EVALUATION OF NATURAL POTENTIAL OF THE AREAS IN PETER THE GREAT BAY (JAPAN SEA) FOR COLLECTING OF OYSTER SPAT

Abstract

Pacific oyster Crassostrea gigas (Thunberg, 1793) is a prospective species for aquaculture in Primorye. Marine farms demand the oyster spat for commercial growing. Abilities of the natural spat collecting are evaluated for 8 areas of Peter the Great Bay with the oyster settlements using the data of plankton surveys conducted in the period from 2001 to 2017. Dense concentrations of the oyster larvae suitable for the spat collecting were found in the following areas: i) the northern Amur Bay (depth < 10 m), ii) Novgorodskaya Bay, iii) Perevoznaya Bay, and iv) the area at southwestern coast of Peschany/Sand Peninsula. In these areas, the larvae were observed rather early (early-middle July), with high abundance (10³ –10⁴ ind./m³ ), and at all stages of ontogenesis including the last one ready for settling in high concentration (10¹ –10³ ind./m³ ). The spat settling occurred there in middle-late July. Sometimes dense but unstable concentrations of the oyster larvae were found in the Troitsa Bay and in the southern Amur Bay (total abundance < 200 ind./m³ , ready for settling < 20 ind./m3 in the years of poor spawning), timing of the settling was also too variable there (from late June to late August), so commercial collecting of the spat is impossible in these areas.