Hanna Shoal is a shallow, natural shoal located off the coast of northwest Alaska in the Chukchi Sea. The region around Hanna Shoal is one of the Chukchi Sea’s most biologically productive areas.

Map of Hanna Shoal in the Chukchi Sea

As a biologically important region for marine mammals and seabirds, Hanna Shoal is an important hunting area for local people.[1][2] The Chukchi Sea is thought to contain significant oil and gas reserves, and the greater Hanna Shoal region has long been part of a public conversation about conservation and extraction.

Geography

This shallow underwater shoal diverts warm water masses flowing northward from the Bering Sea and holds colder water long into the summer season, which in turn allows sea ice to persist longer in this area.[3][4][5] While the shoal is no longer covered by continuous pack ice all year as it historically was, it still has the most reliable ice present on the entire Chukchi shelf.[6]

Fauna

Due to the region’s high primary productivity, rich seafloor, and late summer sea ice, Hanna Shoal is a significant hot spot for wildlife. Pack ice and ice floes are highly important haulout and resting areas for species like the Pacific walrus,[7] polar bear, bearded seal,[8] and ringed seal.[9]

Hanna Shoal is also an important foraging area for many bird species.[10] Species that have been identified in this region are black-legged kittiwake, black guillemot, crested auklet, glaucous gull, ivory gull, northern fulmar, pomarine jaeger, and Ross’s gull.[11]

A major migration corridor for several species crosses the Hanna Shoal region. Bowhead whales traveling past Barrow Canyon cross the region in autumn to access habitats in Russian waters,[1][12] as do beluga whales. Marine birds also migrate through this corridor, including Steller’s eiders,[13] king eiders,[14] ivory gulls,[11][15] and Ross’s gulls.[11][16]

Importance

Hanna Shoal is likely to provide ecosystem resilience to climate change due to the stable physical features of the region that divert water masses and encourage lingering sea ice floes; these dynamics influence the rich seafloor and the local wildlife diversity.[17][18] The unique combination of characteristics that distinguish Hanna Shoal as a key feature of the Chukchi Sea are likely to persist in future decades, making this area a priority for conservation over the long-term. As part of a Bureau of Ocean Energy Management (BOEM) environmental stewardship program, the Hanna Shoal Ecosystem Study was launched. The Hanna Shoal Ecosystem Study is currently working to further reveal why the area is so highly productive.[19]

In 2008, the Minerals Management Service, the predecessor agency to BOEM, sold oil and gas leases in the Chukchi Sea, including in the Hanna Shoal region, for $2.67 billion. Companies, led by Shell, pushed to drill exploration wells in the area.

Hanna Shoal and the surrounding region influenced by its productivity were identified by conservation groups as an Important Ecological Areas of the U.S. Arctic Ocean.[20] In 2015, one million acres of the Hanna Shoal region (defined by the 40-meter depth contour line) were removed from consideration for future oil and gas leasing activities.[21][22] In addition, the 2017–2022 Outer Continental Shelf (OCS) Oil and Gas Leasing Program Draft Programmatic Environmental Impact Statement (DPEIS) recognized the Hanna Shoal Walrus Foraging Area and Walrus Movement Corridor as Environmentally Important Areas[23]

So far, attempted oil and gas development near the shoal has been unproductive. In 2015, one well was completed at the Burger prospect, roughly 10 miles from the Hanna Shoal important area. That well was unsuccessful, and as of July 2016, oil companies have relinquished all but one lease in the Chukchi Sea.[24]

