Rehabilitation of Lake Trout in the Apostle Islands Region of Lake Superior

1968 ◽  
Vol 25 (7) ◽  
pp. 1377-1403 ◽  
Author(s):  
William R. Dryer ◽  
George R. King
Keyword(s):  
Large Scale ◽  
Lake Trout ◽  
Lake Superior ◽  
Juvenile Fish ◽  
Age Groups ◽  
Sea Lamprey ◽  
Commercial Fishery ◽  
Natural Reproduction ◽  
Present Rate ◽  
Trout Fishery

Marked success of rehabilitation of lake trout in Lake Superior has been due principally to the control of the sea lamprey and closure of the lake trout fishery in 1962 and large-scale plantings of yearling lake trout in 1959–66. After the sea lamprey became established in the late 1940s, spawning stocks of lake trout began to decrease and were almost nonexistent by 1960–61. After control of the sea lamprey and closure of the commercial fishery for lake trout in 1962, the abundance of spawning stocks began to rise and reached the highest levels on record in 1964–66. Successful spawning in 1964 and 1965 was demonstrated by catches of age-0 lake trout in 1965 and 1966, the first evidence of natural reproduction since 1959.Plantings of hatchery-reared lake trout in Wisconsin waters of Lake Superior began in 1952. The percentage of hatchery-reared fish in catches of juvenile lake trout increased almost steadily from 1953 to 1965 (when nearly all were of hatchery origin). The abundance of juvenile fish increased from 1959 to 1962 and remained nearly constant in 1962–66. The success of lake trout plantings was highest in 1959–61 but generally declined after 1961; the success of the plantings was inversely related to the abundance of older lake trout.Annual increments of growth of hatchery-reared lake trout varied from 1.1 to 5.0 inches after planting. The average lengths of fish of identical age-groups varied according to gear of capture, depth of water, and season. More than 65% of the season's growth of age-III lake trout took place after September.The findings indicated that the present rate of stocking lake trout may be higher than necessary to maintain optimum abundance.

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

1968 ◽  
Vol 25 (7) ◽  
pp. 1347-1376 ◽  
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.

A Synthesis of Knowns, Unknowns, and Policy Recommendations from the Sea Lamprey International Symposium

1980 ◽  
Vol 37 (11) ◽  
pp. 2202-2208 ◽  
Author(s):  
Carl J. Walters ◽  
George Spangler ◽  
W. J. Christie ◽  
Patrick J. Manion ◽  
James F. Kitchell
Keyword(s):  
International Symposium ◽  
Large Scale ◽  
Fishery Management ◽  
Field Experiments ◽  
Lake Trout ◽  
Sea Lamprey ◽  
Future Research ◽  
Fish Stock ◽  
Total Production ◽  
Pilot Studies

The Sea Lamprey International Symposium (SLIS) has provided a broad spectrum of facts and speculations for consideration in future research and management programs. Many aspects of the laboratory biology and field life history of the sea lamprey (Petromyzon marinus) are now well understood. There is little question that it can now be controlled by chemical larvicides, and perhaps in the future by more efficient integrated control programs. There is correlative evidence (wounds, scars, catch curves) that lamprey caused major mortalities in some fish species, and that control in conjunction with stocking has lead to remarkable recoveries of salmonid stocks in the Great Lakes. However, there are great gaps in understanding about just what the lamprey does under field conditions, and it is not yet possible to reject several hypotheses that assign lamprey a minimum or transient role in fish stock changes. Further studies on details of lamprey biology are, in themselves, unlikely to fill the gaps; one alternative is to conduct a large-scale field experiment involving cessation of lamprey control while holding other factors (fishing, stocking) as steady as possible. If it is decided to proceed with management on the assumption that lamprey are important, without the major field experiments to confirm it, then at least the following steps should be taken: (1) the chemical treatment program should be reviewed in detail, with a view to finding treatment schedules that will minimize frequency and dose rates for lampricide applications; (2) pilot studies on alternative control schemes (sterile male, attractants, barriers) should only be funded if they are statistically well designed (several replicate and control streams), and involve quantitative monitoring of lamprey spawning success and subsequent total production of transforming larvae; (3) the lake trout (Salvelinus namaycush) stocking program should be maintained at its present level, and should involve diverse genotypes rather than a few hatchery strains; (4) growth in the sport fisheries for lake trout should be curtailed, and commercial fisheries should not yet be permitted; (5) a multispecies harvesting policy should be designed that takes into account the buffering effect of each species on lamprey mortality suffered by others (i.e. should some species not be harvested at all, and viewed instead as buffers for more valuable species?); and (6) a program should be developed for restoring, by culture if necessary, native forage species in case the introduced smelt and alewife should collapse under pressure from fishing and prédation by the growing salmonid community.Key words: sea lamprey, proposed research, fishery management, mathematical models, population dynamics

