Fisheries Investigations – 08 Summary

Fisheries Investigations in Crater Lake, Oregon, 1937-1940 by Arthur D. Hasler and D. S. Farner


1. Natural reproduction of both silver salmon and rainbow trout in Crater Lake has been proved by the scale method. The strong 1934 year-class of trout originated from a natural hatch and it constituted 42.4 per cent of all captures over a 4-year period. No salmon were planted in 1939 but that year-class of salmon constituted 76.5 per cent of the 1940 captures.

2. Fishing was more successful from 3:00 p.m. until dusk than earlier in the day.

3. More fishes were caught in July than in August each year.

4. The proportions of the various foods in the diet of Salmonids apparently depends upon their availability.

5. In general, good growth was correlated with a strong year-class in both species. There was no evidence that the present population density is injurious to good growth.

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