Blood acid-base regulation following exhaustive exercise was investigated in freshwater(FW) and seawater(SW) adapted rainbow trout (Salmo gairdneri) of the same genetic stock. Following exhaustive exercise at 10°C, both FW and SW trout displayed a mixed respiratory and metabolic blood acidosis. However, in FW trout the acidosis was about double that of SW trout and arterial blood pH took twice ...

The anti-predator behaviours of a New Zealand freshwater crayfish (Paranephrops zealandicus) to the native long-finned eel (Anguilla dieffenbachii) and the introduced brown trout (Salmo trutta) were investigated. Crayfish modified their behaviour in the presence of both trout and eels. However, a significantly greater number of defensive chela displays and swimming responses were made to eels t...

Complementary DNA-encoding proteins with high homology to steroidogenic acute regulatory proteins (StAR) of mammals were cloned from rainbow trout head kidney and a mixture of several brook trout tissues. A cDNA encoding an MLN64 homolog was also cloned from brook trout. The C-terminal domains of rainbow trout StAR and brook trout StAR were very highly conserved compared with StAR of mammals. I...

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...

Tnp lo~d hybnds were obtained from rainbow trout Oncorhynchus mykiss females crossed w t h sires of brook trout Salvehnus fontinalis arctic char S alpinus and lake trout S namaycush following heat-shock-provoked retention of the second polar body Survlval rates of hybr~ds obtained were ca 50 % The hybnds and the parental specles were challenged with infect~ous pancreatic necrosls vlrus (IPNV) t...

Salmonid fishes are cold water piscivores with a native distribution spanning nearly the entire temperate and subarctic northern hemisphere. Trout in the genus Oncorhynchus are the most widespread salmonid fishes and are among the most important fish species in the world, due to their extensive use in aquaculture and valuable fisheries. Trout that inhabit northwestern Mexico are the southernmos...

The susceptibility of 2 strains of rainbow trout Oncorhynchus mykiss, 1 from North America (TL) and 1 from Germany (GR), to Myxobolus cerebralis (the cause of salmonid whirling disease) was assessed following exposure to the infectious stages (triactinomyxons). Two laboratory experiments were conducted with age-matched rainbow trout of each strain. At the beginning of the study, the 2 trout str...

—Populations of lake trout Salvelinus namaycush in Lake Superior collapsed in the late 1950s due to overfishing and predation by sea lampreys Petromyzon marinus. A binational effort to restore the lean morphotype of lake trout began with the stocking of hatchery-reared fish followed by the chemical control of sea lampreys and closure of the commercial fishery. Previous comparisons of the contem...

Endocrine effects in the aquatic environment are in the focus of scientists and media along with debates on the necessity of further steps in wastewater treatment. In the present study VTG responses were compared to evaluate upgrades at wastewater treatment plants (WWTPs). We investigated several advanced sewage treatment technologies at two WWTPs connected to the Schussen, a tributary of Lake ...