities in a predominately soft sediment habitat. It is predictable that the density and sizes of preferred sea otter prey such as crabs, clams, and urchins will decline in response to otter predation. This will result in fewer opportunities for human harvest, but will also result in ecosystem level changes, as abundance and sizes of prey for other predators, such as octopus, sea stars, fishes, birds and mammals are modified. Sea otters will also modify benthic habitats through excavation of sediments required to extract burrowing infauna such as clams. Effects of sediment disturbance by foraging sea otters are not understood. As the recolonization by sea otters continues, it is also likely that dramatic changes will occur in the species composition, abundance and size class composition of many components of the nearshore marine ecosystem. Many of the changes will occur as a direct result of predation by sea otters; other changes will result from indirect or cascading effects of sea otter foraging, such as increasing kelp production and modified prey availability for other nearshore predators.
Effects of the Exxon Valdez Oil Spill
Sea otters were severely impacted by the 1989 Exxon Valdez oil spill. Estimates of acute spill related mortality range from about 1,000 to 5,500 in the first months after the spill. Scientists with the Alaska Science Center were among the first responders to the 1989 spill and continue work today to document the process of recovery form this spill and to better understand the effects future contamination events on sea otters and the nearshore ecosystems they occupy.
One of the factors limiting our ability to clearly understand and document the spill effects was a lack of accurate estimates of sea otter abundance. This was true for nearly all species in the Gulf of Alaska and remains an impediment in assessing injury from such catastrophes across most landscapes today. Initial research efforts following the spill focused on damage assessment, including developing methods to accurately estimate the abundance of affected populations and studies of reproduction and survival.
Large scale ecosystem level studies of nearshore species and habitats most affected by the spill completed in 1999, found evidence of long-term spill effects among nearshore species dependent on a nearshore food web where benthic invertebrates transfer primary production to upper level consumers such as sea otters and sea ducks. Biochemical and gene techniques suggested that lingering oil may have contributed to a protracted recovery period for nearshore species. Subsequently, surveys of beaches where oil was deposited nearly a decade earlier found unanticipated volumes of oil sequestered in nearly 20 acres of widely distributed soft sediment intertidal beaches in Prince William Sound.
Our most recent surveys of sea otter abundance indicate significant progress toward recovery, when we consider the entire spill affected area in the Sound. By 2009 our estimate of sea otter abundance in the western Sound was nearly 2,000 animals more than our first post spill estimate in 1993 of about 2,000 individuals. However, when we look only at those areas that were most severely affected by the spill, where sea otter mortality approached 90% and where much of the lingering oil has been located, evidence of recovery remains incomplete. Our most recent research, based on the diving behavior of sea otters in the intertidal and published oil encounter rates, indicates that all sea otters in those heavily oiled areas are likely to encounter Exxon Valdez oil at least annually and some as often as weekly. Long term continuation of studies investigating mortality from the annual collections of beach cast sea otter carcasses implicates elevated mortality as the factor most likely contributing to delayed recovery, and suggests that chronic mortality after the spill may meet or exceed the acute mortality experienced after the spill.
Lingering Oil Studies
Sea otters were severely impacted by the 1989 Exxon Valdez oil spill. Estimates of acute spill related mortality range from about 1,000 to 5,500 in the first months after the spill. Scientists with the Alaska Science Center were among the first responders to the 1989 spill and continue work today to document the process of recovery form this spill and to better understand the effects future contamination events on sea otters and the nearshore ecosystems they occupy.
One of the factors limiting our ability to clearly understand and document the spill effects was a lack of accurate estimates of sea otter abundance. This was true for nearly all species in the Gulf of Alaska and remains an impediment in assessing injury from such catastrophes across most landscapes today. Initial research efforts following the spill focused on damage assessment, including developing methods to accurately estimate the abundance of affected populations and studies of reproduction and survival.