Sea lamprey (Petromyzon marinus) size trends in a salmonid stocking context in Lake Superior

2005 ◽  
Vol 62 (10) ◽  
pp. 2354-2361 ◽  
Author(s):  
Jeffrey C Jorgensen ◽  
James F Kitchell
Keyword(s):  
Bayesian Model ◽  
Fish Community ◽  
Bayesian Model Averaging ◽  
Lake Trout ◽  
Pacific Salmon ◽  
Lake Superior ◽  
Petromyzon Marinus ◽  
Control Period ◽  
Model Averaging ◽  
Sea Lamprey

Fish community objectives for Lake Superior call for restoration such that it resembles its historical species composition, to the extent possible, yet allow for supplementation of naturalized Pacific salmonids (Oncorhynchus spp.). To achieve these goals, managers strive to control the sea lamprey (Petromyzon marinus) to levels that cause insignificant (<5%) mortality to host species. While control efforts have been successful, sea lamprey size has increased during the control period. We analyzed long-term sea lamprey size trends and found a significant increase from 1961 to 2003 (F = 36.76, p < 0.001, R2 = 0.473). A local regression revealed two significant size increase periods. We used Bayesian model averaging to find the relationship between sea lamprey size and the stocking of salmonids (lean lake trout (Salvelinus namaycush) and Pacific salmon). Bayesian model averaging identified 91 models, and several regressors were common features in many of the models. Sea lamprey weight was related to stocked lake trout lagged 3, 9, 11, and 13 years, and stocked Pacific salmon lagged 4 years. If sea lampreys can achieve larger sizes attached to Pacific salmonid hosts, and thus inflict more damage, there may be a trade-off for managers in achieving the fish community objectives for Lake Superior.

On Evaluating Measures to Rehabilitate Lake Trout (Salvelinus namaycush) of Lake Superior

1980 ◽  
Vol 37 (11) ◽  
pp. 2057-2062 ◽  
Author(s):  
A. H. Lawrie ◽  
W. MacCallum
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Petromyzon Marinus ◽  
Control Program ◽  
Mortality Rates ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Planting Density ◽  
Hatchery Fish ◽  
Natural Recruitment

The Lake Superior lake trout (Salvelinus namaycush) population is being rebuilt following its collapse in the early 1950s. Estimates are presented of the contributions to this recovery provided directly by the artificial recruitment of hatchery fish, a demonstrable amelioration in mortality rates and a resurgence, lately, of natural recruitment. Of the increased lake trout abundance, 55% on the average was owing to trebling the planting density, 40% to improved survival, and 5% to increasing recruitment of native lake trout. The precise contribution of the sea lamprey (Petromyzon marinus) control program could not be defined for lack of sufficient early data.Key words: lake trout, sea lamprey, rehabilitation, natural recruitment, hatchery stocking

Responses of Lake Trout (Salvelinus namaycush) to Harvesting, Stocking, and Lamprey Reduction

1980 ◽  
Vol 37 (11) ◽  
pp. 2133-2145 ◽  
Author(s):  
Carl J. Walters ◽  
Greg Steer ◽  
George Spangler
Keyword(s):  
Simple Model ◽  
Policy Analysis ◽  
Great Lakes ◽  
Population Regulation ◽  
Lake Trout ◽  
Normal Population ◽  
Lake Superior ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Density Dependent

Sustained yields, declines, and recovery of lake trout (Salvelinus namaycush) can be explained by a simple model that hypothesizes normal population regulation through density dependent body growth, coupled with depensatory lamprey mortality. The model indicates that either lamprey or fishing alone could have caused the Lake Superior decline, though they apparently operated in concert. The presence of depensatory lamprey mortality leads to a "cliff edge" in the system's dynamics, such that catastrophic changes may be repeated in the future. It is not unlikely that Lake Superior is on the verge of a second collapse. Options for dealing with potential disasters include conservative harvesting policies, development of more sensitive monitoring indicators, and modified stocking policies that may speed the coevolution of a viable lamprey/trout association.Key words: lake trout, sea lamprey, simulation, Great Lakes, policy analysis

From Catastrophe to Recovery: Stories of Fishery Management Success

2019 ◽  
Keyword(s):  
Fishery Management ◽  
Lake Trout ◽  
Habitat Degradation ◽  
Lake Superior ◽  
Reproductive Potential ◽  
Keystone Species ◽  
Sea Lamprey ◽  
Wild Fish ◽  
And Performance ◽  
The 1960S

