Reproductive and developmental effects of tributyltin, bisphenol A, and 17 β-estradiol in pale anemones (Aiptasia pallida)

The effects of exposure to estrogenic endocrine-disrupting chemicals in most clades of marine invertebrates are unknown. The purpose of this study was to determine if exposure to 3 such chemicals modulates asexual reproduction and development in pale anemones (Aiptasia pallida). Anemones (n = 18 in each group) were exposed for 21 days to one of 8 treatments: seawater alone, seawater containing vehicle, or seawater containing a low (environmentally relevant) or high dose of tributyltin (TBT), bisphenol A (BPA), or 17 β-estradiol (E2) dissolved in vehicle. The number of asexually generated pedal lacerates produced by each anemone and the number of days required for each lacerate to develop a stomodeum and tentacles were recorded. At the end of the study, parent anemones were homogenized, and total protein content (as a proxy for body size) was quantified by Bradford assay. The roles of chemical treatment and parent anemone size in determining lacerate production were evaluated with binomial-Poisson hurdle models, and their roles in determining development rate were evaluated with generalized linear models. Application of model selection criteria suggested that exposure to E2 (at 45 ng/L) but not to TBT or BPA was associated with increased pedal lacerate production. Neither low nor high doses of any chemical tested affected the number of days required for lacerates to develop into juveniles. Although cnidarians are not thought to express genes homologous to vertebrate estrogen receptors, evidence from this and other studies suggests that estrogens, at least at high doses, are bioactive in these basal metazoans.