Large scale ecosystem level studies of nearshore species and habitats most affected by the spill completed in 1999, found evidence of long-term spill effects among nearshore species dependent on a nearshore food web where benthic invertebrates transfer primary production to upper level consumers such as sea otters and sea ducks. Biochemical and gene techniques suggested that lingering oil may have contributed to a protracted recovery period for nearshore species. Subsequently, surveys of beaches where oil was deposited nearly a decade earlier found unanticipated volumes of oil sequestered in nearly 20 acres of widely distributed soft sediment intertidal beaches in Prince William Sound.
Our most recent surveys of sea otter abundance indicate significant progress toward recovery, when we consider the entire spill affected area in the Sound. By 2009 our estimate of sea otter abundance in the western Sound was nearly 2,000 animals more than our first post spill estimate in 1993 of about 2,000 individuals. However, when we look only at those areas that were most severely affected by the spill, where sea otter mortality approached 90% and where much of the lingering oil has been located, evidence of recovery remains incomplete. Our most recent research, based on the diving behavior of sea otters in the intertidal and published oil encounter rates, indicates that all sea otters in those heavily oiled areas are likely to encounter Exxon Valdez oil at least annually and some as often as weekly. Long term continuation of studies investigating mortality from the annual collections of beach cast sea otter carcasses implicates elevated mortality as the factor most likely contributing to delayed recovery, and suggests that chronic mortality after the spill may meet or exceed the acute mortality experienced after the spill.
Long-term Monitoring
The Alaska Science Center, and in preceding Department of Interior agencies, has been engaged in monitoring various sea otter populations for more than 50 years, since Karl Kenyon’s seminal work in the Aleutian Islands. As sea otter populations have recovered from the fur trade and translocations contributed to expanding populations, the task of sea otter monitoring has become increasingly difficult simply because of the vast and remote nature of sea otter habitat. Moreover, it has become increasingly evident that monitoring of single species, while perhaps necessary for management purposes, often provides little insight as to why changes in abundance occur over time. As a result we have been engaged in the development, design and testing of monitoring protocols for nearshore habitats and species, including sea otters, that might best be described as “ecosystem” or “food web” based monitoring.
The nearshore is considered an important component of the Gulf of Alaska ecosystem, including the region affected by the Exxon Valdez oil spill, because it provides:
- A variety of unique habitats for resident organisms (e.g. sea otters, harbor seals, shorebirds, seabirds, nearshore fishes, kelps, seagrasses, clams, mussels, and sea stars).
- Nursery grounds for marine animals from other habitats (e.g. crabs, salmon, herring, and seabirds).
- Feeding grounds for important consumers, including killer whales, harbor seals, sea otters, sea lions, sea ducks, shore birds and many fish and shellfish.
- A source of animals important to commercial and subsistence harvests (e.g. marine mammals, fishes, crabs, mussels, clams, chitons, and octopus).
- An important site of recreational activities including fishing, boating, camping, and nature viewing.
- A source of primary production for export to adjacent habitats (primarily by kelps, other seaweeds, and eelgrass), as well as a recipient for primary (phytoplankton) and secondary production (zooplankton) transported from offshore systems..
- An important triple interface between air, land and sea that provides linkages for transfer of water, nutrients, and species between watersheds and offshore habitats.
The underlying assumption in our monitoring design is that change will occur, and that careful consideration of what to monitor, may eventually provide insight as to why observed change occurred. In the nearshore ecosystem we work in, primary productivity is provided by at least two independent sources, the micro-algae, or phytoplankton, that occurs near the sea surface and may be transported inshore via currents. The second, and sometimes major contributor to total primary production is through the kelps and sea grasses that are conspicuous features of the nearshore zone. These combined sources of carbon fuel a diverse community of invertebrates, such as mussels, clams, snails, crustaceans, and urchins, that ultimately transfer their energy to various higher trophic level invertebrates and vertebrates, such as fishes, birds (shore birds, sea ducks and others) and mammals (primarily sea otters). Through careful selection of species and processes (growth, survival and diet) we expect to gain a better understanding of the interaction between various trophic levels that will allow us to potentially assign cause to some of the change we expect to see over time.
