Final Observations on the Survival of Planted Lake Trout in South Bay, Lake Huron

1969 ◽  
Vol 26 (9) ◽  
pp. 2413-2424 ◽  
Author(s):  
J. C. Budd ◽  
F. E. J. Fry ◽  
P. S. M. Pearlstone

Yearling lake trout were planted in South Bay, Lake Huron, an area with a sea lamprey population, each year from 1949 to 1955 with the exception of 1950. Fish were recaptured in pound and gillnets. Those recaptured in pound nets were tagged and released. Data from recaptures of tagged fish have been used to calculate yearly population estimates that were used to determine the annual mortality of certain year-classes. The fish were also examined for lamprey wounds and scars and the results tabulated according to the age of the fish.Before age IV annual mortality of South Bay lake trout does not appear to differ significantly from annual mortalities observed in lake trout populations in the absence of sea lampreys. Thereafter, annual mortality rates rise sharply and the population disappears at the age of VI or VII. No spawning population was maintained.Prior to age III no lamprey marks were observed on recaptured lake trout. From ages III to V the percentages of fish bearing lamprey marks increased from 5.2 to 38.8. This trend may continue through age VI but too few data are present to be certain. Before age VI there appears to be a direct correlation between annual lamprey marking rates and annual natural mortality rates.

1976 ◽  
Vol 33 (11) ◽  
pp. 2402-2407 ◽  
Author(s):  
G. R. Spangler ◽  
A. H. Berst

This paper presents the results of plantings in Lake Huron waters of lake trout (Salvelinus namaycush), F1 splake (S. fontinalis × S. namaycush), and the progeny of the backcross between splake males and lake trout females.The planted fish were piscivorous throughout age-groups II – V with rainbow smelt (Osmerus mordax), sticklebacks (Pungitius [?]), and alewives (Alosa pseudoharengus) the dominant food organisms. Hybrid stocks grew more rapidly but attained a somewhat smaller asymptotic length than did lake trout. The F1 hybrids were the earliest to mature with 34% of the males and 4% of the females spawning at age II. Earliest maturity occurred in the backcrosses at age III, in contrast to lake trout which matured predominantly at ages VI and VII. The backcrosses demonstrated a slightly broader thermal and bathymetric distribution during summer than did lake trout, while the F1 hybrids tended to concentrate in the thermocline. Total annual mortality rates (attributed mostly to predation by sea lampreys, Petromyzon marinus) ranged from 62 to 95% for all of the planted stocks.


1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.

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


1980 ◽  
Vol 37 (11) ◽  
pp. 2057-2062 ◽  
Author(s):  
A. H. Lawrie ◽  
W. MacCallum

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


1980 ◽  
Vol 37 (11) ◽  
pp. 2007-2020 ◽  
Author(s):  
B. G. H. Johnson ◽  
William C. Anderson

Incidentally caught predatory-phase sea lampreys were obtained from the commercial fisheries of the Laurentian Great Lakes, together with related catch data, in return for a reward offered to fishermen. Catches of sea lampreys per unit of fishing effort in Lake Superior generally paralleled other indices of sea lamprey abundance. Recently metamorphosed sea lampreys tended to appear early in the season in deepwater fisheries, typically those directed toward cisco (Coregonus spp.), whereas older specimens were taken more often in gear set at shallower depths during summer and fall. The proportion of male sea lampreys in the collections decreased annually between spring and fall, due apparently to a shoreward movement of the males. Large lake trout (Salvelinus namaycush) appeared to be the preferred prey of the sea lamprey. From studies of the stomach contents, sea lamprey feeding activity appeared to reach a peak in late summer or early fall, thereafter declining until the cessation of feeding in early spring. Growth rate reached a maximum in late summer or early fall. Greatest length was attained between January and March, after which a decrease in length was observed. Predatory-phase sea lampreys remained concentrated near the mouths of their parent streams if sufficient numbers of prey were present. Their distribution in the Great Lakes was related to the location of prey.Key words: sea lamprey, predation, Great Lakes fishery


2005 ◽  
Vol 62 (6) ◽  
pp. 1432-1451 ◽  
Author(s):  
Norine E Dobiesz ◽  
David A McLeish ◽  
Randy L Eshenroder ◽  
James R Bence ◽  
Lloyd C Mohr ◽  
...  

