With regard to the number of animal and plant species, the Sea of Japan
is Russia’s richest sea, Peter the Great Bay showing best the wealth of
its flora and fauna. The cold Primorye Current descending from the
north meets a branch of the southern Tsushima current in Japan Sea, The
coast of southern Primorye is unevenly cut by numerous capes, inlets and
straits. Small rivers flow into bays. Animals inhabit some of the islands.
In hot months of the year, open sea waters warm up to 23oC, and in half-closed inlets up to 28oC. Only to the north of Nakhodka the water temperature is slightly lower than in the southwestern part of the sea. In winter, the water sharply cools. Given the water salinity (34), the temperature of littoral waters may be as low as minus 1.8oC. Due to the wide temperature range, the conditions in the sea are suitable for survival of subtropical fauna, and in winter for temperate and even arctic animals. Some animals have adapted to such conditions and some migrate to these areas temporarily.
Thickets of sea grasses occupy vast littoral floor areas. Multicellular algae alone in Peter the Great Bay number 225 species. Laminaria are particularly abundant. This algae is called sea cabbage. Apart from collecting it from natural sites, laminaria is cultivated in large amounts on plantations, its harvests in Primorye being one of the highest in the world. Sea cabbage is used in both raw and preserved form for normal and remedial food. In recent years, people started to manufacture many beneficial substances from it, primarily sodium alginate. This substance is widely used in the food, chemical and textile industries. Other mass alga species are also economically significant. Agar-agar, so essential for confectioners and druggists, is obtained from gracillaria and ahnfeltia.
Phyllospadia, from which expensive paper brands were formerly manufactured, grows on rocky soil under water. Its dried leaves were also used for manufacturing furniture. Fields of Zostera are commonly occur on slimy-sandy pebbly floor, and the young of many commercial animal species that subsequently settle over vast shallows spend their first days in those grasses. Phyllospadix and Zostera are higher plants. They cannot be considered algae. They flower and pollinate under water, but their flowers are unfortunately small and very inconspicuous.
Since the sea is not decorated with flowers, generous nature has provided animals with the form and color of flowers. This primarily relates to Actinia—primitive animals, the closest relatives of algae. Incidentally, good divers can feast their eyes on large and beautiful Actinia in the Sea of Japan. The underwater landscape of bays is also decorated by Ascidia of up to 25 cm tall. They are reminiscent of a two-neck dark red carafe.
Among algae and sea grasses, you can come
across numerous various little crayfish and shrimps at any time of the
year. The most well-known one is the herbacious species. The largest specimens
are up to 18 cm long. Yong individuals are of emerald color. Interestingly
enough, in its first year of life this crustacean develops into a male,
and then into a female. In winter, shrimps migrate deep into the sea.
Primorye is famous for its trepang reserves. Indigenous inhabitants originally called Zolotoi Rog Inlet in Vladivostok the inlet of trepangs. This animal is very popular in the countries of the Far East and Southeastern Asia, and is sometimes called marine ginseng; it is also expensive delicatessen food. Normally, the trepang lives on rocky detritus, near boulders and Zostera thickets. Moving slowly over silted sand, it captures soil particles with its feelers together with microscopic organisms to digest them. It has been revealed that the biologically active substances extracted from the trepang possess a wide pharmacological and antifungal action. The Japanese Cucumaria that lives at great depths and is widespread in all Far Eastern seas, resembles the trepang, and is nutritious and beneficial in many respects.
Starfish and sea urchins are taxonomically closely related to the trepang. Again, flat urchins live on sandy floor sites, often having dug into the soil. Their shell is covered with dark violet felt, as it were. Round urchins, mass representatives of Primorye’s littoral fauna, are very prickly. Scientific studies of these animals have led to numerous discoveries, particularly in embryology. Sea urchin roe is very popular in Asia. In fact, commercial fishery enterprises in Primorye presently land significant numbers of sea urchin for subsequent export to Japan.
Starfish are mass inhabitants in highly diverse underwater communities. Their skeletal plates consist of calcium carbonate to impart them their unusual appearance. These amazing animals delighted antique painters, and four thousand years ago images of starfish
used to decorate Cretan frescoes in Greece. In Japan Sea, there are many starfish species. The ray span of the Amur starfish is up to 32 cm. In quest of food, it crawls at 10 cm a second. This predator feeds on the still slower, and sometimes even completely attached mollusks. Patiria, another no less widespread starfish, is omnivorous. It occurs in large numbers along the coast after storms.
Of animals, whose adult life passes in attached state, the most well known species are oysters and mussels. Pacific mussels frequently occur at small depths. They settle on banks, which often encircle coastal rocks and cliffs in black belts. Neither wave impacts, nor wind gusts in low tide frighten them. Special threads securely retain them on the rock Thin valves that are bluish inside are constantly ejected by waves onto beach pebbles and sand. One can convincingly say that only their immense fertility saves them from complete destruction by predator mollusks, starfish and fish. Significantly, mussels scale vessels and hydraulic structures. On the other hand, being biological percolators, they contribute greatly to purification of coastal waters.
In still deeper areas, you can come across the world’s largest mussels, which are up to 20 cm long. The age of such specimens may reach 100 years. Mussel flesh is tasty and beneficial, but in some places and at a given time these mollusks may accumulate harmful substances and microorganisms in doses dangerous to humans. Mussels are nonetheless successfully cultivated in various countries. According to world statistics, the annual mussel harvest is 40,000 tons.
The most promising object of commercial fishing and cultivation in Japan Sea is the Primorye pecten. It moves by ejecting water at abrupt clamping of its valves. The large lock-muscle, situated in the middle of the shell, is a valuable food product with high nutritional qualities.
