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.

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

1994 ◽  
Vol 51 (4) ◽  
pp. 942-945 ◽  
Author(s):  
A. L. Jensen

After invasion of the Great Lakes by the parasitic marine sea lamprey (Petromyzon marinus), lake trout (Salvelinus namaycush) populations crashed, but there remains some uncertainty concerning the relative importance of sea lamprey predation and harvesting in destruction of the fisheries. Some investigators believe overharvest was important; others think that the sea lamprey alone was enough. Simple models of predation assume monophagous predators and do not predict extinction of prey, but Larkin's modification of the Lotka–Volterra model results in extinction under some circumstances. The dynamics of sea lamprey predation on lake trout were investigated using Larkin's model, and crude estimates of the model parameters indicate that extinction is a likely outcome with or without a fishery.


1980 ◽  
Vol 37 (11) ◽  
pp. 1861-1871 ◽  
Author(s):  
John W. Heinrich ◽  
Jerry G. Weise ◽  
Bernard R. Smith

Biological characteristics of adult sea lampreys, Petromyzon marinus, in the Great Lakes changed in response to lamprey and prey abundance and the chemical control program. Sea lampreys collected as early as 1947, through 1978, from southern Lake Superior, northwestern Lake Michigan, the Ocqueoc River and Canadian shore of Lake Huron, and the Humber River of Lake Ontario were analyzed. Generally, abundance of sea lampreys peaked in each lake before the chemical control program began. The annual mean lengths and weights were relatively low when lampreys were abundant and increased as the numbers were reduced by the control efforts. As an indication of the change in sea lamprey weight per unit change in length, annual log10 weight on log10 length equations were solved at the arbitrary length of 410 mm. The values were plotted against years for each lake and interpreted with respect to chemical treatment periods. All slopes were negative before the control period and positive thereafter. Sea lamprey lengths and weights were low when fish stocks in the Great Lakes were near depletion. As salmonids again became abundant through stocking, lampreys grew larger. In Lake Superior, where detailed records on lake trout abundance have been available since 1959, a significant relation exists between the changes in the sea lamprey estimated weight values at 410 mm and in lake trout abundance (P < 0.01). Male sea lampreys were the dominant sex when populations of the parasite were high. A shift to a preponderance of females occurred as lamprey abundance declined.Key words: Petromyzon marinus, Salvelinus namaycush, abundance, sex ratio, weight–length relationship, chemical control


2011 ◽  
Vol 68 (3) ◽  
pp. 523-533 ◽  
Author(s):  
Lance A. Vrieze ◽  
Roger A. Bergstedt ◽  
Peter W. Sorensen

Stream-finding behavior of adult sea lamprey ( Petromyzon marinus ), an anadromous fish that relies on pheromones to locate spawning streams, was documented in the vicinity of an important spawning river in the Great Lakes. Untreated and anosmic migrating sea lampreys were implanted with acoustic transmitters and then released outside the Ocqueoc River. Lampreys swam only at night and then actively. When outside of the river plume, lampreys pursued relatively straight bearings parallel to the shoreline while making frequent vertical excursions. In contrast, when within the plume, lampreys made large turns and exhibited a weak bias towards the river mouth, which one-third of them entered. The behavior of anosmic lampreys resembled that of untreated lampreys outside of the plume, except they pursued a more northerly compass bearing. To locate streams, sea lampreys appear to employ a three-phase odor-mediated strategy that involves an initial search along shorelines while casting vertically, followed by river-water-induced turning that brings them close to the river’s mouth, which they then enter using rheotaxis. This novel strategy differs from that of salmonids and appears to offer this poor swimmer adaptive flexibility and suggests ways that pheromonal odors might be used to manage this invasive species.


1980 ◽  
Vol 37 (11) ◽  
pp. 1895-1905 ◽  
Author(s):  
P. A. Gllderhus ◽  
B. G. H. Johnson

The chemicals 3-trifluoromethyl-4-nitrophenol (TFM) or a combination of TFM and 2′,5-dichloro-4′-nitrosalicylanilide (Bayer 73) have been used to control the sea lamprey (Petromyzon marinus) in the Great Lakes for about 20 yr. These chemicals cause some mortalities of Oligochaeta and Hirudinea, immature forms of Ephemeroptera (Hexagenia sp.), and certain Trichoptera, Simuliidae, and Amphibia (Necturus sp.). The combination of TFM and Bayer 73 may affect some Pelecypoda and Gastropoda, but its overall effects on invertebrates are probably less than those of TFM alone. Granular Bayer 73 is likely to induce mortalities among oligochaetes, microcrustaceans, chironomids, and pelecypods. No evidence exists that the lampricides have caused the catastrophic decline or disappearance of any species. The overall impact of chemical control of sea lampreys on aquatic communities has been minor compared with the benefits derived.Key words: sea lamprey control, Great Lakes, TFM, Bayer 73, aquatic plants, invertebrates, amphibians


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. 2133-2145 ◽  
Author(s):  
Carl J. Walters ◽  
Greg Steer ◽  
George Spangler

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


2011 ◽  
Vol 68 (7) ◽  
pp. 1157-1160 ◽  
Author(s):  
C. Michael Wagner ◽  
Eric M. Stroud ◽  
Trevor D. Meckley

Here we confirm a long-standing anecdotal observation; the sea lamprey ( Petromyzon marinus ) actively avoids the odor emitted by decaying conspecifics. We extracted the semiochemical mixture produced by the putrefying carcasses of sea lampreys via Soxhlet extraction in ethanol and exposed groups of 10 migratory-phase lampreys to either the putrefaction extract (N = 8) or an ethanol control (N = 8) in a laboratory raceway. Sea lampreys rapidly avoided the putrefaction odor while exhibiting no response to the ethanol control. This response was elicited with a diluted mixture (1:373 000) and was maintained for 40 min (the duration of exposure), after which the lampreys quickly returned to their nominal distribution. The ease with which this odor is obtained, and the rapid and consistent behavioral response, suggests the substance will prove useful as a repellent in the sea lamprey control program carried out in the Laurentian Great Lakes.


1980 ◽  
Vol 37 (11) ◽  
pp. 2193-2196 ◽  
Author(s):  
A. H. Lawrie

A task force of participants convened during the course of the Sea Lamprey International Symposium considered the implications, for management of Great Lakes fisheries, of information provided about known interactions between feeding sea lampreys and the stocks of fish on which they prey. A weighted series of recommendations identified the need for more information or for changes in management practice.Key words: sea lamprey, Great Lakes, Finger Lakes, fishery management, stock concept


1988 ◽  
Vol 45 (8) ◽  
pp. 1406-1410 ◽  
Author(s):  
Roger A. Bergstedt ◽  
Clifford P. Schneider

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.


1980 ◽  
Vol 37 (11) ◽  
pp. 2063-2073 ◽  
Author(s):  
Richard L. Pycha

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


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