Histopathology of Rainbow Trout (Oncorhynchus mykiss) after Long-Term Exposure to Biologically Treated Bleached Kraft Mill Effluent in Experimental Stream Channels

1992 ◽  
Vol 49 (5) ◽  
pp. 939-944 ◽  
Author(s):  
Timothy J. Hall ◽  
Richard K. Haley ◽  
Dennis L. Borton ◽  
Alexander H. Walsh ◽  
Richard E. Wolke
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Exposure Period ◽  
Stream Channels ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Natural Streams ◽  
Tissue Changes ◽  
Kraft Mill Effluent ◽  
Secondary Parasite ◽  
Kraft Mill

Outdoor experimental streams were used to determine the effects of effluent on histopathology of rainbow trout (Oncorhynchus mykiss). Studies were conducted for 10–11 mo using biologically treated bleached kraft mill effluent at concentrations ranging from 0.5 to 2.0 mg∙L−1 of effluent BOD5 (1.3–5.1% v/v) and for 42 mo at 0.5 BOD5 addition (1.5% v/v). Twenty different tissues from randomly selected fish were examined at the end of each exposure period. Lesions or tissue changes observed in fish from both control and effluent-treated streams were of primary or secondary parasite-induced etiology, a condition typical of natural streams. There was an absence of neoplasia over the range of concentrations. Hematocrit, leucocrit, and liver somatic index remained normal throughout the course of effluent exposure. These data corroborate the lack of effluent effects as determined from measurements of trout growth, survival, production, and reproduction.

Rainbow trout (Oncorhynchus mykiss) habitat overlap with wild Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) in natural streams: do habitat and landscape factors override competitive interactions?

2018 ◽  
Vol 75 (11) ◽  
pp. 1949-1959
Author(s):  
Scott D. Roloson ◽  
Kyle M. Knysh ◽  
Michael R.S. Coffin ◽  
Karen L. Gormley ◽  
Christina C. Pater ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Atlantic Salmon ◽  
Oncorhynchus Mykiss ◽  
Salmo Salar ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Habitat Overlap ◽  
Atlantic Salmon Salmo Salar ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Natural Streams

The purpose of this study was to update rainbow trout (Oncorhynchus mykiss) invasion status, delineate factors that increase the invasion probability, and quantify habitat overlap between invasive rainbow trout and native Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) on Prince Edward Island, Canada. Analysis of landscape-level variables in 26 watersheds (14 with and 12 without rainbow trout) demonstrated that watershed slope, percent agricultural land use, and distance to the nearest rainbow trout population significantly increased the probability of rainbow trout establishment. Two independent reach-level fish community surveys were conducted by electrofishing in combination with habitat surveys. Reaches with rainbow trout had higher stream slope, Atlantic salmon were found in wider reaches with larger substrate, and brook trout were typically dominant in headwater reaches with finer substrate. Findings at multiple ecological scales illustrated that rainbow trout invasion success is positively influenced by the presence of high-slope habitat. Habitat separation of the three salmonid species indicates that competition with introduced rainbow trout may not be the most significant threat to native salmonid populations.

scholarly journals The effect of visual isolation on territory size and population density of juvenile rainbow trout (Oncorhynchus mykiss)

2002 ◽  
Vol 59 (2) ◽  
pp. 303-309 ◽  
Author(s):  
I Imre ◽  
J WA Grant ◽  
E R Keeley
Keyword(s):  
Rainbow Trout ◽  
Population Density ◽  
Oncorhynchus Mykiss ◽  
Experimental Tests ◽  
Territory Size ◽  
Control Treatment ◽  
Stream Channels ◽  
Juvenile Salmonids ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Experimental Treatments

Visibility is thought to affect the territory size of visually oriented animals but there have been few experimental tests of the hypothesis. We re-examined the relationship between visibility and territory size in juvenile salmonids to test the hypothesis that increasing habitat heterogeneity results in a reduction in territory size and consequently in higher population densities. Equal densities of young-of-the-year rainbow trout (Oncorhynchus mykiss) were stocked in two experimental treatments with low visibility and a control treatment with high visibility. Visibility was decreased by placing large stones or plywood dividers onto the substrate of experimental stream channels. As predicted, the size of individual territories decreased with decreasing visibility of the habitat. However, the treatments did not differ significantly in population density or growth rate of the fish. While this study confirms the inverse relationship between habitat visibility and territory size, the decrease in territory size did not produce an increase in population density of juvenile salmonids.