As part of the planning efforts of the Exxon Valdez Trustee Council for a long-term science program, in 2001 we were tasked to develop a science and monitoring program for the nearshore ecosystem in the Gulf of Alaska. Through a process of workshops and consultations we developed the Nearshore Restoration and Ecosystem Monitoring program (N-REM, Dean and Bodkin 2006). Coincident with our planning efforts for the Exxon Valdez Trustte Council, the National Park Service was implementing a strategy known as “vital signs monitoring” to develop scientifically sound information on the status and long-term trends of park ecosystems and to determine how well current management practices are sustaining those ecosystems. Subsequently, Park managers from the Southwest Alaska Network (SWAN) recognized that the program we designed for the Exxon Valdez Trustee Council fit their Vital Signs needs and a new partnership was established to implement long term monitoring in the nearshore marine habitat of the SWAN parks.
SWAN consists of five Alaskan park units (Aniakchak National Monument and Preserve, Alagnak National Wild River, Katmai National Park and Preserve, Kenai Fjords National Park, and Lake Clark National Park and Preserve). Collectively these units comprise 9.4 million acres or 11.6 percent of the total land area managed by the National Park Service. Network parks encompass climatic conditions, geologic features, near pristine ecosystems, natural biodiversity, freshwater, and marine resources equaled few places in North America. This network of relatively untouched wilderness parks is a unique resource and offers unparalleled opportunities to study and monitor ecological systems minimally affected by humans. In recognition of this, the SWAN monitoring framework emphasizes (i) establishing reference conditions representing the current status of park, monument, and preserve ecosystems; and (ii) detecting ecological change through time. In 2008, The Exxon Valdez Trustee Council adopted and implemented our nearshore monitoring design in Prince William Sound, extending the SWAN nearshore program from the Gulf of Alaska into Prince William Sound and Kachemak Bay in Cook Inlet. The Gulf of Alaska nearshore monitoring program now consists of four primary sites, including Prince William Sound, Kenai Fjords National Park, Kachemak Bay and Katmai National Park.
Below are data or web applications associated with this project.
Harlequin duck capture and EROD activity data from Prince William Sound, Alaska, 2011, 2013, 2014
Below are multimedia items associated with this project.
Below are publications associated with this project.
Challenges to sea otter recovery and conservation
Historic and Contemporary Status of Sea Otters in the North Pacific
Temporal patterns in the foraging behavior of sea otters in Alaska
The effects of spilled oil on coastal ecosystems: Lessons from the Exxon Valdez spill
Lessons from the 1989 Exxon Valdez oil spill: A biological perspective
2013 update on sea otter studies to assess recovery from the 1989 Exxon Valdez oil spill, Prince William Sound, Alaska
Quantifying long-term risks to sea otters from the 1989 'Exxon Valdez' oil spill: reply to Harwell & Gentile (2013)
Long-term effects of the 'Exxon Valdez' oil spill: Sea otter foraging in the intertidal as a pathway of exposure to lingering oil
Variations of transcript profiles between sea otters Enhydra lutris from Prince William Sound, Alaska, and clinically normal reference otters
Gene transcription in sea otters (Enhydra lutris); development of a diagnostic tool for sea otter and ecosystem health
Distribution and density of marine birds and mammals along the Kenai Fjords National Park coastline - March 2010
Could residual oil from the Exxon Valdez spill create a long-term population "sink" for sea otters in Alaska?
Below are news stories associated with this project.
- Overview
Nearshore ecosystems include many resources that are of high ecological, recreational, subsistence, and economic value. They also are subject to influences from a wide variety of natural and human-caused perturbations, which can originate in terrestrial or oceanic environments. Our research is designed to evaluate sources of variation in the nearshore and how they influence resources of high conservation interest.
