178 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



it represents an oxygen consumption 3 of approxi- 

 mately 50 mg./hour. Yonge (1928), in per- 

 forming experiments on the mode of utilization of 

 dissolved glucose, found that European oysters 

 (Ostrea edulis) removed approximately 20 mg./ 

 hour. He felt that the removal took place in the 

 stomach, and earlier (1926) had concluded that 

 there was no evidence of any enzymes free in the 

 gill mucus. This latter would not be necessary 

 if the substance in question were adsorbed on the 

 mucous train and carried into the alimentary tract. 



40 

 39 



1 30 



■1 25 



t 20 



U 



Sj io 

 o 



* 4 - 



2 - 



8 10 12 14 10 18 

 CARBOHYDRATE CONCENTRATION 

 mg/lltro (arcblnes* equivalent) 



20 22 



Figure 10. — The shift in the carbohydrate-pumpage rela- 

 tion due to temperature. The values are derived from 

 the simultaneous observation of temperature, carbo- 

 hydrate concentration, and bihourly effluent. Curve 

 A-A' is for the temperature range 25° to 30° C, in- 

 clusive; curve B-B' is for 14° to 21° C, inclusive. The 

 temperatures shifted from one range to the other so 

 quickly that there were insufficient frequencies for 

 analysis in the 22.0° to 24.9° C. bracket. The small 

 figures at each point represent the number of samples 

 from which the value is derived. 



25 

 20 



1- I5r— 



-J 

 u. 

 u. 

 li.' 



-) to 



o£ 



It 

 I — 



£0 



111 

 «> 



< 4 



or 

 u 

 > 

 < 



10 — 



8 — 



6 - "_ 



2 4 6 8 10 12 14 16 18 



CARBOHYDRATE CONCENTRATION 

 mg/litre (arobinosa equivalent) 



Figure 11. — Relation between carbohydrate concentra- 

 tion and the bihourly effluent of oysters. Curve A is 

 derived from 3,891 bihourly observations on 12 oysters 

 from May 10, 1949, to November 13, 1949. The flat 

 portion of the curve represents the dominance of phase- 

 II pumping (testing periods) at carbohydrate values of 

 less than 12 mg./l. during the warm months. Curve B 

 is derived from 5,464 hourly observations on 11 oysters 

 for a period of winter temperatures, November 13, 

 1949, to January 31, 1950 Semilog coordinates. 



Table 2. — Removal of carbohydrates from sea water by 

 oyster 74, May 24-June 11, 1949 



•According to our later studies (Collier, Ray, and Magnitzky, manuscript 

 in preparation), the oyster actually does utilize oxygen on a scale commen- 

 surate with this figure. 



i Some of these values were obtained while the oyster was going from phase 

 I to phase II; therefore, the pumping rates shown do not necessarily reflect 

 the correlation of pumping rate and carbohydrate concentration. 



