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.

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

Multivariate Time Series Analysis of the Canadian Fisheries System in Lake Superior

1987 ◽  
Vol 44 (S2) ◽  
pp. s171-s181 ◽  
Author(s):  
Y. Cohen ◽  
J. N. Stone
Keyword(s):  
Time Series ◽  
Fish Species ◽  
Lake Trout ◽  
Interspecific Interactions ◽  
Lake Superior ◽  
Multivariate Time Series ◽  
Policy Decision ◽  
Trophic Relationships ◽  
Catch Per Unit Effort ◽  
Intraspecific Interactions

Data for the Canadian fisheries system in Lake Superior were organized into monthly time series of catch and effort from January 1963 through December 1976 for six fish species. Multivariate, autoregressive (ARMA) models were identified for the system based on data for the first 140 mo. Forecasts were compared to data for the last 28 mo. The structure of the models indicate that (1) within the system, AR processes, as opposed to MA processes, were of overriding importance, (2) intraspecific interactions (inferred from data on catch-per-unit-effort, CPUE) were more prevalent than interspecific interactions, (3) interactions within the system occurred with lags of 1, 4, 12, 24, 25, 28, and 36 mo, (4) some of the trophic relationships among the fish species were revealed by the models, and (5) CPUE time series of lake trout (Salvelinus namaycush) affected, but was not affected by, the CPUE time series of other species. The models were used to forecast catch and CPUE for the last 28 mo, and the data were generally within one standard error of the forecasts. The models may help policy decision makers to explore the effects of inputs (e.g. quota regulations) and feedbacks within the fisheries' system on outputs (e.g. production, CPUE).

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.

Changes in Species Interactions of the Lake Superior Fisheries System After the Control of Sea Lamprey as Indicated by Time Series Models

1990 ◽  
Vol 47 (2) ◽  
pp. 251-261 ◽  
Author(s):  
Jeff N. Stone ◽  
Yosef Cohen
Keyword(s):  
Time Series ◽  
Fish Species ◽  
Species Interactions ◽  
Lake Trout ◽  
Interspecific Interactions ◽  
Sea Lamprey ◽  
Trophic Relationships ◽  
Time Series Models ◽  
Catch Per Unit Effort ◽  
Intraspecific Interactions

Interspecific and intraspecific interactions of fish species in the Canadian commercial fisheries changed following the control of sea lamprey (Petromyzon marinus). These changes were detected by a multivariate time series (MVTS) analysis of monthly time series of catch-per-unit-effort for lake trout (Salvelinus namaycush), lake whitefish (Coregonus clupeaformis), lake herring (C. artedii), chubs (Coregonus spp.), walleye (Stizostedion vitreum), and yellow perch (Perca flavescens). The identified MVTS models reflected known trophic relationships among fish species and indicated that significant intraspecific interactions were more numerous than interspecific interactions. Lake trout interactions with other species appear to have changed due to stocking and diet change. Single species time series models confirmed the lag structure of the MVTS models and were useful for forecasting abundance.

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.

Growth potential and host mortality of the parasitic phase of the sea lamprey (Petromyzon marinus) in Lake Superior

2005 ◽  
Vol 62 (10) ◽  
pp. 2343-2353 ◽  
Author(s):  
Jeffrey C Jorgensen ◽  
James F Kitchell
Keyword(s):  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Pacific Salmon ◽  
Lake Superior ◽  
Petromyzon Marinus ◽  
Maximum Size ◽  
Sea Lamprey ◽  
Growth Potential ◽  
Sea Lampreys ◽  
Host Mortality

Landlocked Lake Superior sea lampreys (Petromyzon marinus) cause a significant but uncertain amount of mortality on host species. We used a sea lamprey bioenergetics model to examine the scope of host sizes vulnerable to death as a consequence of sea lamprey feeding and incorporated the bimodal lake-ward migration of parasitic sea lampreys. At their peak feeding rate and maximum size (P = 1.0, proportion of maximum consumption), spring migrants were capable of killing lean lake trout (Salvelinus namaycush) hosts ≤ 2.0 kg, which was larger than fall migrants (1.8 kg). Spring migrants feeding on Pacific salmon (coho (Oncorhynchus kisutch), Chinook (Oncorhynchus tshawytscha), and steelhead (Oncorhynchus mykiss)) killed hosts ≤ 2.0 kg, but fall migrants killed hosts as large as 2.8 kg. Although there is no direct empirical evidence, bioenergetics modeling suggests that it is plausible that some of the largest sea lampreys in Lake Superior spent more than one summer as parasites. Two-summer parasites readily attained sizes of sea-run adult anadromous sea lampreys and killed hosts from 3 to >5.5 kg in size. The maximum upper limit number of 2-kg hosts killed by two-summer parasites was nearly twice that of one-summer parasites.

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

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