Selection by Brook Trout (Salvelinus fontinalis) and Juvenile Atlantic Salmon (Salmo salar) of Shade Related to Water Depth

1975 ◽  
Vol 32 (9) ◽  
pp. 1652-1656 ◽  
Author(s):  
R. John Gibson ◽  
G. Power

Salmon parr and small brook trout were observed in two stream tanks providing choices of cover. One tank was shallow (24–29 cm) and the other deep (43–50 cm). In the shallow tank brook trout occurred most frequently in shade. When salmon were the sole species, they were most frequently in shade, but were mostly away from shade in the presence of trout. This selection for shade was not evident by either species in the deep tank.

1974 ◽  
Vol 52 (6) ◽  
pp. 677-679 ◽  
Author(s):  
Philip E. K. Symons

Brook trout (Salvelinus fontinalis) ate 26% of 58 juvenile (7–11 cm) Atlantic salmon (Salmo salar) introduced into an artificial stream 24 h before the trout, but they ate only 8% of 60 salmon which had been present long enough to establish territories. Man-made environmental alterations may decrease territorial behavior of young salmon thereby increasing their vulnerability to predation.


2006 ◽  
Vol 84 (6) ◽  
pp. 839-845 ◽  
Author(s):  
R.S. Rajakaruna ◽  
J.A. Brown

Several salmonid species can discriminate kin from non-kin using recognition cues. These are known to involve both genetic and environmental components. This study examined the effect of diet, an environmental cue, on kin discrimination in juvenile Atlantic salmon ( Salmo salar L., 1758) and brook trout ( Salvelinus fontinalis (Mitchill, 1814)). Juveniles were reared in kin and non-kin groups. Three different diets were fed to three kin groups and three non-kin groups. Juveniles were then tested for their ability to discriminate kin. We found that juveniles discriminated individuals between kin and non-kin when they shared a common diet with kin, but did not do so when kin were fed a different diet. Moreover, we predicted that diet and genotype together would provide stronger cues than sharing either dietary cues or genetic cues. When the juveniles were given a choice between kin fed the same diet and kin fed a different diet, they did not show a consistent preference for the former. However, in the absence of kinship, juveniles preferred cues from a common diet, i.e., they preferred cue water conditioned by non-kin sharing a common diet than cue water from non-kin fed a different diet. Our results show that dietary cues affect kin discrimination in juvenile Atlantic salmon and brook trout and provide the first empirical evidence for the influence of diet on kin discrimination in salmonids. The functional explanation of these results is that the preferences in kin discrimination are likely context dependent.


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 ◽  
...  

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.


1972 ◽  
Vol 29 (1) ◽  
pp. 27-29 ◽  
Author(s):  
C. T. Hatfield ◽  
J. M. Anderson

The experiments were conducted in large outdoor concrete pools in which the salmon had access to a safe haven. After exposure for 24 hr to 1.0 ppm of the organophosphate insecticide, Sumithion, Atlantic salmon (Salmo salar) parr were more vulnerable than unexposed fish to prédation by large brook trout (Salvelinus fontinalis). Sumithion at 0.1 ppm, and DDT at 0.07 ppm, had no noticeable effect. The results, particularly for Sumithion, correlate well with previous laboratory work on the effect of insecticides on the learning ability of salmon.


1984 ◽  
Vol 41 (3) ◽  
pp. 469-475 ◽  
Author(s):  
D. M. Rimmer ◽  
U. Paim ◽  
R. L. Saunders

Over three summers we used direct underwater observation to examine the summer to autumn differences in seven microhabitat properties of three age-classes of juvenile Atlantic salmon (Salmo salar) in the Little Sevogle River of northeastern New Brunswick. Salmon of all three age-classes occupied a wide range of water depths during summer, but were concentrated mainly in depths of 24–36 cm. In autumn, they occurred in this range almost exclusively. The streambed stones most closely associated with the individual positions of all ages were always <20 cm in summer and mostly (84–92%) <10 cm in diameter. In autumn, all ages were associated with home stones up to 40 cm in diameter, with 65–83% of the stones exceeding 20 cm; the size of home stones selected increased with fish age in autumn. There was no apparent relationship between the water depth and home stone size distributions occupied by all age-classes and available in the stream during either summer or autumn. Summer focal water velocity (velocity at the fish's snout) was predominantly 10–30 cm∙s−1 for 0+, 10–40 cm∙s−1 for 1+, and 30–50 cm∙s−1 for 2+ salmon, but during autumn it was almost always <10 cm∙s−1 for all ages. The bottom and surface water velocities as well as the maximum water velocity within 1 m of fish stations increased with fish age during summer and autumn. At the summer–autumn transition, 0+ salmon selected higher bottom, surface, and maximum water velocities, 2+ salmon selected lower velocities, but selection by 1+ salmon remained unchanged. We view substrate size followed by water depth as the primary properties influencing stream suitability for juvenile Atlantic salmon in autumn.


2003 ◽  
Vol 60 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Matthew J Raffenberg ◽  
Donna L Parrish

Competitive interactions among stream salmonids in resource-limited environments have been linked to reduced success for many species. Few studies have focused on interactions at scales larger than individual fish or stream reach. We chose to focus our study on these larger scales to provide information for managing species that have complex life histories transcending multiple scales. Our objective was to explore age-0 Atlantic salmon (Salmo salar) growth and survival in relation to trout abundance (introduced rainbow (Oncorhynchus mykiss) and native brook (Salvelinus fontinalis) trout) and prey resources at 24 stream reaches across two Vermont watersheds that flow into the Connecticut River. Simple linear and multilinear regressions were conducted on response and predictor variables related to fish and invertebrate prey. Age-0 Atlantic salmon survival was greatest at the site with highest trout abundance; however, no linear relationships to trout abundance were detected possibly because Atlantic salmon growth and survival were highly variable across sites. In contrast, a positive significant multivariate relationship was identified among age-0 Atlantic salmon survival, the abundance of age-1+ brook trout (i.e., 100–130 mm), and benthic prey abundance. These results suggest that stocking streams based on trout abundance may not increase Atlantic salmon growth and survival during the first summer of life.


1984 ◽  
Vol 41 (2) ◽  
pp. 377-380 ◽  
Author(s):  
P. M. Ryan

The catch per unit effort (CPUE) data of brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo salar) in fyke nets set in two small lakes in central Newfoundland were compared with population densities estimated with Schnabel multiple mark–recapture experiments each spring and fall from 1978 to 1982. The catchability of brook trout did not differ significantly between lakes or seasons, and CPUE was an index of the relative abundance of trout within and between lakes. In contrast, the catchability of Atlantic salmon differed greatly between lakes and varied seasonally, being greater in the spring but less in the fall than the catchability of brook trout. Comparisons of relative salmon abundance between lakes or of the relative abundance of brook trout to Atlantic salmon within or between lakes require a correction for seasonal differences in the catchability of salmon.


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