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Geology topics

R. W. Gould

Publications and source records attributed to R. W. Gould.

9 recordsLinked to original sources
USGS2006

Effects of temperature on biochemical reactions and drug resistance of virulent and avirulent Aeromonas salmonicida

Incubation temperatures of 11°, 18° and 28° did not substantially affect biochemical reactions of either virulent or avirulent forms of Aeromonas salmonicida subspecies salmonicida. The only change observed, amygdalin fermentation, was positive at 11° and 18° but negative at 28°C. Several isolates utilized sucrose, a characteristic not normally recognized for A. salmonicida subspecies salmonicida. Antimicrobial susceptibility screening indicated resistance to novobiocin increased at the higher incubation temperatures. Standardized drug sensitivity testing procedures and precise zone diameter interpretive standards for bacterial fish pathogens are needed.

Journal of Fish Diseases↗
USGS2006

Some potentials and limits of the leucocrit test as a fish health assessment method

The sensitivity of the leucocrit as a stress tolerance and fish health assessment method was evaluated by subjecting juvenile coho salmon, Oncorhynchus kisutch , or steelhead trout, Salmo gairdneri , to standardized crowding, handling, temperature and disease challenges. The leucocrit was a sensitive indicator of the physiological stress resulting from crowding at population densities of 0·2–0·4 kg l −1 , and to the stress of handling and to temperature changes. It was relatively insensitive to physiological sampling procedures which supports its continued development as a stress assessment method. In the case of fish diseases, subclinical or active Renibacterium salmoninarum and Yersinia ruckeri infections had essentially no effect on leucocrit values. In contrast, active Aeromonas salmonicida infections significantly depressed the leucocrit. However, no change was seen during the subclinical (incubation) phase prior to the development of an epizootic. Thus, the potential of the leucocrit as a fish health assessment method appears limited.

Journal of Fish Biology↗
USGS1987

Safe pre-release disease treatment with formalin for fall chinook salmon smolts

Standard formalin treatment (167 μL/L for 1 h) applied to presmolts and smolts of fall chinook salmon ( Oncorhynchus tshawytscha) 80, 62, 52, 38, 24, and 10 d prior to seawater exposure did not affect freshwater growth or survival during a 20-d period in seawater. There was no consistent effect of treatment on gill Na + , K + -ATPase activity.

Progressive Fish-Culturist↗
USGS1986

Increased walleye egg hatch and larval survival after protease treatment of eggs

Various techniques for eliminating the clumping of newly spawned walleye eggs (Stizostedion vitreum) were evaluated by measuring hatch, growth, and survival. Percent hatch was highest (83%) in egg groups water hardened in 0.01% protease solution. Other water‐hardening techniques tested were: (1) continuous stirring; (2) 250 mg/L tannic acid solution; and (3) bentonite clay suspension. Low hatching percentages for eggs continuously stirred or treated with bentonite were attributed to fungus. Fungus was minimal on eggs treated with protease or tannic acid. Fish hatched from each egg treatment group were intensively cultured for 21 d in one of four rearing environments: (1) well water; (2) well water receiving 1% sea salt for the initial 3 d; (3) well water receiving a 6‐mL daily addition of antifoam emulsion for the initial 9 d; or (4) well water receiving both the 1% sea salt and antifoam treatments. There was slightly higher survival in larval fish hatched from eggs treated with protease or tannic acid and reared in well water containing 1% sea salt. We observed no differences in average fish length among the test groups.

Progressive Fish-Culturist↗
USGS1985

Direct fluorescent antibody technique for the detection of bacterial kidney disease in paraffin-embedded tissues

The direct fluorescent antibody technique (FAT) was successfully used to detect the causative agent of bacterial kidney disease (BKD), Renibacterium salmoninarum, in Bouin's solution flexed and paraffinembedded egg and tissue sections. This method is superior to gram stain and may be particularly useful in detecting the BKD organism in fish with low-grade infection.

Fish Pathology↗
USGS1979

Immersion vaccination of sockeye salmon (Oncorhynchus nerka) with two pathogenic strains of Vibrio anguillarum

Sockeye salmon ( Oncorhynchus nerka ) were immersion-vaccinated in suspensions containing 5 × 10 7 , 5 × 10 6 , 5 × 10 5 , or 5 × 10 4 bacteria/mL of bivalent or monovalent, formalin-killed Vibrio anguillarum , Types I and II. The fish were split into two lots and held for 54 d. At that time one lot was challenged with living, virulent V . anguillarum , Type I, and one with living, virulent V . anguillarum , Type II. Immunization with bivalent bacterin effectively protected the fish from vibriosis, but monovalent vaccine was effective only against the homologous challenge. Immunization with the highest concentration of Type I monovalent bacterin resulted in 0% Type I and 58% Type II challenge mortality. Immunization with the highest concentration of Type II monovalent bacterin resulted in 41% Type I and 0% Type II challenge mortality. Immunization with the highest concentration of bivalent Type I/Type II bacterin resulted in 2% mortality in both challenges. Protective bacterins were effective at concentrations down to 5 × 10 5 bacteria/mL. Key words : immersion vaccination, bivalent vaccines, Vibrio anguillarum , vibriosis.

Journal of the Fisheries Research Board of Canada↗
USGS1978

Spray vaccination: A method for the immunization of fish

An economical, efficacious vaccine delivery system for immunizing fish has been developed which employs a liquid spray apparatus operated at pressures up to 7.0 kg/cm 2 (0 to 100 lb/in 2 ). A bacterin consisting of formalin-killed Vibrio anguillarum culture was both antigenic and immunogenic when sprayed on coho salmon(Oncorhynchus kisutch)and rainbow trout(Salmo gairdneri). The technique, referred to as spray(shower)vaccination, was found to confer higher levels of immunity against virulent V. anguillarum than oral vaccination.

Fish Pathology↗