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The Effect of Fin Removal on Fingerling Lake Trout (Cristivomer Namaycush)
Author(s) -
Shetter David S.
Publication year - 1951
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1950)80[260:teofro]2.0.co;2
Subject(s) - fish fin , fin , dorsal fin , fish <actinopterygii> , hatchery , trout , biology , fishery , zoology , body weight , fish measurement , anatomy , materials science , composite material , endocrinology
Four lots of fish marked by fin removal were held at the State fish hatchery, Marquette, Michigan, to ascertain the amount of fin regeneration, comparative survival, and comparative growth which would follow this treatment over varying periods of time. It was determined that the following percentages of the surviving marked fish should be recognizable (regeneration 0–50 percent of the fin area) in the future: 1944 mark, dorsal and adipose fins clipped, 90.4 percent; 1945 mark, right pectoral fin clipped, 96.5 percent; 1946 mark, left pectoral fin clipped, 89.8 percent; 1947 mark, right pelvic fin clipped, 64.1 percent. Observations of fin regeneration suggested further that the calculated numbers of marked fish surviving in the mortality‐growth experiments conducted at the same time should be adjusted upward, as it was demonstrated that from 0.2 to 20.8 percent of the survivors of the regeneration experiments had fully regenerated fins when examined at various times during the course of the experiments. The difference in mortality which occurred among marked and normal lake trout fingerlings in experiments performed under identical conditions and initiated with equal numbers of fish was concluded to be of insignificant proportions for the 1944, 1945, and 1947 markings. However, on the basis of chi‐square tests for the departure of normal marked fish from the originally established ratio, removal of the left pectoral fin appears to have resulted in a 16.1 percent increase in instantaneous mortality among fish of the 1946 experimental group. Comparison of the growth of normal and marked lake trout fingerlings held in the same ponds indicates that removal of the dorsal and adipose fins (1944), right pectoral fin (1945), or right pelvic fin (1947) had no effect on the growth of marked fish; the differences had no statistical significance. However, the left pectoral mark used in 1946 appears to have slowed growth of the fish so marked by a small (8.6 millimeters), but statistically significant amount.