Reproductive performance of two generations of female semidomesticated mink fed diets containing organic mercury contaminated freshwater fish

Semidomesticated female mink (Mustela vison) were fed daily diets containin g 0.1 ppm, 0.5 ppm, and 1.0 ppm of total mercury. Piscivorous and nonpisciv orous fish naturally contaminated with organic mercury were used to prepare the diets. Twenty-month-old females (G1 generation) that were exposed to t he experimental diets for approximately 400 days in 1994 and 1995 and their 10-month-old female offspring (G2 generation) that were exposed to mercury for approximately 300 days in 1995, were all mated to 10-month-old males. Males were fed the diet containing 0.1 ppm mercury 60 days prior to the mat ing season. Diets containing 0.1 ppm and 0.5 ppm were not lethal to G1 and G2 females for an exposure period of up to 704 days. At the age of 11 month s, mortalities occurred in 1994 for G1 females (30/50) and in 1995 for G2 f emales (6/7) fed the 1.0 ppm mercury diet after 90 days and 330 days of exp osure, respectively. The length of the gestation periods and the number of kits born per female were not different among dietary groups for the two ge nerations of females. The proportion of females giving birth was low for al l groups, except for the G1 females fed the 0.1 ppm diet. There was an inve rse relationship between whelping proportion and exposure group, but was no t statistically significant. There was evidence that kits were exposed to m ercury both in utero and/or during lactation as indicated by the presence o f mercury in their livers. Mercury exposure did not influence the survival and growth of neonatal kits.