Optimal Use of Creel Survey Data in Assessing Population Behaviour: Lake Opeongo Lake Trout (Salvelinus namaycush) and Smallmouth Bass (Micropterus dolomieui), 1936–83

1987 ◽  
Vol 44 (S2) ◽  
pp. s229-s238 ◽  
Author(s):  
B. J. Shuter ◽  
J. E. Matuszek ◽  
H. A. Regier
Keyword(s):  
Lake Trout ◽  
Total Mortality ◽  
Salvelinus Namaycush ◽  
Fish Population ◽  
Smallmouth Bass ◽  
Fishing Mortality ◽  
Assessment Data ◽  
Creel Survey ◽  
Micropterus Dolomieui ◽  
Independent Assessment

Creel survey and independent assessment data on the lake trout (Salvelinus namaycush) and smallmouth bass (Micropterus dolomieui) populations of Lake Opeongo were evaluated. Annual estimates of total mortality, fishing mortality, and abundance were generated for each population over the period 1936–83. Large variations in survey efficiency, angler efficiency, fishing mortality, and abundance were identified over this period. We argue that a creel survey, which is expected to provide reliable information on fish population dynamics, requires an overall study design which includes collection of data on the number and relative efficiency of different kinds of anglers and periodic assessment studies aimed at providing independent checks on both survey effectiveness and population behaviour.

Limnological Characteristics of Ontario Lakes in Relation to Associations of Walleye (Stizostedion vitreum vitreum), Northern Pike (Esox lucius), Lake Trout (Salvelinus namaycush), and Smallmouth Bass (Micropterus dolomieui)

1977 ◽  
Vol 34 (10) ◽  
pp. 1592-1601 ◽  
Author(s):  
M. G. Johnson ◽  
J. H. Leach ◽  
C. K. Minns ◽  
C. H. Olver
Keyword(s):  
Lake Trout ◽  
Climatic Factors ◽  
Low Frequency ◽  
Northern Pike ◽  
Esox Lucius ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Stizostedion Vitreum ◽  
Pike Esox Lucius ◽  
Micropterus Dolomieui

Commonest lake types of the 15 combinations of four fish species (walleye, Stizostedion vitreum vitreum; northern pike, Esox lucius; lake trout, Salvelinus namaycush and smallmouth bass, Micropterus dolomieui) were walleye–pike (22%), pike "only" (19%), lake trout "only" (16%) and smallmouth bass "only" (10%). Lake trout–walleye and lake trout–walleye–smallmouth bass types were extremely rare. Lake depth and area were variables of greatest significance in distinguishing lake types by discriminant analysis. Climatic factors explained the general geographic distribution of smallmouth bass. Hypotheses to explain the low frequency of walleye in small lakes include possibilities of (1) low probability of successful coexistence of pike and walleye, (2) lack of wind fetch to clear spawning areas, and (3) "Lebensraum requirement" of the walleye. Key words: limnology, Percidae, methodology, Ontario lake types, Stizostedion vitreum vitreum, Esox lucius, Salvelinus namaycush, Micropterus dolomieui, distribution, associations

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.

Estimate of Lamprey-Induced Mortality in a Lake Trout (Salvelinus namaycush) Population

1980 ◽  
Vol 37 (11) ◽  
pp. 2151-2158 ◽  
Author(s):  
William D. Youngs
Keyword(s):  
Lake Trout ◽  
Risk Model ◽  
Age Groups ◽  
Total Mortality ◽  
Salvelinus Namaycush ◽  
Likelihood Method ◽  
Fishing Mortality ◽  
Regression Methods ◽  
Trout Population ◽  
Cayuga Lake

