Trout Production and Eels in Bill Lake, Saguenay County, Quebec

1973 ◽  
Vol 30 (9) ◽  
pp. 1398-1401 ◽  
Author(s):  
J. F. O’Connor ◽  
G. Power
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Annual Production ◽  
Anguilla Rostrata ◽  
Apparent Position ◽  
Trout Population ◽  
American Eels

Competition and predation by American eels (Anguilla rostrata) is believed to have substantially reduced trout population and production in Bill Lake. Brook trout (Salvelinus fontinalis) occurred at densities of 7/ha; biomass of 0.34 kg/ha and annual production was estimated at 0.21 kg/ha. This is considerably less than values for trout density, biomass, and production in other lakes in the Matamek watershed from which eels appear to be absent. Eels in Bill Lake are old and large but not numerous, in keeping with their apparent position as top carnivores.

Experimental Plantings of Brook Trout (Salvelinus fontinalis) from Furunculosis-Infected Stock

1968 ◽  
Vol 25 (12) ◽  
pp. 2643-2649 ◽  
Author(s):  
L. A. McDermott ◽  
A. H. Berst
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Infected Fish ◽  
Aeromonas Salmonicida ◽  
Control Fish ◽  
Southern Ontario ◽  
Trout Population ◽  
Hatchery Stock ◽  
Associated Species ◽  
Made In

Preliminary sampling revealed the presence of furunculosis disease in the resident brook trout population of the southern Ontario trout stream used in this study.Two plantings of marked yearling brook trout were made in the study area in 1966; one in the spring, and the other in the fall. The spring planting consisted of 1000 brook trout with a predetermined incidence of furunculosis infection and an equal number of trout with no evidence of infection. The fall planting consisted of 2000 brook trout with a known incidence of furunculosis infection.The stream was electrofished periodically during the 2-year period after the first planting. A total of 445 brook trout (140 of the planted hatchery stock, and 305 resident trout) and 127 fish of associated species were captured and examined for the presence of Aeromonas salmonicida, causative agent of furunculosis.Recovery rates of the "infected" and "noninfected" stocks of brook trout were similar, and there was no evidence of transmission of A. salmonicida from the infected fish to the control fish, nor the resident population of brook trout and other species of fish captured.

scholarly journals Brook trout (Salvelinus fontinalis) extinction in small boreal lakes revealed by ephippia pigmentation: a preliminary analysis

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Alexandre Bérubé Tellier ◽  
Paul E. Drevnick ◽  
Andrea Bertolo
Keyword(s):  
Brook Trout ◽  
Fish Assemblages ◽  
Salvelinus Fontinalis ◽  
Sediment Cores ◽  
Experimental Studies ◽  
Cost Effective ◽  
Fish Predation ◽  
Boreal Lakes ◽  
Predation Pressure ◽  
Trout Population

<p>Ephippium pigmentation is a plastic trait which can be related to a trade-off between visual predation pressure and better protection of cladoceran eggs against different types of stress. Experimental studies showed that planktivorous fish exert a greater predation pressure on individuals carrying darker ephippia, but little is known about the variation of ephippium pigmentation along gradients of fish predation pressure in natural conditions. For this study, our experimental design included four small boreal lakes with known fish assemblages. Two of the lakes have viable brook trout (<em>Salvelinus fontinalis</em>) populations, whereas the other two lakes experienced brook trout extinctions during the 20<sup>th</sup> century. Cladoceran ephippia were extracted from sediment cores at layers corresponding to the documented post- extinction phase (1990's) and from an older layer (1950's) for which the brook trout population status is not known precisely. Our first objective was to determine whether brook trout extinction has a direct effect on both ephippium pigmentation and size. Our second objective was to give a preliminary assessment of the status of brook trout populations in the 1950's by comparing the variation in ephippia traits measured from this layer to those measured in the 1990's, for which the extinction patterns are well known. Cost-effective image analysis was used to assess variation in pigmentation levels in ephippia. This approach provided a proxy for the amount of melanin invested in each ephippium analysed. Our study clearly shows that ephippium pigmentation may represent a better indicator of the presence of fish predators than ephippium size, a trait that showed a less clear pattern of variation between lakes with and without fish. For the 1990's period, ephippia from fishless lakes were darker and showed a slight tendency to be larger than ephippia from lakes with brook trout. However, no clear differences in either ephippium size or pigmentation were observed between the 1990's and 1950's layers within each lake. This suggests that brook trout extinction already occurred before the 1950’s, or that brook trout population abundance was already extremely low before and after the 1990’s. Our preliminary study shows that ephippium pigmentation can be used as a tool to quickly assess present and past predation levels on zooplankton when only sediment samples are available.</p>

Brook Trout (Salvelinus fontinalis) Population Structure in Acidified Lac Tantaré, Quebec

