The direct predatory effects of introduced rainbow trout Oncorhynchus mykiss on native longnose dace Rhinichthys cataractae were examined using a series of in-stream enclosures to determine if presence, density, or acclimation period of rainbow trout influenced survival of longnose dace. The number of longnose dace remaining in enclosures over the first 72 hours after rainbow trout introduction...

Plasma immunoreactive t-GTH and androgens, sperm production and biochemical changes in seminal fluid were studied during the spermiation period in rainbow trout. The volume of sperm collected by hand-stripping was very low (< 0.1 ml) at the onset of spermiation, increased slowly during the next 4 weeks and sharply thereafter. Plasma t-GTH was high (6 ng/mi) at the onset and then decreased ; the...

A study was undertaken to compare the virulence and serum killing resistance properties of Atlantic salmon and rainbow trout Yersinia ruckeri isolates. Five isolates, covering heat-stable O-antigen O1, O2 and O5 serotypes, were tested for virulence towards fry and juveniles of both species by experimental bath challenge. The sensitivity of 15 diverse isolates to non-immune salmon and rainbow tr...

Abstract:  The optimum dose of UV irradiation to produce gynogenesis rainbow trout, Oncorhynchus mykiss with emphasis of Hertwing effect and photoreactivation (PR) was investigated. For this purpose, the sperm of rainbow trout were inadiated with UV at 2010±200 µw.cm-2 intensity in different alternatives of 0, 1, 3, 5, 8, 10, 15, 20, 25, 35 and 45 minutes and allowed to fertilize normal ova; th...

The direct predatory effects of introduced rainbow trout Oncorhynchus mykiss on native longnose dace Rhinichthys cataractae were examined using a series of in-stream enclosures to determine if presence, density, or acclimation period of rainbow trout influenced survival of longnose dace. The number of longnose dace remaining in enclosures over the first 72 hours after rainbow trout introduction...

Ž . Rainbow trout Oncorhynchus mykiss of initial average weight 150 g and brook trout Ž . SalÕelinus fontinalis initially weighing 124 g on average, were reared at different growth rates Ž . Ž . by feeding either a high H, close to satiation or low L, half of H ration of a commercial diet. Fish were reared for 6 to 15 weeks in order to reach same size class. Fast growth increased whole Ž . Ž . ...

of the wildlife resources and a producer of additional fish and game via hatcheries and habitat management. Sometimes these roles of commodity versus stewardship are at odds. Such is the case where the DWR stocks exotic species such as rainbow trout to provide recreational fishing while attempting to conserve populations of native species such as the cutthroat trout. Cutthroat are the only trou...

The susceptibility of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) to the monogenean Discocotyle sagittata in the United Kingdom was assessed by experimental infection of naive fish. One month postinfection with 100 oncomiracidia/host, brown trout harbored significantly lower burdens (27.7 worms/host +/- 4.13 SE) than rainbow trout (47.8 worms/host +/- 3.90; P = 0.002). Th...