Two groups of brown trout Salmo trutta L. were studied, one after natural exposure to PKD-infected waters, the other after laboratory challenge by intraperitoneal inoculation with PKDinfected kidney tissue from rainbow trout Salmo gairdneri Richardson. Subclinical PKD developed in both groups; renal intraluminal myxosporean organisms were observed in both groups. The implications of these findi...

Despite being genetically very closely related, the marble trout Salmo marmoratus and the brown trout Salmo trutta exhibit marked phenotypic differences, particularly with regard to skin pigmentation. Histological analysis of skin from the head and gill cover of differently aged individuals of the two species was carried out in order to characterize differences in skin structure. The basic stru...

The host specificity and distribution of Eubothrium crassum (Bloch, 1779) and Eubothrium salvelini (Schrank, 1790), morphologically fairly similar pseudophyllidean tapeworms parasitizing salmonid fish, were critically assessed on the basis of morphological and genetic evaluation of extensive material collected from different definitive hosts and geographical regions in Europe. Eubothrium crassu...

Seven species of the genus Trichodina Ehrenberg, 1838 were identified during a sampling programme of twenty freshwater fish species from approximately sixty sites in Scotland, England and Wales. Species found include: Trichodina acuta Lom, 1961 from Cyprinus carpio L., Carassius auratus L., Oncorhynchus mykiss (Walbaum), Salmo trutta L. and Phoxinus phoxinus L.; Trichodina domerguei Wallengren,...

 The endocrine cells of Salmo trutta macrostigma stomach and pyloric caeca have been investigated using immunohistochemical techniques. 8 antisera were tested and 6 of them were detected in the endocrine cells serotonin, somatostatin, substance P, galanin, CCK and neuropeptide Y. These immunoreactive cells are described for the first time in the stomach and pyloric caeaca of Salmo trut...

Metapopulation dynamics over the course of an invasion are usually difficult to grasp because they require large and reliable data collection, often unavailable. The invasion of the fish-free freshwater ecosystems of the remote sub-Antarctic Kerguelen Islands following man-made introductions of brown trout (Salmo trutta) in the 1950's is an exception to this rule. Benefiting from a full long te...

Since fish form an important source of human food, a considerable amount of data is available concerning their distribution and size under natural conditions. This is especially true for the Salmonidae because of their popularity with sporting fishermen. With the development of commercial hatcheries, there has been a certain amount of experimental work concerning the effect of various factors o...

The success of invasive species is frequently attributed to phenotypic plasticity, which facilitates persistence in novel environments. Here we report on experimental tests to determine whether the intensity of cryptic coloration patterns in a global invader (brown trout, Salmo trutta) was primarily the result of plasticity or heritable variation. Juvenile F1 offspring were created through expe...

A technique for the hypophysectomy of the brown trout is described which might be applicable to other salmonids. Hypophysectomy produced a decrease in water turnover which was corrected by prolactin therapy. Hypophysectomy resulted in a decrease in the next flux of osmotic water. Both osmotic and diffusional water permeabilities were evenly decreased after hypophysectomy, such that the ratio of...

It has long been known that brown trout (Salmo trutta Linn.) grow to different sizes in different waters, and there has been much speculation concerning the factors determining these differences. Dahl (1918-19) suggested that the food supply and the degree of crowding were important; also that small, slowly growing trout were derived from smaller ova than those growing more rapidly. Southern (1...