Bowhead Whale Contaminant Monitoring

Principal Investigators Raphaela Stimmelmayr, D.V.M., Ph.D.
Collaborators Jenny Bolton and Gina Ylitalo, NOAA North West Fisheries Science Center, Seattle , Washington
Funding State of Alaska Coastal Impact Assistance Program; North Slope Borough


Contaminant monitoring of subsistence harvested bowhead whales remains a priority for the Alaska Eskimo Whaling Commission (AEWC), the North Slope Borough Department of Wildlife Management (NSB-DWM), and communities of northern Alaska due to impacts on human and wildlife health and the conservation biology and management of the bowhead whale. Concentrations of POPs in bowhead whale tissues, appear to be declining at rates comparable with previously reported temporal trends in Arctic biota. International action taken to restrict the use and production of many POPs (e.g. Stockholm Convention) has been effective in driving this decline. Levels of POPs in bowhead blubber and muscle meat are now approximately one half to one quarter what they had been in the 1990s, and many classes of these contaminants appear to be continuing to decline. The current study contributes to the body of literature on contaminants in baleen whales, which remain less well studied than toothed whales. This work could not have been done without the long standing support and help of the AEWC and the Whaling Captains Village Associations for the NSB DWM bowhead harvest monitoring program.


  • Blubber POPs were markedly lower in 2006–2015 than in samples from 1997 to 2000.
  • Most blubber POPs showed significant declining trends between 2006 and 2015.
  • Rates of decline similar to those reported for Arctic biota (i.e. other marine mammals) generally.
  • First report of PBDE (flame retardants) levels in bowhead whales, which are mostly <3 ng/g, ww.


Bowhead Whale Contaminant and Nutrient Study

Principal Investigators Todd M. O’Hara, D.V.M., Ph.D.
Collaborators See Subproject information
Funding CIFAR (Cooperative Institute For Arctic Research) through NOAA, State of Alaska Coastal Impact Assistance Program, NSB


Completed in 2003. See subprojects for individual summaries.

The NSB-DWM worked to assess contaminant levels from global pollution sources in North Slope wildlife used for subsistence foods. We also looked at nutrient levels of bowhead whales especially. We learned more about how contaminants and nutrient related chemicals tell us about our food web, environment, and the animals we use.

These studies demonstrate that the levels of contaminants found in bowhead whale tissues are low, and the associated risks to human health are very low. The nutritional value of these foods is important to the health of the people on the North Slope. It is important to continue to collect baseline contaminant data to monitor levels over time.

For a plain language report on these bowhead findings, as well as other subsistence species, click here.

To find out more about contaminants, click here.

Subproject: The bowhead whale as a potential indicator species for monitoring the health of the western Arctic/Bering Sea Ecosystem using blubber, histology, metal and mineral indices

Principal Investigators Todd M. O’Hara, D.V.M., Ph.D.
Collaborators John Blake (IAB-UAF), Gerald Bratton(TAMU), Michael Castellini (IMS-UAF), Teri Rowles (NMFS), John Stein (NMFS), Cheryl Rosa (UAF, Ph.D. dissertation)
Funding CIFAR (Cooperative Institute For Arctic Research) through NOAA, State of Alaska Coastal Impact Assistance Program, NSB

Summary: Completed in 2003.

Project Objectives:

  1. Determined normal range values for basic nutritional and health parameters (blubber characteristics, essential and non-essential elements, structure of basic tissues) in the bowhead whale.
    1. Blubber thickness (depth and girth), chemical composition (lipids, water, calories), and tissue structure (light microscopy and special stains) were assessed.
    2. Essential and non-essential elements (heavy metals) were measured in liver and kidney.
    3. Tissue structure (light microscopy) characteristics related to nutritional status in liver (glycogen, lipid and lipofuscin stores), pancreas (zymogen granules), and intestine (mucosal microvilli) and any evidence of inactivity/atrophy were examined.
    4. Documentation of “normal” structure of basic tissues and evaluation for evidence of disease were conducted.
  2. Used data from Objective I to identify the parameters most important in determining the health status of other mysticetes residing in the Bering Sea or Western Arctic that are harvested or stranded.
  3. Used data from Objective I to help determine the role of the bowhead whale as an indicator of ecosystem health and development of an optimized protocol for assessing mysticete health for the Bering Sea and Western Arctic, and other regions.

