14 U. S. BUREAU OF FISHERIES. 



shortly to be published two papers by this author on the life history 

 and fish-cultural significance of some of the insects most commonly 

 present in fishponds. 



A paper consisting largely of compilation and analysis of published 

 European and American data concerning the culture of fresh-water 

 crustaceans ("shrimp," etc.) as food for fishes in hatcheries and in 

 ponds Avas completed during the year by Dr. W. C. Kendall and 

 submitted for publication. It is believed that the culture of some 

 kinds of Crustacea as food for fish would be economically feasible 

 under certain conditions, depending much upon locality and the 

 immediate surroundings, of a particular fish-cultural plant. 



A service of no little importance was rendered when Dr. Emmeline 

 Moore, who has conducted several investigations for the Bureau, was 

 detailed to visit some of the fish-cultural stations and advise with 

 superintendents regarding the best use of plants in fishponds. 

 Against what might have been assumed to be obvious handicaps, 

 the advice of this investigator quickly established itself in the con- 

 fidence and esteem of practical fish-culturists. Her work commanded 

 such attention that her services were drafted by a State Government 

 which could offer more favorable conditions of employment than this 

 Bureau. 



The greatest need in the fish-cultural experiment work of the 

 Bureau is continuity and the application of persistence, skill, and 

 judgment, and this need can be met only by the making of the special 

 provision of personnel which the conditions may be found to warrant. 



STUDIES OF DISEASES OF FISH. 



Closely related to fish-cultural experimental work is the study of 

 the diseases of fish and the conditions which occasion mortality or 

 diminished vitality of fishes. The parasites of fishes also demand 

 attention, not only because of their unfavorable efi'ect upon the 

 vitality of the fish but because the presence of parasites, even such 

 as are not injurious, renders fish less attractive to the consumer and 

 accordingly diminishes the market A'alue of the fish. Diseases of fish 

 are of reaf concern from an economic point of view, not only for the 

 resulting direct losses to food supply but for the mortality of eggs, 

 fry, or fingerling in hatcheries, which causes serious losses in effi- 

 ciency and entails a substantial loss of public funds expended in fish- 

 cultural operations. As a matter of fact, fish pathology is a broad 

 subject for the studies of pathological and other unfavorable condi- 

 tions throw light upon the various fish-cultural practices and espe- 

 cially upon the propriety of use and the value of the several sorts 

 of foods employed in artificial feeding. 



The routine work of the fish pathologist. Dr. Franz Schrader, in- 

 cluded investigation into reports of fish mortalities in various parts 

 of the country, examination of specimens sent to the Bureau for the 

 determination of the cause of disease or death, and trips to the sta- 

 tions in connection with epidemics among fish or unsatisfactory con- 

 ditions among fry. 



An analysis of the so-called white-spot disease in fish eggs has 

 been virtually completed. Tt is apparent that the ordinary occurrence 

 of this disease finds its cause in careless handling of the eggs, be it in 

 the course of stripping or during transportation. Bacterial agency 