References

  1. 1 2 Kuletz, K., M. Ferguson, B. Hurley, A. Gall, E. Labunski, and T. Morgan, "Seasonal spatial patterns in seabird and marine mammal distribution in the Pacific Arctic: Identifying biologically important pelagic areas", "Progress in Oceanography", May 2015. Retrieved 2016-08-16.
  2. ↑ Ayers, J., A. Blacow, B. Enticknap, C. Krenz, S. Murray, S. Roberts, G. Shester, J. Short, and J. Warrenchuk, "Important Ecological Areas in the Ocean: a Comprehensive Ecosystem Protection Approach to the Spatial Management of Marine Resources - an Oceana Discussion Paper", August 23, 2010. Retrieved 2016-08-16.
  3. ↑ Weingartner, T. J., K. Aagaard, R. Woodgate, S. Danielson, Y. Sasaki, and D. Cavalieri, "Circulation on the north central Chukchi Sea shelf", Deep-Sea Research Part II, December 2005. Retrieved 2016-08-16.
  4. ↑ Martin, S. and R. Drucker, "The effect of possible Taylor columns on the summer ice retreat in the Chukchi Sea", "Journal of Geophysical Research", May 1997. Retrieved 2016-08-18.
  5. ↑ Spall, M., "Circulation and water mass transformation in a model of the Chukchi Sea", "Journal of Geophysical Research: Oceans (1978-2012)", May 2007. Retrieved 2016-08-18.
  6. ↑ Weingartner, T., E. Dobbins, S. Danielson, P. Winsor, R. Potter, and H. Statscewich, "Hydrographic variability over the northeastern Chukchi Sea shelf in summer-fall 2008–2010", "Continental Shelf Research", September 2013. Retrieved 2016-08-18.
  7. ↑ Jay, C., A. Fischbach, and A. Kochnev, "Walrus areas of use in the Chukchi Sea during sparse sea ice cover", "Marine Ecology Progress Series 468". November 2012. Retrieved 2016-08-18."
  8. ↑ Aerts, L., A. McFarland, B. Watts, K. Lomac-MacNair, P. Seiser, S. Wisdom, A. Kirk, and C. A. Schudel, "Marine mammal distribution and abundance in an offshore sub-region of the northeastern Chukchi Sea during the open-water season", "Continental Shelf Research 67", September 2013. Retrieved 2016-08-18.
  9. ↑ Moore, S. and H. Huntington, "Arctic marine mammals and climate change: impacts and resilience", "Ecological Applications 18", March 2008. Retrieved 2016-08-18.
  10. ↑ Smith, M., N. Walker, C. Free, M. Kirchhoff, N. Warnock, A. Weinstein, T. Distler, and I. Stenhouse, "Marine Important Bird Areas in Alaska: Identifying Globally Significant Sites Using Colony and At-sea Survey Data", Audubon Alaska: Anchorage, September 2012. Retrieved 2016-08-18.
  11. 1 2 3 Drew, G., Piatt, J., and Renner, M.,"User’s guide to the North Pacific Pelagic Seabird Database 2.0", U.S. Geological Survey Open-File Report, July 2015. Retrieved 2016-08-18.
  12. ↑ Hauser, D., K. Laidre, R. Suydam, and P. Richard, "Population-specific home ranges and migration timing of Pacific Arctic beluga whales (Delphinapterus leucas)", "Polar Biology", August 2014. Retrieved 2016-08-18.
  13. ↑ Martin, P. D., D. C. Douglas, and T. Obritschkewitsch, ["Distribution and movements of Steller's eiders in the non-breeding period"], Unpublished manuscript, U.S. Fish and Wildlife Service and U.S. Geological Survey, Fairbanks, AK. 2009.
  14. ↑ Oppel, S., D. L. Dickson, and A. N. Powell, "International importance of the eastern Chukchi Sea as a staging area for migrating king eiders", "Polar Biology 32", May 2009. Retrieved 2016-08-16.
  15. ↑ Mallory, M. L., I. J. Stenhouse, G. Gilchrist, G. Robertson, J. C. Haney, and S. D. MacDonald, "Ivory Gull (Pagophila eburnea)", "The Birds of North America Online - Cornell Lab of Ornithology", 2008. Retrieved 2016-08-18.
  16. ↑ Blomqvist, S. and M. Elander, "Sabine's gull (Xema sabini), Ross's gull (Rhodostethia rosea) and Ivory gull (Pagophila eburnea) gulls in the Arctic: A review", "Arctic 34", June 1981. Retrieved 2016-08-18.
  17. ↑ Gunderson, L., "Ecological Resilience-In Theory and Application", "Annual Review of Ecological Systems 31", November 2000. Retrieved 2016-08-18.
  18. ↑ Christie, P. and M. Sommerkorn, "RACER: Rapid Assessment of Circum-Arctic Ecosystem Resilience", World Wildlife Fund- Global Arctic Programme, 2012. Retrieved 2016-08-18.
  19. ↑ Bureau of Ocean Energy Management, "Hanna Shoal Ecosystem Study", 2011.
  20. ↑ Audubon, Oceana, Pew, World Wildlife Fund, and Ocean Conservancy, "A Synthesis of Important Areas in the U.S. Chukchi and Beaufort Seas", April 2015. Retrieved 2016-08-18.
  21. ↑ Boots, M. and Utech, D., "President Obama Protects Untouched Marine Wilderness in Alaska", 2015-01-27. Retrieved 2016-08-18.
  22. ↑ Rosen, Y., "Chukchi Sea shoal newly closed to oil leasing is well known as biological hot spot", 2015-02-02. Retrieved 2016-08-18.
  23. ↑ Bureau of Ocean Energy Management, "Outer Continental Shelf Oil and Gas Leasing Program: 2017-2022 Draft Programmatic Environmental Impact Statement" Archived 2016-08-09 at the Wayback Machine, March 2016. Retrieved 2016-08-18.
  24. ↑ Oceana, "Companies Gives Up Arctic Ocean Leases", 2016. Retrieved 2016-08-18.

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