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

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.

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

Journal of the Fisheries Research Board of Canada ◽

10.1139/f72-124 ◽

1972 ◽

Vol 29 (6) ◽

pp. 795-805 ◽

Cited By ~ 15

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-247 ◽

1980 ◽

Vol 37 (11) ◽

pp. 2063-2073 ◽

Cited By ~ 23

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

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-248 ◽

1980 ◽

Vol 37 (11) ◽

pp. 2074-2080 ◽

Cited By ~ 42

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

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Lake Michigan's Capacity to Support Lake Trout (Salvelinus namaycush) and Other Salmonines: An Estimate Based on the Status of Prey Populations in the 1970s

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f85-060 ◽

1985 ◽

Vol 42 (3) ◽

pp. 449-454 ◽

Cited By ~ 37

Author(s):

G. W. Eck ◽

Edward H. Brown Jr.

Keyword(s):

Lake Michigan ◽

Lake Trout ◽

Physiological Stress ◽

Total Mortality ◽

Salvelinus Namaycush ◽

Predatory Fish ◽

Natural Mortality ◽

Alosa Pseudoharengus ◽

Mass Balance Equation ◽

The Status

We used a mass balance equation relating total mortality of age II and older alewives (Alosa pseudoharengus) to their removals by predatory fish and other sources of mortality as the basis for estimating that the forage base in Lake Michigan could support an additional 13 000 to 21 000 t of lake trout (Salvelinus namaycush) or a total lake trout biomass between 15 000 and 23 000 t. This biomass estimate is projected with biomasses of other trout and salmon held at 1979 levels. Major premises of this approach are that (1) the sustained availability of age II and older alewives to salmonines will ultimately limit the expansion of salmonine stocks, (2) the alewife population was oscillating without trend during 1973–80, and (3) additional limited predation on alewives would be compensated by a reduction in natural mortality caused by physiological stress and disease.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-257 ◽

1980 ◽

Vol 37 (11) ◽

pp. 2151-2158 ◽

Cited By ~ 5

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

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Dynamics and Exploitation of Mature Walleyes, Stizostedion vitreum vitreum, in the Nipigon Bay Region of Lake Superior

Journal of the Fisheries Research Board of Canada ◽

10.1139/f68-121 ◽

1968 ◽

Vol 25 (7) ◽

pp. 1347-1376 ◽

Cited By ~ 11

Author(s):

R. A. Ryder

Keyword(s):

Lake Trout ◽

Lake Superior ◽

Total Mortality ◽

Inland Waters ◽

Commercial Fishery ◽

Sea Lampreys ◽

Wood Fibres ◽

High Concentrations ◽

Trout Fishery ◽

Hexagenia Limbata

Walleye stocks in Nipigon Bay of Lake Superior were homogeneous with those in tributary inland waters but were discrete from Black Bay stocks. Returns from 2200 tagged walleyes in Lake Superior and tributary inland waters between 1955 and 1958 varied from 7.8 to 31.0% for 2 years after release. The commercial fishery in Lake Superior recovered 64.9% of the tags, the sports fishery in inland waters captured 27.6%. Fish tagged in the Nipigon River travelled a mean distance of 11.8 miles from the point of release and were recovered in 191 days (average). Total mortality rates for Nipigon Bay walleyes were 55.0% (1955–57). Mature walleyes on the spawning grounds in the Nipigon River in 1957 were estimated at 22,000, and fish in Nipigon Bay over 14 inches (total length) the same year at 41,000. All male walleyes were mature at 15 inches and females at 18 inches. Walleyes exploitation rates increased with the decline of the lake trout fishery. Wounding and scarring rates by sea lampreys increased during 1955–57 but never exceeded 1.0% on adult walleyes. Severe pollution on the west side of Nipigon Bay originated from a kraft mill. High concentrations of total solids and dense sedimentation of wood fibres created an environment unfavourable to Hexagenia limbata and Pontoporeia affinis. The recent elimination of the walleye fishery in Nipigon Bay is most likely attributable to industrial pollution rather than to overexploitation or sea lamprey predation.

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Survey of the Genetic Variation Among Eastern Lake Superior Lake Trout (Salvelinus namaycush)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f81-222 ◽

1981 ◽

Vol 38 (12) ◽

pp. 1738-1746 ◽

Cited By ~ 24

Author(s):

Terrence R. Dehring ◽

Anne F. Brown ◽

Charles H. Daugherty ◽

Stevan R. Phelps

Keyword(s):

Genetic Variation ◽

Gel Electrophoresis ◽

Lake Trout ◽

Lake Superior ◽

Salvelinus Namaycush ◽

Starch Gel Electrophoresis ◽

Average Heterozygosity ◽

Management Implications ◽

Salmonid Species ◽

Starch Gel

Patterns of genetic variation among lake trout (Salvelinus namaycush) of eastern Lake Superior were examined using starch gel electrophoresis. We used 484 individuals sampled from three areas, representing three morphological types (leans, humpers, and siscowets). Of 50 loci examined, 44 were monomorphic in all groups sampled. Genetic variation occurs at six loci AAT-1,2, MDH-3,4, ME-1, and SOD-1. The average heterozygosity found (H = 0.015) is low relative to other salmonid species. A significant amount of heterogeneity exists among the 10 lake trout samples. These differences are due to variation within as well as between morphological types. The significance and management implications of these data are discussed.Key words: genetic variation, lake trout, Salvelinus namaycush, Lake Superior

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POPULATION DYNAMICS OF MALAYAN LEAF FISH (Pristolepisgrooti Blkr.) IN RANAU LAKE, SOUTH SUMATRA

Indonesian Fisheries Research Journal ◽

10.15578/ifrj.24.2.2018.125-131 ◽

2018 ◽

Vol 24 (2) ◽

pp. 125

Author(s):

Sevi Sawetri ◽

Subagdja Subagdja ◽

Dina Muthmainnah

Keyword(s):

Mortality Rate ◽

Growth Parameters ◽

Total Mortality ◽

Natural Mortality ◽

Fishing Mortality ◽

Frequency Data ◽

Length Frequency ◽

Lake Ecosystems ◽

Exploitation Rate ◽

Length Frequency Data

The Malayan leaf fish or locally named as kepor (Pristolepis grooti) is one of important biotic components in Ranau Lake ecosystems. This study aimed to estimate population dynamic and exploitation rate of kepor in Ranau Lake, South Sumatera. The population parameters are estimated based on length frequency data which were collected in March to October 2013. Growth parameters and fishing mortality rates were calculated using FiSAT software package. The results showed that kepor’s growth was negative allometric, which tended to gain length faster than weight. Kepor population was dominated (42%) by individual length of 10.0 to 11.0 cm. Predicted length infinity (L) was 17.28 cm with high value of growth rates (K) of 1.4 year-1. The natural mortality rate (M) is 2.57 year-1, the fishing mortality rate (F) is 5.36 year-1 and total mortality rate (Z) is 7.93 year-1. The exploitation rate of Malayan leaf fish in Ranau Lake (E = 0.68 year-1) has passed the optimum score.

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