@mastersthesis {15041, title = {The Japanese Oyster Drill, Ocenebra japonica, in Netarts Bay, Oregon}, year = {1972}, note = {Sometime around 1930-1934, year-old Japanese oysters (Crassostrea gigas) were imported into Netarts Bay, as part of an early commercial growing operation. Along with them came the Japanese oyster drill, Ocenebra japonica. While the commercial oyster farms declined (the last commercial harvest was in 1957), the oyster drill remained. This population is located on a sand island at the back of the bay ({\textquoteright}Drill Island{\textquoteright} ). Netarts Bay is the only Oregon estuary where the drill is found. This thesis documents a study to locate the drill, learn about its movements, activities and feeding habits. The author points out that it is an "opportunity to study a pest-species at a time when it is not yet a pest." (p.2) Maps, charts, original bw photographs.}, pages = {65 p.}, school = {Oregon State University}, type = {Masters Thesis}, edition = {M. S.}, chapter = {General Science}, address = {Corvallis, OR}, abstract = { It has been shown that large localized population of Ocenebra japonica exists on a sandy low tide island in the tail of Netarts Bay. Introduced with Crassostrea gigas planted in the 1930{\textquoteright}s, the Japanese drill lives in association with relict oysters left behind by the defunct industry. Data from spat-baited traps furnished an index of distribution, and indicated the drills may move outward and downward in the summer, returning to the relicts for protection from winter weather when temperatures fall. Snails fed mono-specific diets of C. gigas, cockles (Clinocardium nuttalli), and Olivella biplicata were tested to determine prey preference. Naive (field) and starved specimens were also tested, and statistical comparison of these results demonstrated prey preference could be dietetically altered, and confirmed that C. nuttalli was the chief prey item in the field. A single spring spawning was noted, but few juvenile drills (< 18 mm) were recorded. The presence of numerous small prey- - some of which had been drilled- -and of a population distribution similar to literature reports indicate the population is viable. Fifty-three juveniles grew an average of 8. 76 mm in 85 days of unrestricted feeding. Local control measures for this potentially serious pest are discussed.}, keywords = {invertebrates, Japanese oyster drill = Ocenebra japonica, molluscs, Netarts Bay, Pacific oyster = Crassostrea gigas, theses}, url = {https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/3t945v39g}, author = {Squire, Douglas Richard} }