Publications

The movements of 23 northern Squawfish Ptychocheilus oregonensis were monitored by radiotelemetry below a Columbia River hydroelectric dam during the out-migration of juvenile anadromous salmonids in 1984 and 1985. The work was done as part of a study to relate predator abundances and distribution to juvenile salmonid mortalities associated with dams. Northern Squawfish remained in...

The U.S. Fish and Wildlife Service has an ongoing program to assess the feasibility of reestablishing naturally spawning populations of Lahontan cutthroat trout in the Truckee River-Pyramid Lake system in Nevada. Previous in situ egg-survival studies have documented a 100 percent mortality of cutthroat trout eggs artificially planted in potential spawning gravels in the Truckee River...

No abstract available

We developed a portable electric barrier to aid in the capture of adult chinook salmon Oncorhynchus tshawytscha undergoing spawning migrations up a turbid stream in south-central Alaska. In 1981, we tagged and released 157 chinook salmon after diverting them from the main-stem Killey River into a conventional trap with the aid of the electric barrier. On the basis of returns of tagged...

Principal components of water reuse systems include ammonia removal, disease control, temperature control, aeration, and particulate filtration. Effective ammonia removal techniques include air stripping, ion exchange, and biofiltration. Selection of a particular technique largely depends on site-specific requirements (e.g., space, existing water quality, and fish densities). Disease...

Annulus formation on opercula of the cui-ui Chasmistes cujus in Pyramid Lake, Nevada, was validated over an 8-year interval. Many fish were old, as old as 41 years of age, As many as three annuli were hidden (covered by supporting bone) in older fish. Growth was rapid during the first 10 years, slow from 10 to 20 years, and extremely slow or nil after 20 years. Age and growth were...

For greatest survival, first-feeding halibut Paralichthys californicus and diamond turbot Hypsopsetta guttulata required food by the day of total yolk absorption. Some halibut larvae survived if fed 1 or 2 d after yolk depletion, but their growth rate was significantly less than larvae fed earlier. Survival of 3-wk-old larvae was greater in treatments with shorter starvation periods. A...

Abstract not available

The number of sockeye salmon, Oncorhynchus nerka, in Alaska's Karluk River (Fig. 1) declined from millions to thousands during the early part of the present century. Rounsefell (1958) discussed alternative explanations for the decline including a general loss offertility ofthe system as the number of salmon carcasses declined, competition, overfishing, subtle changes in climate, and...

No abstract available.

Digestive tract evacuation in northern squawfish (Ptychocheilus oregonensis) (170–1900 g) was studied in fish allowed to feed voluntarily on salmon (4–70 g) at three water temperatures (10, 15, and 20 °C). Squawfish were sacrificed at 1- or 2-h intervals until evacuation approximated 90%. Amount of food evacuated for a given time interval increased approximately three times as the...

No abstract available