Annual breeding in a captive smalltooth sawfish, Pristis pectinata

Abstract

The critically endangered smalltooth sawfish Pristis pectinata reproduces biennially in central west Florida, U.S.A. Here we demonstrate that smalltooth sawfish are physiologically capable of reproducing annually in a captive environment. The smalltooth sawfish are held in an open system, with abiotic conditions that vary naturally with the surrounding environment in The Bahamas. This suggests wild smalltooth sawfish may also be capable of annual reproduction provided there are adequate prey resources, limited competition and mate availability.

The role of aquaria in the advancement of elasmobranch reproductive biology

“…This approach underrepresents natural variation among individuals, and can, at times, lead to discrepancies in accurately describing the reproductive cycle of a species. For example, in the Smalltooth Sawfish (Pristis pectinata) reproduction was estimated to occur on a biennial cycle in situ (Carlson and Simpfendorfer, 2015;Feldheim et al, 2017), but was observed to occur annually ex situ (Flowers et al, 2020), indicating that females are physiologically capable of reproducing every year. Animals held in human care have access to ample food resources and, potentially, reduced stressors, which could remove energetic obstacles that may result in animals having prolonged time between breeding cycles in situ.…”

“…Animals held in human care have access to ample food resources and, potentially, reduced stressors, which could remove energetic obstacles that may result in animals having prolonged time between breeding cycles in situ. Importantly, Smalltooth Sawfish are critically endangered, and their biennial reproduction could be a result of resource limitation(s) such as food or mates in situ (Flowers et al, 2020), the latter of which may contribute to why parthenogenesis has been observed in this wild population of elasmobranchs (Fields et al, 2015). Nevertheless, documentation of this important life history discrepancy through information gleaned from aquaria has important implications for recovery and management of this severely impacted species.…”

“…For example, these efforts are being trialed by the StAR project that represents a multi-institutional effort spanning aquaria, academia, government, for-profit, and non-profit institutions to re-wild this species in the Indo-Pacific. If successful, this project could lay the ground work for other critically endangered species such as the Bowmouth Guitarfish (Rhina ancylstoma; Hanna and Hazeres, 2021), and sawfish (Pritis species; Flowers et al, 2020) where breeding has occurred.…”

Kinship assessment and insights into reproductive behaviour of the Critically Endangered green sawfish Pristis zijsron in Western Australia

“…Little is known about the reproductive biology of sawfishes, genealogical relationships, or incidence of inbreeding within populations, hindering the development of effective population assessments and management plans (Chapman et al, 2011; Elhassan, 2018; Feldheim et al, 2017; Flowers et al, 2020; Kyne et al, 2021; Thorson, 1976). Pedigrees can be used to fill these data gaps but are rarely able to be constructed based on direct observations for elasmobranchs (Brooks et al, 2016; Dibattista et al, 2008; Holmes et al, 2018; Mourier & Planes, 2013).…”