Sea of Okhotsk ecology
The Sea of Okhotsk, located in the Russian Far East, is a biologically rich and ecologically significant marine environment, extending over approximately 611,000 square miles. This sea is characterized by its cold temperatures, particularly in the winter, and experiences considerable seasonal variations, including extensive ice cover and varying precipitation levels. The region supports a diverse range of marine wildlife, including numerous fish species such as pollock, salmon, and various crustaceans, as well as a variety of marine mammals like the endangered Kuril harbor seal and gray whale.
The Sea of Okhotsk is also home to many seabird species, particularly around the Kuril Islands, which host large colonies. Indigenous communities have lived along its shores for millennia, maintaining deep cultural ties to the marine ecosystem. However, this unique ecology faces significant threats from climate change, which has led to a notable decline in sea ice, as well as from industrial pressures, such as offshore oil and gas exploration. These activities raise concerns about environmental degradation and its impact on both the local ecosystems and the livelihoods of Indigenous peoples reliant on the sea's resources. As such, ongoing research and international collaboration are crucial to understanding and mitigating the ecological challenges faced by the Sea of Okhotsk.
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Sea of Okhotsk ecology
- Category: Marine and Oceanic Biomes.
- Geographic Location: Russia.
- Summary: A wild and unique seascape, this biome is now threatened by climate change and ongoing development schemes, fueled by national and international interest.
The Sea of Okhotsk is located in the Russian Far East region, adjacent to the western Pacific Ocean. It is partially enclosed by the Russian Kamchatka Peninsula to its east, Japan and the island of Sakhalin to its southwest, and the Kuril Islands to the southeast. This ecoregion is highly sensitive to climate change and has experienced a number of changes, including changed patterns of sea ice. The sea stretches across some 611,000 square miles (1,583,000 square kilometers) and is one of the most biologically productive seas worldwide.
The Sea of Okhotsk is the coldest sea in East Asia. Its temperatures during winter compare to the Arctic. Its western and northern regions experience severe winter weather due to influences from the continent. From October through April, temperatures are bitter and the area is ice-covered and dry, with little precipitation. A milder maritime climate occurs in the south and southeast due to oceanic influences. February’s average monthly air temperature in the northeastern region is minus 4 Fahrenheit (F) (minus 20 Celsius [C]); north and west of the sea, it is minus 11 F (minus 24 C); and in the southern and southeastern parts it averages 19F (minus 7 C). The average August temperature is 54 F (12 C) in the northeast; 57 F (14 C) in the north and west; and 64 F (18 C) in the south and southeast.
Annual precipitation varies from 16 inches (40 centimeters) in the north, to 28 inches (70 centimeters) in the west, and about 41 inches (104 centimeters) in the south and southeast.
During the winter, navigation on the Sea of Okhotsk becomes difficult, or even impossible, due to the formation of large ice floes. Large amounts of freshwater from the Amur River, which reaches the sea at the Straight of Tartary at the southwestern end of the Sea of Okhotsk, lowers the salinity in this area—and results in lowering the freezing point of the sea here. The thickness and distribution of ice floes depend on many factors: the location, the time of year, water currents and wind systems, and sea temperatures.
Wildlife
The Sea of Okhotsk presents a vast shoreline mostly made up of gravel and cliffs, interspersed with large bays and tidal mudflats. The region is relatively poorly populated, apart from various fishing villages. Only Magadan in the north, and Sakhalin Island in the southwest, harbor larger population centers. Other cities and ports include Korsakov, Ayan, and Okhotsk. The volcanic Kuril Islands chain is sparsely populated, mostly in the south. (Tensions between Russia and Japan exist surrounding some of the southern islands and associated marine regions of the Kurils).
The sea is recognized globally for its fisheries, namely pollock, herring, sardine, flounder, cod, capelin, smelts (also called frostfish), and salmon (all Pacific salmon species occur here); species such as crab, squid, shrimp, and sea urchin are also heavily pursued in southern regions, destined for Asian markets. Caviar (ikra in Russian) is highly sought after, and local sturgeon species in the Amur and Sakhalin region are of global conservation concern because of Overfishing, illegal fisheries, and poor straddling stock management.
Sea of Okhotsk is also home to many marine mammals, including the endangered species of Kuril harbor seals and gray whales. Other marine mammals that inhabit the region include the North Pacific right whale, bowhead whale, Baird’s beaked whale, Arnoux’s beaked whale, beluga, Dall’s porpoise, harbor porpoise, sea otter, Stellar’s sea lion, Pribilof fur seal, Okhotsk ringed seal, Pacific bearded seal, ribbon seal, and spotted seal.
