System Simulation of the Predatory Activities of Sea Lampreys (Petromyzon marinus) on Lake Trout (Salvelinus namaycush)

1975 ◽  
Vol 32 (5) ◽  
pp. 623-631 ◽  
Author(s):  
Patrick F. Lett ◽  
F. W. H. Beamish ◽  
G. J. Farmer
Keyword(s):  
Lake Trout ◽  
Petromyzon Marinus ◽  
Salvelinus Namaycush ◽  
Commercial Fishing ◽  
Stochastic Dynamic ◽  
Age Classes ◽  
Trout Population ◽  
Sea Lampreys ◽  
Population Structures ◽  
The Mean

A stochastic dynamic model was developed to evaluate the simulated and empirical interactions between sea lampreys (Petromyzon marinus) and two lake trout (Salvelinus namaycush) population structures, one without and the other with previous lamprey predation.An arithmetic increase in lampreys induced a geometric decline in trout, which was dependent on the number of age-classes and the mean weight of trout. Large trout, when present, were subject to most of the lamprey predation allowing survival of smaller trout. Lethality increased exponentially with lamprey size resulting in peak lake trout mortality during fall near the end of the lamprey’s feeding period. Lake trout scarring data could be used only as an index of lamprey abundance when trout:lamprey ratios and trout population structures were known. The simulation suggested that sea lampreys and lake trout could coexist if large trout are not removed by commercial fishing and if some exogenous factor controlled lamprey abundance.

Classification of Sea Lamprey (Petromyzon marinus) Attack Marks on Great Lakes Lake Trout (Salvelinus namaycush)

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Petromyzon Marinus ◽  
Attachment Site ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Oral Disc ◽  
Field Assessment ◽  
Sea Lampreys

Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.Key words: sea lamprey, attack marks, lake trout, Great Lakes

Accumulation of PCBs by Lake Trout (Salvelinus namaycush): An Individual-Based Model Approach

1993 ◽  
Vol 50 (1) ◽  
pp. 97-109 ◽  
Author(s):  
Charles P. Madenjian ◽  
Stephen R. Carpenter ◽  
Gary W. Eck ◽  
Michael A. Miller
Keyword(s):  
Uncertainty Analysis ◽  
Lake Michigan ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Prey Fish ◽  
Age Classes ◽  
Individual Based Model ◽  
Trout Population ◽  
Different Levels ◽  
Model Approach

To explain the variation in growth and in concentration of polychlorinated biphenyls (PCBs) among individual fish, an individual-based model (IBM) was applied to the lake trout (Salvelinus namaycush) population in Lake Michigan. The IBM accurately represented the variation in growth exhibited by the different age classes of lake trout. Uncertainty analysis of the IBM revealed that mean PCB concentration for the lake trout population was most sensitive to PCB concentration in their prey. The variability in PCB concentration among lake trout individuals was not adequately explained by the IBM, unless variation in prey fish PCBs was included in the model. To accomplish this, the simulated lake trout population was divided into subsets subjected to different levels of PCB concentration in the prey fish. Thus, model results indicated that variability in prey fish PCB concentration was an important component of the variation in PCB concentration observed among individual lake trout comprising the Lake Michigan population.

Returns of Hatchery-Reared Lake Trout in Southern Lake Superior, 1955–62

1967 ◽  
Vol 24 (2) ◽  
pp. 281-298 ◽  
Author(s):  
Richard L. Pycha ◽  
George R. King
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Petromyzon Marinus ◽  
Salvelinus Namaycush ◽  
Osmerus Mordax ◽  
Commercial Fishery ◽  
Sea Lampreys ◽  
Average Size ◽  
Better Than ◽  
Made In

Experimental plantings of fin-clipped lake trout (Salvelinus namaycush) of various ages have been made in southern Lake Superior since 1952. The catch of planted lake trout by the commercial fishery was used to measure the success of stocking. Estimates of total returns were based on samples of 8.2 to 21.2% of the Wisconsin catches in 1955–62 and 36.4 to 46.8% of the Michigan catches in 1959–62. Marked lake trout were assigned to various plantings according to the fin mark, length of fish, readings of age from scales, and locations of capture.Estimated returns from Wisconsin plantings of 9-month-old lake trout varied from 2.1 to 6.4%. Wisconsin releases of 16-month-old fish yielded returns of 5.7 to 37.3%. Returns from plantings in Michigan were 0.3% for 9-month-old fish and 1.5 to 3.8% for 16-month-old fish. The ratios of the returns from plantings of 16-month-old fish to those of 9-month-old fish were 3.9:1 for Wisconsin releases and 6.7:1 for Michigan releases. Lake trout planted in Wisconsin generally survived better than those released in Michigan. Returns from fish planted at ages of 17 to 40 months in Michigan in 1958–59 were far greater than those from 16-month-old fish released in Michigan, but were not as high as from the most successful plantings of 16-month-old fish in Wisconsin. Lake trout released in 1960 from shore and from boats survived equally well.Average size of lake trout at release was more closely related to survival than any other factor. All except 1 of 10 highly successful releases were of fish larger than 22 per lb, and all 6 poor releases were of fish smaller than 34 per lb. Fish that ran 22 to 33 per lb survived only moderately well. A size of 17 to 20 fish per lb appears to be close to optimum.Abundance of native lake trout, American smelt (Osmerus mordax), and sea lampreys (Petromyzon marinus) all appeared to be unrelated to stocking success. The only apparent method of rapidly improving the success of stocking is to rear all lake trout to an average size of 17 to 20 per lb.

