Mating system in a captive population of a dasyatid ray, the southern stingray (Hypanus americanus Hildebrand and Schroeder 1928), at the National Aquarium, Baltimore, Maryland

Abstract

The southern stingray, Hypanus americanus, is a common coastal ray, ranging from New Jersey to Brazil, including the Gulf of Mexico and Caribbean Sea. It is an important resource for ecotourism in the Bahamas and Cayman Islands. It is a hardy species that survives many years as well as commonly reproduces in captivity. Despite the fact that many aspects of its life history have been described from captive as well as wild conspecifics, the mating system is not well understood. Behavioral polyandry has been well documented in both groups. While genetic polyandry or multiple paternity appears to be common in many species of elasmobranchs, it has not been reported in the southern stingray. The goal of this investigation is to document multiple paternity as an aspect of the mating system in this species based upon a population of reproductively active southern stingrays that were maintained at the National Aquarium. Amplicon deep-sequencing using next generation sequencing (NGS) technology was used to determine multiple paternity. The two-step PCR approach combined Illumina’s dual indexing strategy and species-specific primers. Results confirmed multiple paternity, and that two to three potential sires were involved. Since it was documented in this group of captive rays, it is likely to occur in wild conspecifics given the similar polyandrous mating events. Although the southern stingray is not a species of concern for extinction, it is an important consideration for population management. This investigation provided the first documented case of multiple paternity in a dasyatid ray, and only the second case in a viviparous batoid.