Some of these species show a connectivity with Bering Sea populations, including with Alaska and British Columbia. Walrus were nearly extirpated in this region in the early twenty-first century because of decreasing sea ice and increasing vessel traffic. Other wildlife in the surrounding area includes many sea- and shore-birds. Large migrations of waterbirds occur here, including endangered species. The Kuril Islands are home to many millions of seabirds, including northern fulmars, tufted puffins, murres, kittiwakes, guillemots, auklets, petrels, and cormorants.
Human Impact
Indigenous populations inhabited the Sea of Okhotsk region for millennia. Several Indigenous communities continue to live along the long shoreline (most Japanese Ainu have withdrawn from the Kuril Islands, however). With their subsistence practices, these spiritual and material cultures still show high interdependency with the sea. Therefore, they are some of the first to experience and suffer from environmental changes, such as the decline of maritime resources due to human expansion and climatic changes.
The Sea of Okhotsk shelf, which runs along the coast, has been identified as having significant zones of potentially recoverable oil and gas accumulation. Pressures are growing for offshore oil and gas exploitation and extraction. These demands are not only fueled by Russian interests, but also by Japan, China, Korea, and India. The construction of one of the largest liquefied natural gas plants in the world, and its associated pipeline, on Sakhalin is an example. International financing plays a major role in such endeavors. Subsequently, with consumption and the amount of shipping required on the rise, tanker traffic and extreme weather conditions in the region have increased the risk of oil spills. The North Pacific Marine Science Organization (known as PICES) has provided a forum for the exchange of marine data in response to previous spills. However, there is still major international concern over this issue.
Because of climate change, rising average air temperatures, changing sea surface temperatures, changing air circulation patterns, and circulation cycles of carbon in this ecoregion have all been affected. Migration routes of salmon and other fish have been impacted. Sea ice is used by marine mammals to facilitate their migration routes, and changing amounts and duration of sea ice cover have compromised this. Between about 1980 and 2020, sea ice decreased in the region by about 30 percent.
The Sea of Okhotsk comes mainly under the governance of Russia, but the issue of who has sovereignty over the Kuril Islands involves Japan. In the early twenty-first century, the environmental organizations Sakhalin Environment Watch (closed in 2023) and the California-based Pacific Environment and Resources Center led independent experts to the Kurils to review local monitoring methods, spill prevention, and response measures. However, there remains much research to be done on the continuing changes in climate factors and how these will impact species throughout the ecoregion.
Bibliography
Artukhin, Yu B. “Seabird Aggregation around Vessels during the Winter Trawl Fishery for Walleye Pollock in the Sea of Okhotsk.” Russian Journal of Marine Biology, vol. 44, no. 7, 2018, pp. 592–97, doi.org/10.1134/S1063074018070027. Accessed 1 Dec. 2024.
Artukhin, Yu B. “Winter Seabird Populations in Open Waters of the Sea of Okhotsk.” Russian Journal of Marine Biology, vol. 45, no. 1, 2019, pp. 6–14, doi.org/10.1134/S1063074019010024. Accessed 1 Dec. 2024.
Bailey, Scott C. M. Russia and Japan in the Sea of Okhotsk A Global History of Maritime Travel and Cultural Encounters, 1600-1900. Taylor & Francis Group, 2024.
Gerasimov, Yuri, and Falk Huettmann. “Shorebirds of the Sea of Okhotsk: Status and Overview.” Stilt, vol. 50, no. 15, 2006.
Huettmann, Falk. “Marine Conservation and Sustainability of the Sea of Okhotsk in the Russian Far East: An Overview of Cumulative Impacts, Compiled Public Data, and a Proposal for a UNESCO World Heritage Site.” Ocean Year Book, edited by M. Nijhoff, Halifax, Nova Scotia, 2008.
Newell, Josh. The Russian Far East: A Reference Guide for Conservation and Development. 2nd ed., Daniel and Daniel Publishers, 2004.
North Pacific Marine Scientific Organization. “Third Workshop on Okhotsk Sea and Adjacent Areas.” . Accessed 1 Dec. 2024.
Sato, Yukinobu, et al. “Sea Ice and Waves in the Sea of Okhotsk from 1989 to 2012.” Cold Regions Science and Technology, vol. 223, 2024, doi.org/10.1016/j.coldregions.2024.104219. Accessed 1 Dec. 2024.
Semkin, P.Y., et al. "Effect of River Runoff on the Hydrochemical Characteristics of Water in Udskaya Bay and Nilolaya Bay (the Sea of Okhotsk) in Summer." Oceanology, vol. 61, 2021, pp. 338-50, doi.org/10.1134/S0001437021030139. Accessed 1 Dec. 2024.