The Sea of Japan Large Marine Ecosystem (LME) is a semi-enclosed sea with an area of approximately 978,000 square kilometers (km2), a volume of 1,713,000 cubic kilometers (km3), and a mean depth of 1,350 meters (m). The Sea of Japan (also known as the East Sea) is connected to the Sea of Okhotsk, the Northern Pacific Ocean and the East China Sea through four shallow straits. The Tsushima Current, a small branch of the warm Kuroshio Current, enters the Sea of Japan through the Tsushima Strait between Kyushu and Korea and flows out to the Pacific through the Tsugaru and Soya Straits. Climate is the primary force driving the LME, with intensive fishing as the secondary driving force. LME book chapters and articles pertaining to this LME include Terazaki, 1999.
For maps of currents around Japan and in the Sea of Japan LME, see Terazaki, 1989, p. 38, and Terazaki, 1999, p. 200. The meandering Tsushima Current creates large-scale cyclonic and anticyclonic eddies. For information on the bottom topography (continental shelf, bathyal and abyssal zones), see Morgan, 1989. The limited flow through the four shallow straits contributes to the semi-enclosed character of this LME. For a map of surface temperatures in summer and winter, see Terazaki, 1999, p. 204. The northwestern Sea of Japan is colder, with sharp temperature declines in winter and the presence of ice in the Tartarskiy Strait from November to April. Seasonal temperatures vary by 20 degrees Celsius in the northwest, and 14 degrees Celsius in the south. The Sea of Japan Large Marine Ecosystem is considered a Class I, highly productive (>300 grams of Carbon per square meter per year (gC/m2-yr)) ecosystem based on SeaWiFS global primary production estimates. For information on hydrographic conditions, primary production in winter and summer, phytoplankton, zooplankton and micronekton, see Terazaki, 1999. The zooplankton community shows low variance in taxonomic groups and species. Five zooplankton groups account for over 99 percent of the biomass: copepods (Neocalanus cristatus, N. plumchrus, N. flemingeri), euphausiids (Euphausia pacifica, Thysanoessa longipes), chaetognaths (Sagitta elegans), amphipods (Themisto japonica, Primno macropa, Cyphocaris challengeri), and mysids (Meterythrops microphathalma). Diatom blooms occur primarily in the spring. The number of benthic species decreases with depth, with 53 species of macrobenthos at 1,000-2,000 m, 25 species at 2,000-3,000 m, and 5 species below 3,000 m (see Zenkevitch, 1963; and Terazaki, 1999). Tropical to Arctic animal populations occur in the Sea of Japan LME.
Fish and Fisheries
The Japanese sardine is an abundant pelagic fish constituting more than 70% of the total catch. Other species harvested include scad, mackerel, yellowtail, and the common Japanese squid. The average total catch is 1 million tons. Long term fluctuations of the sardine population have been observed. They are accompanied by noticeable geographic shifts in spawning and nursery grounds. For a map of spawning grounds of the sardine population, see Terazaki, 1999, p. 216. The maximum Japanese sardine catch was 1.1 million tons in 1989 after 10 years of poor sardine harvests. For annual fluctuations in catches of anchovy, round herring, yellowtail, mackerel, scad and common squid, from 1950 to 1990, see Terazaki, 1999. Scad migrates into the Sea of Japan LME through the Tsushima Strait. The cold or warm eddies occurring along the Tsushima Current offer good fishing grounds for mackerel. The spawning grounds of the common squid are in the East China Sea and coastal waters of southern Honshu and Kyushu. The fishing methods for yellowtail (Seriola quingeradiata) are the set net, the purse seine and the gill net. The University of British Columbia Fisheries Center has detailed fish catch statistics for this LME. Click on the graph below for more information.
Pollution and Ecosystem Health
In the 1960s, rapid economic growth and heavy industries concentrating along Japanese coastal areas caused water pollution, damage to fishery resources and red tides. Strict laws and standards have since improved the quality of coastal waters. Mercury contamination in the Agano River near Niigata on the Sea of Japan coast produced a second case of Minamata disease. Cadmium contamination in the Jinzu River in Toyama resulted in a disease called Itai-itai. Excessive land reclamation and coastal development have led to the destruction of some mangrove areas and harmed coral reefs in the south of the Sea of Japan LME. Oil pollution is a significant problem along major shipping routes. An increasing number of accidents have occurred in recent years. Japan is affected by sea level rise and has resorted to dikes to keep flooding problems at bay. Intrusions of seawater into aquifers is a problem. The former Soviet Union reportedly dumped radioactive waste in the Sea of Japan.
The Sea of Japan coastline is highly developed, with commercial ports and fishery harbors. Parts of the coast are protected by seawalls and breakwaters against storm surges, high waves, and beach erosion. Japan has a densely populated coastal zone. The fisheries sector is an important industry for Japan. It is very reliant on the sea for its supply of fish, seaweed and other marine resources. Japan maintains one of the world's largest fishing fleets and accounts for nearly 15% of the global catch. The coastal zone is used to harvest marine resources, and for petroleum exploration, industrial development, waste dumps and recreation. An efficient transport system links the islands. The lack of natural resources means that fuel, raw materials and food have to be imported in large quantities. As a result, Japan is very reliant on trade and international shipping. Industry is heavily dependent on these imported raw materials and fuels. The main ports in this LME are Otaru, Sakata, Fushiki, Tsuruga, and Maizuru.
