Lake Trout (Salvelinus namaycush) Growth Potential Predicted from Cisco (Coregonus artedii) Population Structure and Conductivity

1989 ◽  
Vol 46 (9) ◽  
pp. 1531-1538 ◽  
Author(s):  
Edward A. Trippel ◽  
F. William H. Beamish
Keyword(s):  
Lake Trout ◽  
Fork Length ◽  
Growth Efficiency ◽  
Salvelinus Namaycush ◽  
Growth Potential ◽  
Food Sources ◽  
Stepwise Multiple Regression ◽  
Order Of Magnitude ◽  
Mean Size ◽  
Coregonus Artedii

Trophic dynamics between lake trout (Salvelinus namaycush) and cisco (Coregonus artedii) were examined in a set of 10 northwestern Ontario lakes that ranged in conductivity by nearly an order of magnitude. Diets revealed the possibility of interspecific competition for invertebrate prey prior to initiation of piscivory by lake trout at approximately 200 mm fork length (FL). Von Bertalanffy growth equations (based on otolith ages) were used to estimate time to attain this length (1.4–3.0 yr). Contrary to anticipated results, lake trout reached this size more rapidly in lakes with high cisco abundance. Presumably, this relationship was caused by improved food conditions for young trout in some of the more productive waterbodies. However, after removing the collinearity between lake conductivity and nonpiscivorous growth by regression analysis, there was no relationship between the time for lake trout to reach 200 mm and cisco abundance. Piscivorous growth varied (L∞ = 508 to 740 mm) extensively among the 10 populations and was likely a function of growth efficiency from different food sources. Using stepwise multiple regression, 81% of the L∞ variation among lakes was explained by cisco abundance and mean size. Linear regression between L∞ and mean size of trout (but not trout abundance) on conductivity generated significant positive relationships.

Changes in fish populations affected by the construction of the La Grande complex (Phase I), James Bay region, Quebec

1995 ◽  
Vol 73 (10) ◽  
pp. 1860-1877 ◽  
Author(s):  
Jean-Claude DesLandes ◽  
Sylvie Guénette ◽  
Yves Prairie ◽  
Réjean Fortin ◽  
Dominique Roy ◽  
...  
Keyword(s):  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Time Intervals ◽  
Complex Phase ◽  
Coregonus Artedii ◽  
Secondary Productivity ◽  
Longnose Sucker ◽  
The Impact

Catches per unit of effort (CPUE) with experimental gill nets, recruitment, growth, and condition were monitored between 1977 and 1992 to evaluate the impact of impoundment on the main fish species of La Grande 2, Opinaca, and Caniapiscau reservoirs and the Boyd–Sakami diversion. CPUE and recruitment of northern pike (Esox lucius) and lake whitefish (Coregonus clupeaformis) increased markedly at most stations after impoundment and decreased at the end of the series. The lake whitefish and cisco (Coregonus artedii) showed their most striking rise in CPUE at two bay stations of La Grande 2 and Opinaca reservoirs. CPUE and recruitment of the longnose sucker (Catostomus catostomus), white sucker (Catostomus commersoni), and lake trout (Salvelinus namaycush) (Caniapiscau) showed a general decrease following impoundment. CPUE for the walleye (Stizostedion vitreum) also decreased at several stations; however, the two most southerly stations in La Grande 2 reservoir and the Boyd–Sakami station showed high CPUE during the series. Concentration–redistribution phenomena explain part of the observed variations in CPUE. Correlation analyses showed that walleyes and white suckers were attracted to the warmer, more turbid stations, and that the high primary and secondary productivity of bay stations attracted the coregonines. Growth and condition of the main species increased during variable time intervals after impoundment and decreased at the end of the series.

