Most northern fur seals inhabit the Pribilof Islands, in Alaska. These remote islands are off the coast of mainland Alaska, in the Bering Sea. Organisms there are largely influenced by the ocean circulation which varies with trade winds. In addition, the extremely remote distance between the islands and the mainlands makes the Pribilof Islands more vulnerable. (Danielson,2012)

The red circle highlights the Pribilof Islands

Map of Alaska highlighting Pribilof Islands, September 2006,  Eric Gaba


  • Climate change brings significant changes to northern America, with the increased concentration of CO2, entire ecosystems are dominated by the warmer temperature and higher sea levels(IPCC). The abnormalities influence both inland and aquatic species. My case study chooses Alaska northern fur seals as the "victim" representative of climate change. Northern fur seals are listed as an endangered species in the 1970s, when 50% population decreased abruptly(Noah, 2019). Loss of sea ice, prolonged storms, and extreme weather, brings both direct and indirect impacts of climate change.


  • Extreme climate variations
  • Sea ice loss
  • Sea level rise
  • Stronger El Niño
  • Algal blooms


  • Seals' migration patterns are disrupted by climate variations
  • Seals' habitat decreases but their predator's living space enlarged as the loss of sea ice
  • Nutrient loss triggered by sea level rise
  • Food availability changes, particularly fish group shift as the violent El Nino effects
  • Polluted marine ecosystem with harmful algal bloom

Migration related threats

  • Stronger currents 
  • More frequent storms 


  •  Climate change: The climate change-induced strong winds process obstacles to fur seals' migration routes, especially for the seals' pups.
  • The sea surface temperature(SST)-sea ice concentration(SIC) studies show that the positive relationship between SST and wind speed in sea ice dominated areas and a negative correlation over open water condition. The presence of sea ice would indicate a correlation between SST and wind speed(Zhang,2018).  The vast thermal difference between open water and sea ice increase the temperature gradients, largely disrupt the atmosphere stability (Zhang,2018).

In Alaska, the negative relationship between surface winds and SST and the present of SIC trigger abnormal wind flows, making wind strength unstable. 

  • Migration: During December to April, seals to migrate to avoid the severe cold and to reserve energy for the summer and next year's breeding season (Lea,2009). It is impossible for fur seals to confront the abnormal strong winds during the long migration journey, the elongated period exposes seals to uncertainties. Especially for seal pups, that experience more extended migration period. During the long journey, lack of parental care, pup seals might directly be harmed by the storms and currents, and indirectly be threatened by predators like killer whales. 

This video describes Northern fur seals migration.  

Provided by NOAA National Marine Fisheries Service, NOAA Marine Mammla Lab 

Habitat disruption

  • Sea ice loss
  • Loss of habitat
  • Nutritient deficiencies 

- In Alaska, the climate changes related to sea ice retreat leads to direct impacts on coastal mammals and human beings. Warmer temperature induces the loss of sea ice, lead to acidification, and reduces economic productivity (Huntington, 2015). Sea ice presence is much shorter than before. representing a loss of habitat for nursing the pup seals (Burn, 1970). 

- Stronger predator threats

For fur seals and polar bears, which mostly rely on the sea ice, the warmer weather leads to sea ice melting and population decreases. The loss of sea ices benefits certain species, which are more adept to fewer sea ices conditions, like killer whales. Without the sea ices as shelter, it is easier for predators to spot their prey (Moore and Huntintong, 2008). Climate changes make fur seals' living condition more adverse and create a better condition for their predators. The cumulative impacts on habitat loss far fur seals and greater forces for predators strongly decrease seals' population, induce more injuries and deaths, 


Arctic sea ice loss under different time period.  

produced by Goddard Scientific Visualization Studio,2011-07-06, credit to NASA/Goddard

-The decrease in productivity

 Loss of sea ice also impacts fertility. As both physical and biological cycles in Bering seas mostly rely on the sea ice, the melting of sea ice could not support the transportation cycle of nutrients. insufficient surface ice will affect the distribution of salinity and temperature. As a result, the overall decrease of primary production impacts the trophic levels and influence the fundamental nutritional needs of all the marine mammals(Niebauer, 1990). Even in recent years, SLR in Alaska is more and more severe than before, which brings more significant nutrition loss, largely influences marine mammals

El Niño

  •  El Niño is a kind of weather pattern, which most disturbed the normal weather phenomenon. On the one hand, El Niño would promote global warming, but on the other hand, global warming will strengthen the influences of El Niño (CHO, 2016). ENSO oscillation is a pattern of pressure, temperature and rainfall fluctuation that can have a global climate impact.