The five countries sharing the governance of this LME are Russia, China, North Korea, South Korea, and Japan. There are conflicts arising from the very name of the Sea of Japan, called the East Sea by South Korea and East Sea of Korea by North Korea. North Korea has a 50 nautical mile military boundary line in the Sea of Japan. There is a demarcation line between North and South Korea, and a dispute over the Liancourt Rocks, claimed by Japan. While the fishing interests of each country are different, a coordination of fishing efforts needs to be achieved. In terms of environmental protection, bilateral agreements have been concluded between China, South Korea, Japan and Russia. There is a Japan-Russia joint study program on marine pollution in the Sea of Japan. In 1994, an Action Plan for the Protection, Management and Development of the Marine and Coastal Environment of the Northwest Pacific (NOWPAP) was adopted under the auspices of UNEP. It aims to protect the environment of the Sea of Japan by enlisting the cooperation of the countries sharing those seas.
Articles and LME volumes
- Morgan, J., 1989. Large Marine Ecosystems in the Pacific Ocean. In K. Sherman, L.M. Alexander, and B.D. Gold, eds. Biomass Yields and Geography of Large Marine Ecosystems. AAAS Selected Symposium 111. Westview Press. Boulder CO. 377-394. ISBN: 0813378443
- Terazaki, Makoto, 1989. "Recent Large-Scale Changes in the Biomass of the Kuroshio Current Ecosystem" in Kenneth Sherman and Lewis M. Alexander (eds.), Biomass Yields and Geography of Large Marine Ecosystems (Boulder: Westview) AAAS Selected Symposium 111, pp.37-65. ISBN: 0813378443
- Terazaki, Makoto, 1999. The Sea of Japan Large Marine Ecosystem. in Q. Tang and K. Sherman, eds. The Large Marine Ecosystems (LMEs) of the Pacific Rim. Blackwell Science. 199-220.
- Hamabe, M. and Shimizu, T., 1969. Ecological studies on the common squid, Todarodes Pacificus Steenstrup, mainly in the southwestern waters of the Japan Sea. Bull. Jap. Sea Reg. Fish. Res. Lab. 16:13-55.
- Hong G.H., Kim S.H., Lee S.H., Chung C.S., Tkalin A.V., Chaykovskaya E.L., Hamilton T.F., 1999. Artificial radionuclides in the East Sea (Sea of Japan) proper and Peter the Great Bay.Marine Pollution Bulletin, 38, 933-943.
- Imai, M. Ebara, S., Okimura, H., and Kadono, K., 1990. On the nutrients in the Tsushima Warm Current water (in Japanese). Umi to Sora 66:93-111.
- Japan Sea National Fisheries Research Institute, 1991. The Latest Trend of Fisheries Resources in the Japan Sea (in Japanese).
- Kachur A.N., Tkalin A.V., 2000. Sea of Japan. In: Seas at the Millenium: An Environmental Evaluation ] (ed. By C.Sheppard). Elsevier Science, 467-480.
- Kano, Y. Baba, N., and Ebara, S., 1984. Chlorophyll-a and primary production in the Japan Sea. Oceanogr. Mag. 34:31-39.
- Kato, M., 1979. Age assigned to dredged siltstone samples and piston core samples. Cruise Rep. Geol. Surv. Japan 13:70-72.
- Marumo, R., Nemoto, T., Omori, M., Aizawa, Y., Terazaki, M., Araki, M., Kawaguchi, K., Komaki, Y, and Honda, T., 1972. Distribution Collected with Norpac Net, ORI Net and IKMT. in R. Marumo (ed.), Preliminary Report of the Hakuho Maru Cruise Kh-70-4 (IBP Cruise). Tokyo: Ocean Research Institute, University of Tokyo, pp. 16-22.
- Masuzawa, T. and Kitano, Y., 1983. Sulfate reduction and sulfide deposition in deep-sea sediments from the southwestern Japan Sea. J. Oceanogr. Soc. Japan 39:251-258.
- Morioka, Y., 1981. Zooplankton production in the Toyama Bay in March-May, 1978. Bull. Jap. Sea Reg. Fish. Res. Lab. 32:57-64.
- Morioka, Y., 1985. Distribution of zooplankton in the Japan Sea. Bull. Jap. Soc. Fish. Oceanogr. 47/48:63-66.
- Nagata, H. and Kitani, K., 1987. Vertical distribution of chlorophyll-a along the PM line in the Japan Sea. Bull. Jap. Sea Reg. Fish. Res. Lab. 37:13-19.
- Nishimura, S., 1965. The zoogeographical aspect of the Japan Sea, Part II. Publs. Seto Mar. Biol. Lab. 13:81-101.
- Nishimura, S., 1968. The zoogeographical aspect of the Japan Sea, Part IV. Publs, Seto Mar. Biol. Lab. 15:329-352.
- Nishimura, S., 1969. The zoogeographical aspect of the Japan Sea, Part V. Publs. Seto Mar. Biol. Lab. 17:67-142.
- Nishimura, S., 1983. Okhotsk Sea, Japan Sea, East China Sea. In: Ecosystems of the World, Estuaries and closed seas, B.H. Ketchum, ed. 375-402.
- Oba, T. Kato, M., Kitazato, H., Koizumi, I., Omura, A., Sakai, T., and Takayama, T., 1991. Paleoenvironmental changes in the Japan Sea during the last 85,000 years. Paleoceanography 6:499-518.
- Terazaki, M., 1993. Deep sea adaptation of epipelagic chaetognatha Sagitta elegans in the Japan Sea. Mar. Ecol. Progr. Ser. 98:79-88.
- Tkalin A.V., 1995. Investigations of marine environment radioactivity in the dumping areas and coastal zone of the Sea of Japan. Arctic Research of the United States, 9, 88-89.
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