PKOGRESS IN BIOLOGICAL INQUIRIES, 193 611 



FISH DISEASES 



Herring disease. — During July, 1930, Dr. H. S. Davis in company 

 with the State inspector and officials of the Federal Food and Drug 

 Administration visited some of the more important fishing centers 

 on the coast of Maine in an effort to obtain first-hand information 

 regarding the so-called herring disease. This disease first became 

 prevalent in 1929 and has been the cause of considerable anxiety to 

 the herring and sardine industry since that time. 



It was found that the disease was apparently fully as prevalent 

 in 1930 as during the previous summer, although at the time it ap- 

 peared to be declining in severity. Later in the season, however, con- 

 ditions again became worse ; and, at the urgent request of the sardine 

 packers, the bureau has undertaken a thorough investigation of the 

 disease. This investigation is being conducted in cooperation with 

 the State of Maine, which is defraying most of the expenses. A lab- 

 oratory has been established at Eastport, Me., and provided with the 

 necessary equipment for investigating all phases of the disease. A 

 sardine boat has been chartered by the State, and this will enable the 

 investigators to visit the weirs in the vicinity of Eastport and col- 

 lect their own fish if necessary. 



George E. Daniel with the assistance of several of the State sardine 

 inspectors is now actively engaged in a study of the disease. He will 

 be joined later in the season by Frederic F. Fish. 



The disease is evidently due to a microorganism belonging to the 

 obscure genus known as Ichthyosporidium or Ichthyophonus. Al- 

 though several different parasites belonging to the genus have been 

 described, practically nothing is known regarding the organisms or 

 their life history. Even the affinities of the genus are very uncertain. 

 The parasites were originally thought to belong to the Haplospo- 

 ridia, a group of protozoa, but it now appears more probable that 

 they are in reality more closely related to some of the lower fungi 

 (Chytridinise). The appearance of the parasites in the herring sup- 

 port the latter theory. 



The parasite occurs in all parts of the body but is especially 

 abundant in the muscles and liver. The development of the para- 

 site is apparently not affected by seasonal changes since the ap- 

 pearance of the diseased fish is identical whether taken during the 

 winter or in the summer. Furthermore, preliminary studies at East- 

 port indicate that fully as large a percentage of the fish taken in 

 winter are infected as during the summer. 



Trout diseases. — Studies on f urunculosis and the gill disease have 

 been continued by Doctor Davis at the Pittsford station. A severe 

 outbreak of furunculosis provided an opportunity for additional 

 studies on this disease, which, everything considered, is probably the 

 most serious infection known to occur in trout. Particular atten- 

 tion was paid to the pathology of the disease, which previously had 

 received relatively little attention from investigators. Furunculosis 

 has appeared at several of the bureau's hatcheries during the last year 

 or two, and it is evident that the disease is yearly becoming more 

 prevalent. Unless great precautions are taken to prevent its spread, 

 it will soon become as common as in Europe. 



