Density Dynamics and Size Composition of Bivalve Mollusk Larvae of the Genus Mya in Peter the Great Bay (Sea of Japan)

The seasonal population size of planktonic larvae of mollusks of the soft-shell clam genus Mya were studied in Vostok Bay. The larvae occurred in plankton from the first third of June to early September. The highest density of larvae (279.7 ± 98.7 specimens/m³) was found in late June. In early July, larval numbers decreased sharply, and at the end of the first third of July, only single Mya larvae were found in the plankton. Another increase in larval population was observed in early and late August. The larvae varied in length from 175 to 325 m in June–July and from 150 to 250 m in August. It is likely that the larvae of two species of Mya, M. arenaria and M. uzenensis, are present in the plankton of Vostok Bay.     

Reproductive Phenology of the Brown Alga Analipus japonicus in Peter the Great Bay (Sea of Japan)

The alga Analipus japonicus (Harv.) Wynne displays a distinct seasonal pattern in its development in Peter the Great Bay (Sea of Japan). In winter and spring, it occurs only in the form of basal crusts, and vertical axes develop in the summer–autumn period. It reproduces mostly asexually from July to November. Algae with unilocular sporangia occur very seldom, only in June and July.     

Effects of water from Nakhodka Bay (Peter the Great Bay, Sea of Japan) on the early development of the Sea UrchinStrongylocentrotus intermedius

Our studies show that seawater from different sites in Nakhodka Bay has a deleterious effect on the development of the sea urchinStrongylocentrotus intermedius. As development proceeded to the pluteus I stage, the percentage of abnormal larvae maintained in water from Nakhodka, Novitskogo, and Vrangelya Bights increased markedly (66.7±2.2, 67.1±2.6, and 54.6±1.8%, respectively). These larvae developed more slowly, were smaller, and differed from those in the control in the intensity of color of their echinochrome granules. In water from Nakhodka and Novitskogo bights, larval survival rates were lower than in the control. This suggests that the water of Nakhodka Bay is heavily polluted, especially in its harbor areas.     

Arenicolous mycelial fungi from the littoral of the Vostok Bay (Peter the Great Bay,the Sea of Japan)

The taxonomic composition of marine mycelial fungi was determined in the interstitial habitats of the Vostok Bay littoral (Peter the Great Bay, the Sea of Japan). A total of 39 species of ascomycetes and anamorphic fungi were detected and identified. The predominant species of the intertidal zone were Corollospora maritima, C. lacera, Carbosphaerella leptosphaerioides, Arenariomyces trifurcatus (Ascomycota), Alternaria alternata, Scolecobasidium arenarium, and Zalerion maritimum (anamorphic fungi). The complete list of species of obligately marine ascomycetes and anamorphic fungi from the interstitial habitats of the Vostok Bay littoral is presented for the first time     

Organochlorine Pesticides in Fishes and Mollusks from Lower Reaches of the Tumen River and of the Contiguous Part of Peter the Great Bay (Sea of Japan)

The content of persistent organochlorine pesticides (DDT and its metabolites, -, - and -isomers of hexachlorocyclohexane, HCH) were studied in the tissues and organs of some fish and molluskan species from the lower reaches of the Tumen River and the contiguous part of Peter the Great Bay (Sivuchya Bay and Zapadnaya Bay of the Furugelm Isl.) and Amursky bay. The highest total content of HCHs (785.60 ng/g of gross mass) was revealed in the digestive gland of the Japanese scallop Mizuhopecten yessoensis from Zapadnaya Bay and in the brain and the liver of the starry flounder Platichthys stellatus from the Tumen River (390.80 and 340.29 ng/g of gross mass). The maximum total content of DDT (270.70 ng/g of gross mass) was recorded in the brain of the dark plaice Pleuronectes obscurus from Zapadnaya Bay and in the liver of the far eastern smooth flounder Pleuronectes pinnifasciatus, caught in Amursky Bay to the west of Skrebtsov Isl. (212.80 ng/g of gross mass). The level of HCHs and DDT in mollusks and flounders from Zapadnaya Bay was higher than that in the same species from Sivuchya Bay. The concentration of organochlorine pesticides (OCP) in P. pinnifasciatus from the inner part of Amursky Bay at Skrebtsov Isl. was higher than in individuals of that species from the open part of the Bay at Peschany Pen. The DDT/DDE and DDT/DDT ratios evidenced the recent entry of DDT into the ecosystem of Peter the Great Bay. The southwest part of Peter the Great Bay, from the mouth of the Tumen River up to Furugelm Isl, was contaminated by HCHs to a greater extent than Amursky Bay. OCPs accumulated in appreciable quantities in the organs of fishes and mollusks of Peter the Great Bay, though their present content does not exceed sanitary–hygienic standards, a subsequent monitoring of their concentrations in biota is necessary.     