Poster presentations:

Other presentations and publications from this project:

  • Castellini, MA. 2000. History of polar whaling: insights into the physiology of the great whales. Comparative Biochemistry and Physiology 126(2):153-159.
  • Castellini, M., et al. 1999. The role of blubber in assessing body condition. Abstract. 13th Biennial Conference on the Biology of Marine Mammals.
  • Mau, T.L., et al. 1999. Biochemical Composition of Whale and Seal Blubber. Poster presented at the Experimental Biology Meeting, Washington, D.C., April 17-21, 1999.
  • Mau, T.L., et al. 1999. Seasonal Distribution of Energy Stores in the Bowhead Whale. Poster presented at the Biennial Conference of Marine Mammals, Maui, HI, Nov 27-Dec 3, 1999.
  • O’Hara, T.M., et al. 1999. Organochlorine contaminant levels in Eskimo harvested bowhead whales of arctic Alaska. Journal of Wildlife Diseases. 35(4):741-752.
  • O’Hara, T.M., et al. 2000. Persistent organic pollutants in bowhead whales and northern fur seals of Alaska. Persistent Organic Pollutants (POPs) in the Arctic: Human Health and Environmental Concerns (Arctic Monitoring Assessment Program), Rovaniemi, Finland, January 19, 2000. Extended abstract in press.

Victoria Woshner collecting bowhead samples for contaminants study at the whale butchering site on the sea ice. Photo: Craig George

Subproject: Study of food chain pathways – environment to humans

Principal Investigators Todd M. O’Hara, D.V.M., Ph.D.
Co-Principal Investigators Larry Duffy, Erich Follmann (UAF), Karim-Aly Kassam (University of Calgary), Derek Muir (NWRI, Environment Canada), Dave Norton (Arctic Rim Research)
Graduate Students Lara Dehn (UAF), Paul Hoekstra (University of Guelph)
UAF, University of Calgary, NWRI, Environment Canada, University of Guelph
CIFAR (Cooperative Institute For Arctic Research) through NOAA, State of Alaska Coastal Impact Assistance Program, NSB

Summary: Completed in 2003.

Project Objectives:

Human and Chemical Ecology of Arctic Pathways by Marine Pollutants:

  1. Encourage local community participation in planning and implementing research strategies.
  2. Use an ecosystems approach to determine the effects of contaminants on food web and biomagnification.
  3. Determine pathways/linkages of contaminant accumulation in species that are consumed by top predators, including humans, and determine sub-regional differences in contaminant levels.

Objective I Human Ecology

The objectives of the Human Ecology Research were to:

Local community participatory mapping techniques, semi-structured interviews and the direct participation of community members in research design, data collection and implementation, research and data collection on the human ecology of indigenous arctic marine communities were undertaken in the communities of Holman, NWT (1998-1999), Wainwright, Alaska (1999-2000), and in Novoe Chaplino, Russia. (2000-2001).


  • Kassam, K. and Wainwright Traditional Council. 2001. “Passing on the Knowledge: Mapping Human Ecology in Wainwright, Alaska.” Arctic Institute of North America of the University of Calgary. Pp. 82.

Objective II Chemical Ecology: Marine waters & zooplankton


This is good news, and we hope the future trend will be even lower levels of these chemicals.


Objective III Chemical Ecology: Stable Isotopes and Organochlorine Contaminants in the Bowhead Whale

Organochlorine Contaminants (OCs)


The concentrations of the OCs in the tissues (liver and blubber) of the bowhead whale were at expected levels, low compared to other arctic marine mammals, but considered “high” as compared to domestic animals (cattle, dogs). These landed whales all appeared healthy. This paper confirmed the relatively low levels of OCs in bowheads that was reported earlier and did so with a greater sample size. This work established that OCs accumulate with age (bioaccumulation) in male bowhead whales, as expected.


