Aspects of the biology of the lake whitefish, Coregonus Clupeaformis (Mitchill) in Hogan's Pond, Avalon Peninsula, Newfoundland.

Chen, Maynard Y. (1967) Aspects of the biology of the lake whitefish, Coregonus Clupeaformis (Mitchill) in Hogan's Pond, Avalon Peninsula, Newfoundland. Masters thesis, Memorial University of Newfoundland.

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Abstract

Systematic arrangement of lake whitefish was reviewed. Morphological features of the transplanted whitefish population in Hogan’s Pond were analysed and compared with the original Lake Erie population. Lake whitefish in Hogan’s has a smaller body size, relatively shorter snout, bigger eyes, longer fins, much shorter depth, more numerous gill rakers than Lake Erie whitefish; and has more lateral-line scales than any other population of the same species in North America, being 85.5. Osteology of Coregonus clupeaformis and in relation to that of other salmonid fishes were reviewed. -- Samples of whitefish were collected in 1965 and 1966. Age-group and age-group VI were dominant in these collections. The mean age for 258 fish was about 5 years. Fish with length between 271-310 mm. (fork length) and weight 201-280 grams constitute more than 62% of the total fish. -- The growth rate of young fish was smooth, however, the growth rate of older fish was so poor that a great degree of emaciation was noted. The length-weight relationship for 258 can be expressed by the equation: -- W = 0.1148 L²·²⁷⁷⁹. -- The average coefficient of condition for 258 fish was 1.072. -- The sexes were almost equally represented (53.3% males). Youngest mature male and female whitefish belonged to age-group II with a length of about 242 mm. (fork length). All fish shorter than 220 mm were immature, longer than 320 mm. were mature. -- Average fecundity of 35 female whitefish examined was 2.954 eggs, with egg diameters ranging from 1.0 to 2.7 mm. -- A rare case hermaphroditism of Coregonus clupeaformis was found in one specimen with ovo-testis on the left gonad. -- Food supply for Hogan’s Pond whitefish was found too small for them. The chief food items for these adult fish are Daphinia sp., Cyclops sp., and Amphipoda. Bottom fauna occupy only small proportions of food contents.

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