The most well known and popular of edible mollusks are naturally oysters. The giant or Pacific oyster lives in the Russian Far East, Korea, China and Japan. It prefers to settle in slightly freshened waters of bays at depths of up to 7 m. The mollusk can both winter under ice and withstand the heat of sunrays in low tide. Its shell size may be as much as 70 cm. In Peter the Great Bay, from late June through August, you can watch oysters ejecting little turbid clouds. These are roes. A large female would spawn them to as many as 100 million! When fertilized, they develop to turn into larvae visible well only under a microscope. The larvae would swim in the thick of water to be carried by current over great distances. In one month, they would descend to the sea floor to crawl in search of a suitable settling site and, having found it, would attach themselves very firmly to underwater objects.
This oyster species was imported for
cultivation to successfully adapt on both seaboards of North America, around
Australia, Britain, France and many other countries. The world consumption
of oysters is about 770 thousand tons.
Primorye’s principal wealth is naturally fish. Apart from valuable salmon species—the gorbusha, keta and brook masu salmon, which live in the sea, but spawn in fresh water, current catches mainly consist of mintai (Theragra chalcogramma). Several years ago, the iwashi herring was also landed galore.
Mintai is the most numerous cod species in the Pacific. In Peter the Great
Bay, it arrives only in winter and early spring to spawn and fatten. The world catch of mintai amounts to 4 million tons, and half of this goes to Russia’s credit. Although its rapid growth and maturation maintain mintai reserves at a high level, its commercial fishery is regimented. Today, a know-how has been devised to obtain tasty products from mintai, e.g. salted roe and liver in oil, when only recently Russian fishermen in the Far East regarded mintai as rubbish.
Only recently, iwashi, the Far Eastern sardine, placed second in the catches of Russia’s fishery fleet. Six hundred thousand tons were landed annually. Due to the high fluctuation in its population, whose causes are not always clear to specialists, the commercial catches are not constant. It was landed in large quantities until the nineteen forties, when it stopped approaching Primorye shores to feed up. In the nineties, Iwashi had returned in great numbers to previous fattening sites to presently only leave again.
Herring is a very valuable commercial species and highly popular among Russians. It is a typically gregarious open sea species. The Pacific herring intensely fattens at the coasts, feeding on small plankton organisms. Its fatness may be as much as 18-25%. The herring population strongly fluctuates, too. Herring spawns its roe on rocks, grasses and algae.
To enhance herring survival, biologists have developed methods for creating artificial spawning grounds. Many amateur fishermen in Primorye very much like to catch herring in late fall, when it can grab empty hooks. At that time, people buy fishing licenses.
Among Japan Sea inhabitants, there are numerous unusual and yet commercial animal species. These include the octopus and squid. The giant octopus is one of the largest in the world. Its body alone is 60 cm long, but together with the feelers its overall length sometimes exceeds 3 m. Large specimens weighing about 50 kg live in underwater grottoes, among heaps of stones, and under cliffs. Frogmen come across this interesting animal quite often. Octopuses prey on various crabs, mollusks and fish. By means of its suckers, the octopus can attach itself to the skin and especially to the frogman/s suit; yet, there are no reliable cases of divers being lengthily held, or moreover of their death. Small octopuses sometimes occur in empty valves of large mussels. Placed in an aquarium, they would eject an ink liquid to mask themselves and rapidly change their color.
A very well known species is the Kamchatka crab. Its leg span may attain 150 cm. It is widespread from Korea to Bering Strait and along the American coast at depths of up to 270 m. In early April, it approaches the coast to reproduce.
The females are smaller than the males. Commercial crab fishing is off limits. When mating, the male would hold the female firmly with his claws. Even when surfaced, the male would for a long time keep his mating partner in his claws. Crabs eat small mollusks, crustaceans, worms and other sea floor inhabitants. Crab is obtained commercially chiefly off the shores of Western Kamchatka, where in some years almost eight million specimens were landed. Many years of crab fishery in different places had reached its maximum. Recently the ban on crab fishing in the northwest of Japan Sea was lifted, and Primorye fishermen began to land about 1.8 thousand tons of crab annually. Significantly, the weight of a giant crab equals 7 kg. The leg contents only is consumed as food. In recent years, the valuable chitosan was obtained from the crab’s chitin shell. The residue water remaining after preparing canned crab may be used to prepare various aromatic additives.
As for aggressive and poisonous animals, there are not too many of them in Primorye. Dangerous shark species occur quite rarely in the coastal zone, and we do not know of cases when sharks attacked humans.
The jellyfish may present the only serious danger for swimmers at Primorye coasts. This medusa is small, not more than 4 cm in diameter. Through its transparent dome, you distinctly see a cross formed by its internal organs. The jellyfish lives at small depths in quiet inlets. Most of the day, it hangs by securing itself to underwater vegetation leaves to look out for small crayfish. The medusa strikes its victim with special stinging cells on contacting it. The jellyfish presents danger to humans because when its feeler contacts the skin it poisons the body. The burn is accompanied by pain, and occasionally by serious suffocation. Few serious cases were reported. In 1987, 239 ambulance calls were registered in Vladivostok to treat people stung by medusas. In 1988, there were 214 calls, and in 1989, when the number of medusas was larger, only 163 calls. In serious cases, the victim is sent to the local toxicological center. As a rule, hospital treatment is over after 3-4 days. People who like to frequent wild, remote beaches and frogmen should avoid places overgrown with sea grass. The chance to meet the jellyfish on an well-organized beach is very small.
Yu. YAKOVLEV, Cand. Sci. (Biology), Institute
of Marine Biology, Far East Branch, Russian Academy of Sciences.