  • It accounts for one-third of the ice and sea surface temperature variability in Bering sea and can have significant effects on fish distribution. The fish distribution will affect fur seals, as the crucial relationship between seals food foraging and the abundance of Pollock(Huntington, 2017).


  • El Niño also threatens the underwater ecosystem especially the coral reefs, the primary food for some fish species (Huntington, 2017). Fur seals' food storage will be uncertain as to the shift of Pollock and squid; it is difficult for them to find substitutes. Moreover, the competition between fur seals and human fisheries becomes stronger as the fish becomes limited resources. Lack of stable food supply largely threats the fur seals existences.

This video introduce the phenomenon of ENSO and its overall climate effects 

What is ENSO, El nino, La nina, Southern Oscillation, Walker Circulation | UPSC / IAS

Amit  Sengupta. Published on Nov 26, 2017

Harmful Algal Bloom

Harmful algal blooms: effectively lower underwater oxygen levels, threatening marine life and associated with algae-produced toxins(J. Heisler, 2008).

  • As the climate changes, Alaska’s annual average temperature increased to 3.5°F from 1949 to 2005 (NOAA, 2013). Through the phytoplankton monitoring in Kachemak Bay National Estuarine Research Reserve(Walker, 2018). The overall increased temperature leads to abnormal warming to tend in the Gulf of Alaska and even transited across the Gulf of Alaska, and Bering sea(Stabeno, 2007). In conclusion, the warming in Alaska is entirely and violently covered the whole region, and the increased temperature seriously influences every part. Thus, through convection, the warmer atmosphere will increase the marine temperature.


  • Harmful algal blooms are a common phenomenon in warm areas especially in tropical regions, but recently the more heated Arctic area also triggered this phenomenon. Through Burek’s study, harmful algal bloom becomes more common among marine mammals in Alaskan waters(Burek,2008). When zooplankton, clams mussels eat algae, the algal toxins will accumulate in the tissues, and the toxins will pass through the food chain to high-level predators such as fish, birds who consume the contaminated ones, and induce illness even death(ADAPT Alaska)


Phytoplankton Bloom in the Bering Sea amo 20092801, NASA, 8 October 2009

  • Through the background information collected by the Northern Alaska Pinniped Unusual Mortality Event(, samples like feces, urine, serum from the marine mammals. And through the analyze of National Marine Fisheries(NMFS). It detected that Northern fur seals’ fecal and serum have Domoic acid, which induced by Algal toxins. 


  • The wild spread algal bloom indeed threatened the subsistence of Northern fur seals. As I mentioned before, fur seals are experiencing a more extended migration period which enlarges the threats of algal toxins. Also, fur seals’ food like squid and Pollock exposed to the algal toxins, and when seals eat them, the bioaccumulation might elongate the half-life of toxins, and threatens seals’ subsistence. 


  • There are some assumptions about the plunging decrease of northern fur seals in recent years. As the former mortality of seals were contributed to hunting, as Alaskans depend on seals furs to resist cold weather and release food shortage. But the hunting number of seals did not show the apparent increase, thus leading to the consideration of another reason. As the warmer temperature makes the ice layer thinner than before, which makes it dangerous for hunters to go out to hunt. Also, without enough ice, the surface friction is difficult to resist the wind above. Thus, make it harder to track (Huntington, 2017). Some scientists assume that the global climate change might contribute to this abnormal decrease number of seals, as the sea level rises reduce seals' living habitats and induce food shortage. Furthermore, many seals pups are experiencing much longer migrating period caused by the harass of strong winds. For all of the reason listed above, it is undoubtedly that the global climate changes have impacts towards northern fur seals (Huntington, 2017).


Saint Paul Island, Alaska, foreground, fur seals on rookery and in water. Saint Paul Village in distance

 Fur seal rookeries, reef rookery, Garbotch rookery; Alaska, St. Paul Island, Pribilof Islands

  • As far as I am concerned, there are still some obstacles while building up the fur seals adaptation plans. The Probilif islands are remote from the Alaska mainland, the isolated location combined with poor transportation makes the assistance from mainland hard to approach to the islands. In addition, fur seals’ activity range is too wide and complex to track and update. Even though the satellites could collect some pieces of information, but the seals under different age-group will present different migration pattern, it will take a long term to figure out the representatives from each group. From my perspective, the funding and technologic updates are the most necessary, the local area supposes to make their own research organization to collect the information on time. And the abundance of financial support could ensure the enactment of adaptation. 


