| Autor: |
Rowland, Stuart J., Nixon, Mark, Landos, Matthew, Mifsud, Charlie, Read, Phil, Boyd, Peter |
| Předmět: |
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| Zdroj: |
Aquaculture Research; Jun2006, Vol. 37 Issue 9, p869-876, 8p, 1 Chart, 4 Graphs |
| Abstrakt: |
Infestations of parasitic monogenean trematodes ( Lepidotrema bidyana and Gyrodactylus sp.) on freshwater silver perch ( Bidyanus bidyanus Mitchell) in earthen ponds were treated with formalin (37% formaldehyde). Concentrations of 30 and 40 mg L−1 formalin were effective, but fish in ponds treated with 20 or 25 mg L−1 remained infested. At temperatures of 24.1–26.9°C, concentrations of 30 or 40 mg L−1 formalin caused dissolved oxygen (DO) to decline from 10.1–11.9 to 3.0–3.3 and 1.2–1.7 mg L−1, respectively, within 36–42 h of treatment. In addition, pH declined from 7.2–8.4 to 6.3–6.7, within 36 h and turbidity decreased over 48 h. In the ponds where DO was 1.2–1.7 mg L−1, silver perch showed signs of severe stress, but continuous aeration (10 hp ha−1) for 3 days and inflow of well-oxygenated water for 6–8 h prevented mortalities. At temperatures of 13.2–15.7°C, concentrations of 30 or 40 mg L−1 formalin caused DO to decline from 9.0–10.0 to 6.0–8.1 mg L−1 and pH from 7.0–7.3 to 5.9–6.6 within 72 h. Total ammonia-nitrogen increased over 72 h in ponds treated with 30 or 40 mg L−1 formalin. Fish became re-infested with L. bidyana in all ponds within 30 days of treatment. A concentration of 30 mg L−1 formalin is recommended as a treatment for monogeneans on silver perch in ponds, but aeration is necessary to maintain adequate water quality at higher temperatures. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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