Acidification of the La Cloche Mountain Lakes, Ontario, and Resulting Fish Mortalities

1972 ◽  
Vol 29 (8) ◽  
pp. 1131-1143 ◽  
Author(s):  
Richard J. Beamish ◽  
Harold H. Harvey
Keyword(s):  
Sulfur Dioxide ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Mountain Lakes ◽  
Single Source ◽  
Catostomus Commersoni ◽  
General Study ◽  
Ph Measurements ◽  
Coregonus Artedii ◽  
Lake Herring

The loss of populations of lake trout (Salvelinus namaycush), lake herring (Coregonus artedii), white suckers (Catostomus commersoni), and other fishes in Lumsden Lake was attributed to increasing levels of acidity within the lake. An absence of fishes was also observed in nearby lakes. In some lakes, acid levels have increased more than one hundredfold in the last decade. The increases in acidity appear to result from acid fallout in rain and snow. The largest single source of this acid was considered to be the sulfur dioxide emitted by the metal smelters of Sudbury, Ont.In 1971, pH measurements were taken from 150 lakes in the general study area 65 km southwest of Sudbury. Some 33 of these lakes showed a pH of less than 4.5 and were described as "critically acidic." An additional 37 lakes had a pH in the range of 4.5–5.5 and were termed "endangered" lakes.

Long-Term Effects of Diet on the Biology of the Lake Trout and the Fishery in Lake Opeongo, Ontario

1970 ◽  
Vol 27 (1) ◽  
pp. 125-146 ◽  
Author(s):  
N. V. Martin
Keyword(s):  
Lake Trout ◽  
Feeding Activity ◽  
Salvelinus Namaycush ◽  
Point Of View ◽  
Average Weight ◽  
Coregonus Clupeaformis ◽  
Long Term Effects ◽  
Food Content ◽  
Coregonus Artedii

From 1936 to 1965 food content was examined in 17,171 Lake Opeongo lake trout (Salvelinus namaycush). The diet is analysed from the point of view of frequency of occurrence of foods, their weight, feeding activity of trout, size of trout and size of food, and seasonal and annual changes in food habits.In the late 1940's and early 1950's perch, Perca flavescens, largely disappeared from the diet. The lake trout initially turned to lake whitefish, Coregonus clupeaformis, and then to the cisco, Coregonus artedii, introduced into Lake Opeongo in 1948.As a result of these dietary changes lake trout are now heavier and rate of growth has improved. Age and size at maturity is later and there are fewer infertile fish. Egg counts, egg size, and ovary weights are now greater, particularly in the medium-sized lake trout.In the fishery the average weight of individual trout taken has almost doubled. About 25% more of the immature stock is exploited by the recent fishery. The harvest and catchability of lake trout has remained generally constant on a numerical basis but show an improvement on a poundage basis in the more recent years. The possible effects of these changes on the character of the fishery are discussed.

Predation by Freshwater Seals on the Fish Community of Lower Seal Lake, Quebec

1978 ◽  
Vol 35 (6) ◽  
pp. 844-850 ◽  
Author(s):  
G. Power ◽  
Jean Gregoire
Keyword(s):  
Brook Trout ◽  
Fish Community ◽  
Lake Trout ◽  
Fork Length ◽  
Salvelinus Namaycush ◽  
Phoca Vitulina ◽  
Unit Weight ◽  
Potential Yield ◽  
Spawning Period ◽  
Show Evidence

The presence of freshwater harbor seals (Phoca vitulina) in Lower Seal Lake, Quebec, has drastically modified the lake's fish community. Lake trout (Salvelinus namaycush) are the most affected; they are small (rarely exceed 55 cm fork length), their growth rate is faster than in neighboring lakes, their longevity is greatly reduced, the age at sexual maturity has been halved, and individual fecundity per unit weight has increased at the expense of egg diameter. Brook trout (S. fontinalis), the dominant fish species in the lake, show evidence of high mortality rates in the lake, but are protected during the vulnerable spawning period because their spawning sites are dispersed in tributary streams. Rough calculation suggests the seal population is small and that it consumes the lake's potential yield of fish annually. Key words: predation, freshwater seals, Phoca vitulina, Salvelinus namaycush, Salvelinus fontinalis

A Simulation Model of Lake Trout Growth

1971 ◽  
Vol 28 (6) ◽  
pp. 815-819 ◽  
Author(s):  
S. R. Kerr
Keyword(s):  
Simulation Model ◽  
Growth Model ◽  
Lake Trout ◽  
Growth Efficiency ◽  
Equation System ◽  
Growth Increments ◽  
Predator Size ◽  
Mean Size ◽  
The Mean

Kerr (J. Fish. Res. Bd. Canada 28: 809–814, 1971) described an equation system based upon metabolic constraints and foraging limitations that predicts level of rations and growth efficiency as a function of the availability of the prey resource. An algorithm that extends the equation system to a growth model is described here. With reference to increasing predator size, and to the mean size and abundance of prey, the model computes successive growth increments while holding the equations to the configuration that maximizes the ratio of growth efficiency to rations. When given information on the mean size and density of prey organisms, the model accurately predicts observed patterns of lake trout growth.