1984 ◽  
Vol 41 (6) ◽  
pp. 865-877 ◽  
Author(s):  
Jean-Jacques Frenette ◽  
Julian J. Dodson
Keyword(s):  
Population Structure ◽  
Brook Trout ◽  
Sexual Maturity ◽  
Reproductive Effort ◽  
Salvelinus Fontinalis ◽  
Individual Growth ◽  
Toxic Stress ◽  
Age Classes ◽  
Recruitment Failure ◽  
Trout Population

To present evidence of acid-induced stress, we studied the population structure and distribution of brook trout (Salvelinus fontinalis) in acidified Lac Tantaré, Quebec. Trout greater than 21 cm (FL) represented only 16.2 and 10% of the population sampled in 1979 and 1980, respectively. Survival rates of trout from 1979 to 1980 indicated higher survival among individuals > 25 cm, mortality occurring primarily among fish of 13–25 cm. The marked decline in numbers of fish occurring at 21 cm coincided with the size at which 50% of the female trout population reached sexual maturity, suggesting that postspawning mortality contributes to the high mortality observed among these fish. Comparisons of population and individual growth rates revealed that smaller fish of age-classes 1 to 5 suffer higher mortality than do the larger individuals of these age-classes, implicating mortality agents other than those related to spawning. We provide evidence to support the hypothesis that the most probable cause of mortality is size-related differential exposure to toxic stress whereby small brook trout (< 25 cm) are found in lake areas (brooks) exhibiting the most potentially toxic combination of pH and aluminum, thus enhancing the exposure of the most susceptible part of the population to toxic stress. Large brook trout [Formula: see text] are found in the "safest" lake areas (springs), thus diminishing the exposure of the least susceptible part of the population to toxic stress and enhancing survival. Female trout exhibit delayed sexual maturity relative to other Quebec populations, attaining 50% maturity at age 3 and a length of 21–24 cm such that the major part of the population's reproductive effort is provided by those fish representing only 15% of the population in 1979 and 1980. During the October spawning season, 20% of potential spawners exhibited retarded oogenesis. These reductions in reproductive effort and changes in spawning site selection provide evidence in support of the hypothesis that recruitment failure may be occurring in the Tantaré brook trout population.

Resource partitioning between brook trout (Salvelinus fontinalis Mitchill) and creek chub (Semotilus atromaculatus Mitchill) in selected oligotrophic lakes of southern Quebec

1982 ◽  
Vol 60 (7) ◽  
pp. 1612-1617 ◽  
Author(s):  
Pierre Magnan ◽  
Gérard J. FitzGerald
Keyword(s):  
Spatial Distribution ◽  
Resource Partitioning ◽  
Brook Trout ◽  
Food Habits ◽  
Salvelinus Fontinalis ◽  
Niche Shift ◽  
Sympatric Populations ◽  
Semotilus Atromaculatus ◽  
Trout Population ◽  
Creek Chub

The spatial distribution, food habits, and growth of an allopatric brook trout (Salvelinus fontinalis) population was compared with a trout population coexisting with creek chub (Semotilus atromaculatus). Sympatric trout differed in spatial distribution and food habits from allopatric trout suggesting a niche shift of the trout when they live with creek chub. Also, although there is a certain overlap in diet and spatial distribution, sympatric populations of the two species differed on these resource axes. However, growth of sympatric trout is not clearly related to the presence or absence of the creek chub, suggesting that factors other than interspecific competiton may affect growth in the seven study lakes.

Impact of Brook Trout (Salvelinus fontinalis) Predation on the Crayfish Orconectes virilis in Three Michigan Lakes

1979 ◽  
Vol 36 (10) ◽  
pp. 1191-1196 ◽  
Author(s):  
H. Gowing ◽  
W. T. Momot
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
First Year ◽  
Orconectes Virilis ◽  
Trout Population ◽  
Production Growth ◽  
First Year Of Life ◽  
The Cost ◽  
Slow Growing ◽  
Northern Michigan

The crayfish Orconectes virilis is a major component of the benthos of three small lakes in northern Michigan. These lakes contained stocked brook trout (Salvelinus fontinalis) populations (age-0 and age-I) at densities of 188, 411, and 1398 fish/ha. Crayfish were preyed upon by brook trout, but only during their first year of life. Two-year production of age-0 crayfish was approximately 94 kg in each lake; brook trout consumed only about 1–2% in lakes with lower density offish. Even with greater trout density and accompanying higher rate of exploitation (40%), there was no impact on recruitment of young crayfish because compensatory mortality of crayfish occurred in lakes with less trout predation. However, stocking trout at higher densities decreased trout growth and condition. While 2-yr production was highest (59 kg/ha) in the lake stocked at the highest density and lowest (17 kg/ha) in one stocked at the lowest density, the former was achieved at the cost of a very slow growing trout population. Most of the crayfish production is not utilized as trout food but enters the non-predatory pool of detrital organic matter. Key words: Orconectes virilis, brook trout, predation, production growth, mortality

Upstream movement by nonnative brook trout (Salvelinus fontinalis) promotes invasion of native cutthroat trout (Oncorhynchus clarki) habitat