Polychlorinated Biphenyls (PCB) Isomers


Chemical techniques showed that sexual maturation affected the accumulation of certain PCB isomers and is likely related to specific enzyme or tissue changes occurring in the bowhead whale. This work indicates that the bowhead is likely metabolizing (biotransforming and eliminating) these chemicals.



Persistent metabolites of PCBs were detected in bowhead whale blubber and plasma. With continued sampling of these whales we will be able to determine if the concentrations are staying the same, decreasing or increasing in this population over time.


Trophic Ecology using Carbon, Nitrogen and Sulfur Isotopes


This paper describes the chemical food web “signature” or trophic ecology of the bowhead whale. The tissue composition of the whale changes based on where and what it eats. This is critical information for management of offshore activities and the health of the bowhead whale. These data (chemical signature of nitrogen stable isotopes) also confirmed that the bowhead whales feed low on the food chain during spring and fall.


  • Hoekstra PF, et al. 2002. Trophic ecology of bowhead whales (Balaena mysticetus) compared with that of other arctic marine biota as interpreted from carbon-, nitrogen-, and sulfur-isotope signatures. Canadian Journal of Zoology 80:223-231.

Collecting smaller bowhead samples in the lab from a piece of bowhead whale blubber for contaminants study. Photo credit: Craig George

In summary for OCs in bowhead whales:

These studies have provided a foundation for additional studies to address OCs concentrations changing over time and metabolite formation (possible mechanism for excretion). These data were submitted to the Arctic Monitoring Assessment Program (AMAP).

Journal Articles on Nutrition and Contaminants Studies of Bowhead Whales

Fatty Acids in Blubber of the Bowhead Whale


The publication reports on the analysis of omega-3 and omega-6 fatty acids in the blubber of bowhead whales. They found that the blubber was high in omega-3 fatty acids, and that omega-6 fatty acids rarely occurred. They concluded that due to the importance of omega-3 fatty acids in the treatment and prevention of diseases found to be increasing in Alaska Natives, such as high blood pressure, heart disease, stroke, diabetes, arthritis and depression, the subsistence use of these tissues provides important health benefits.

Blubber chemical composition and organochlorine analysis at Environmental Conservation Division, Northwest Fisheries Science Center, National Marine Fisheries Service. Blubber samples analyzed for both lipid content and proportions of lipid classes, including wax esters, triglycerides, free fatty acids, cholesterol and phospholipids, using thin-layer chromatography with flame ionization detection:

  • Metals analysis via atomic absorption spectrophotometry (AAS) at Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University (TAMU), College Station, Texas.
  • Document reliance by indigenous arctic marine communities in Canada, Alaska and Russia on arctic resources at risk from chemical pollutants.
  • Incorporate traditional knowledge systems of subsistence harvesting.

Baseline data was obtained for Northern Alaska and Canada:

  • Zooplankton (copepods) is an important food item for the bowhead whale.
  • It is important to study the water and zooplankton as this represents the major pathway for these contaminants to enter the food chain of the bowhead whale and other arctic marine animals.
  • The organochlorine contaminants (OCs) are generally lowest in northern Alaska water and zooplankton.

Bowheads were sampled over a 3.5-year period during the spring and fall from Barrow and Kaktovik. The results showed a clear pattern that indicates the bowhead whale feeds in the eastern Beaufort Sea:

  • Fall versus spring whales in Barrow had clearly different tissue levels of stable isotopes of carbon.
  • Between the village of Kaktovik versus Barrow, fall whales caught at these two sites displayed significantly different tissue composition of the stable isotope of carbon indicating feeding likely occurs between these two villages.

The concentrations of the OCs were found at expected levels, no harmful health effects are expected in the animals. Based on previous studies (O’Hara et al., 1999) and this study concerning OCs in bowheads, the bowhead whale is not likely a significant source of contaminants for humans and should be considered a nutritious traditional food. These chemistry studies also support the importance of the Beaufort Sea in Alaska as an important feeding area as the body tissue chemical composition reflects that of the area and the prey (“you are what you eat”). It is important to consider biological factors in the interpretation of OCs data including season landed, sex, geographic area landed, size, age, trophic level (place on food chain), tissue sampled, metabolism, and others.


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