Allozyme Variability in Local Populations of the Chiton Ischnochiton hakodadensis from Differently Polluted Areas of Peter the Great Bay, Sea of Japan

Allozyme variability in ten polymorphous loci and three samples of the chiton Ischnochiton hakodadensis from Peter the Great Bay, Sea of Japan, was examined by gel electrophoresis. The samples were collected in different areas of the Bay: clean, heavily polluted with petroleum hydrocarbons and detergents, and heavily polluted with heavy metal combinations. It was established that the genetic similarity of the samples was very high, but their differences in allele frequencies, observed heterozygosity, and heterozygote deficiency in some loci were statistically significant. We suppose that allozyme differences between the studied chiton samples are the result of selection to resist anthropogenic pollution of the habitat.     

The Meiobenthos in the Area of Japanese Scallop Cultivation in Minonosok Bay (Peter the Great Bay,Sea of Japan)

In Minonosok Bay, in a region of long-term industrial mariculture of mollusks, a steady biohydrochemical complex with increased organic matter content has been formed, in which the meiobenthos community was represented by a rather complete set of taxonomic groups of low population density. There were 16 groups (order, class) of the meiobenthos revealed, and the greatest population density was recorded in the central part of the bay under installations with suspended mollusks, (333000 ind./m²). Nematodes dominated in the eumeiobenthos; however, crustaceans prevailed in the bottom water layer and sediments at stations with increased oxygen content. Bivalves and gastropods dominated in the pseudomeiobenthos. Correlation analysis has revealed the dependence of the population density of the total meiobenthos and eumeiobenthos on the type of ground. There were 42 nematode species revealed; Axonolaimus seticaudatus, Enoplolaimus medius, Daptonema sp., Paracomesoma sp., and Oncholaimium paraolium dominated. Three nematode taxocens were discriminated by dominating species in the population density and results of cluster analysis of the data. Detritivorous nematodes prevailed in all types of ground. A correlation was found between the index of species diversity of nematodes and the content of organic carbon in the ground.     

Microelement composition of the green alga Ulva fenestrata from Peter the Great Bay, Sea of Japan

Concentrations of heavy metals Fe, Mn, Cu, Zn, Pb, Cd, and Ni were determined in the thalluses of the green alga Ulva fenestrata sampled from different locations in Peter the Great Bay (Sea of Japan). According to the metal concentrations in Ulva, the degree of pollution of the surveyed areas in Peter the Great Bay decreases in the following series: Amur Bay > Ussuri Bay > Nakhodka Bay > Vostok Bay > the water area of Far Eastern State Marine Nature Biosphere Reserve. The microelement composition of Ulva from open-shore stations reflects the heavy metal pollution level of water areas as a whole. The concentrations of trace elements in U. fenestrata from closed coastal areas are indicative of marine coastal water pollution from local sources. Generally, metal concentrations in U. fenestrata from Peter the Great Bay are similar to heavy metal levels in non-polluted or weakly polluted coastal areas of the world.     

