Amphibian population declines and extinctions are occurring even in the world's least impacted areas. The introduction and spread of nonnative predators is one of many proposed causes of amphibian declines. Correlational studies have shown a negative relationship between introduced fishes and declining amphibians, but little direct experimental evidence is available. This study experimentally m...

Redband trout (Oncorhynchus mykiss gairdneri) migrations were tracked between March 2007 and June 2009 in the Donner und Blitzen River, Oregon, USA, using radio telemetry and PIT tags. We investigated the upstream extent and timing of spawning migrations for two groups of trout, considered the factors that influenced the rate of trout migration and explored the seasonal patterns of redband trou...

1Authors would like to thank D. Jesenšek, the head of the Hatchery Tolmin, for excellent cooperation. 2To whom correspondence should be addressed. Received December 16, 1996. Accepted March 17, 1997. Figure 1. Twelve alleles representing 16 different genotypes. Lanes 1 to 2: brown trout from the Ohrid lake; lanes 3 to 10: the Danubian and Atlantic brown trout; lane 11: hybrid between marble and...

the purpose of this study is determining of some immunity and blood serum parameters in brood stock and grower fish before and after of stripping to evaluate the effect of breeding physiological changes on immunity and serum indexes. in this study 15 male trout fish (oncorhynchus mykiss) including 5 in the stage of grower, 5 before stripping and 5 after stripping randomly were considered. blood...

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...

Current distributions of native brook trout (Salvelinus fonfinalis) in the southern Appalachians are restricted to upper elevations by multiple factors, including habitat requirements, introduced rainbow (Oncorhynchus mykiss) and brown (Salmo fnrtia) trout, and other human activities. Present-day distribution of brook trout habitat is already fragmented. Increased temperatures predicted by vari...

This study examined whether changes in the properties of mitochondria from red muscle of rainbow trout Oncorhynchus mykiss are accompanied by ultrastructural changes during cold acclimatisation. We compared measurements at five levels of organisation in red muscle of winter(1 °C) and summer(16 °C) acclimatised trout. We examined (1) maximal rates of pyruvate and palmitoyl carnitine oxidation by...

Ammonia has been documented as a respiratory gas that stimulates ventilation, and is sensed by peripheral neuroepithelial cells (NECs) in the gills in ammoniotelic rainbow trout. However, the hyperventilatory response is abolished in trout chronically exposed (1+ months) to high environmental ammonia [HEA; 250 μmol l(-1) (NH4)2SO4]. This study investigates whether the brain is involved in the a...

We compared seawater tolerance, gill Na(+)/K(+)-ATPase and Na(+)/K(+)/2Cl(-) cotransporter (NKCC) abundance, and mitochondria-rich cell (MRC) morphology of three salmonids, lake trout Salvelinus namaycush, brook trout Salvelinus fontinalis and Atlantic salmon Salmo salar. They were transferred directly from 0 p.p.t. (parts per thousand; freshwater) to 30 p.p.t. seawater, or transferred graduall...

We hypothesized that body shape differences between Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), rainbow trout (Oncorhynchus mykiss), and their hybrids may influence swimming ability and thus play an important role in the invasion of nonnative rainbow trout and hybrid trout into native cutthroat trout populations. We reared Yellowstone cutthroat trout, rainbow trout, and recipro...