Evaluating the growth potential of sea lampreys (Petromyzon marinus) feeding on siscowet lake trout (Salvelinus namaycush) in Lake Superior

2011 ◽  
Vol 37 (2) ◽  
pp. 343-348 ◽  
Author(s):  
Eric K. Moody ◽  
Brian C. Weidel ◽  
Tyler D. Ahrenstorff ◽  
William P. Mattes ◽  
James F. Kitchell
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Petromyzon Marinus ◽  
Salvelinus Namaycush ◽  
Growth Potential ◽  
Sea Lampreys

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.

Sex Ratios and Lengths of Adult Sea Lampreys (Petromyzon marinus) from a Lake Ontario Tributary

1974 ◽  
Vol 31 (1) ◽  
pp. 122-124 ◽  
Author(s):  
I. C. Potter ◽  
F. W. H. Beamish ◽  
B. G. H. Johnson
Keyword(s):  
Narrow Range ◽  
Sex Ratios ◽  
Petromyzon Marinus ◽  
Lake Ontario ◽  
Sea Lamprey ◽  
Adult Males ◽  
Sea Lampreys ◽  
Males And Females ◽  
The Mean ◽  
Humber River

The mean lengths of adult males and females of the sea lamprey (Petromyzon marinus) migrating into the Humber River from Lake Ontario in each of the years 1968–1972 varied little, and were similar to those found by other workers in recently established populations in the upper lakes. In contrast, the ratio of males to females, which lay within the narrow range of 1:1 to 1.26:1, was similar to those reported for long-established populations.

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

Genetic Differences in Retention of Swimbladder Gas Between Two Populations of Lake Trout (Salvelinus namaycush)

1974 ◽  
Vol 31 (8) ◽  
pp. 1351-1354 ◽  
Author(s):  
P. Ihssen ◽  
J. S. Tait
Keyword(s):  
Brook Trout ◽  
Depth Distribution ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Genetic Differences ◽  
Trout Population ◽  
Two Populations

Lake trout (Salvelinus namaycush) derived from two populations differed in retention of swimbladder gas. The two reciprocal interpopulation crosses were intermediate to the parent populations. The two F1 hybrids obtained by crossing fish from each lake trout population with brook trout (S. fontinalis) were also found different in retention. Gas retention was correlated with depth distribution of the parent populations, high retention being associated with deeper distribution.

Assessment of Sea Lamprey (Petromyzon marinus) Predation by Recovery of Dead Lake Trout (Salvelinus namaycush) from Lake Ontario, 1982–85

1988 ◽  
Vol 45 (8) ◽  
pp. 1406-1410 ◽  
Author(s):  
Roger A. Bergstedt ◽  
Clifford P. Schneider
Keyword(s):  
Lake Trout ◽  
Stock Assessment ◽  
Petromyzon Marinus ◽  
Lake Ontario ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Fish Stock ◽  
Annual Fish ◽  
Dead Fish ◽  
Fish Stock Assessment

During 1982–85, 89 dead fake trout (Salvelinus namaycush) were recovered with bottom trawls in U.S. waters of Lake Ontario: 28 incidentally during four annual fish-stock assessment surveys and 61 during fall surveys for dead fish. During the assessment surveys, no dead lake trout were recovered in April–June, one was recovered in August, and 27 were recovered in October or November, implying that most mortality from causes other than fishing occurred in the fall. The estimated numbers of dead lake trout between the 30- and 100-m depth contours in U.S. waters ranged from 16 000 (0.08 carcass/ha) in 1983 to 94 000 (0.46 carcass/ha) in 1982. Of 76 carcasses fresh enough to enable recognition of sea lamprey (Petromyzon marinus) wounds, 75 bore fresh wounds. Assuming that sea lamprey wounding rates on dead fish were the same as on live ones of the same length range (430–740 mm), the probability of 75 of the 76 dead lake trout bearing sea lamprey wounds was 3.5 × 10−63 if death was independent of sea lamprey attack, thus strongly implicating sea lampreys as the primary cause of death of fish in the sample. The recovery of only one unwounded dead lake trout also suggested that natural mortality from causes other than sea lamprey attacks is negligible.

Recovery of Planted Brook Trout, Splake, and Rainbow Trout from Selected Ontario Lakes

1972 ◽  
Vol 29 (2) ◽  
pp. 129-142 ◽  
Author(s):  
J. M. Fraser
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Fish Community ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Low Fertility ◽  
Salmo Gairdneri ◽  
White Sucker ◽  
The Mean ◽  
Brook Stickleback

Recoveries of hatchery-reared brook trout (Salvelinus fontinalis), splake (Salvelinus namaycush × S. fontinalis), and rainbow trout (Salmo gairdneri), planted in lakes having different resident fishes, were highest (9–30%) in a lake in which minnows and the brook stickleback were the only other fishes. Recoveries, by angling and gillnetting, were considerably lower (2–15%) in two lakes containing the white sucker and minnows, and still lower (0.5–5%,) in two lakes containing spiny-rayed species as well. Recoveries were lowest (< 0.5%) in a lake having a complex fish community that included native brook and lake trout. Planted splake and rainbow trout generally yielded higher returns, in weight, than brook trout in comparable situations.The low survival of planted fish was apparently due to the low fertility of the waters and to competition with, or predation by, resident fish species. Predation by fish-eating birds and mammals may also have had an effect.The weight of the catch of salmonids exceeded the weight planted in only one lake. Here, the mean yield of planted salmonids was 8.4 kg/ha per year in comparison with 2.6 to < 0.5 kg/ha per year in the five other study lakes.

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