Prevention and treatment of Nitrite toxicity in juvenile steelhead trout (Salmo gairdneri)

Journal of the Fisheries Research Board of Canada
By:  and 

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Abstract

The efficacy of mineral salts, pH, and tetramethylthianine (methylene blue) treatment in reducing the acute toxicity of nitrite to fingerling steelhead trout (Salmo gairdneri) was determined using a static bioassay system at 10 °C. The acute toxicity (96-h LC50) was reduced by a factor of about 24 for 5-g steelhead and 13 for 10-g fish when the total water hardness was increased from 25 to 300 mg/L (as CaCO3). NaCl or CaCl2 additions (0–200 mg/L) reduced toxicity by a factor of up to 3 for NaCl and 50 for CaCl2. Increasing the pH from 6.0 to 8.0 decreased toxicity by a factor of about 8 for the smaller and 3 for the larger fish. Methylene blue at 0.1 or 1.0 mg/L was effective in decreasing acute toxicity. For alleviating methemoglobinemia, removing the fish to freshwater for 48 h was about as effective as 1.0 mg/L methylene blue. Chronic exposure in soft water to 0.03 mg/L NO2-N for 6 mo caused no significant growth reduction, gill histological changes, hematological dyscrasias, or impaired ability of the smolts to adapt to 30‰ seawater and grow for an additional 2 mo. Key words: nitrite, toxicity, fish, methylene blue, pH, salts, acute toxicity, chronic toxicity

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Prevention and treatment of Nitrite toxicity in juvenile steelhead trout (Salmo gairdneri)
Series title Journal of the Fisheries Research Board of Canada
DOI 10.1139/f78-132
Volume 35
Issue 6
Year Published 1978
Language English
Publisher NRC Research Press
Contributing office(s) Western Fisheries Research Center
Description 6 p.
First page 822
Last page 827
Online Only (Y/N) N
Additional Online Files (Y/N) N