FISHERIES, GAME AND FORESTS. 1 89 



Recommendations. 



My attention was first called to the epidemic in October, 1899, after it had been 

 running for a period of five months and after thousands of fish had died. It was quite 

 evident that the disease was then widespread and that nothing could be done to save 

 the remainder. The question to be considered is how to prevent future out- 

 breaks of like nature in this and in other localities. Unfortunately this cannot be 

 answered until we know where the parasite lives when not in the body of the fish. 

 A systematic examination of the suspended organisms in the waters, such as Cypris, 

 Daphnia, Gammarus, Cyclops or other Crustacea, might throw some light on the 

 question, but until this is ascertained the only recommendations that can be made are 

 such as the director of the Northport hatchery has undoubtedly carried out in the 

 present instance, viz. : 1) to exercise the most careful prophylactic measures. As 

 soon as any fish shows the first evidence of the disease it should, of course, be 

 removed and buried or burned (Pfeiffer, Ludwig and others recommended these 

 methods in the case of Myxosporidiosis), the remaining fish should all be inspected at 

 intervals and all sickly ones should be removed. 2) In the present case, before 

 stocking the ponds anew, I should recommend that the water be drained off and the 

 bottoms be left exposed to the sun for a few months. The runways should be 

 scrubbed and all growths removed. Every fish now in the ponds should be removed 

 and not allowed to contaminate the fish in neighboring streams. 3) Care must be 

 taken not to interbreed with the diseased fish, for although it is perhaps improbable 

 that the disease germ is transmitted in this way. yet it is possible, especially as the 

 testis is the chief seat of reproduction of the parasite. 4) The water must be kept 

 perfectly clean and cold ; not only dead fish but refuse of all kinds should be carefully 

 removed. 5) The vitality of the fish must be sustained ; fungoid growths must be 

 constantly watched for and removed. 6) Constant interbreeding of the same limited 

 variety of fish should be avoided; new blood should be introduced frequently. 7) The 

 food of the fish should be carefully inspected and should not be allowed to stand 

 exposed to flies and ether insects, but should be fresh. 



These homely recommendations, which every fish breeder knows and probably 

 applies, are the only precautionary measures that I can suggest, and even where they 

 are most rigorously enforced the disease may spread until it becomes epidemic. The 

 fish breeder must add this newly discovered organism to the many chances he takes 

 in rearing fine fish. 



Department of Zoology, \ 



Columbia University, New York. ] 



