Record Details
Mercury accumulation in fish from Cottage Grove Reservoir and its tributaries
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Mercury accumulation in fish from Cottage Grove Reservoir and its tributaries |
| Names |
Worcester, Thomas C
(creator) Buhler, Donald R. (advisor) |
| Date Issued | 1979-02-22 (iso8601) |
| Note | Graduation date: 1980 |
| Abstract | A fish sampling program was initiated at Cottage Grove Reservoir in June of 1974 to investigate mercury accumulation in the fish. Samples were collected periodicallv from June to November, 1974, and from June, 1975 through January, 1976 from both the reservoir and its tributaries. Species collected included spring chinook salmon Oncorhynchus tshawytscha, rainbow trout Salmo gairdneri, cutthroat trout Salmo clarki clarki, largemouth bass Micropterus salmoides, and brown bullhead Ictalurus nebulosus. Cutthroat trout and spring chinook salmon sampled from a tributary of Cottage Grove Reservoir in 1974 and 1975 had significantly less mercury in their muscle tissue than similar fish collected from the reservoir (P < 0.05). All species of fish except the 1+ brown bullheads collected in 1974, tended to accumulate mercury with time. Many of the fish sampled had mercury levels two to three times the FDA guideline of 0.5 [mu] Hg/g. It also appeared that predatory fish accumulated higher mercury levels than non-predatory species. The percent of mercury as methylmercury in all species ranged from 4.3 to 100, with most fish containing between 60% and 90% methylmercury. Mercury uptake from the food accounted for a significant percentage of the total mercury uptake of the 0+ spring chinook collected in 1974. The average methylmercury concentration in the diet of the fish was estimated to be 0.23 [mu]g Hg/g. The significant difference in mercury concentration and total body burden of mercury of the spring chinook collected from the Coast Fork of the Willamette River and Cottage Grove reservoir suggested that two separate populations of chinook might exist (P < 0.05). Yearling chinook salmon collected from the reservoir in the spring of 1976 with greater than 0.20 [mu] Hg/g in the muscle tissue had greater mortality in saltwater than the control fish which had mercury concentrations below 0.10 [mu]g Hg/g. |
| Genre | Thesis/Dissertation |
| Topic | Fishes -- Mercury content -- Oregon -- Cottage Grove Lake |
| Identifier | http://hdl.handle.net/1957/18931 |
