Abstract

One-hundred and three bottom samples taken at Fish Lake, Utah from July, 1969 to June, 1970 were analyzed to determine the abundance, distribution, and standing crop of the bottom fauna species and to relate their availability to the amount of food eaten by the trout. Twenty-three taxa, representing three phyla and 19 families were collected. An amphipod, Gammarus limnaeus, in the littoral zone, and a tubificid worm, Rhyacodrilus coccineus, in the sublittoral and profundal zones, were the most abundant species. All 23 species were unevenly distributed in the littoral zone, whereas, only eight were found in the sublittoral and five in the profundal zones. Standing crop of invertebrates was greatest in the littoral zone in November, 1969. Analysis of the stomach contents of 135 lake trout and 1105 rainbow trout revealed that bottom invertebrates contributed only small amounts to the diet; differing from previous studies where bottom invertebrates were of major importance in the trout's diet.

Degree

College and Department

Life Sciences; Plant and Wildlife Sciences

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