There is no specific climate change related adapting strategies towards northern fur seals. But there have some conservation strategies from NOAA to protect fur seals. Furthermore, there are some adaptation strategies which concern with the whole climate change hazards in Alaska also could increase the resilience of the local marine animals.

Narrow adaptations

  • Regulating, monitoring, co-managing subsistence use of Northern fur seals.
  • Monitoring population abundance and distribution.
  • Educating the public about northern fur seals and the threats they face. 
  • Removing debris from tracking entangled northern fur seals(NOAA).

Monitoring and Event Response (University of Washington, 2016)

  • Enhance routine water quality and shellfish monitoring with better HAP detection methods, training, and strategies.
  • Add sensors t ocean observing systems for low-cost, long-term observation of HABs and related ocean conditions
  • Demonstrate operational capabilities for forecast models to enhance HAB early warning capability

This program helps NOAA and relative departments to recognize when marine animals are at risk from harmful algae, and largely assist coastal areas to make decisions that safeguard the local lives.

Co-management plan

Management plans (Lyons,2000):

  • Monitoring and Research programs, Harvest and Rookery Management
  • Education and Information: Training, funding, the outline of future goals, activities identify information and conservation needs. 

Research program: 

  • Assessment of population abundance and trends using conventional science methods
  • Assessment of habitat use and seasonal movements.
  • Assessment of sources of mortality

Climate hazards adaptation methods

  • Monitoring: Alaska is not fully prepared to detect the sudden climate variations due to a lack of stream gaging sites. Funding and implementations are needed to build a complete monitoring system(Robert, 2010). 
  • Research: through fish community structure and abundance, to do the predator-prey studies, and feeding studies. Control the variety of aquatic habitats through replication(Robert,2010).

Build up resilience

 The Alaska Climate Science center accompanies with the U.S. Fish and Wildfire Service, and other entities to create some workshops in the whole coastal area in Alaska. Those workshops gathered local resources together to do resource management, estimation, and future planning to advance coastal resilience(Robards, 2018). The local decision making is important to conserve coastal creatures, as the scientific method has to accompany with indigenous knowledge. Thus, the local workshops gathered both scientists and indigenous people could exert stronger influences.


Qiwen Zheng is in the class of 2021 at St.Lawrence University, major in Environmental study. She is from Chong Qing, China, the middle part of China. Prior to entering college, she completes her education in China. Through the growing and learning experiences, she gradually realized the environment regulating shortages in China. Thus, she chose environmental study as the major, and try to understand the grand overview of environmental issues and regulation methods. 


2017 northern fur seal adult male counts on the pribilof islands, alaska. Retrieved from

Cambridge University Press. doi:10.1017/CBO9781316164624.008 Retrieved from

Coowe Walker, M. S., Jacob Argueta, Steve Baird, Syverine Bentz, M. S., Chris Guo, Rosie Masui, . . . Jessica Shepherd, M. A. (2018). Evaluation of kachemak bay national estuarine research reserve; public meeting. ( No. 83). Washington: Federal Information & News Dispatch, Inc. Retrieved from ProQuest Public Health Retrieved from

H. J. Niebauer, & Robert H. Day. (1989). Causes of interannual variability in the sea ice cover of the eastern bering sea. GeoJournal, 18(1), 45-59. doi:10.1007/BF00722385

Heisler, J., Glibert, P. M., Burkholder, J. M., Anderson, D. M., Cochlan, W., Dennison, W. C., . . . Suddleson, M. (2008). Eutrophication and harmful algal blooms: A scientific consensus. Harmful Algae, 8(1), 3-13. doi:10.1016/j.hal.2008.08.006

Huntington, H. P., Carmack, E., Wassmann, P., Wiese, F., Leu, E., & Gradinger, R. (2015). A new perspective on changing arctic marine ecosystems: Panarchy adaptive cycles in pan-arctic spatial and temporal scales. Ocean sustainability in the 21st century (pp. 109-126). Cambridge: Cambridge University Press. doi:10.1017/CBO9781316164624.008 Retrieved from

