BACTERIAL DISEASE OF FRESH-WATER FISHES. 

 Summary of Experiment No. 6. 



279 



Species. 



Number 



offish. 



Fish lost from 

 injuries. 



Fish lost from 

 disease. 



Total loss of fish. 



Buffalofish 

 Crappie . - 

 Bluegill . . 



Number. 



Per cent. 

 o 

 14.63 



Number. 

 25 



Per cent. 

 59-52 

 26.83 



Number. 

 25 

 17 



Per cent. 

 59- 52 

 41.46 



Experiment No. 7. — September 6, 1919, 36 buffalofish and 3 crappie were seined from 

 the same pond as in the preceding experiment and placed in the inclosure. The next 

 day eight buffalofish were found dead, evidently from the effects of injuries due to handling. 

 All the fish were removed from the inclosure on September 9. There were 17 dead 

 buffalofish, 8 living badly diseased buffalofish, and 3 badly diseased crappie. The 

 remaining fish were in good condition. 



Summary of Experiment No. 7. 



Experiment No. 8. — Since there was a possibility in the above experiments that the 

 fish might have injured themselves on the poultry wire in trying to escape from the 

 inclosure a fine-meshed seine was attached to stakes so as to form another inclosure by 

 the side of the one constructed of poultry netting. September 10, 21 buffalofish and 12 

 crappie were placed in this inclosure. These fish were taken from a different pond from 

 that used in the preceding experiments, but conditions were much the same, except 

 that the pond was somewhat farther from the station. 



Summary of Experiment No. 8. 



While the above experiments are only preliminary and too much weight should 

 not be placed on the results, it is evident that the conditions are especially favorable 

 for the development of this disease among rescued fish and that in all probability it 

 causes a very considerable mortality during warm weather. Much of the rescue work 

 is carried on in the fall and early winter, and with the low temperatures then prevailing 

 there is no doubt much less danger of infection by bacteria, but on this point we have 

 no data at present. 



It is obvious that great care should be exercised to injure the fish as little as pos- 

 sible and that, whenever practicable, rescue operations should not be undertaken until 