Relationship of Mercury Concentrations in Lake Trout (Salvelinus namaycush) and Smallmouth Bass (Micropterus dolomieui) to the Physical and Chemical Characteristics of Ontario Lakes

1989 ◽  
Vol 46 (3) ◽  
pp. 426-434 ◽  
Author(s):  
Michael J. McMurtry ◽  
Donna L. Wales ◽  
Wolfgang A. Scheider ◽  
Gail L. Beggs ◽  
Patricia E. Dimond
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Lake Trout ◽  
Water Hardness ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Stepwise Multiple Regression ◽  
Lake Area ◽  
Micropterus Dolomieui ◽  
The Relationship

Concentrations of mercury in dorsal muscle tissue of lake trout (Salvelinus namaycush) from Ontario lakes were positively correlated with variables indicating lake dystrophy (dissolved organic carbon, colour, iron, transparency) and were also correlated with watershed area and lake area. Stepwise multiple regression selected dissolved organic carbon as the only variable which explained a significant amount of variation (37%) in mercury concentrations in lake trout. The relationship between dissolved organic carbon and mercury appeared to be strongest in the group of lakes with values of dissolved organic carbon less than 4.0 mg∙L−1. In contrast, mercury concentrations in smallmouth bass (Micropterus dolomieui) were correlated with variables reflecting both water hardness (magnesium, calcium, conductivity) and acidity (pH, alkalinity). The relationship was inverse for the water hardness variables and positive for acidity. Stepwise regression identified three variables significant in explaining variation in mercury in smallmouth bass: calcium, dissolved organic carbon, and latitude. Mechanisms that may explain the effects of organic matter, water hardness, and acidity on mercury accumulation by fish are discussed.

Effects of forestry roads on reproductive habitat and exploitation of lake trout (Salvelinus namaycush) in three experimental lakes

2000 ◽  
Vol 57 (S2) ◽  
pp. 97-104 ◽  
Author(s):  
John M Gunn ◽  
Rod Sein
Keyword(s):  
Lake Trout ◽  
Natural Populations ◽  
Fork Length ◽  
Salvelinus Namaycush ◽  
Spawning Habitat ◽  
Trout Population ◽  
Access Road ◽  
Short Term Study ◽  
Opaque Plastic ◽  
Spawning Sites

This study was designed to test the effects of two potential impacts of forest access roads on lake trout (Salvelinus namaycush) lakes in the Boreal Shield ecozone: (i) loss of reproductive habitat through siltation and (ii) increased access and exploitation. During an 9-year study (1991-1999) in Whitepine Lake, access to seven original spawning sites and over 250 alternate spawning sites was progressively removed by covering the substrate with opaque plastic sheeting to simulate siltation. No effects on recruitment of lake trout have yet been detected. Mark-recapture estimates of juvenile (<370 mm fork length) abundance remained high, mean body size did not increase, and emergent alevins continued to be produced from the alternate spawning sites each year. Similar results occurred in a short-term study in Helen Lake. The lack of obvious effects of reproductive habitat loss was in sharp contrast with the rapid and severe effects that fishing pressure exerted on the lake trout population in Michaud Lake where access was improved by construction of a 12-km forest access road. These findings suggest that lake trout can tolerate substantial losses in spawning habitat, but natural populations, particularly in small lakes, must be protected from excessive exploitation.

