Although much is known about the effects of electroshock on fish physiology, consequences to the immune system and disease progression have not received attention. Our objectives were to determine the effects of electroshock on selected immune function in juvenile spring chinook salmon Oncorhynchus tshawytscha, the mechanism of any observed alteration,...
A technique that uses hypotonic lysis of erythrocytes was optimized for the purification of leukocytes from the peripheral blood and anterior kidney (pronephros) of rainbow trout Oncorhynchus mykiss. Comparisons of initial blood dilution (1:2, 1:4, and 1:6) and the time of exposure to hypotonic conditions (10, 20, and 40 s)...
Twenty-two steelhead trout (Salmo gairdneri) containing coded wire tags (CWT's) were captured in gillnets fished by the Oshoro-Maru in the Gulf of Alaska and along 180 during 1982-85. These fish originated from North American streams and hatcheries in British Columbia, Idaho, and Washington. One fish was age 0.1, 16 were...
Experiments were designed to determine whether and how steelhead Oncorhynchus mykiss affect chinook salmon O. tshawytscha when the two species are confined together. In a behavioral experiment, we observed groups of juvenile chinook salmon and steelhead together and groups of chinook salmon alone to determine whether the steelhead were aggressive...
Among the many birds attracted to gardens, hummingbirds can be the most appealing. Not only are these “garden jewels” fun to watch, hummingbirds play an important role in our environment by pollinating flowers and feeding on insects. Attracting hummingbirds to your garden is easy. You have a good chance of...
The cultural and ecological values of Pacific lamprey (Lampetra tridentata) have not been understood by Euro-Americans and thus their great decline has almost gone unnoticed except by Native Americans, who elevated the issue and initiated research to restore its populations, at least in the Columbia Basin. They regard Pacific lamprey...
We conducted a 3-year study of helminth parasites to assess their effect on the lesser prairie-chicken Tympanuchus pallidicinctus. Helminth parasites were found in most of the examined wild prairie chicken carcasses: 95% had eye worm Oxyspirura petrowi, 92% had stomach worm Tetrameres sp., and 59% had caecal worm Subulura sp....
The Willamette River, one of only 14 American Heritage Rivers, flows through the most densely populated and agriculturally productive region of Oregon. Previous biological monitoring of Willamette River fish detected elevated frequencies of skeletal deformities in fish from certain areas of the lower (NP [NP], rivermile [RM] 26-55) and middle...
This report is an attempt to address some critical information gaps regarding the effects of dikes and tide gates on coastal ecosystems and fisheries resources. The authors have identified the information needs during their work with landowners, community organizations, and resource management agencies and through a compilation and summary of...
We used mark-recapture methods to estimate age-specific apparent survival rates for male Lesser Prairie-Chickens (Tympanuchus pallidicinctus), a gamebird of conservation concern. A total of 311 male prairie-chickens (135 yearlings, 176 adults) were captured and banded during a 5-year study in southwest Kansas. Time-since-marking models were used to estimate apparent survival...
The ability to ascertain gender and age of juvenile grouse is essential for determining gender-specific population age structure and studying timing of reproductive events, respectively. We examined outer rectrix feathers from juvenile Lesser Prairie-Chickens (Tympanuchus pallidicinctus) captured at 30–40 and 50–60 days post-hatching. Blood samples were collected from most chicks...