2003 ◽  
Vol 60 (12) ◽  
pp. 1502-1516 ◽  
Author(s):  
Douglas P Peterson ◽  
Kurt D Fausch
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Cutthroat Trout ◽  
Early Summer ◽  
Oncorhynchus Clarki ◽  
Mature Adults ◽  
Trout Population ◽  
Population Spread ◽  
Local Movement ◽  
Similar Body

To understand how immigration and emigration influence the processes by which invading nonnative brook trout (Salvelinus fontinalis) displace native cutthroat trout (Oncorhynchus clarki), we studied trout movement in long segments of three mountain streams in Colorado during 1999–2001. Over 3500 trout were captured and marked at weirs and during electrofishing, both within and downstream of stream segments. Nearly 80% of brook trout captured at weirs were moving upstream, whereas almost 65% of cutthroat trout were moving downstream. Brook trout movements peaked in early summer and again in fall. Brook trout immigration rates from downstream source populations were high, and in one stream, invaders repopulated a segment where they were removed within 8 months. Immigrant brook trout were typically mature adults in similar body condition to the general population. Brook trout immigrated from a range of distances, with local movement within 250 m more frequently detected, but fish also moved from many distances up to 2 km away within a summer. Brook trout encroachment and invasion was characterized by a wave of local movement exerting biotic pressure on the downstream limit of the cutthroat trout population and jump dispersers moving upstream beyond the invasion front promoting rapid population spread.

Chemically mediated avoidance behavior in wild brook trout, Salvelinus fontinalis: the response to familiar and unfamiliar predaceous fishes and the influence of fish diet

1992 ◽  
Vol 70 (2) ◽  
pp. 288-292 ◽  
Author(s):  
MaryLouise Keefe
Keyword(s):  
Atlantic Salmon ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Predatory Fish ◽  
Behavior Patterns ◽  
Fish Diet ◽  
Wild Populations ◽  
American Eel ◽  
Juvenile Trout ◽  
American Eels

Choice experiments were used to determine whether juvenile wild brook trout would avoid chemical traces of predaceous fishes found in their native stream; the fishes used were the red fin pickerel (Esox americanus) and American eel (Anguilla rostrata), and a predaceous fish with which the trout had no prior experience, the Atlantic salmon (Salmo salar). Juvenile trout avoided pickerel odors but did not avoid water conditioned by American eels. They also avoided water conditioned with Atlantic salmon. A second experiment using trout from two wild populations demonstrated that the brook trout's avoidance of Atlantic salmon was a response to the salmon's piscivorous diet. These results suggest that brook trout do not avoid odors of all predaceous fishes and are capable of altering their behavior patterns in response to a change in the diet of a predatory fish.

scholarly journals Deep Learning for Automated Detection and Identification of Migrating American Eel Anguilla rostrata from Imaging Sonar Data

2021 ◽  
Vol 13 (14) ◽  
pp. 2671
Author(s):  
Xiaoqin Zang ◽  
Tianzhixi Yin ◽  
Zhangshuan Hou ◽  
Robert P. Mueller ◽  
Zhiqun Daniel Deng ◽  
...  
Keyword(s):  
Deep Learning ◽  
Fish Passage ◽  
Automated Detection ◽  
Anguilla Rostrata ◽  
Automated Method ◽  
Detection And Identification ◽  
And Migration ◽  
Imaging Sonar ◽  
American Eels ◽  
Deep Learning Model

Adult American eels (Anguilla rostrata) are vulnerable to hydropower turbine mortality during outmigration from growth habitat in inland waters to the ocean where they spawn. Imaging sonar is a reliable and proven technology for monitoring of fish passage and migration; however, there is no efficient automated method for eel detection. We designed a deep learning model for automated detection of adult American eels from sonar data. The method employs convolution neural network (CNN) to distinguish between 14 images of eels and non-eel objects. Prior to image classification with CNN, background subtraction and wavelet denoising were applied to enhance sonar images. The CNN model was first trained and tested on data obtained from a laboratory experiment, which yielded overall accuracies of >98% for image-based classification. Then, the model was trained and tested on field data that were obtained near the Iroquois Dam located on the St. Lawrence River; the accuracy achieved was commensurate with that of human experts.

Parasite-induced susceptibility to predation in diplostomiasis

Parasitology ◽  
1982 ◽  
Vol 85 (3) ◽  
pp. 495-501 ◽  
Author(s):  
P. Brassard ◽  
M. E. Rau ◽  
M. A. Curtis
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Marked Decrease ◽  
Infected Fish ◽  
Induced Susceptibility ◽  
Diplostomum Spathaceum

Guppies (Lebistes reticulatis) exposed to doses as low as 25 cercariae of Diplostomum spathaceum for 30 min were consistently and significantly more susceptible to predation by brook trout (Salvelinus fontinalis) than uninfected controls. The increase in susceptibility to predation was correlated with a marked decrease in the activity of infected fish.

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