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.

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.

Origin and Geography of the Fish Fauna of the Laurentian Great Lakes Basin

1981 ◽  
Vol 38 (12) ◽  
pp. 1539-1561 ◽  
Author(s):  
Reeve M. Bailey ◽  
Gerald R. Smith
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Lake Superior ◽  
Fish Fauna ◽  
Secondary Contact ◽  
Species Differentiation ◽  
Stizostedion Vitreum ◽  
Great Lakes Basin ◽  
Geological Evidence ◽  
The Past

The native fishes of the Great Lakes basin consist of 153 species, 64 genera, and 25 families. The total ichthyofaunal lists for the several lakes and (in parentheses) their tributary basins are as follows: Nipigon (and tributaries), 40; Superior, 53 (82); Michigan, 91 (135); Huron, 90 (112); St. Clair and Detroit River 108; Erie, 106 (125); Ontario, 95 (125). (These totals include 21 introduced species, most named species of ciscoes and chubs, and the blue pike (Stizostedion vitreum glaucum).)Several areas show notable within-species differentiation. Tributaries to Lake Ontario are part of a zone of secondary contact of a few small, nonmanaged, subspecies that entered the basin from both eastern and western glacial refugia. In the Great Lakes themselves, stocks of lake trout (Salvelinus namaycush), ciscoes, walleyes (Stizostedion vitreum vitreum), and a few nonmanaged species stem from differentiation within the basin or reflect interglacial events that occurred in Mississippi refugia.Species distribution patterns suggest colonization of the Great Lakes by 122 kinds solely from Mississippi basin refugia, 14 kinds only from Atlantic drainage refugia, and dual refugia for at least 18 kinds. Geological evidence provides some support for this interpretation. It is unlikely that any species colonized the Great Lakes from an Alaskan refuge in the past 14 000 yr.The ciscoes and chubs of the genus Coregonus include numerous genetically differentiated stocks, some of which may predate the opening of the Great Lakes in the past 14 000 yr. This conclusion is based on the occurrence in Lake Nipigon and Lake Superior of several forms that must have colonized prior to 9000 yr ago when the last access existed from Lake Superior to Lake Nipigon. At least four and perhaps up to eight forms of Great Lakes coregonines probably survived (or differentiated during) the last glaciation south of the ice in proglacial waters at the heads of major river systems. There is no evidence to support the hypothesized post-Wisconsinan dispersal of any of these forms from a northwestern refugium or their Pleistocene derivation by introgression with a Eurasian species.Despite the evidence for some long-standing genetic differentiation within Coregonus, morphological and biochemical characters fail to support the unequivocal recognition within the Great Lakes of more than one to four current biological species (apart from clupeaformis). The presently recognized species are groups of stocks whose position in the classification system is problematical. The named groups (two of which are extinct) included numerous stocks that were (or are) isolated by homing behavior specific to time and place. The lack of intrinsic reproductive isolation among forms increases their vulnerability to extinction because rare forms apparently hybridize with common forms spawning at adjacent times or places.Key words: biogeography, Coregonus, fish, Great Lakes, introduced fishes, Pleistocene, species, subspecies

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

Short-Term Survival of Lake Trout Released from Commercial Gill Nets in Lake Superior

1997 ◽  
Vol 17 (1) ◽  
pp. 136-140 ◽  
Author(s):  
Michael P. Gallinat ◽  
Hock H. Ngu ◽  
J. Dale Shively
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Short Term ◽  
Term Survival ◽  
Gill Nets ◽  
Short Term Survival

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.

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

Movements of Hatchery-Reared Lake Trout in Lake Superior

1965 ◽  
Vol 22 (4) ◽  
pp. 999-1024 ◽  
Author(s):  
Richard L. Pycha ◽  
William R. Dryer ◽  
George R. King
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Lake Superior ◽  
Salvelinus Namaycush ◽  
Surface Currents ◽  
Gill Nets ◽  
East Lake ◽  
History Of ◽  
Keweenaw Peninsula

The history of stocking of lake trout (Salvelinus namaycush) in the Great Lakes is reviewed.The study of movements is based on capture of 24,275 fin-clipped lake trout taken in experimental gill nets and trawls and commercial gill nets.Yearling lake trout planted from shore dispersed to 15-fath (27-m) depths in [Formula: see text]. Most fish remained within 2 miles (3.2 km) of the planting site 2 months, but within 4 months some fish had moved as much as 17 miles (27 km). The highest abundance of planted lake trout was in areas 2–4 miles (3.2–6.4 km) from the planting site even 3 years after release. Distance moved and size of fish were not correlated.Dispersal of lake trout begins at planting and probably continues until the fish are mature. Most movement was eastward in southern Lake Superior and followed the counterclockwise surface currents. Movement is most rapid in areas of strong currents and slowest in areas of weak currents or eddies. Movement to areas west of the Keweenaw Peninsula was insignificant from plantings in Keweenaw Bay and nil from other plantings farther east. Lake trout planted in the eastern third of the lake dispersed more randomly than those planted farther west. Few fish moved farther offshore than the 50-fath (91-m) contour. Lake trout planted in Canadian waters made insignificant contributions to populations in US waters.

scholarly journals Assessment of the Lake Trout Fishery in Lake Superior: 1929-1950

1978 ◽  
Vol 107 (4) ◽  
pp. 543-549 ◽  
Author(s):  
A. L. Jensen
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Trout Fishery

Declining Survival of Lake Trout Stocked during 1963–1986 in U.S. Waters of Lake Superior

1994 ◽  
Vol 14 (2) ◽  
pp. 395-402 ◽  
Author(s):  
Michael J. Hansen ◽  
Mark P. Ebener ◽  
Richard G. Schorfhaar ◽  
Stephen T. Schram ◽  
Donald R. Schreiner ◽  
...  
Keyword(s):  
Lake Trout ◽  
Lake Superior

Survey of the Genetic Variation Among Eastern Lake Superior Lake Trout (Salvelinus namaycush)

1981 ◽  
Vol 38 (12) ◽  
pp. 1738-1746 ◽  
Author(s):  
Terrence R. Dehring ◽  
Anne F. Brown ◽  
Charles H. Daugherty ◽  
Stevan R. Phelps
Keyword(s):  
Genetic Variation ◽  
Gel Electrophoresis ◽  
Lake Trout ◽  
Lake Superior ◽  
Salvelinus Namaycush ◽  
Starch Gel Electrophoresis ◽  
Average Heterozygosity ◽  
Management Implications ◽  
Salmonid Species ◽  
Starch Gel

Patterns of genetic variation among lake trout (Salvelinus namaycush) of eastern Lake Superior were examined using starch gel electrophoresis. We used 484 individuals sampled from three areas, representing three morphological types (leans, humpers, and siscowets). Of 50 loci examined, 44 were monomorphic in all groups sampled. Genetic variation occurs at six loci AAT-1,2, MDH-3,4, ME-1, and SOD-1. The average heterozygosity found (H = 0.015) is low relative to other salmonid species. A significant amount of heterogeneity exists among the 10 lake trout samples. These differences are due to variation within as well as between morphological types. The significance and management implications of these data are discussed.Key words: genetic variation, lake trout, Salvelinus namaycush, Lake Superior

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