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Ecologically or Biologically Significant Areas (EBSAs)

  published: 12 Jun 2015

Wrangel-Gerald Shallows and Ratmanov Gyre

General Information
The Wrangel – Gerald Shallows and Ratmanov Gyre is a shelf area in the Russian part of the Chukchi Sea. Unlike most shelves in the Russian Arctic seas, it is not influenced by the discharge of great Eurasian rivers. Most of the area is filled by water originating from the Bering Sea, which enters through the Bering Strait in seasonal pulses and circulates in the Chukchi Sea (Zalogin and Kosarev, 1999). There is a large, stable gyre in the eastern part of this area (known as the Ratmanov Gyre), which stabilizes the conditions, provides a significant supply of nutrients and high primary production that fluxes to the bottom, and is the basis for stable and persistent benthic communities (Sirenko et al., 2009a). The biomass of benthic infauna and epifauna is very high (Speer and Laughlin, 2011: A). Around Wrangel Island, landfast ice and polynyas are formed. The formation of polynyas off Wrangel Island is a result of the interaction between the Arctic and the Siberian anticyclones. The area is largely untouched by human activities. This area provides a spring migratory pathway for hundreds of bowhead whales daily, as well as beluga whales, polar bears, Pacific walrus and gray whales during summer and autumn (Speer and Laughlin, 2011: A). There are no proven endemic species in the area, however, several species have been described in the Chukchi Sea that are thus far known only in this region (Sirenko, 2009). In winter, the polynyas adjacent to Wrangel Island form an area with a high concentration of ringed (Phoca hispida) and bearded (Erignathus barbatus) seals and their predators — polar bears (Ursus maritimus) (Belikov et al., 1998). The area serves as a feeding area for seabirds, walruses and cetaceans.
The report on identifying Arctic marine areas of heightened ecological significance (AMSA IIc) revealed the waters off Wrangel Island and the central shelf of the Chukchi Sea as important areas (AMAP/CAFF/SDWG, 2013: figures 9 A and B, table 14, areas 5 and 6). Here, it is considered as a single area meeting EBSA critiera. Wrangel and Gerald Shallows and Ratmanov Gyre is relatively well covered by historical Russian data and the information from the recent RUSALKA Project. The IUCN/NRDC Workshop to Identify Areas of Ecological and Biological Significance or Vulnerability in the Arctic Marine Environment (Speer and Laughlin, 2011) also identified an area named “Chukchi and Beaufort Sea Coast” as meeting nearly all the CBD criteria.
Description of the location
Arctic
The area extends from the waters around Wrangel Islands, along the midline of De Long Strait to 180 W, then along the 30 m isobaths to Gerald Island, including part of Gerald Trench, and to the latitude somewhat east of Cape Serdtse-Kamen’ at 173 W. The northern boundary conventionally follows the 100 m isobaths. This area lies within the EEZ and territorial sea of the Russian Federation.
