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United States Department of the Interior, Fred A. Seaton, Secretary and Wildlife Service, Arnie J. Suomela, Commissioner

Fishery Leaflet 462

Washington 25, D. C. July 1958

FIN ROT AND PEDUNCLE DISEASE OF SALMONID

By 1/ S . F. Snieszko_ Bacteriologist Branch of Fishery Research Bureau of Sport Fisheries and Wildlife

INTRODUCTION CAUSE OF THE DISEASE

These two diseases are discussed to­ In fin rot bacteria are implicated. Some gether because both are most likely caused by may be well known fish pathogens as Hemophilus bacteria. Both diseases are very inadequately piscium or . In peduncle . known. It seems likely that in both diseases disease the infected tissues show the presence , myxobacteria may play an important role. of long thin gram -negative bacteria which are Their differentiation from other bacterial fish strikingly similar to known fish -pathogenic diseases may often be difficult. myxobacteria. In May of 1958 myxobacteria of the type were isolated from a yearling IDENTIFICATION brook trout at Leetown, West Virginia .

Fin rot symptoms may also occur in the SOURCE AND RESER VOIR OF INFECTION course of some better known fish diseases as ulcer disease and furunculosis. This disease is Unknown. characterized by fins becoming opaque first at the margin. This condition usually progresses MODE OF TRANSMISSION toward the base. Fins also become thicker due to proliferation of epithelium. In advanced Unknown. cases fins are frayed with rays protruding like stretched fingers. Bacteria of various shapes INCUBATION PERIOD or even fungal mycelia may be abundant. Unknown. Peduncle disease is characterized by swelling, inflammation, discoloration, and gradual PERIOD OF COMMUNICABILITY necrosis of the caudal peduncle. Disease is always fatal. Unknown.

SUSCEPTmILlTY AND RESISTANCE Y Headquarters: Eastern Fish Disease Lab., Leetown (P .0. Kearneysville) Unknown. West Virginia

1 RANGE van Duijn, C., Jr. 1956. Diseases of Fishes. Water Life. Fin rot is very common in hatchery­ London, England. Tail and fin raised smallfingerlings of salmonid fishes. rot pp. 95-97. Peduncle disease is not common. In rainbow Use of Phenoxethol and Acriflavine for trout it usually follows rough handling. The the treatment of fishes is occurrence of the se disease s in warm -water described. fishes seems to be less frequent. * Eicher, C. J., Jr. OCCURRENCE 1947. Dual treatment for bacterial fin rot. Prog. Fish-Cult., Vol. 9, ~in rot is common among hatchery­ pp. 94-95. raise d fingerling trout. Peduncle disea se is Prolonged or flush treatment with much less common. formalin followed by malachite green Du sh treatment. A safe and apparently METHODS OF CONTROL effective treatment if administered in time. Treatment method inadequately Fin rot, if treated in time, responds described. well to external disinfectants as copper sulphate, formalin, malachite green and others. Clean­ * Hewitt, E. R. liness in hatchery tanks is r ecommended. 1937. Fin rot eliminated by continued Peduncle disease being a systemic infection is tank sterilization. Prog. Fish­ usually fatal. Chem'1therapeutic drugs have Cult., No. 33, pp. 19-20. not been tried as yet. Frequent disinfection with chlorine of hatchery troughs from which fish were removed for t:1e duration of treatment. ANNOTATED BffiLIOGRAPHY This sanitary measure seems effective but is time and labor consuming. A. Fin Rot (Tail Rot) B. Peduncle Disease Connel, F. H. 1937. Chlorine treatment of bacterial fin * Davis, H. S. rot of trout. Prog. Fish -Cult., 1935. Culture and Diseases of Game No . 34, pp. 6-9. Fishes. University of California Chlorine in form of calcium hypochlorite Press, Berkeley, Cal. pp. 273-274. is use d. Free chlorine concentration in Good description of symptoms. Cause water should not be more than 2 p. p. m . and control insufficiently known. Treatment should last for 2 minutes and be stopped with sodium thiosulfate. This * Wood, E. M. and W. T. Yasutake seems to be a good treatment method but 1956. Histopathology of fish: III. Peduncle extreme care is required in order not to ("Cold Water") Disease. Prog. fish. Cult., Vol. 18, pp. 58-61. Illus. In opinion of the reviewer this paper con­ * Dlvis, H. S. tains description not only of peduncle 1953. Culture and Diseases of Game disease but chiefly the histopathology of Fishes. University of California Columnaris disease in Pacific salmon. Press, Berkeley, Cal. Fin rot Possibly also an infection with a virus. pp.258-260. Bacteria were not identified. Control Very good description of the disease and is not discussed. of treatment methods.

* Papers indicated by an asterisk are of special importance to fish culturists.

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