USE OF SURFACE MUCUS AS A BIOMARKER FOR ENDOCRINE DISRUPTION IN Fundulus grandis

Reproductive investment and endocrine health are normally assessed using assays which typically rely on blood collection, which is often lethal to small fishes. Surface mucus collection offers a less invasive methodology to determine concentration of 11-ketotestosterone (11-KT) and vitellogenin (VTG). This project seeks to (1) validate and confirm the use of mucal swabs as an effective and non-lethal alternative to determine concentrations of 11-KT and VTG of Fundulus grandis through comparative assays of blood plasma, and (2) use this minimally invasive method to evaluate potential endocrine disruptions in F. grandis undergoing chronic exposure to a water accommodated fraction (WAF) of crude oil, and (3) assess potential differences in endocrine disruption at the population level based on exposure history.

Mucus and plasma samples were collected from male and female F. grandis. Both 11-KT and VTG showed significant positive relationships between their concentrations in the plasma and mucus. Four different populations of F. grandis with different exposure histories were exposed to WAF for 60 days, and post-WAF conditions for 40 days.  Assessment of mucosal 11-KT concentrations showed that endocrine disruption was observed in many populations throughout time with a severe decline 40 days post-WAF. Changes in concentrations of 11-KT and VTG where significant with the linear relationship of time, treatment and population. Exposure history also had a significant effect on 11-KT concentrations; exposed reference site males had a decrease in 11-KT concentrations, while concentrations of 11-KT of exposed males from contaminated sites increase. Exposed females showed near null concentrations of mucosal VTG when exposed to WAF regardless of exposure history. These data demonstrate the utility of mucus sampling as a less invasive tool to assess endocrine disruption in captive fishes, allowing to assess reproductive investment and potential.