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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #76382
Title: SEXUAL DIFFERENCES IN MORTALITY AND SUBLETHAL STRESS IN CHANNEL CATFISH FOLLOWING A 10 WEEK EXPOSURE TO COPPER SULFATE

Author
item PERKINS, E - UM DEPT PHARMACOLOGY
item Griffin, Billy
item HOBBS, MELISSA - UA
item Franks, Jan
item WOLFORD, L - UM DEPT PHARMACOLOGY
item SCHLENK, DAN - UM DEPT PHARMACOLOGY

Submitted to: Aquatic Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Channel catfish were exposed for 10 weeks to three levels of copper sulfate in their culture tank water. At 2 week intervals, 6 fish were sampled and copper levels in muscle and liver tissue were measured.Measures of whole weight, length, and liver weight were taken and used in formula to calculate stress indicators. No deaths occurred in the untreated and low dose groups. Mortalities occurred in the intermediate and high dose groups Copper binding proteins in the liver increased in line with increasing levels of copper in the tissue.Males showed substantial signs of stress and died in greater numbers than did females at the same copper sulfate concentrations. The higher resistance of females to copper toxicity suggests a mechanism of protection that has not been previously reported.

Technical Abstract: Male and female channel catfish (ictalurus punctatus) were treated for 10 weeks with concentrations of copper sulfate giving 220, 354, and 465 ug Cu/L. Fish were sampled at 2 week intervals and copper levels in muscle and hepatic tissure were measured. Hepatic accumulation began within the first 2 weeks of treatment, peaked at 4 to 6 weeks and declined before the end of the exposure. No mortality was seen in controls or at 220 mg Cu/L. Lethality was seen within the first week in the 354 and 465 ug Cu/L exposures with males being more susceptible than females. Metallothionein levels showed an increasing trend through the 6-week time period followed by a general decrease toward control levels. The pattern of hepatic MT was similar to that os hepatic copper accumulation, with a correlation coefficient (r) of 0.767 (p < 0.001). No substantial change in sublethal stress indicators occurred in females; however a decreasing tendency was seem in males. Correlation analysis of hepatic copper with somatic measures showed a significant relationship in both sexes. When hepatic Mt was compared to somatic indices, significant correlations were observed in males, but not females. An unreported mechanism for copper metabolism is indicated.