Pelagic larvae of bivalve mollusks of Amursky Bay, Sea of Japan

Abstract

Larvae of 63 Bivalvia taxa were found in Amursky Bay. Of these, 47 were identified to the species level. Larvae of 55 taxa were found throughout the bay. The highest species diversity was recorded in the northeastern part and in the center of the southern part of the bay, as well as at the exit from it. Larvae of Mactra chinensis, Mytilus coruscus, Crassostrea gigas, Teredo navalis, Mya japonica, and Mysella ventricosa were widely distributed in the bay. The maximum numbers of species were observed in July and September. A comparison of species lists using the set-theory method showed that the species complexes typical of different parts of Amursky Bay are formed under the influence of the Razdolnaya River runoff flow from the north and marine waters coming from the south. The mean density of larvae during the observation period was 1100 specimens/m3 in the northern and 735 specimens/m3 in the southern part of the bay. The highest density of larvae in Amursky Bay was observed at the end of June, the beginning of July, and in September; the minimal larval density occurred in April, May, and August. While the species diversity was similarly high, the density of larvae was significantly higher in Amursky Bay than in the nearby Ussuriisky Bay.