Huntington, H. P., Quakenbush, L. T., & Nelson, M. (2017). Evaluating the effects of climate change on indigenous marine mammal hunting in northern and western alaska using traditional knowledge. Frontiers in Marine Science, 4 doi:10.3389/fmars.2017.00319

IPCC (2014). Retrieved from

Lyons, C., Carothers, C., & Reedy, K. (2016). A tale of two communities: Using relational place-making to examine fisheries policy in the pribilof island communities of st. george and st. paul, alaska. Maritime Studies, 15(1), 1-23. doi:10.1186/s40152-016-0045-1

Kathy A. Burek, Frances M. D. Gulland, & Todd M. O'Hara. (2008). Effects of climate change on arctic marine mammal health. Ecological Applications, 18(2), S134. doi:10.1890/06-0553.1

NOAA weather buoy back online in alaska (2013). . Arlington: Compass Publications

Noah Greenwald, Kieran F Suckling, Brett Hartl, & Loyal Mehrhoff. (2019). Extinction and the U.S. endangered species act. PeerJ PrePrints, doi:10.7287/peerj.preprints.27471v2

RENEE CHO. (2016). El niño and global Warming—What’s the connection? Retrieved from

Robards, M. D., Huntington, H. P., Druckenmiller, M., Lefevre, J., Moses, S. K., Stevenson, Z., . . . Williams, M. (2018). Understanding and adapting to observed changes in the alaskan arctic: Actionable knowledge co-production with alaska native communities. Deep-Sea Research Part II, 152, 203-213. doi:10.1016/j.dsr2.2018.02.008

Robert Clark, Alvin Ott, Mary Rabe, Douglas Vincent Lang, & Douglas Woodby. (2010). Climate hazards adaptation methods:(Alaska Department of Fish and Game Divisions of Sport and Commercial Fisheries. Habitat. And Wildlife Conservation) Retrieved from

The University of Washington, Oregon Department of Fish and Wildlife, NMFS Northwest Fisheries Science Center, University of Strathclyde, and University of California–Santa Cruz (2016) MERHAB: An Early Warning System for Pseudo-nitzschia Harmful Algal Blooms on Pacific Northwest Outer-Coast Beaches

Zhang, J., Stegall, S. T., & Zhang, X. (2018). Wind–sea surface temperature–sea ice relationship in the Chukchi–Beaufort seas during autumn. Environmental Research Letters, 13(3), 34008. doi:10.1088/1748-9326/aa9adb

Media citations

Tom Wilberding, Northern fur seal, female, Flickr, May 26, 2018

Eric Gaba, Map of Alaska highlighting Pribilof Islands, Wikimedia Commons, made by Messedrocker based on Image:Map of Alaska highlighting Anchorage Municipality.png and Image:Map of Alaska highlighting Juneau City and Borough.png, September 2006,

Jim Greenhill, St. Paul Island, Alaska, on Nov. 6, 2010. About 500 people live on the island 775 miles west of Anchorage in the Bering Sea. The Alaska National Guard brought Christmas to the island early Nov. 6 as part of its 54th annual Operation Santa Claus outreach to the state's remote communities. (U.S. Army photo by Staff Sgt. Jim Greenhill) (Released), Wikimedia Commons, 6 November 2010,_Alaska_5.jpg

NOAA national marine fisheries service NOAA Marine mammal lab, Northern Fur Seal, Apr 17, 2015

Goddard Scientific Visualization Studio, Declining Arctic Sea Ice, NASA/Goddard, 2011-07-06

Amit Sengupta, What is ENSO, El nino, La nina, Southern Oscillation, Walker Circulation | UPSC / IAS, YouTube, Nov 26, 2017

NASA, Phytoplankton Bloom in the Bering Sea, Acquired October 8, 2009, this true-color image shows peacock-hued splashes of color off the coast of Alaska, near St. Paul Island.

Bill Briggs, Saint Paul Island, Alaska, foreground, fur seals on rookery and in water. Saint Paul Village in distance, Wikimedia Commons,20 February 2005,_Alaska_05s_Ak331.JPG

Stefan Claesson, Fur seal rookeries, reef rookery, Garbotch rookery; Alaska, St. Paul Island, Pribilof Islands, NOAA photo library,  August 1891,_Pribilof_Islands,_1891.jpg

Byrd Vernon, northern fur seal, pixnio, 2016-08-10.