Return to Ecosystems >> Marine Ecosystems
Sea Otter Population Assessment
With the exception of 13 small remnant populations, sea otters were extirpated from their historic range in the north Pacific Ocean during the 18th and 19th centuries as a result of the commercial harvest for their fur. During most of the 20th century, through protection and reintroduction, sea otter populations generally increased in abundance and distribution such that most of their range in Alaska, with the exception of southeast Alaska, was occupied by 2000. Although population abundance data are incomplete, there is evidence of increasing, stable and declining sea otter populations in different areas within their range. The factors that ultimately regulate sea otter population abundance are not completely understood, but can include predation, human harvest, food limitation, disease and catastrophic events such as oil spill. There is good evidence that the recent declines in sea otters in SW Alaska are related to killer whale predation and the Exxon Valdez oil spill reduced the size of the western Prince William Sound population in 1989. Human harvest of sea otters can adversely affect sea otter abundance, evidenced by the commercial fur trade leading to near extirpation. Because sea otters occupy relatively small home ranges and do not migrate, sustainable harvest requires management at appropriate spatial scales. Recently, harvest of sea otters for subsistence have been increasing, although effects of the harvest at current levels on population trend are unknown. Because sea otter populations occur over vast and remote areas and may display divergent trends in abundance over relatively small spatial scales, determining population status and trends can be challenging.
Methods to assess sea otter population status and trends are important to evaluate the recovery of populations and the potential effects of human perturbations (e.g., harvest, contaminants, and habitat modifications) on populations. This information is important to resource managers in identifying potential conflicts, identifying mechanisms of change, and improving the ability to detect and respond to change from human induced sources.
Objectives of our sea otter population assessment studies include: 1) develop and test methods to identify the degree of population structuring among north Pacific sea otter populations, 2) develop and test techniques to accurately and precisely estimate the status of sea otter populations, 3) develop and test methods to identify cause(s) of change in the status and numeric trends of sea otter populations, 4) develop and test methods to determine the role of density dependent processes in affecting change in sea otter populations, and 5) evaluate the effects of population reductions and translocations on sea otter genetic variability.
Role of Sea Otters in Structuring Nearshore Communities
Sea otters provide one of the best documented examples of top-down forcing effects on the structure and function of nearshore marine ecosystems in the North Pacific Ocean. Much of our knowledge of the role of sea otters as a source of community variation resulted from the spatial and temporal pattern of sea otter population recovery since their near extirpation about 100 years ago. During most of the early 20th century sea otters were absent from large portions of their habitat in the north Pacific. During the absence of sea otters, many of their prey populations responded to reduced predation through increased densities and sizes. Since the middle of the 20th century sea otter populations have been recovering previous habitats, due to natural dispersal and translocations. Following the recovery of sea otters, scientists have continued to provide descriptions of nearshore marine communities and have been able to contrast those communities before and after the sea otters return. At least three distinct approaches have proven valuable in understanding the effects of sea otters. One is contrasting communities over time, before and after recolonization by sea otters. This approach, in concert with appropriate controls, provides an experimentally rigorous and powerful study design allowing inference to the cause of the observed changes in experimental areas. Another approach consists of contrasting different areas at the same time, those with, and those without the experimental treatment (in this case, sea otters). A third approach entails experimentally manipulating community attributes and observing community response, usually in both treatment and control areas. All these opportunities currently present themselves at various locations throughout the sea otters’ range.
One area of recent reoccupation is Glacier Bay in Southeast Alaska, where sea otters were absent until as recently as 1994, but currently number > 4000 individuals. We are using this situation in Glacier Bay as a laboratory to experimentally evaluate the role of sea otter in structuring coastal marine communities in a predominately soft sediment habitat. It is predictable that the density and sizes of preferred sea otter prey such as crabs, clams, and urchins will decline in response to otter predation. This will result in fewer opportunities for human harvest, but will also result in ecosystem level changes, as abundance and sizes of prey for other predators, such as octopus, sea stars, fishes, birds and mammals are modified. Sea otters will also modify benthic habitats through excavation of sediments required to extract burrowing infauna such as clams. Effects of sediment disturbance by foraging sea otters are not understood. As the recolonization by sea otters continues, it is also likely that dramatic changes will occur in the species composition, abundance and size class composition of many components of the nearshore marine ecosystem. Many of the changes will occur as a direct result of predation by sea otters; other changes will result from indirect or cascading effects of sea otter foraging, such as increasing kelp production and modified prey availability for other nearshore predators.