DISCLAIMER: The designations employed and the presentation of material in this map do not imply the expression of any opinion whatsoever on the part of the Secretariat concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
Area Details
The area covers the coastal zone of Wrangel and Gerald islands, along with an extensive shelf area, which, unlike in most Russian Arctic seas, is not influenced by the discharge of great Eurasian rivers. Rivers entering the western Chukchi Sea are generally small, and their signal does not extend further than the narrow zone along the continental coast (Zalogin and Kosarev, 1999). The bottom topography is relatively complex compared to the Siberians seas and includes moderately deep (to 50 – 70 m) trenches. Most of the area is filled by water originating in the Bering Sea, which enters through the Bering Strait in seasonal pulses and circulates in the Chukchi Sea, generally in an anti-clockwise direction (Zalogin and Kosarev, 1999). The water column is relatively homogenous in winter; rapid stratification develops in spring owing to the metlint of sea ice and the warming of opening water, while later in the summer both salinity and temperature of the surface waters increase as a result of further warming and greater input of Pacific water (Zalogin and Kosarev, 1999). A large, stable gyre in the eastern part of this area, first discovered by Ratmanov in 1937, is an important characteristic of the area (figure 2). This feature is referred to mere as the Ratmanov Gyre, although this name is not widely accepted in the oceanographical literature. This gyre stabilizes the conditions, provides a significant supply of nutrients and high primary production that fluxes to the bottom, and is the basis for stable and persistent benthic communities (Sirenko et al., 2009a) (figure 3). The area is ice-covered for most of the year but recently the duration of the ice-free season has been increasing. Around Wrangel Island, landfast ice and polynyas are formed. The formation of polynyas off Wrangel Island is a result of the interaction between the Arctic and the Siberian Anticyclones. The different and changing year-to-year interactions of the processes originating in these centres of atmospheric activity explain the inter-annual variability of polynyas in the East Siberian and the Chukchi seas. During warm years the Arctic Anticyclone weakens and shifts to the Canadian sector of the Arctic, resulting in the dominance of a system favouring polynya development in the Chukchi Sea (Gavrilo and Popov, 2011). The lead system at the transition between landfast and drifting ice has been described as “a wonder of nature,” providing a spring migratory pathway for hundreds of bowhead whales daily, as well as beluga whales, polar bears, Pacific walrus and gray whales during summer and autumn. The Chukchi Sea has massive phytoplankton blooms, which, along with annual sea ice algae production, cannot be fully exploited by the zooplankton communities. Hence, much of this high production is exported unmodified to the benthos, resulting in an impressively high biomass of benthic infauna and epifauna” (Speer and Laughlin, 2011: A).
The conditions in the area appear to be dynamic, and ecological processes are very sensitive to changes in climate, in particular variability in sea ice. A potential threat is related to offshore oil and gas exploration, which will likely take place within the next decade.
References
AMAP/CAFF/SDWG, 2013. Identification of Arctic marine areas of heightened ecological and cultural significance: Arctic Marine Shipping Assessment (AMSA) IIc. Arctic Monitoring and Assessment Programme (AMAP), Oslo. 114 pp. Belikov S., Boltunov A., Belikova T., Belevich T.,Gorbunov Yu. 1998. Marine mammals. The distribution of marine mammals in the Northern Sea Route area. INSROP Working Paper No 118–1998. Oslo: The Fridtjof Nansen Institute. — 49 p. Belikov S.Ye., Boltunov A.N., Gorbunov Yu.A. 2002. Seasonal distribution and migrations of whales of the Russian Arctic based on results of long_term observations by aerial ice reconnaissance and drifting stations “North Pole”. In: A.A. Aristov, V.M. Belkovich, V.A. Zemsky, V.A. Vladimirov and I.V.Smelova (eds). Marine mammals (Results of researches conducted in 1995–1998). Moscow: Marine Mammals Council. — Pp. 21–50. (In Russian). Bogoslovskaya L., Votrogov L., Krupnik I. 1982.The bowhead whale off Chukotka: migrations and aboriginal whaling. Reports of the International Whaling Commission, 32: 391–399. Gavrilo M.V., Popov A.V. 2011. Sea ice biotopes and biodiversity hotspots