Food habits of Salmo trutta and Salvelinus fontinalis (Pisces: Salmonidae) in relation to seasonal changes and mitigative liming effects in Dogway Fork of the Cranberry River, West Virginia.
Date of Award
College of Science
Type of Degree
Dr. Donald Tarter
Leonard J. Deutsch
Dogway Fork, a tributary of the Cranberry River in West Virginia, is acidic due to acid precipitation and poorly buffered soils. This study is part of a long-term investigation involving the effects of continuous limestone neutralization on the fishes and benthos of an acid stream. Prior to treatment in 1988, the stream had a pH of 4.5 and there were no fish present. Since treatment began, the pH of the stream has risen to 6.8. Nine species of fish have been collected and six species have reproduced following the improvement in water quality. Densities of specific acid-sensitive benthic macroinvertebrates have also increased after treatment. For the food habit study, brook and brown trout were collected seasonally by electrofishing and stomach contents were removed by flushing with a bulb pipette. Benthic samples were collected in duplicates using a modified Surber sampler. Statistical analyses were done to determine which taxa were the most abundant or most common in the diet and which taxa were most preferred by both trout species. Ivlev’s electivity index was used to determine which taxa each trout species was selecting for in the diet. Percent similarity among seasons and Morisita’s and Horn’s indices were calculated to determine the overlap in diet between seasons for brook and brown trout. Chironomid midges were the most abundant, common, and preferred taxon by both trout species in the spring season. Mayfly nymphs and hymenopterans were the most abundant components of the diet of both trout species in the summer and fall seasons. Mayfly nymphs, stonefly nymphs, and caddisfly larvae were the most important food items in the winter diets of both trout. Nematodes were also very abundant in the brook trout diet in the fall and winter. Mayfly nymphs and hymenopterans, as a whole, appeared to be the most important food items in the diet of both trout species for the year. Chironomid midges also appeared to be important components of the diet of both trout species.
Many of the organisms found within the diet of both trout species were not found in Dogway Fork before treatment began. Based on similarities with other studies, it appeared that mitigative liming changed the water quality allowing more species of macroinvertebrates to inhabit the stream and be utilized by brook and brown trout as food.
Brown trout – Food.
Brook trout – Food.
Aquatic liming – West Virginia.
Morgan, Jason A., "Food habits of Salmo trutta and Salvelinus fontinalis (Pisces: Salmonidae) in relation to seasonal changes and mitigative liming effects in Dogway Fork of the Cranberry River, West Virginia." (1999). Theses, Dissertations and Capstones. 1698.
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