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The relative efficiency of nylon and cotton gill nets for taking lake trout in Lake Superior

Journal of the Fisheries Research Board of Canada

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DOI: 10.1139/f62-071

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Abstract

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.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The relative efficiency of nylon and cotton gill nets for taking lake trout in Lake Superior
Series title:
Journal of the Fisheries Research Board of Canada
DOI:
10.1139/f62-071
Volume:
19
Issue:
6
Year Published:
1962
Language:
English
Publisher:
NRC Research Press
Contributing office(s):
Great Lakes Science Center
Description:
10 p.
First page:
1085
Last page:
1094
Online Only (Y/N):
N
Additional Online Files (Y/N):
N