title: Modeling impacts on populations: fathead minnow (Pimephales promelas) exposure to the endocrine disruptor 17beta-trenbolone as a case study.
abstract: Evaluation of population-level impacts is critical to credible ecological risk assessments. In this study, a predictive model was developed to translate changes in fecundity of the fathead minnow (Pimephales promelas) in a short-term laboratory toxicity test to alterations in population growth rate. The model uniquely combines a Leslie population projection matrix and the logistic equation. Application of the model requires only a life table for the organism of interest, a measure of carrying capacity for the given population, and an estimation of the effect of a stressor on vital rates. The model was applied to investigate population dynamics for fathead minnow exposed to the androgen receptor agonist 17beta-trenbolone. Organismal-level responses for fathead minnows exposed to varying levels of 17beta-trenbolone were used to determine projected alterations in a population existing in a small body of water containing varying concentrations of the androgen. Fathead minnow populations occurring at carrying capacity and subsequently exposed to 0.027 microg/L of 17beta-trenbolone exhibited a 51% projected decrease in average population size after 2 years of exposure. Populations at carrying capacity exposed to concentrations of 17beta-trenbolone > or = 0.266 microg/L exhibited a 93% projected decrease in average population size after 2 years of exposure. Overall, fathead minnow populations exposed to continued concentrations of 17beta-trenbolone equal to or greater than 0.027 microg/L were projected to have average equilibrium population sizes that approached zero.
authors.affiliation: Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, 9311 Groh Rd., Grosse Ile, MI 48138, USA. miller.davidh@epa.gov
authors.forename: David H
authors.initials: DH
authors.lastname: Miller
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Ankley
mesh_terms: D000728:Androgens; D000818:Animals; D003530:Cyprinidae / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004777:Environment; D004781:Environmental Exposure; D005260:Female; D005298:Fertility / Q000187:drug effects; D005544:Forecasting; D008962:Models, Theoretical; D011157:Population Dynamics; D011944:Receptors, Androgen / Q000378:metabolism; D018570:Risk Assessment; D014204:Trenbolone Acetate / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000728:Androgens; D011944:Receptors, Androgen; D014874:Water Pollutants, Chemical; D014204:Trenbolone Acetate