Limnological and Biological Observations in the Region of the Ungava or Chubb Crater, Province of Quebec

1955 ◽  
Vol 12 (4) ◽  
pp. 487-498 ◽  
Author(s):  
N. V. Martin
Keyword(s):  
Deep Water ◽  
Vascular Plants ◽  
Crater Lake ◽  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Fork Length ◽  
Salvelinus Namaycush ◽  
Surface Oxygen ◽  
Secchi Disc ◽  
Total Solids

Ungava Crater Lake, at 73° 41′ W.L. and 61° 17′ N.L., lies in a meteoritic crater of the northern Quebec tundra. The lake is nearly circular, 1.7 miles in diameter, with steep walls and a maximum known depth of 825 feet. Secchi disc transparency was 35 metres. Summer surface temperatures were 3–4 °C., of the deep water a little less. Surface oxygen was abundant, pH was 6.5–6.6. Total solids in the water were less than 20 parts per million, and hardness was only 1.7 p.p.m. Three kinds of mammals and 14 of birds were found in the crater region. Arctic char, Salvelinus alpinus, were the only fish taken in the crater lake. Specimens up to 21.8 inches fork length and 18 years old were taken; they fed on insects and other char. Char in other nearby waters grew somewhat faster but ate the same foods; mature females as small as 4.0 inches were seen. Lake trout, Salvelinus namaycush, in a lake near the crater reached 33.5 inches and 15.8 pounds. Growth was very slow, the greatest age determined being 21 years, at 13 pounds. Twenty-nine species of vascular plants were collected close to the crater.

scholarly journals Influence of food web structure on the growth and bioenergetics of lake trout (Salvelinus namaycush)

2002 ◽  
Vol 59 (10) ◽  
pp. 1593-1605 ◽  
Author(s):  
Ivano Pazzia ◽  
Marc Trudel ◽  
Mark Ridgway ◽  
Joseph B Rasmussen
Keyword(s):  
Lake Trout ◽  
Assimilation Efficiency ◽  
Growth Efficiency ◽  
Salvelinus Namaycush ◽  
Fish Growth ◽  
Energy Budgets ◽  
Caloric Content ◽  
Food Web Structure ◽  
Metabolic Costs ◽  
Consumption Rates

In this study, we compared energy budgets of lake trout (Salvelinus namaycush) populations in contrasting food webs. Nonpiscivorous lake trout (NPLT) reached a much smaller size and grew at a much slower rate than piscivorous lake trout (PLT) populations. Food consumption rates were, on average, 2–3 times higher in NPLT when they were expressed on a wet weight basis. However, only a slight (less than 10%) difference in their energy intake was detected once consumption rates were corrected for differences in prey caloric content. Growth efficiency was approximately two times lower in NPLT compared with PLT, while their metabolic costs were higher and their assimilation efficiency was lower. It is most likely that the increased metabolic costs were associated with higher foraging costs, since more feeding attempts must be made to acquire a given quantity of food when fish are feeding on smaller prey. Furthermore, the portion of indigestible matter is likely to be higher in the diet of NPLT than in PLT (i.e., chitin vs. bone). These results are consistent with theoretical models of fish growth that show that lake trout must have access to larger prey, even if they are rare, to reach larger body sizes.

Quantifying importance of marine prey in the diets of two partially anadromous fishes

2011 ◽  
Vol 68 (11) ◽  
pp. 2020-2028 ◽  
Author(s):  
Heidi K. Swanson ◽  
Karen A. Kidd ◽  
James D. Reist
Keyword(s):  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Salvelinus Namaycush ◽  
Arctic Char ◽  
Food Sources ◽  
Future Research ◽  
Anthropogenic Stressors ◽  
Trout Population ◽  
Marine Food ◽  
Pelagic Prey

The importance of marine prey sources for partially anadromous fishes has received little study and is complicated by considerable plasticity in life history. We determined proportional contributions of marine, freshwater benthic, and freshwater pelagic prey to anadromous and resident Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush) from several partially anadromous populations in the Canadian Arctic. Bayesian mixing models (MixSIR) applied to δ34S and δ13C ratios in lake-specific models indicated that marine prey accounted for 90%–91% of anadromous Arctic char diet and 60%–66% of anadromous lake trout diet. When these estimates were combined with proportion of anadromous individuals in partially anadromous populations, marine food sources accounted for 31%–44% of Arctic char population productivity and 16%–26% of lake trout population productivity. Although future research is needed to refine and quantify variability around these estimates, our results will allow better predictions of the effects of anthropogenic stressors on partially anadromous fishes.

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