A competing risk model was applied to mortality occurring in a lake trout population subjected to fishing and lamprey parasitism. Two indices are proposed as a measure of lamprey-induced mortality in the lake trout (Salvelinus namaycush) population: the average number of wounds per fish (W/F) and the average number of scars per fish (S/F) accumulated by a cohort over a period of 1 yr. These indices were used as a measure of the force of lamprey-induced mortality. Fishing mortality was estimated from angler returns of tags on lake trout. Tag returns were also used in a maximum likelihood method to estimate survival of lake trout. Fishing and lamprey-induced mortality components of the model were analyzed by linear regression methods with the force of total mortality (i) as the independent variable. The component for lamprey-induced mortality (either W/F or S/F) did not contribute significantly to the reduction in variation of the force of total mortality, but the component for fishing mortality was significant. A negative coefficient for some analyses associated with the component for lamprey-induced mortality suggested a possible conditioning influence by other factors. Growth of lake trout was examined as a possible conditioning factor but analyses suggested that growth did not influence survival. Lamprey did not apparently cause any appreciable mortality in the lake trout population, age 4 and older, in Cayuga Lake during the years studied. It was not possible to consider younger age-groups of lake trout. Keywords: lake trout, lamprey, mortality

Impacts of road access on lake trout (Salvelinus namaycush) populations: regional scale effects of overexploitation and the introduction of smallmouth bass (Micropterus dolomieu)

2009 ◽  
Vol 66 (2) ◽  
pp. 212-223 ◽  
Author(s):  
Scott D. Kaufman ◽  
Ed Snucins ◽  
John M. Gunn ◽  
Wayne Selinger
Keyword(s):  
Lake Trout ◽  
Scale Effects ◽  
Regional Scale ◽  
Winter Season ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Excessive Pressure ◽  
Fishing Activity ◽  
Remote Lakes

In lake trout ( Salvelinus namaycush ) lakes of northeastern Ontario, Canada, aerial surveys of fishing activity on individual lakes (N = 589) and quantitative gillnet surveys (N = 65) were used to assess the effects of road access on angling effort and the presence of introduced smallmouth bass ( Micropterus dolomieu ). Angling effort, particularly during the open-water season, was highest and often exceeded estimated sustainable levels on lakes with good road access. Approximately 25% of the remote lakes also received excessive pressure during the winter season. Angler numerical responses to lake trout abundance were detected in remote lakes, but not in road-accessible lakes. Smallmouth bass were more prevalent in lakes with road access and human settlement (either cottages or lodges), supporting the theory that they were introduced into these lakes. Lake trout populations were depleted throughout much of the study range. Even without road access or smallmouth bass, lake trout abundance was still 47% lower than in unexploited reference lakes. When bass and (or) road access were present, lake trout abundance decreased by 77%. Remote lake trout populations in this area are clearly vulnerable to the negative impacts of improved access, a vector for both overexploitation and species introductions.

An Energetics Model for Lake Trout, Salvelinus namaycush: Application to the Lake Michigan Population

1983 ◽  
Vol 40 (6) ◽  
pp. 681-698 ◽  
Author(s):  
Donald J. Stewart ◽  
David Weininger ◽  
Donald V. Rottiers ◽  
Thomas A. Edsall
Keyword(s):  
Lake Michigan ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
High Energy ◽  
Alosa Pseudoharengus ◽  
Fishing Mortality ◽  
Age Classes ◽  
Short Term ◽  
Conversion Efficiencies

An energetics model is implemented for lake trout, Salvelinus namaycush, and applied to the Lake Michigan population. It includes an egestion function allowing any proportional mix of fish and invertebrates in the diet, a growth model accounting for both ontogenetic and seasonal changes in energy-density of predator and prey, a model for typical in situ swimming speed, and reproductive energy losses due to gametes shed. Gross conversion efficiency of energy by lake trout over their life (21.8%) is about twice the efficiency of converting biomass to growth because they store large amounts of high-energy fats. Highest conversion efficiencies are obtained by relatively fast-growing individuals, and over half the annual energy assimilated by older age-classes may be shed as gametes. Sensitivity analysis indicates a general robustness of the model, especially for estimating consumption by fitting a known growth curve. Largest sensitivities were for the intercept and weight dependence coefficients of metabolism. Population biomass and associated predatory impact of a given cohort increase steadily for about 3.5 yr then decline steadily after fishing mortality becomes important in the fourth year in the lake. This slow response time precludes manipulation of lake trout stocking densities as a means to control short-term prey fluctuations. Predation by lake trout on alewife, Alosa pseudoharengus, has been increasing steadily since 1965 to about 8 400 t∙yr−1, and is projected to rise to almost 12 000 t∙yr−1 by 1990.

