434 U. S. BUREAU OF FISHERIES 



damage. This pest is not subject to control measures effective in 

 other sections of the country' because of its different biological re- 

 actions. Even in the middle of December when the water tempera- 

 ture averaged 10° to 12° C, egg cases of this species were found 

 containing all stages of developing young from early embryos to 

 small snails ready to escape. A detailed study of this drill is essen- 

 tial not only for the benefit of the Japanese oyster, but also for the 

 protection of the native oyster of the Pacific coast. 



YORK RIVER POLLUTION INVESTIGATION 



In October 1935, under a special allotment of $20,000 received 

 from the P. W. A., the Bureau began investigations at York River, 

 Va., to determine what effect, if any, the pulp mill wastes discharged 

 at West Point, Va., have on the oysters of this region. Local oyster- 

 men reported that the oysters were in poor condition, that many 

 were stunted and discolored, with shells so thin they could almost 

 be crushed in the hand. Formerly the York River oysters were 

 noted for their superior quality and especially prized in the New 

 York market. Dr. N. A. Wells was in charge of the field work, 

 assisted by Dr. W. A. Chipman, A. D. Hasler, and L. Garriss. 



This investigation has consisted mainl}^ in field and laboratory 

 studies on the effects of various concentrations of pollutants on the 

 survival of oysters, their physiology, rate of feeding, and on the 

 accumulation of glycogen in their tissues under various environ- 

 mental conditions. 



A building was leased in Yorktown, Va., and converted into a 

 laboratory with a running sea-water system. Labor as well as con- 

 siderable construction material A^as provided by the Fort Eustis 

 Transient Camp under the direction of Paul B. Murphy. The Vir- 

 ginia Commission of Fisheries cooperated in the project making 

 available the Margiierite^ a 65-foot Diesel powered boat. 



After the first week in October field stations were established, 

 water and oyster samples being collected at stated intervals for 

 chemical analysis. Up to the end of the year, eight cruises have 

 been made on the York River, and three on the Piankatank River, 

 which was selected for control observations. 



Due to the efforts of Mr. Richard Armstrong, Commissioner of 

 Fisheries of Virginia, the State appropriated $500 to defray the 

 expense of planting experimental beds of oysters in the York and 

 Piankatank Rivers during the Bureau's pollution studies. Between 

 November and early January, seven beds were planted in the York 

 River and two in the Piankatank. Samples of oysters were taken 

 at regular intervals from these beds and analyzed as to glj^cogen 

 content, shell weight, shell liquor, etc. Water samples vrere taken 

 at the same time for chemical analysis. 



Observations thus far show that living oysters in the upper part 

 of the York River, near the pulp mill, have shells that are extremely 

 thin and soft. Since this poor condition indicates that something 

 may be interfering with the normal metabolism of the oyster, ex- 

 periments are being planned to study calcium metabolism. It is of 

 interest to note here that this abnormal shell condition has not been 

 observed to exist in any other river emptying into the Giesapeake 

 Bay, or in the bay proper. 



