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

Abstract

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.