Date of Award


Degree Type


Degree Name

Master of Science (MS)

Author's Department


First Advisor

L. Stephen Whitley


48-hr, 96-hr, and incipient median tolerance limits of channel catfish (Ictalurus punctatus Rafinesque) to copper and hexavalent chromium were determined at temperatures of 50, 60, 70, and 80 F. Standard static bioassay procedures were used. The incipient TLm for copper ranged from 0.56 ppm to 2.15 ppm and from 22.5 to 39.5 ppm for hexavalent chromium. The 48-hr and 96-hr results were somewhat higher. The highest resistance for both metals occurred at 70 F. At 80 F, however, there was a sharp decrease in tolerance. Increased oxygen consumption and opercular movement offer a possible explanation since they would cause more metal to be drawn into the fish. Death from copper was attributed to destruction of the gill epithelium. Although no internal investigations were made, chromium was though to have caused death by damaging the gut epithelium. Further studies are needed to determine long-term safe levels, mechanisms of lethal action, and accumulation and elimination in the tissues.

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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.