We review the status of the Lake Huron fish community between 1970 and 1999 and explore the effects of key stressors. Offshore waters changed little in terms of nutrient enrichment, while phosphorus levels declined in inner Saginaw Bay. Introduced mussels (Dreissena spp.) proliferated and may have caused a decline in Diporeia spp. This introduction could have caused a decline in lake whitefish (Coregonus clupeaformis) growth and condition, with serious repercussions for commercial fisheries. Bythotrephes, an exotic predatory cladoceran, and other new exotics may be influencing the fish community. Sea lampreys (Petromyzon marinus) remained prevalent, but intensive control efforts on the St. Mary's River may reduce their predation on salmonines. Overfishing was less of a problem than in the past, although fishing continued to reduce the amount of lake trout (Salvelinus namaycush) spawning biomass resulting from hatchery-reared fish planted to rehabilitate this species. Massive stocking programs have increased the abundance of top predators, but lake trout were rehabilitated in only one area. Successful lake trout rehabilitation may require lower densities of introduced pelagic prey fish than were seen in the 1990s, along with continued stocking of hatchery-reared lake trout and control of sea lamprey. Such reductions in prey fish could limit Pacific salmon (Oncorhynchus spp.) fisheries.


2005 ◽  
Vol 62 (10) ◽  
pp. 2343-2353 ◽  
Author(s):  
Jeffrey C Jorgensen ◽  
James F Kitchell

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.


1980 ◽  
Vol 37 (11) ◽  
pp. 2074-2080 ◽  
Author(s):  
Bruce L. Swanson ◽  
Donald V. Swedberg

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


1968 ◽  
Vol 25 (11) ◽  
pp. 2257-2268 ◽  
Author(s):  
J. C. Budd ◽  
F. E. J. Fry ◽  
J. B. Smith

Lake trout (491 in all), Salvelinus namaycush, planted as yearlings in Lake Manitou in 1952 were tagged at age VII when taken in trap nets during spawntaking operations. At the same time 259 native adult trout of unknown age were also tagged. In spawntaking operations in subsequent years tag numbers were noted for tagged fish recaptured and the fish returned to the lake after normal spawntaking. Both groups were estimated to have suffered a decrement of 25% per year. The lake trout planted were given a distinctive fin clip on planting so that comparisons of recaptures of tagged and untagged planted fish permitted estimates of the survival of the total plant. The mean annual mortality rate from the time of planting was also estimated at 25%. Trout planted later appeared to have suffered a similar mortality rate. Observations on planted lake trout of known age indicated that the peak age for first spawning in females was age VI. There is no predation by sea lamprey in Lake Manitou.


1967 ◽  
Vol 24 (10) ◽  
pp. 2117-2136 ◽  
Author(s):  
Daniel W. Coble

Information on ecology and dynamics of white suckers, Catostomus commersoni (Lacépède), in South Bay, Lake Huron, was obtained from experimental fishing over more than a decade and from a tagging program in 1955 and 1956. (A total of 1667 suckers were tagged and 8% of them were subsequently recovered.) The fish moved about extensively in the bay, minimal distance travelled averaging 3.8 km during a summer. Nevertheless, it was necessary to divide the bay into discrete fishing areas for calculating population and mortality estimates. The length–weight relationship of adult suckers in June was W = 5.883 × 10−4 L2.92262; where W is weight in pounds and L is fork length in inches. Growth averaged only about 7.6 mm/year, and an annulus was not formed on the scales every year. In 1956 the population may have amounted to about 160,000 adult white suckers, or 23 fish per hectare or 17.5 kg/hectare, for the part of the bay less than 36 m deep. The exploitation rate appeared to be less than 2%. The annual survival rate of suckers larger than approximately 38 cm appeared to be about 70–75% decreasing with size of fish. Although it is not known if the size of the population has changed, the size composition changed between 1953 and 1964 through the loss of larger fish. Marked changes in the fauna of South Bay subsequent to the late 1940's include the invasion of the sea lamprey, Petromyzon marinus Linnaeus, and the alewife, Alosa pseudoharengus (Wilson), the disappearance of the lake trout, Salvelinus namaycush (Walbaum), and the decline of the population of the cisco, Coregonus (= Leucichthys) artedii LeSueur. The loss of the larger fish in the white sucker population was probably caused by the sea lamprey, for it occurred after the destruction of the lake trout population and corresponded with increased incidence of lamprey scarring of suckers.


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