Bacteriological studies of oyster beds.

Bacteriological studies are being made of oyster reefs in the Galveston Bay area to determine the extent of fecal pollution of the oysters and the water over the oyster reefs. Factors which might influence the degree of pollution or indicate pollution are observed, these factors being as follows: time of day, season of the year, depth of the reef, depth at which water sample is collected, temperature of air and water, specific gravity, turbidity and salinity of the water, pH of water and oysters, rainfall on watershed discharging into the area, tides, direction and velocity of wind, and the general weather conditions. To date samples have been collected during the months March, July, August, September, and October of this year. More collections are needed before the significance of some of the above factors is evident. The oyster reefs studied are the three most frequently used for commercial harvesting and present a variety of conditions. Most evidence of pollution was observed in March when the most probable numbers of coliform organisms per 100 ml of water were: 13.852 and 948. Collection in March followed a heavy rainfall which might explain these results. During July, August, September and October, evidences of pollution were much less but present, numbers of coliform organisms ranging from 0-11/100ml of water and 0-49/100 ml of oysters. One reef has shown more constant evidence of pollution than the others.