STATE OF RESOURCES AND FISHERY OF MANILA CLAM RUDITAPES PHILIPPINARUM (ADAMS ET REEVE, 1848) IN THE LOSOS BIGHT AND BUSSE LAGOON (ANIVA BAY, OKHOTSK SEA) IN 2010–2016

Landings of manila clam Ruditapes philippinarum were steady high in 2010–2016 and exceeded the recommended volume that caused deterioration of its resources in the areas of large aggregations. Any significant growth of the clam colonies in the surveyed area could not be expected in the nearest future because of continuing press of fishery. Total stock of Ruditapes philippinarum in the Aniva Bay is estimated as 240 t, including 203 t of clams with commercial size.

Prospects for using the Busse Lagoon as a natural source for producing the spat of japanese scallop Mizuhopecten yessoensis

Reproduction of japanese scallop Mizuhopecten yessoensis in the Busse Lagoon (Sakhalin Island) is investigated. Abiotic environments influence on duration of early stages in its life cycle is determined. Interannual variability of the scallop larvae abundance and timing of its settling on substrata is traced. The Busse Lagoon is recommended for using as a natural source of seeding material (spat) of japanese scallop.

The influence of tidal dynamics on exchange of meroplankton (Bivalvia, Gastropoda) between the Busse Lagoon and adjacent marine area of the Aniva Bay

Exchange of Bivalvia and Gastropoda larvae between the Aniva Bay and Busse Lagoon is described on results of the plankton survey conducted in the connecting Suslov Channel in 2014. Taxonomic composition of meroplankton is described. Tide-induced water exchange through the channel is estimated, as well. The total water flux is evaluated for each tidal cycle using the data on the water level in the lagoon and on the area of its water mirror. The main factor of the larvae exchange is the tidal water flow that reaches the rate of 4 knots both for ebb and tide currents. The meroplankton from the lagoon is transported by the ebb current rather far to the sea, and its reverse drift with the tide current back to the lagoon looks doubtful, so export of the meroplankton from the lagoon is detected, with certain seasonal dynamics. The export is the most intensive in early summer (July) because of earlier spawning in the lagoon, which water is warmed quicker on shallows. The exchange decreases in August, when the water temperature is the highest both in the lagoon and in the Aniva Bay and many species spawn actively in both areas. Both reverse transport and export of the larvae are low in September because of the water cooling and cessation of the spawning.