Data were collected from natural and introduced fishes present in Ferndale Lake, a small (120 ha) sport fishing reservoir in Camp County, east Texas. Levels of pH measured in the lake during the study period ranged from 3.5 to 5.3. Monthly field surveys and experimental manipulations were designed to evaluate quantitatively the signs of stress at various biological levels. Lethal limits to low pH were quantified for largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus) to be pH 3.8 and 4.0,respectively. Mean blood pH (+ 1 SD) of 59 bluegill was 7.41 (j 0.16), with no significant difference (P-0.05) among groups from Ferndale Lake and Moss Lake (Cooke Co., Texas) under experimental conditions, even when severe stress was externally apparent. In a dual-trough horizontal pH gradient, bluegill behavioral avoidance was observed at pH levels below 7.0. Individual testing of 40 bluegill in pH gradient of 5.2 to 7.6 resulted in median occupation of pH 7.1,with an interquartile range of pH 6.9 to 7.3. Decreased community structure and population "well being" compared to early studies cannot be attributed entirely to recent acidic condition. Separating potential stress due to lake conditions from that due to heavy biotic predation by sport fishing in a small reservoir is difficult.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc663820 |
| Date | 08 1900 |
| Creators | Prete, Philip J. (Philip John) |
| Contributors | Beitinger, Thomas L., Stanford, Jack Arthur, 1947-, Zimmerman, Earl G. |
| Publisher | North Texas State University |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | v, 65 leaves: ill., map, Text |
| Rights | Public, Prete, Philip J. (Philip John), Copyright, Copyright is held by the author, unless otherwise noted. All rights |
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