Food study based on the stomach content analyses
of spring and coho salmon collected from various localities
along the southern British Columbia coast during the summer
of 1957 revealed that herring followed by Crustacea formed
the most important item of the diet of the two species. Coho
salmon exhibited more pelagic and varied diet than spring
salmon caught in the same area. Definite seasonal fluctuations
in the composition of food and feeding intensity were noticed,
considerable amounts of Crustacea were taken in early summer
months and after that fish assumed importance. July and
August mark the period when the feeding activity is intense
in both the species.
Qualitative and quantitative differences in the
feeding conditions on the east and west coasts of Vancouver
Island warrant the establishment of two food type areas. The
differences in growth of fish on the two coasts as related to
feeding conditions are discussed. Although, herring is the
major food item of both spring and coho salmon, evidences are
presented in support of the hypothesis that a reduction in
herring stock abundance due to predation would not affect
salmon catches.
Based on ova measurements and maturity index values
fish have been classified into immature and maturing. It
appears that almost all coho salmon available to the commercial
fishery are maturing, spring catches on the other hand include large percentage of both immature and maturing fish.
Immature and maturing female springs divide at a fork length
of 74 cm., cohos do so at an approximate fork length of 52
A volume method for the determination of egg numbers
present in the ovary has been developed, the average percentage
error between the calculated and actual counts being 5.3. it
was found that the absolute fecundity is positively correlated
to fish length and negatively to egg size but the magnitude of
the effect of fish length on absolute fecundity is about four
times greater than that of egg size. / Science, Faculty of / Zoology, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41674 |
| Date | January 1958 |
| Creators | Prakash, Anand |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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