in the East Siberian Sea and the waters of Chukotka. In: V.A. Spiridonov., M.V. Gavrilo, N.G. Nikolaeva, E.D. Krasnova (eds) 2011. Atlas of the Marine and Coastal Biodiversity of the Russian Arctic. Moscow, WWF Russia, pp. 38–39. Golikov A.N., Sirenko B.I., Petryashov V.V., Gagaev S.Yu. 2009. Distribution of bottom communities in the Chukchi Sea from results of diving investigations. In: B.I. Sirenko (ed) Ecosystems and biological resources of the Chukchi Sea and adjacent areas. Explorations of the Fauna of the Sea, St. Petersburg, Zoological Institute of RAS, 64 (72),pp. 56–62 (in Russian). Sirenko B.I. 2009a. The present state of investigations of the Chukchi Sea fauna. In: B.I. Sirenko (ed) Ecosystems and biological resources of the Chukchi Sea and adjacent areas. Explorations of the Fauna of the Sea, St. Petersburg, Zoological Institute of RAS, 64 (72), pp. 5–27 (jn Russian). Sirenko B.I., Bluhm B., Iken K. Crain K., Gladish V. 2009b. ROV investigations on the composition and quantitative distribution of epifauna in the Chukchi Sea. In: B.I. Sirenko (ed) Ecosystems and biological resources of the Chukchi Sea and adjacent areas. Explorations of the Fauna of the Sea, St. Petersburg, Zoological Institute of RAS, 64 (72), pp. 20 –212. Spiridonov V.A. 2011. Biogeographical regionalization. Species diversity in the Russian Arctic seas: pelagic and sea ice biota, micro- and meiofauna. Macrobenthos: species diversity and group domination in the communities. In: V.A. Spiridonov., M.V. Gavrilo, N.G. Nikolaeva, E.D. Krasnova (eds) 2011. Atlas of the Marine and Coastal Biodiversity of the Russian Arctic. Moscow, WWF Russia, pp. 16-21. Vetrov A.A., Romankevich E.V. 2011. Primary production and fluxes of organic carbon to the seabed in the russian Arctic seas as a response to the recent warming. Oceanology, 51(2): 266–277.
Status of submission
Areas described as meeting EBSA criteria that were considered by the Conference of the Parties
  • dec-COP-12-DEC-22
Assessment of the area against CBD EBSA criteria
C1: Uniqueness or rarity Medium
There are no proven endemic species in the area, however several species have been described from the Chukchi Sea that are thus far known only in this region (Sirenko, 2009). Benthic communities in the south-eastern part of the area within the Ratmanov Gyre are very distinct owing to its unusually high biomass for the Arctic (Sirenko and Gagaev, 2007; Sirenko et al., 2009 a, b).
C2: Special importance for life-history stages of species High
In winter, the polynyas adjacent to Wrangel Island form an area with high concentration of ringed (Phoca hispida) and bearded (Erignathus barbatus) seals and their predators: polar bears (Ursus maritimus) (Belikov et al., 1998). The area serves as a feeding area for seabirds, walruses and cetaceans. Of particular importance for walrus feeding could be rich benthic communities located within the Ratmanov Gyre off Serdtse-Kamen’ Cape (Sirenko et al., 2009a).
C3: Importance for threatened, endangered or declining species and/or habitats High
Gray whales (Eschrichtius robustus) of the Californian-Chukchi population and bowhead whales (Balaena mysticetus) migrate from their wintering grounds and move to the Chukchi Sea in June. In summer and autumn bowhead whales forage and travel up to Wrangel Island and further east (Bogoslovskaya et al., 1982; Belikov et al., 2002; Gavrilo and Popov, 2011).
C4: Vulnerability, fragility, sensitivity, or slow recovery High
Sea ice habitats are particularly sensitive to climate change; polar bears are particularly suffering from decreasing sea ice.
C5: Biological productivity High
The Chukchi Sea shows increased pelagic primary production and carbon flux to the bottom in comparison to the seas of the Siberian shelf, and there is a trend to its increase (Vetrov and Romakevich, 2011). The areas near Wrangel Island and within the Ratmnanov Gyre are of particular importance. Most of the pelagic production contributes to the benthic flux and is utilized for building up an unusually high benthic biomass, in particular in the communities dominated by Macoma clacarea (Sirenko and Gagaev, 2007; Sirenko et al., 2009a) (figures 2, 3).
C6: Biological diversity High
The Chukchi Sea has a considerably higher richness of marine species than the seas of the Siberian shelf (Sirenko, 2009, Spiridonov, 2011; Spiridonov et al., 2011), and the present area holds most of the species known in the area. The area holds the broadest range of benthic community types known for the Chukchi Sea (Sirenko et al., 2009a,b).
C7: Naturalness High
This is largely untouched area.