Steroid Hormone Metabolite Levels in European Minks: Implications for the Conservation of a Threatened Species

Captive management of endangered species is a common conservation strategy. Monitoring the endocrine response related to reproduction and the increase of fecal cortisol metabolites is key to evaluating reproductive well-being and condition. We noninvasively assessed the endocrine status of captive European minks (Mustela lutreola) housed at Foundation for Research in Ethology and Biodiversity [FIEB] (a Spanish biodiversity conservation center) by measuring fecal glucocorticoid cortisol metabolite levels and testosterone, and progesterone metabolite levels. Males showed higher fecal cortisol and testosterone metabolite levels while no differences in fecal progesterone metabolite levels were found between sexes. Fecal levels of the three hormones were positively correlated. Individuals born in FIEB had lower fecal cortisol metabolites than those born in other centers and their values did not increase due to captivity duration. Hormone values obtained in FIEB could serve as a reference for this species management. However, further studies are required to ensure the well-being and reproductive success of captive and wild populations.