A Finding of the Crab Planes marinus Rathbun, 1914 (Decapoda: Grapsidae) in Peter the Great Bay,Sea of Japan

A crab Planes marinus Rathbun, 1914 was found on a drifting buoy in Peter the Great Bay (Sea of Japan). The crab probably arrived in the bay with subtropical waters penetrating into this area during the summer period.     

Fauna of Sipunculans (Sipuncula) of Vostok Bay, Sea of Japan

Fauna and systematics of sipunculans inhabiting Vostok Bay, Sea of Japan, are discussed. A revision of the local species of sipunculans is performed for the first time. On the basis of study of outer and inner morphology, some species are reduced to synonyms. Extended diagnoses are proposed for all registered species. An identification key is presented for the sipunculans of Vostok Bay.     

Biochemical and pathogenic properties of the natural isolate of Shewanella algae from Peter the Great Bay, Sea of Japan

Pathogenic properties of the natural isolate of Shewanella algae from the coelomic fluid of the sea cucumber Apostichopus japonicus (Peter the Great Bay, Sea of Japan) were investigated. The isolate had oxydative metabolism, was positive for ornithine decarboxylase, cytochrome oxidase, catalase, DNase and gelatinase, hemolytically active, did not produce acid from carbohydrates, and did not hydrolyze urea and esculin. The strain was resistant to penicillin, amoxicillin, and ampicillin and susceptible to tetracycline and carbenicillin. Among cellular fatty acids, 13:0-i, 15:0-i, 16:0, 16:1(n-7), 17:0-i, and 17:0-ai dominated. These biochemical properties made it possible to attribute the isolated bacteria to the genus Shewanella and identified as S. algae. The cells of this bacterium were introduced into the coelomic cavity of another echinoderm, the sea urchin Strongylocentrotus nudus. As a result, in about 24 h the animals became slow and 3-8 days after the inoculation died. Dividing bacteria were being found during the experiment in the coelomic fluid as well as in the phagosomes of amoebocytes, i.e. cells acting as phagocytes in the coelomic fluid. The studies of the invasive properties of strain 156 showed that bacterial cells entered the subcuticular space of S. nudus and A. japonicus through the cuticle and stayed there for a long time without penetrating epithelium and exerting toxic effect upon the organisms of the laboratory animals. Pathogenic effect of S. algae can be manifested only if the cutaneous epithelium is destroyed permitting it to penetrate the lower tissue layers. The toxicity of S. algae is confirmed by in vitro experiments. The inoculation of the embryonic cells of S. nudus with samples of this bacterium caused the death of 10% of cells within an hour and 100% of cells within 12 h after inoculation. The results of the investigations demonstrate that S. algae could produce opportunistic infection in the sea cucumber A. japonicus and the sea urchin S. nudus, which may be natural reservoirs of this human pathogen.     

Production characteristics of the population of the red algaAhnfeltia tobuchiensis in Baklan Bight (Peter the Great Bay, Sea of Japan)

Spatial distribution and production characteristics of the population of the unattached red algaAhnfeltia tobuchiensis (Kanno and Matsubara) Mak were studied in Baklan Bight (Sea of Japan) in September 1990 and June 1991. The following environmental factors were determined: the level of photosynthetically active radiation (PAR) penetrating the water column; the water temperature; and the content of oxygen, nitrogen, phosphorus, and dissolved organic substance. the main factor limiting the net primary production (NPP) of theA. tobuchiensis population in Baklan Bight appears to be PAR intensity at the surface of the stratum. In June and September, respectively it constituted about 10% and 0.2% of the PAR on the sea surface. By means of regression analysis, the following equations were obtained to describe the relationship between NPP at the surface of the stratum and the environmental factors studied, PAR intensity being the principal variable: NPP=0.02+0.81 PAR (in June) and NPP=0.02+0.23PAR (in September). In June and September, the NPP of theA. tobuchiensis stratum amounted to 17.2 and 1.3 g/(m² day), and the biomass to 21 and 31 thousand tons, respectively. During the eight months, its distribution changed considerably. In June and September, the daily biomass growth equaled 140.7 and 8.5 t, respectively. A 10-cm-thick layer displayed the highest production characteristics.     