Effects of the Exxon Valdez Oil Spill
Sea otters were severely impacted by the 1989 Exxon Valdez oil spill. Estimates of acute spill related mortality range from about 1,000 to 5,500 in the first months after the spill. Scientists with the Alaska Science Center were among the first responders to the 1989 spill and continue work today to document the process of recovery form this spill and to better understand the effects future contamination events on sea otters and the nearshore ecosystems they occupy.
One of the factors limiting our ability to clearly understand and document the spill effects was a lack of accurate estimates of sea otter abundance. This was true for nearly all species in the Gulf of Alaska and remains an impediment in assessing injury from such catastrophes across most landscapes today. Initial research efforts following the spill focused on damage assessment, including developing methods to accurately estimate the abundance of affected populations and studies of reproduction and survival.
Large scale ecosystem level studies of nearshore species and habitats most affected by the spill completed in 1999, found evidence of long-term spill effects among nearshore species dependent on a nearshore food web where benthic invertebrates transfer primary production to upper level consumers such as sea otters and sea ducks. Biochemical and gene techniques suggested that lingering oil may have contributed to a protracted recovery period for nearshore species. Subsequently, surveys of beaches where oil was deposited nearly a decade earlier found unanticipated volumes of oil sequestered in nearly 20 acres of widely distributed soft sediment intertidal beaches in Prince William Sound.
Our most recent surveys of sea otter abundance indicate significant progress toward recovery, when we consider the entire spill affected area in the Sound. By 2009 our estimate of sea otter abundance in the western Sound was nearly 2,000 animals more than our first post spill estimate in 1993 of about 2,000 individuals. However, when we look only at those areas that were most severely affected by the spill, where sea otter mortality approached 90% and where much of the lingering oil has been located, evidence of recovery remains incomplete. Our most recent research, based on the diving behavior of sea otters in the intertidal and published oil encounter rates, indicates that all sea otters in those heavily oiled areas are likely to encounter Exxon Valdez oil at least annually and some as often as weekly. Long term continuation of studies investigating mortality from the annual collections of beach cast sea otter carcasses implicates elevated mortality as the factor most likely contributing to delayed recovery, and suggests that chronic mortality after the spill may meet or exceed the acute mortality experienced after the spill.
Lingering Oil Studies
Sea otters were severely impacted by the 1989 Exxon Valdez oil spill. Estimates of acute spill related mortality range from about 1,000 to 5,500 in the first months after the spill. Scientists with the Alaska Science Center were among the first responders to the 1989 spill and continue work today to document the process of recovery form this spill and to better understand the effects future contamination events on sea otters and the nearshore ecosystems they occupy.
One of the factors limiting our ability to clearly understand and document the spill effects was a lack of accurate estimates of sea otter abundance. This was true for nearly all species in the Gulf of Alaska and remains an impediment in assessing injury from such catastrophes across most landscapes today. Initial research efforts following the spill focused on damage assessment, including developing methods to accurately estimate the abundance of affected populations and studies of reproduction and survival.
Large scale ecosystem level studies of nearshore species and habitats most affected by the spill completed in 1999, found evidence of long-term spill effects among nearshore species dependent on a nearshore food web where benthic invertebrates transfer primary production to upper level consumers such as sea otters and sea ducks. Biochemical and gene techniques suggested that lingering oil may have contributed to a protracted recovery period for nearshore species. Subsequently, surveys of beaches where oil was deposited nearly a decade earlier found unanticipated volumes of oil sequestered in nearly 20 acres of widely distributed soft sediment intertidal beaches in Prince William Sound.
Our most recent surveys of sea otter abundance indicate significant progress toward recovery, when we consider the entire spill affected area in the Sound. By 2009 our estimate of sea otter abundance in the western Sound was nearly 2,000 animals more than our first post spill estimate in 1993 of about 2,000 individuals. However, when we look only at those areas that were most severely affected by the spill, where sea otter mortality approached 90% and where much of the lingering oil has been located, evidence of recovery remains incomplete. Our most recent research, based on the diving behavior of sea otters in the intertidal and published oil encounter rates, indicates that all sea otters in those heavily oiled areas are likely to encounter Exxon Valdez oil at least annually and some as often as weekly. Long term continuation of studies investigating mortality from the annual collections of beach cast sea otter carcasses implicates elevated mortality as the factor most likely contributing to delayed recovery, and suggests that chronic mortality after the spill may meet or exceed the acute mortality experienced after the spill.
