| Abstract: | The twenty-four-hour median lethal concentrations (24-hour LC50) of total ammonia nitrogen (TA-N) to channel catfish (Ictalurus punctatus) at pH 7, 8, and 9 (total hardness, 40 mg/liter; temperature, 21–25 C) were 263.6 ± 11.3 (SE), 38.8 ± 1.8, and 4.5 ± 0.2 mg/liter, respectively. The 24-hour LC50 of un-ionized ammonia nitrogen (UIA-N) concentration at pH 8 was significantly higher (1.82 ± 0.06 mg/liter) than at pH 7 or 9 (1.39 ± 0.06 and 1.49 ± 0.12 mg/liter). Enrichment of the water to 440 mg/liter total hardness at pH 7 significantly increased the 24-hour LC50 of TA-N and UIA-N (356.3 ± 16.4 and 1.79 ± 0.07). Fish exposed to 25 mg/liter TA-N for 12 hours at pH 7 and 8 showed no differences from control fish in hematocrit, percent total plasma protein, or plasma and muscle chloride. Plasma sodium showed no difference between control and experimental groups at pH 7; however, a significant decrease occurred in fish exposed to 25 mg/liter TA-N at pH 8. No differences in blood pH were found between the control groups and fish exposed to 100 and 200 mg/liter TA-N at pH 7, and to 10 and 25 mg/liter TA-N at pH 8. Plasma sodium depletion is suggested as a contributing mechanism of ammonia toxicity. |
| Genre: | Article |
| ProdID: | 70006968 |
| Citation Author: | Tomasso J. R.; Goudie, C. A.; Simco, B. A.; Davis, K. B. |
| Citation Contributing Office: | Leetown Science Center |
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| Citation End Page: | 234 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Transactions of the American Fisheries Society |
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| Citation Number Of Pages: | 6 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | 6 p. |
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| Citation Public Comments: | None |
| Citation Publisher: | Taylor & Francis |
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| Citation Search Results Text: | Effects of environmental pH and calcium on ammonia toxicity in channel catfish; 1980; Article; Journal; Transactions of the American Fisheries Society; Tomasso J. R.; Goudie, C. A.; Simco, B. A.; Davis, K. B. |
| Citation Start Page: | 229 |
| Citation Volume: | 109 |
| Citation Year: | 1980 |
| Type: | citation/reference |
| Text: | Effects of environmental pH and calcium on ammonia toxicity in channel catfish; 1980; Article; Journal; Transactions of the American Fisheries Society; Tomasso J. R.; Goudie, C. A.; Simco, B. A.; Davis, K. B. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1577/1548-8659(1980)109<229:EOEPAC>2.0.CO;2 |
| Date Other: | Sun, 1 Jan 2012 12:57 -0600 |
| Publisher: | Taylor & Francis |
