PROGRESS IN" BIOLOGICAL INQUIRIES, 19 3 617 



left, while on the higher ground the living ones were very poor. No 

 marketable oysters remained on the beds. The green-colored, clear 

 water normally found over the oyster beds had been changed to a 

 coffee-brown color which was quite opaque. This change took place 

 subsequent to the beginning of operations by the pulp mill at Shel- 

 ton, Wash. It was found that Oakland Bay contained about 26,000 

 acre-feet of water of which an average of 200 acre-feet was renewed 

 each day by tidal action. The pulp mill operation acknowledges 

 the dumping of 70,000 gallons of sulphite liquor into the bay beside 

 certain wash waters. It is possible to calculate the concentration of 

 sulphite liquor in the bay at any time from a mathematical formula 

 taking into account the proportion of liquor to sea water, the number 

 of acre-feet of liquor discharged into Oakland Bay by the mill per 

 day, the number of acre-feet of new sea water brought in by tidal 

 action each day, the volume of the bay in acre-feet, and the time in 

 days. By this formula the equilibrium concentration may be cal- 

 culated when a given amount of sulphite liquor is added each day. 

 The discharge of 70,000 gallons per day at the mill would bring about 

 a concentration of 1 part of liquor to 930 of water in Oakland Bay. 

 which concentration, laboratory experiments showed, would seri- 

 ously affect oysters. The State fishery inspectors show in then- 

 reports that several times as much liquor was discharged at the mill 

 as was used in these calculations. 



During June and July experiments were conducted on the spawn- 

 ing of the native oysters. It was found that the larvae were dis- 

 charged from the mantle cavity of the parent when they were taken 

 into the laboratory or handled in any way, unless great precaution 

 was used. This discharge took place regardless of the. stage of 

 development of the larvae and suggests that seed-moving operations 

 of the oyster growers should be completed before the oysters " come 

 into spawn." 



Efforts to rear larvae in aerated tanks were not successful. The 

 young lived and grew, but they maintained a symmetrical shape and 

 did not set within the normally expected time. In the mantle cavity 

 of the mother, development took place normally in the laboratory. 

 Under constant temperature conditions the incubation period was 

 reduced from 14 days to 6 days. 



ANALYSIS OF OYSTER BOTTOMS 



A mechanical analysis of some oyster bottoms of Georgia was made 

 by W. H. Dumont to ascertain if there is any correlation between the 

 grain size of the particles and the consistency of the bottom. It 

 was found that no relation existed between the amount of clay or 

 sand and the degree of softness. This was especially shown in two 

 samples taken within 20 feet of each other in Georgia in March — 

 one was a hard gray clay while the other was a soft brown mud. 

 A mechanical analysis by the pipette method showed the grain sizes 

 of both to be nearly identical. The only differences found were a 

 higher organic content and faster rate of settling of the particles of 

 the hard clay sample. 



At the request of the Bureau of Fisheries the Bureau of Public 

 Roads made several additional tests, but was unable to find any 



