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Annulus formation on scales of four species of coregonids reared under artificial conditions

Journal of the Fisheries Research Board of Canada

Out-of-print
By:
DOI: 10.1139/f68-188

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Abstract

Scales from known-age coregonids reared in the laboratory were examined to determine when annuli formed and to learn possible factors of their formation. Scales were taken monthly from marked fish for periods up to 21 months. Scales were also examined from fish that died and from preserved specimens of young-of-the-year for each species. Two marks formed on almost all scales each calender year. The stronger formed during March-April and the weaker in October-November. Both marks had all the usual characteristics of an annulus but the spring mark was considered the annulus and the fall mark an accessory check. The annulus formed during a period of constant temperatures and of little change in growth or increasing growth. The accessory check formed during a period of declining temperatures (1-5 degrees F, or 0.6-2.8 degrees C, per month) and of little change in growth or declining growth. Most fish grew throughout the winter; the only exceptions were one bloater (Coregonus hoyi) and several of the largest lake whitefish (C. clupeaformis). Fish were always given all the food they would eat to eliminate availability of food as a factor of mark formation. The temperature of the water during the winter (50 ±. 0.3 F; 10.0 ±. 0.2 C) did not arrest metabolic activity. The growth rate was related more closely to day length than to other variables examined.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Annulus formation on scales of four species of coregonids reared under artificial conditions
Series title:
Journal of the Fisheries Research Board of Canada
DOI:
10.1139/f68-188
Volume
25
Issue:
10
Year Published:
1968
Language:
English
Publisher:
NRC Research Press
Publisher location:
Ottawa, Ontario
Contributing office(s):
Great Lakes Science Center
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of the Fisheries Research Board of Canada
First page:
2111
Last page:
2122