Long-term Monitoring
The Alaska Science Center, and in preceding Department of Interior agencies, has been engaged in monitoring various sea otter populations for more than 50 years, since Karl Kenyon’s seminal work in the Aleutian Islands. As sea otter populations have recovered from the fur trade and translocations contributed to expanding populations, the task of sea otter monitoring has become increasingly difficult simply because of the vast and remote nature of sea otter habitat. Moreover, it has become increasingly evident that monitoring of single species, while perhaps necessary for management purposes, often provides little insight as to why changes in abundance occur over time. As a result we have been engaged in the development, design and testing of monitoring protocols for nearshore habitats and species, including sea otters, that might best be described as “ecosystem” or “food web” based monitoring.
The nearshore is considered an important component of the Gulf of Alaska ecosystem, including the region affected by the Exxon Valdez oil spill, because it provides:
- A variety of unique habitats for resident organisms (e.g. sea otters, harbor seals, shorebirds, seabirds, nearshore fishes, kelps, seagrasses, clams, mussels, and sea stars).
- Nursery grounds for marine animals from other habitats (e.g. crabs, salmon, herring, and seabirds).
- Feeding grounds for important consumers, including killer whales, harbor seals, sea otters, sea lions, sea ducks, shore birds and many fish and shellfish.
- A source of animals important to commercial and subsistence harvests (e.g. marine mammals, fishes, crabs, mussels, clams, chitons, and octopus).
- An important site of recreational activities including fishing, boating, camping, and nature viewing.
- A source of primary production for export to adjacent habitats (primarily by kelps, other seaweeds, and eelgrass), as well as a recipient for primary (phytoplankton) and secondary production (zooplankton) transported from offshore systems..
- An important triple interface between air, land and sea that provides linkages for transfer of water, nutrients, and species between watersheds and offshore habitats.
The underlying assumption in our monitoring design is that change will occur, and that careful consideration of what to monitor, may eventually provide insight as to why observed change occurred. In the nearshore ecosystem we work in, primary productivity is provided by at least two independent sources, the micro-algae, or phytoplankton, that occurs near the sea surface and may be transported inshore via currents. The second, and sometimes major contributor to total primary production is through the kelps and sea grasses that are conspicuous features of the nearshore zone. These combined sources of carbon fuel a diverse community of invertebrates, such as mussels, clams, snails, crustaceans, and urchins, that ultimately transfer their energy to various higher trophic level invertebrates and vertebrates, such as fishes, birds (shore birds, sea ducks and others) and mammals (primarily sea otters). Through careful selection of species and processes (growth, survival and diet) we expect to gain a better understanding of the interaction between various trophic levels that will allow us to potentially assign cause to some of the change we expect to see over time.
As part of the planning efforts of the Exxon Valdez Trustee Council for a long-term science program, in 2001 we were tasked to develop a science and monitoring program for the nearshore ecosystem in the Gulf of Alaska. Through a process of workshops and consultations we developed the Nearshore Restoration and Ecosystem Monitoring program (N-REM, Dean and Bodkin 2006). Coincident with our planning efforts for the Exxon Valdez Trustte Council, the National Park Service was implementing a strategy known as “vital signs monitoring” to develop scientifically sound information on the status and long-term trends of park ecosystems and to determine how well current management practices are sustaining those ecosystems. Subsequently, Park managers from the Southwest Alaska Network (SWAN) recognized that the program we designed for the Exxon Valdez Trustee Council fit their Vital Signs needs and a new partnership was established to implement long term monitoring in the nearshore marine habitat of the SWAN parks.
