Invasion

Invasion Description

1st Record: Coast Oyster Co.CA/Humboldt Bay (before 1991, Hedgecock et al. 1993; Moore et al. 2011) This Coast Oyster stock was imported independently of the Taylor Shellfish stock. Of 30 specimens of this stock, one wa C. gigas (Hedgecock et al. 1993).

Geographic Extent

WA/Willapa Bay (Willapa Bay Oysters.com, http://willapa-oysters.com/kumamotos.html?gclid=CJTKhIbbyMQCFYI6gQodQBQAhg); Newport/OR/Yaquina Bay (Robinson 1992, cultured); Crescent City/CA/Pacific Ocean (2005, Moore et al. 2011, experimental planting); Coast Oyster Co.CA/Humboldt Bay (1991, Hedgecock et al. 1993; Moore et al. 2011)

Anja Robinson.1992 Gonadal cycle of Crassostrea gigas kumamoto (Thunberg) in Yaquina Bay, Oregon and optimum conditions for broodstock oysters and larval culture. Aquaculture Volume 106, Issue 1, 15 August 1992, Pages 89-97 Abstract The reproductive cycle of Kumamoto oysters collected from commercial oyster grounds in Yaquina Bay, Oregon, was determined monthly over a 3-year period. Gonads contained some ripe gametes throughout the year. Maximum frequency of sexually mature oysters occurred in August–September and declined rapidly in October–November to a minimum in March. Gametogenesis commenced in May and the first mature ova appeared in Jun-–July. Conditioning for spawning trials was conducted at 20 °C and 24 °C four times a year. At 24 °C production of gametes occurred 2 to 4 weeks earlier than at 20 °C. By beginning conditioning in May or June, the conditioning period in the laboratory could be reduced by 2 to 6 weeks. Larval survival and number of spat collected was also increased by reducing the laboratory conditioning period. In experiments carried out at five temperatures and five salinities, the optimum conditions for larval rearing ranged from 24 to 28 °C and from 20 to 25%o.