<i>Abstract</i>.—The Lake Trout <i>Salvelinus namaycush</i> is a keystone species in the Laurentian Great Lakes that supported valuable fisheries throughout the basin until the 1950s. However, Lake Trout populations declined to near extirpation in nearly all of the lakes by the 1960s because of the combined effects of overfishing, Sea Lamprey <i>Petromyzon marinus</i> predation, and habitat degradation. To restore self-sustaining Lake Trout populations in Lake Superior, state, provincial, federal, and tribal agencies agreed to an interjurisdictional management framework that allowed them to articulate and institute (1) clear and common goals and actions for recovery, (2) early and intensive lakewide stocking of hatchery-reared Lake Trout to enhance failing stocks, (3) early and effective lakewide controls on mortality caused by Sea lampreys and fisheries, and (4) standardized lakewide evaluations of population trajectories and performance. Stocking was initiated in Lake Superior in 1950 and expanded after 1953, prior to effecting Sea Lamprey or fishery controls, thereby introducing large numbers of hatchery-origin fish that grew to maturity shortly after mortality was reduced. Abundant suitable nearshore spawning habitat was widely available for naive lean hatchery-origin Lake Trout, and native lean Lake Trout persisted in some areas. The Sea Lamprey-selective pesticide TFM (3-trifluoromethyl-4-nitrophenol) was applied first in Lake Superior in 1958 because of the presence of remnant native Lake Trout populations, which set the stage for closure of fisheries and good survival of newly stocked and remnant wild fish. As a consequence of these four factors, stocked fish exceeded historical density of wild fish by the 1980s in many areas and thereby generated enhanced reproductive potential when combined with remnant wild fish. Lake Trout recovery in Lake Superior is an extraordinary example of agency cooperation toward a common goal for managing recovery of an ecologically important shared resource.

Vulnerability, Stability, and Coherence of the Fish Community in Lake Superior

1987 ◽  
Vol 44 (S2) ◽  
pp. s404-s410 ◽  
Author(s):  
Y. Cohen ◽  
J. N. Stone ◽  
T. L. Vincent
Keyword(s):  
Fish Species ◽  
Spectrum Analysis ◽  
Structural Changes ◽  
Lake Trout ◽  
Lake Superior ◽  
Sea Lamprey ◽  
Dominant Frequency ◽  
Vulnerability Analysis ◽  
Predatory Fish ◽  
Before And After

Vulnerability analysis and spectrum analysis were found useful in examining potential structural changes in fisheries systems influenced by large perturbations. In the 1950's the Ontario fisheries of Lake Superior experienced a major perturbation due to invasion by sea lamprey (Petromyzon marinus). Vulnerability analysis indicated that invasion by sea lamprey and the consequent shifting of the fisheries to more intensive fishing on lower trophic level species resulted in higher vulnerability of the predatory fish species; i.e. likelihood of extinction increased. Spectrum analysis was then applied to the yield series of five fish species from Lake Superior. Analysis of the data before and after invasion by sea lamprey indicated major structural changes in the fishery: (1) except for lake trout (Salvelinus namaycush), either the dominant amplitude, the dominant frequency, or both decreased; (2) partial coherencies between pairs of yield series changed after the invasion; (3) lake whitefish (Coregonus clupeaformis) and lake trout replaced lake herring (C. artedii) as the species whose fluctuations in commercial yield were most highly synchronized with those of the other species of commercial importance.

Status of the Lake Trout Fishery in Lake Superior

1951 ◽  
Vol 80 (1) ◽  
pp. 278-312 ◽  
Author(s):  
Ralph Hile ◽  
Paul H. Eschmeyer ◽  
George F. Lunger
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Trout Fishery

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

Lake Superior Revisited 1984

1987 ◽  
Vol 44 (S2) ◽  
pp. s23-s36 ◽  
Author(s):  
Wayne R. MacCallum ◽  
James H. Selgeby
Keyword(s):  
Fish Community ◽  
Lake Trout ◽  
Pacific Salmon ◽  
Lake Superior ◽  
Sea Lamprey ◽  
Osmerus Mordax ◽  
Coregonus Clupeaformis ◽  
Rainbow Smelt ◽  
Coregonus Artedii ◽  
Historical Levels

The Lake Superior fish community has changed substantially since the early 1960s, when control of the sea lamprey (Petromyzon marinus) became effective. Self-reproducing stocks of lake trout (Salvelinus namaycush) have been reestablished in many inshore areas, although they have not yet reached pre-sea lamprey abundance; offshore lake trout are probably at or near pre-sea lamprey abundance. Stocks of lake whitefish (Coregonus clupeaformis) appear to have fully recovered; commercial catches are at or above historical levels. Lake herring (Coregonus artedii) are recovering rapidly in U.S. waters and are abundant in western Canadian waters. The population of rainbow smelt (Osmerus mordax), which declined in the 1970s, is recovering. Pacific salmon (Oncorhynchus) are becoming more abundant as a result of increased stocking in U.S. waters and are reproducing in most suitable tributaries; they have become significant in anglers' creels.

Sign in / Sign up

Export Citation Format

Share Document