Lake Opeongo: Effects of Exploitation and Introductions on the Salmonid Community

1972 ◽  
Vol 29 (6) ◽  
pp. 795-805 ◽  
Author(s):  
N. V. Martin ◽  
F. E. J. Fry
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Lake Trout ◽  
Total Mortality ◽  
Smallmouth Bass ◽  
Fishing Pressure ◽  
Sport Fishery ◽  
Trout Population ◽  
Lake Waters

Lake Opeongo, a 58.6 km2 lake in the highlands of Algonquin Park, Ontario, has been under study since 1936. Due to little human development of the area, environmental conditions have been stable but because of its geological setting and location the lake waters are relatively unproductive.The smallmouth bass introduced in 1928 has had no apparent major impact on the salmonid community but has served to buffer fishing pressure on the lake trout. The cisco introduction in 1948 resulted in faster growing, better conditioned, and more fecund lake trout but has also contributed to their later maturity. Weight production of trout increased and in recent years stronger classes have apparently resulted from the improvement in fecundity. Declines in the perch and benthic insects and a decrease in growth rate of certain fishes since the mid-1950s are apparently related to the cisco introduction.Harvest of lake trout by the sport fishery has varied from 630 to 2700 fish/year representing a long term yield of 0.33 kilos/ha. Mean total mortality rate is 50%/year and exploitation has served to double the mortality rate after the trout have entered the fishery. Year-class production is correlated with spawning escapement and exploitation has limited recruitment to the trout population.

Changes in Mortality of Lake Trout (Salvelinus namaycush) in Michigan Waters of Lake Superior in Relation to Sea Lamprey (Petromyzon marinus) Predation, 1968–78

1980 ◽  
Vol 37 (11) ◽  
pp. 2063-2073 ◽  
Author(s):  
Richard L. Pycha
Keyword(s):  
Fishery Management ◽  
Lake Trout ◽  
Lake Superior ◽  
Petromyzon Marinus ◽  
Total Mortality ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Catch Per Unit Effort ◽  
Instantaneous Rate ◽  
Unit Effort

Total mortality rates of lake trout (Salvelinus namaycush) of age VII and older from eastern Lake Superior were estimated from catch curves of age distributions each year in 1968–78. The instantaneous rate of total mortality Z varied from 0.62 to 2.31 in close synchrony with sea lamprey (Petromyzon marinus) wounding rates on lake trout. The regression of transformed Z on the index of lamprey wounding, accounted for over 89% of the variation in lake trout mortality (r2 = 0.893). An iterative method of estimating rates of exploitation u, instantaneous rates of fishing mortality F, K (a constant relating sample catch per unit effort to population size), instantaneous normal natural mortality rate M, and instantaneous rate of mortality due to sea lamprey predation L from the sample catch per unit effort and total catch by the fishery is presented. A second method using the results of a 1970–71 tagging study to estimate the mean F in 1970–77 yielded closely similar results to the above and is presented as corroboration. The estimates of u, F, and M appear to be reasonable. F ranged from 0.17 in 1974 to 0.42 in 1969 and M was estimated at 0.26. L varied from 0.21 in 1974 to 1.70 in 1968. Management implications of various policies concerning sea lamprey control, exploitation, and stocking are discussed.Key words: lake trout, sea lamprey, lamprey control, mortality, predation, Lake Superior, fishery, management

Decline and Recovery of the Lake Superior Gull Island Reef Lake Trout (Salvelinus namaycush) Population and the Role of Sea Lamprey (Petromyzon marinus) Predation

1980 ◽  
Vol 37 (11) ◽  
pp. 2074-2080 ◽  
Author(s):  
Bruce L. Swanson ◽  
Donald V. Swedberg
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Petromyzon Marinus ◽  
Total Mortality ◽  
Mortality Rates ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Steady Increase ◽  
Egg Deposition

