EFFECTS OF CRUDE OIL POLLUTION ON OYSTERS 
IN LOUISIANA WATERS 1 
By Paul S. Galtsoff, Ph. D., Herbert F. Prytherch, Ph. D., Robert O. Smith, and Vera 
Koehring, Ph. D., United States Bureau of Fisheries 
CONTENTS 
Page 
Foreword 144 
Introduction (P. S. Galtsoff and H. F. Prytherch) 144 
Preliminary field investigations, 1933 (H. F. Prytherch) 146 
Survey of oyster bottoms in areas affected by oil-well pollution, 1934 (R. O. Smith) 150 
Methods 150 
General conditions 150 
Lake Barre 152 
Lake Felicity and Lake Chien 152 
Terrebonne Bay 153 
Timbalier Bay 153 
Lake Raccourci 154 
Lake Pelto and Pelican Lake 154 
Examination of oyster beds at mouth of Bayou Grey and Little Lake 155 
Conclusions 156 
Experimental studies of the effect of oil on oysters 158 
Review of the literature (P. S. Galtsoff) 158 
Survival of oysters in oil-polluted water (H. F. Prytherch) 159 
Experiments with surface film of oil 160 
Survival of oysters in sea water passed through oil 161 
Immersion of oysters in oil 162 
Effect of oil on glycogen content of oysters 163 
Experiments with brine 164 
Effect of brine on glycogen content of oysters 167 
Effect of oil on feeding of oysters (P. S. Galtsoff and R. O. Smith) 167 
Effect on the adductor muscle 167 
Effect of oil and oil well bleed-water on the rate of feeding of oysters 170 
Carmine cone method 171 
Drop counting apparatus 172 
Preparation of water-soluble fraction of oil 174 
Results obtained with the cone method 174 
Results obtained with the drop-counting method 183 
Effect of bleed water on the rate of feeding 188 
Effect of consecutive treatments 191 
Effect of crude oil on diatoms (P. S. Galtsoff and V. Koehring) 193 
Method 194 
Effect of heavy surface layer of oil on Nitzschia culture 196 
Effect of oil held on the bottom 197 
Effect of water-soluble fraction of oil 199 
Effect of oil held in collodion bags 200 
Effect of brine on Nitzschia 200 
Discussion and conclusions (P. S. Galtsoff) 204 
Bibliography 208 
i Bulletin no. 18. Approved for publication, June 3, 1935. 
143 
