Publications

Loma salmonae (Putz et al., 1965) infections were observed in five groups of coho salmon, Oncorhynchus kisutch, reared in seawater net-pens in Washington State, U.S.A. in 1984–1986. Ultrastructural characteristics, size of spores, tissues and host infected, and geographical location identified the microsporidium as Loma salmonae. Preserved spores measured 4.4×2.3 (4–5.6×2–2.4) μm and exhibited 14–

Infectious diseases remain one of the most important limitations to the successful propagation of aquatic animals. Most of the losses caused by pathogens in aquaculture could be prevented by health inspection, adequate environment and sound management practices. Effective control measures, mainly based upon 1) avoidance of pathogens 2) modification of the environment 3) improvement of host resista

We examined the behavioral and physiological responses of wild and hatchery-reared cutthroat trout Oncorhynchus clarki subjected to a single electroshock, electroshock plus marking, and multiple electroshocks in natural and artificial streams. In a natural stream, cutthroat trout released after capture by electrofishing and marking showed distinct behavioral changes: fish immediately sought cover,

Infectious hematopoietic necrosis (IHN) continues to be a serious virus disease of salmonids with epizootics recorded in both wild and hatchery populations (Williams and Amend 1976; Carlisle et al 1979; Groberg and Fryer 1983; Saft and Pratt 1986; Traxler 1987; Follett et al 1987; Meyers et al 1988). While originally enzootic in western North America, the virus appears to be spreading further (San

A non-manipulative method for deriving empirical expressions of population growth parameters from simple field data is presented. The derived expressions can be used to assess the intensity and form of density dependence and interspecies interactions, and have potential for parameterizing more mechanistic models of population dynamics and for use in applied ecology, e.g. land management or environ

The tissue response of Salmo gairdneri Richardson, against the myxosporean parasite. Ceratomyxa shasta (Noble), was investigated using histological techniques, scanning electron microscopy and immunological methods. The progress of infection in C. shasta‐susceptible and resistant steelhead and rainbow trout was examined by standard histological techniques and by indirect fluorescent antibody metho

The number of fish viruses isolated in cell culture or observed by electron microscopy continues to increase rapidly. Until recently, most viruses that were isolated from finfish and characterized were found to be members of the Rhabdoviridae, Iridoviridae, or Herpesviridae (Wolf and Mann 1980). In a comprehensive review of fish viruses published in 1984, there were no picornaviruses and only two

The first isolates of infectious hematopoietic necrosis virus (IHNV) recovered from rainbow trout Oncorhynchus mykiss (formerly Salmo gairdneri) in France and Italy were compared to six representative strains from North America by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of virion polypeptides and neutralization by monoclonal antibodies (MAbs). All three IHNV isolates f

Since 1982, anemias occurring in stocks of yearling coho (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha) have been associated with serious losses at hatcheries in the Pacific Northwest, USA. The anemia is often accompanied by infections with external fungus (e.g. Saprolegnia) or the bacterial pathogens Cytophaga psychrophila or Renibacterium salmoninarum (Holt and Rohovec 1984

Steelhead (Salmo gairdneri) collected from various sites in nine drainages in northwestern Washington were genetically characterized at 65 protein-coding loci by starch-gel electrophoresis. Genetic differentiation within and among drainages was not significant, and genetic variation among drainages was much less than that reported in British Columbia; these results may be the consequence of gene f

We have reported the isolation of a paramyxovirus from stocks of adult chinook salmon (Oncorhynchus tshawytscha) returning to coastal rivers of Oregon, USA (Winton et al 1985). The isolates were obtained from kidney and spleen tissues using the chinook salmon embryo cell line, CHSE-214. Initial cytopathic effect (CPE) was slow to develop, requiring 28 days incubation at 18°C. The virus replicated

We determined the capture efficiency of a beach seine as a means of improving abundance estimates of small fishes in littoral areas. Capture efficiency for 14 taxa (individual species or species groups) was determined by seining within an enclosure at night over fine and coarse substrates in the John Day Reservoir, Oregon–Washington. Mean efficiency ranged from 12% for prickly sculpin Cottus asper