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.

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.

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.

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

The Relative Efficiency of Nylon and Cotton Gill Nets for Taking Lake Trout in Lake Superior

1962 ◽  
Vol 19 (6) ◽  
pp. 1085-1094 ◽  
Author(s):  
Richard L. Pycha
Keyword(s):  
Relative Efficiency ◽  
Sharp Increase ◽  
Lake Trout ◽  
Lake Superior ◽  
Efficiency Ratio ◽  
Gill Nets ◽  
The Past ◽  
Trout Fishery ◽  
Biased Estimates ◽  
Gill Netting

The change from cotton to nylon twine for gill nets in 1949–52 resulted in a sharp increase in the efficiency of the most important gear used for taking lake trout in Lake Superior, and, consequently, biased estimates of fishing intensity and abundance severely.From early May to the end of September 1961, short gangs (2000 or 4000 linear feet) of cotton and nylon nets were fished in parallel sets for lake trout. A total of 343,000 feet of gill netting was lifted. Nylon nets were 2.25 times as efficient as cotton nets for taking legal-sized fish and 2.8 times as efficient for undersized lake trout. The average lengths of legal, undersized, and all lake trout taken in nets of the two materials did not differ greatly. The percentage of the catch which was undersized (less than 1.25 lb, dressed weight) was 20.8 in nylon nets and 17.7 in cotton. The relative efficiency of cotton and nylon nets showed no trend during the season. The efficiency ratio determined in this study was closely similar to that obtained by earlier workers.Correction of estimates of fishing intensity and abundance for the greater efficiency of the nylon nets used since 1951 has not been attempted. The drastic decline of the lake trout fishery has forced fishermen to make changes in fishing practices in the past few years that cause new bias of an unknown extent to estimates of fishing intensity.

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

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.

Fleet Dynamics of the Commercial Lake Trout Fishery in Michigan Waters of Lake Superior during 1929–1961

2004 ◽  
Vol 30 (2) ◽  
pp. 252-266 ◽  
Author(s):  
Michael J. Wilberg ◽  
Charles R. Bronte ◽  
Michael J. Hansen
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Trout Fishery ◽  
Fleet Dynamics
Sign in / Sign up

Export Citation Format

Share Document