THIRTY-NINTH BIENNIAL REPORT 31 



The industries doing the damage are fruit and vegetable canneries, 

 freezers, dehydraters, milk plants, and slaughter houses. The waste from 

 these plants decomposes and removes the dissolved oxygen from the river 

 water. Studies by the Fish and Game Pollution Detail showed that in 

 1943 the oxygen dropped almost to the point where the river was lethal 

 to salmon; in 1944 the river was actually lethal. The Pollution Detail 

 made studies in collaboration with the State Board of Health, and 

 arranged to have extra water released into the river to dilute the polluted 

 water to the point where salmon could survive. When the Pollution Detail 

 was disbanded, the job was turned over to the Bureau of Marine Fish- 

 eries. This bureau then tested the river several times daily, and watched 

 for the arrival of the salmon at the mouth of the Tuolumne. When the 

 fish appeared in numbers, the necessary additional water was released 

 from the Don Pedro Dam by the Turlock Irrigation District. The extra 

 water raised the oxj^gen content to the point where salmon could survive, 

 and the run went through without incident. Approximately the same 

 thing happened in 1945 except that the pollution was worse and more 

 water was required. A temporary reduction in the flow of extra water 

 resulted in the death of some salmon. 



Pollution — Stanislaus River: On October 7, 1944, the sewer pond 

 of the City of Escalon broke its banks and emptied into the Stanislaus 

 River, killing all or nearly all fish between that point and the mouth of 

 the river. Escalon has since built an adequate disposal system which will 

 go into operation as soon as delivery is made on a long-overdue sewer 

 pump. 