scholarly journals Population density and territory size in juvenile rainbow trout, Oncorhynchus mykiss: implications for population regulation

2012 ◽  
Vol 69 (6) ◽  
pp. 1121-1128 ◽  
Author(s):  
J.L.A. Wood ◽  
J.W.A. Grant ◽  
M.H. Belanger
Keyword(s):  
Rainbow Trout ◽  
Population Density ◽  
Oncorhynchus Mykiss ◽  
Population Size ◽  
Local Population ◽  
Minimum Size ◽  
Territory Size ◽  
Stream Channels ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

We manipulated population density of juvenile rainbow trout ( Oncorhynchus mykiss ) across a range of realistic densities in artificial stream channels, while controlling food abundance in two different ways: in Experiment 1, the total amount of food was held constant over a threefold increase in density, whereas in Experiment 2, the per capita amount of food was held constant over an eightfold increase in density. We tested the contrasting predictions that territory size (i) is not affected by population density; (ii) decreases with population density as 1/n, where n = the local population size; or (iii) decreases with population density but towards an asymptotic minimum size. In Experiment 1, territory size decreased with increasing population density. With the broader range of densities used in Experiment 2, territory size initially decreased with density and then leveled off at a minimum territory radius of 20–30 cm. Our results suggest an asymptotic minimum size of about 0.2 m2 for a 5 cm rainbow trout, similar to what is observed for high-density conditions in the wild. This minimum territory size could potentially set an upper limit on local population density and help regulate the population size of stream salmonids.

Copper metabolism and gut morphology in rainbow trout (Oncorhynchus mykiss) during chronic sublethal dietary copper exposure

2001 ◽  
Vol 58 (2) ◽  
pp. 293-305 ◽  
Author(s):  
Collins N Kamunde ◽  
Martin Grosell ◽  
John NA Lott ◽  
Chris M Wood
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Granule Cells ◽  
Copper Metabolism ◽  
Exposure Period ◽  
Whole Body ◽  
Electron Microscopic ◽  
Dietary Copper ◽  
Cu Content ◽  
Rainbow Trout Oncorhynchus Mykiss

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 11 (control), 300 (medium), and 1000 µg Cu·g–1 (high) (as CuSO4·5H2O) in the diet for 28 days at a daily ration of 4% wet body weight, with a background waterborne Cu concentration of 3 µg·L–1. There was no effect of dietary Cu on growth, condition factor, or food conversion efficiency. Whole-body Cu content increased continuously over the exposure period in all groups and was twofold and fourfold higher than controls at day 28 for the medium- and high-Cu diets, respectively. Copper accumulated mainly in liver and gut tissue, with the latter stabilizing by day 14. Accumulation also occurred in gill, kidney, and carcass. Plasma Cu concentration was not different from the controls whereas Cu in bile was greatly elevated, an indication of increased hepatobiliary excretion. Dietary Cu pre-exposure decreased the uptake of waterborne Cu across the gills, providing the first evidence of homeostatic interaction between the two routes of uptake. Electron microscopic observations of the midintestine revealed numerous mitochondria, lysosomes, lamellated bodies, and extensive lamellar processes in the enterocytes. Apoptosis, mitosis, and eosinophilic granule cells were more apparent in Cu-exposed fish.

The essential oils of some medicinal plants on the immune system of rainbow trout (Oncorhynchus mykiss)

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
A Ghasemi Pirbalouti ◽  
E Pirali ◽  
G Pishkar ◽  
S Mohammadali Jalali ◽  
M Reyesi ◽  
...  
Keyword(s):  
Immune System ◽  
Rainbow Trout ◽  
Medicinal Plants ◽  
Oncorhynchus Mykiss ◽  
Essential Oils ◽  
Rainbow Trout Oncorhynchus Mykiss
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