Preliminary Age Estimates for Female Southern Stingrays (Hypanus americanus) from Southwestern Florida, USA

IntroductIon The Southern Stingray, Hypanus americanus (previously Dasyatis americana), is a common whiptail stingray of western Atlantic coastal waters, including the Caribbean Sea and the Gulf of Mexico (Robins and Ray 1986, Last et al. 2016). Although this stingray is important to ecotourism in the Caribbean Sea (Corcoran 2006) and is routinely captured as bycatch within southern trawl fisheries (Graham et al. 2009), it is currently not under direct threat of overexploitation. While biological and behavioral information has been reported for this species based on studies of both captive (Henningsen and Leaf 2010) and wild individuals (Funicelli 1975, Chapman et al. 2003, Corcoran 2006, Semeniuk et al. 2007), significant gaps in life history remain. The species is considered data deficient by the International Union for Conservation of Nature (IUCN) (Grubbs et al. 2016). Age information forms the basis for calculations of growth and mortality rates, as well as productivity, making it one of the most important variables for estimating a population’s status, including assessments of the risks associated with exploitation (Cailliet and Goldman 2004). Henningsen and Leaf (2010) provided initial age data on captive southern stingrays; however, no complementary work has been conducted on wild populations. Since growth in captivity may not accurately reflect growth in the wild (Mohan 1996), the goal of the present study was to provide preliminary age— at—width estimates of wild caught specimens using counts of growth bands from vertebral centra.