Histopathology of the digestive gland of the bivalve mollusk Crenomytilus grayanus (Dunker, 1853) from southwestern Peter the Great Bay, Sea of Japan

The histomorphology of the digestive gland of the bivalve mollusk Crenomytilus grayanus from Sivuchya Bay, which is located in the southwest of Peter the Great Bay and subjected to the effect of polluted waters of Tumannaya River, was studied. Pathological changes of the digestive tubules, channels, and connective tissue of the gland were recorded in all the mussels studied. The epithelium of the tubules and channels was characteristic with erosive disturbances and by heavy vacuolization of digestive cells; connective tissue of the gland was specified by cells with lipofuscin (granulocytomes) and by foci of cells necrosis and lysis. Nervous fibers running in the gland were swollen in some mollusks. Strongly basophilic spherical formations, presumably one of the development stages of a parasitic plasmodium, were found in the granulocytomes and among vesicular cells of connective tissue of all the mussels. It was concluded that pathological changes in digestive gland of Gray’s mussel might be caused by chronic pollution of the bay and by parasitic invasion.     

Dynamics of Fish Colonization of an Experimental Artificial Reef in Peter the Great Bay,Sea of Japan

An experimental artificial reef (AR) was built in Peter the Great Bay (Sea of Japan) to compensate for the biotope of Zostera destroyed by sea urchins. After eight years, the number of fish species on the AR increased from 5 to 18 and the fish biomass increased from 3.07 up to 37.1 g/m². Nonmigrating species (Opisthocentrus, young-of-the-year rockfishes, elegant sculpin) formed the bulk of the population; and migrant species (flounders, frog and great sculpins, sea raven) made up the greater portion of the biomass (up to 34 g/m²). Cage reefs are recommended to compensate for destroyed habitats, particularly Zostera beds.Original Russian Text Copyright ¢ 2005 by Biologiya Morya, Markevich.     

Morphometric characteristic of sex cells and seasonal changes of female gonads of Cucumaria japonica (Semper, 1868) (Echinodermata: Holothuroidea) from Peter the Great Bay, Sea of Japan

The oocytes at different stages of development were characterized morphometrically, and seasonal changes in female gonads of the Far-eastern edible holothurian Cucumaria japonica (Semper, 1868) from the Peter the Great Bay were described. Groups of oocytes and categories of sexual tubules corresponding to different stages of development of gonads were distinguished. Free laying oocytes were divided into several groups, i.e., oocytes 3, 4 and 5. The greatest size of C. japonica oocytes was 460 μm. In various seasons of the year there was greater growth of oocytes in the gonads, which reached its maximum volume during reproduction of the holothurians. The gonads developed asynchronously. All the stages of development were observable simultaneously in the gonads of each individual of this species during the reproductive cycle, and the stage of fast growth prevailed. C. japonica spawned twice a year, in May–June and from July to October. Unreleased oocytes were subjected to resorption.     

The Meroplankton of Amurskii Bay (Peter the Great Bay,Sea of Japan)

Russian Journal of Marine Biology - The composition and seasonal dynamics of meroplankton in Amurskii Bay (Sea of Japan) were studied for the first time. The total survey period exceeded two years....     

Reproduction and development of the limpet Limalepeta lima (Dall, 1918) (Gastropoda: Lepetidae) from Peter the Great Bay, Sea of Japan

Reproduction and larval development of the limpet Limalepeta lima (Dall, 1918) were studied under laboratory conditions for the first time. L. lima breeds in early July; it exhibits external fertilization and the pelagic lecithotrophic type of development. Larvae, juvenile, and adult specimens have different shell sculptures. Development from fertilization to settling and metamorphosis continues for 4–5 days at a water temperature of 16°C.