SWAN consists of five Alaskan park units (Aniakchak National Monument and Preserve, Alagnak National Wild River, Katmai National Park and Preserve, Kenai Fjords National Park, and Lake Clark National Park and Preserve). Collectively these units comprise 9.4 million acres or 11.6 percent of the total land area managed by the National Park Service. Network parks encompass climatic conditions, geologic features, near pristine ecosystems, natural biodiversity, freshwater, and marine resources equaled few places in North America. This network of relatively untouched wilderness parks is a unique resource and offers unparalleled opportunities to study and monitor ecological systems minimally affected by humans. In recognition of this, the SWAN monitoring framework emphasizes (i) establishing reference conditions representing the current status of park, monument, and preserve ecosystems; and (ii) detecting ecological change through time. In 2008, The Exxon Valdez Trustee Council adopted and implemented our nearshore monitoring design in Prince William Sound, extending the SWAN nearshore program from the Gulf of Alaska into Prince William Sound and Kachemak Bay in Cook Inlet. The Gulf of Alaska nearshore monitoring program now consists of four primary sites, including Prince William Sound, Kenai Fjords National Park, Kachemak Bay and Katmai National Park.
- Data
Below are data or web applications associated with this project.
Filter Total Items: 25Harlequin duck capture and EROD activity data from Prince William Sound, Alaska, 2011, 2013, 2014
This data set includes capture information and ethoxyresorufin-O-deethylase (EROD) activity results for harlequin ducks sampled during March 2011, 2013, and 2014 in western Prince William Sound, Alaska. - Multimedia
Below are multimedia items associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 40Challenges to sea otter recovery and conservation
Similar to other species that in recent centuries experienced unregulated human exploitation, sea otters were extirpated throughout large portions of their historic range in the North Pacific. For most of the twentieth century, with cessation of the fur trade and because of concerted efforts at conservation, sea otters recovered much of their historic range and abundance. Late in the twentieth cenAuthorsBrenda E. Ballachey, James L. BodkinHistoric and Contemporary Status of Sea Otters in the North Pacific
Similar to other species that in recent centuries experienced unregulated human exploitation, sea otters were extirpated throughout large portions of their historic range in the North Pacific. For most of the twentieth century, with cessation of the fur trade and because of concerted efforts at conservation, sea otters recovered much of their historic range and abundance. Late in the twentieth cenAuthorsJames L. BodkinTemporal patterns in the foraging behavior of sea otters in Alaska
Activity time budgets in apex predators have been proposed as indicators of population status relative to resource limitation or carrying capacity. We used archival time-depth recorders implanted in 15 adult female and 4 male sea otters (Enhydra lutris) from the northernmost population of the species, Prince William Sound, Alaska, USA, to examine temporal patterns in their foraging behavior. Sea oAuthorsGeorge G. Esslinger, James L. Bodkin, André R. Breton, Jennifer M. Burns, Daniel H. MonsonThe effects of spilled oil on coastal ecosystems: Lessons from the Exxon Valdez spill
Oil spilled from ships or other sources into the marine environment often occurs in close proximity to coastlines, and oil frequently accumulates in coastal habitats. As a consequence, a rich, albeit occasionally controversial, body of literature describes a broad range of effects of spilled oil across several habitats, communities, and species in coastal environments. This statement is not to impAuthorsJames L. Bodkin, Daniel Esler, Stanley D. Rice, Craig O. Matkin, Brenda E. Ballachey, Brooke Maslo, Julie L. LockwoodLessons from the 1989 Exxon Valdez oil spill: A biological perspective
On March 24, 1989, the tanker vessel Exxon Valdez altered its course to avoid floating ice, and ran aground on Bligh Reef in northeastern Prince William Sound (PWS), Alaska (Figure 1). The tanker was carrying about 53 million gallons of Prudhoe Bay crude, a heavy oil, and an estimated 11 million gallons spilled (264,000 barrels or about 42 million liters) in what was, prior to the Deepwater HorizoAuthorsBrenda E. Ballachey, James L. Bodkin, Daniel Esler, Stanley D. Rice2013 update on sea otter studies to assess recovery from the 1989 Exxon Valdez oil spill, Prince William Sound, Alaska
