Publications

Since 1951 a disease, usually occurring in late spring or early summer, has caused severe losses in 3- to 12-month-old fingerling sockeye salmon in hatcheries in the State of Washington. The disease is characterized by an explosive outbreak, mortality usually 80 percent or greater, and a residual spinal deformity in a small percentage of the surviving fish, and its specificity for the one species

Viruses are probably the cause of a wide spectrum of fish diseases. Although relatively few virus diseases of fish are known today, some of the diseases of unknown etiology, as well as some diseases presently accepted as due to bacteria, protozoa, fungi or nutritional deficiencies, possibly will be recognized eventually as virus diseases. Some viruses may induce proliferative tissue changes wherea

An epizootic among rainbow trout (Salmo gairdnerii) in a private trout farm, resulting from a species of Ichthyosporidium that caused very high mortality rates in all ages of trout, reported from the State of Washington.

SOME DIFFICULTY has been experienced in raising fry and young fingerlings at the Puyallup hatchery of the Washington State Department of Game, a hatchery now in its fourth year of operation. There has been evidence of gas in the yolk-sac fry, and the mortality was always excessive among the fingerlings while reared in the hatchery troughs. The mortality rate decreased and evidence of gas-bubble di

Production records for 1885, 1891–1908, and 1929–49, indicate cyclic fluctuations for several important species of fish. The average annual take (all species) of 3,582,000 pounds in 1929–49 was 3,503,000 pounds below the 1891–1908 mean of 7,085,000 pounds. Decline in the output of lake herring alone from 5,841,000 pounds in 1891–1908 to 1,070,000 pounds in 1929–49—a drop of 4,771,000 pounds—more t

GILL DISEASE among fish, a disease which is characterized by a proliferation of the gill epithelium, has been attributed to a number of different causes. Generally, there are two recognized types: the eastern or bacterial type, in which long filamentous bacteria can always be demonstrated; and the western type, in which, by definition, bacteria cannot be demonstrated.

No abstract available.

Development of the salmon resources of the lower Columbia River Basin appears as sound insurance against the threat of a serious reduction in the runs to the upper river areas through the multiple-purpose programs of water development now under way by the Corps of Engineers, the Bureau of Reclamation, and private interests. Any comprehensive plan for the full development of the fisheries resources

A streptomycete and pseutdomonad were isolated from blueback salmon, Oncorhynchuis nerka (WValbaum), and shown to be pathogenic to fish. Trhese organisms were isolated from young blueback salmon taken from a gr'oup that developed an increasing mortality after feeding about a month at the United States Fishery Station, Leavenworth, Washington. A superficial examination revealed only the presence of

Bacterial gill disease when uncontrolled causes heavy losses among hatchery fish. The disease is characterized by a proliferation of the gill epithelium overlaid with masses of myxobacteria. The characteristic hyperplasia probably causes death by preventing the proper interchange of gases between the water and the blood stream of the fish. A number of strains of myxobacteria differing primarily in

I was glad to see "Fact and Fiction in Spawntaking" by Wood and Dunn (1948) in a recent issue of the PROGRESSIVE FISH CULTURIST. Having spent two seasons at the Yellowstone Park station, I also attempted to find ways of increasing the efficiency of fertilization and several years ago conducted a few experiments along these lines. From these experiments I obtained some "facts and fiction" that I be

BACTERIAL GILL DISEASE, a common epizootic among hatchery fish, can be controlled by copper sulphate dips, as stated by Davis (1945), or by prolonged treatments with Roccal, as noted by Fish (1947). The use of copper sulphate is not without danger because of variation in toxicity according to the hardness of the particular water supply; also, the toxicity and efficacy of Roccal have varied conside