Publications

A practical and economical method for anaesthetizing adult salmon and steelhead trout in the fish trucks used in the Grand Coulee fish salvage program is described. The method consists in generating a predetermined carbon-dioxide concentration in the 1000-gallon tanks of the trucks through the successive addition of predissolved sodium bicarbonate and dilute sulphuric acid in proper...

Costiasis, or the disease produced by the flagellated protozoan ectoparasite, Costia necatrix, is of considerable importance in the artificial propagation of both warm- and cold-water fishes. In spite of its importance, costiasis seldom is accurately diagnosed probably because of the extremely small size and sedentary nature of the causative organism. A general resume of the specific...

After the completion of the eхреriments reported recently, in which the efficacy of formalin in controlling infections of Gostia mecatrix was demonstrated, the author was afforded an opportunity to test the value of formalin solutions in combatting established mixed infections of (Gyrodactylus, Tricbodina, Cyclochaeta) and a stalked protozoan on rainbow trout fingerlings. This...

No parasite common to hatchery salmon and trout possesses quite so varied a reputation as does Octomitus salmonis. Discovered, studied, and described independently, but essentially simultaneously, by Dr. Emmeline Moore and Dr. H. S. Davis, Octomitus salmonis was introduced to fish culture during the early twenties. This easily found and widely distributed parasite, once recognized, was...

In an evaluation of the efficiency of trout culture, the author presents a detailed analysis of complete loss records from 288 individual lots of trout at twenty-two hatcheries in the western United States. Summarized data are given to show the percentage loss of eggs, fry, and fingerlings by progressive one-half inch size groups. The accumulative percentage loss is also included to...

In a search for more effective disinfectants to combat parasitic diseases of hatchery fish, the authors report results from a series of experiments designed to determine the toxicity of varying exposures to concentrations of formalin, sodium p‐phenolsulphonate, ammonium sulphate, and sodium benzoate. Non‐toxic concentrations of these disinfectants were tested, in addition to the usual...

The smallest and most destructive of the ectoparasitic protozoans infecting salmon and trout, Costia necatrix, has unfortunately been relegated to virtual obscurity during the past few years. Few references to this parasite can be found in the recent literature and, where such things are discussed, one seldom hears a mention of Costia necatrix. This apparent lack of interest in Costia...

The question has sometimes been raised whether or not any permanent injury may be inflicted upon fish eggs through their subjection to the relatively low temperatures prevailing in egg cases during shipment. This question may be argued in either direction purely upon the basis of indirect evidence which can be summoned in support of either contention. In so far as is known, this question...

Henneguya salminicola was described in 1919 by Dr. H. B. Ward from cysts found in the body musculature of a silver salmon (Oncorhynchus kisutch Walbaum) taken from the Stickeen River in southeastern Alaska. Ward described the cysts as “pyriform, fairly uniform in size, and hard to the touch. . . . The cysts measured 3 to 6 mm in diameter and were found everywhere through the muscle mass...

With the comparatively recent evolution of fish hatching into true fish culture the problems offered by fish disease have likewise evolved from more or less of a petty annoyance into a first class headache.

The prevention or control of epidemics of fish diseases by applying a disinfecting solution in a uniform concentration directly to the water supply of a fish pond or trough for a definite period of time has been exceedingly slow in development. In so far as can be determined, the original idea should be credited to. Marsh and Robinson (1910). In their work on the control of algae in fish...

A largemouth black bass fingerling preserved in formalin was sent to the U.S. Bureau of Fisheries Pathology Laboratory at Seattle, Washington, during the autumn of 1937, by a hatchery employee at Miles City, Montana. The fish exhibited several wart-like protuberances on the caudal peduncle, which aroused the curiosity of Mr. H. C. Topel, in charge of fish distribution at Miles City. He...