On March 24, 1989, the tanker vessel Exxon Valdez ran aground in Prince William Sound, Alaska, spilling an estimated 42 million liters of Prudhoe Bay crude oil. Oil spread in a southwesterly direction and was deposited on shores and waters in western Prince William Sound (WPWS). The sea otter (Enhydra lutris) was one of more than 20 nearshore species considered to have been injured by the spill. SAuthorsBrenda E. Ballachey, Daniel H. Monson, George G. Esslinger, Kimberly A. Kloecker, James L. Bodkin, Lizabeth Bowen, A. Keith MilesQuantifying long-term risks to sea otters from the 1989 'Exxon Valdez' oil spill: reply to Harwell & Gentile (2013)
Recovery of sea otter populations in Prince William Sound (PWS), Alaska, has been delayed for more than 2 decades following the 1989 ‘Exxon Valdez’ oil spill. Harwell & Gentile (2013; Mar Ecol Prog Ser 488:291–296) question our conclusions in Bodkin et al. (2012; Mar Ecol Prog Ser 447:273-287) regarding adverse effects that oil lingering in the environment may have on sea otters. They agree that eAuthorsBrenda E. Ballachey, James L. Bodkin, Daniel H. MonsonLong-term effects of the 'Exxon Valdez' oil spill: Sea otter foraging in the intertidal as a pathway of exposure to lingering oil
The protracted recovery of some bird and mammal populations in western Prince William Sound (WPWS), Alaska, and the persistence of spilled 'Exxon Valdez' oil in intertidal sediments, suggests a pathway of exposure to consumers that occupy nearshore habitats. To evaluate the hypothesis that sea otter (Enhydra lutris) foraging allows access to lingering oil, we contrast spatial relations between forAuthorsJames L. Bodkin, Brenda E. Ballachey, Heather A. Coletti, George G. Esslinger, Kimberly A. Kloecker, Stanley D. Rice, John A. Reed, Daniel H. MonsonVariations of transcript profiles between sea otters Enhydra lutris from Prince William Sound, Alaska, and clinically normal reference otters
Development of blood leukocyte gene transcript profiles has the potential to expand condition assessments beyond those currently available to evaluate wildlife health, including sea otters Enhydra lutris, both individually and as populations. The 10 genes targeted in our study represent multiple physiological systems that play a role in immuno-modulation, inflammation, cell protection, tumor supprAuthorsA. Keith Miles, Lizabeth Bowen, Brenda E. Ballachey, James L. Bodkin, M. Murray, J.L. Estes, Robin A. Keister, J.L. StottGene transcription in sea otters (Enhydra lutris); development of a diagnostic tool for sea otter and ecosystem health
Gene transcription analysis for diagnosing or monitoring wildlife health requires the ability to distinguish pathophysiological change from natural variation. Herein, we describe methodology for the development of quantitative real-time polymerase chain reaction (qPCR) assays to measure differential transcript levels of multiple immune function genes in the sea otter (Enhydra lutris); sea otter-spAuthorsLizabeth Bowen, A. Keith Miles, Michael Murray, Martin Haulena, Judy Tuttle, William van Bonn, Lance Adams, James L. Bodkin, Brenda E. Ballachey, James A. Estes, M. Tim Tinker, Robin Keister, Jeffrey L. StottDistribution and density of marine birds and mammals along the Kenai Fjords National Park coastline - March 2010
From March 21, 2010 to March 24, 2010, a winter marine bird and mammal skiff-based survey along the coast of Kenai Fjords National Park (KEFJ) was completed. This was the second winter survey completed for KEFJ since 2008. The primary objectives of the SWAN winter surveys are to characterize the species composition, density and distribution of the overwintering marine ducks prior to their migratioAuthorsHeather A. Coletti, George G. Esslinger, James L. BodkinCould residual oil from the Exxon Valdez spill create a long-term population "sink" for sea otters in Alaska?
Over 20 years ago, the Exxon Valdez oil tanker spilled 42 million L of crude oil into the waters of Prince William Sound, Alaska, USA. At the time of the spill, the sea otter (Enhydra lutris) population inhabiting the spill area suffered substantial acute injuries and loss. Subsequent research has resulted in one of the best-studied species responses to an oil spill in history. However, the questiAuthorsDaniel H. Monson, Daniel F. Doak, Brenda E. Ballachey, James L. Bodkin - News
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