The Gull Island Reef lake trout (Salvelinus namaycush) population was one of the few in Lake Superior that was not annihilated by the combined effects of excessive fishing and sea lamprey (Petromyzon marinus) predation. Following control of the lamprey in the early 1960s, this population of lake trout began a slow but steady increase in the average age and numbers of lake trout. Total annual mortality rates for spawning lake trout were 32% for age VI fish, 48% for ages VII–VIII, and 75% for ages IX and older. These total mortality rates included a 7.3% exploitation rate u, a 20% natural mortality n, and annual lamprey-induced mortalities of 6% for ages V–VI, 24%, for ages VII–VIII, and 56% for ages IX and older fish. The estimated number of lake trout eggs deposited annually on Gull Island Reef from 1964 to 1979 ranged from 3.3 million eggs in 1965 to 28 million eggs in 1979, with a mean of 9 million eggs per year. At present levels of lamprey predation, the estimated egg to spawning fish return rate on Gull Island Reef is 0.18%.Key words: lake trout, sea lamprey, survival, population structure, egg deposition

Population Biology of Lake Trout (Salvelinus namaycush) of Lake Superior before 1950

1971 ◽  
Vol 28 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Gary T. Sakagawa ◽  
Richard L. Pycha
Keyword(s):  
Mortality Rate ◽  
Population Biology ◽  
Lake Trout ◽  
Lake Superior ◽  
Indirect Evidence ◽  
Total Mortality ◽  
Growth Yield ◽  
Salvelinus Namaycush ◽  
Natural Mortality ◽  
Trout Population

Scale samples collected in 1948 were used to estimate the instantaneous total mortality rate (0.70) and growth for lake trout (Salvelinus namaycush) in Lake Superior before the population had been significantly reduced by the sea lamprey (Petromyzon marinus). Indirect evidence indicates that the instantaneous natural mortality rate was probably 0.10–0.25. The Ricker model was used to calculate yield per recruitment, which varied with natural mortality and growth. Natural mortality was more critical than growth; yield per recruitment increased 183.3% with a 60% decrease in instantaneous natural mortality (from 0.25 to 0.10). For the prelamprey lake trout population the yield per recruitment was about 12–34 lb; the recruitment of about 3.6–10.1 million lake trout of age 1.5 resulted in an annual commercial production of 4 million lb.

Estimated Impacts of SO2 Emissions from Sudbury Smelters on Ontario's Sportfish Populations

1992 ◽  
Vol 49 (S1) ◽  
pp. 87-94 ◽  
Author(s):  
John E. Matuszek ◽  
Donna L. Wales ◽  
John M. Gunn
Keyword(s):  
Water Quality ◽  
Brook Trout ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Quality Improvements ◽  
So2 Emissions ◽  
Acidic Lakes ◽  
Local Impacts

Impacts of acidification on the major sportfish species in Ontario (lake trout (Salvelinus namaycush), brook trout (S. fontinalis), smallmouth bass (Micropterus dolomieu), and walleye (Stizostedion vitreum)) were estimated from the results of extensive water quality surveys conducted during the period 1978–85. Local impacts, within the 17 000 km2 area most affected by emissions from Sudbury smelters, were also estimated and compared with the provincial values. The estimated numbers of acidic lakes in Ontario in which viable sportfish populations have disappeared were 119 lake trout lakes (5.1% of known lake trout lakes), 34 brook trout lakes (1.6%), 52 smallmouth bass lakes (2.2%), and 14 walleye lakes (0.3%). Most of these affected lakes were in the Sudbury zone, where fish populations, particularly those of lake trout, began declining more than 30 yr ago. The estimated numbers of critically acidic lakes in the Sudbury zone were 94 lake trout lakes, 14 brook trout lakes, 18 smallmouth bass lakes, and 7 walleye lakes. More recent sampling of a subset of Sudbury lakes indicated that substantial water quality improvements have occurred as a result of emission reductions from Sudbury smelters.

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