Temperature effects on Pacific oyster embryos subjected to spent sulfite liquor

• Main Author: Will, Theodore
• Other Authors: Dimick, Roland E., Fisheries and Wildlife, Oregon State University. Graduate School
• Format: Master Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Oysters; Embryology > Mollusks; Pacific oyster
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/zg64tp98r

An exploratory study of 48-hour Pacific oyster embryo bioassays employing spent sulfite liquor (SSL) in test concentrations ranging from 10 to 45 ppm was made at two incubation temperatures, 20° and 24° C. Fourteen separate bioassays, each employing embryos originating from three to four different parentages, were conducted at the Yaquina Bay Laboratory during the summer of 1964. Comparative SSL bioassays at 20° and 24° C showed that significantly greater numbers of normal oyster larvae were always produced at an incubation temperature of 24° than at 20° (p < 0.01). In addition, the comparative median effective concentration (EC₅₀) values obtained from ten separate daily bioassays indicated that in each case the inimical affects of SSL were considerably less at 24° than at 20°. The calculated reductions in toxicity ranged from 17.1 to 60.3 percent, resulting in an average of 34.0 percent toxicity decrease. Further, 24° C incubated larvae were considerably more normal in appearance, and length measurements of larvae made from 20° and 24° control groups from the same parentage showed significantly larger sizes at 24°. A probable explanation of the cause for diminished inimical effects of SSL on Pacific oyster embryos when incubated at 24° C as compared to 20° is that the higher temperature was probably nearer the optimum for embryonic development of the species.