A novel intrauterine satellite transmitter to identify parturition in large sharks

Abstract

Determining where and when animals give birth is critical for establishing effective conservation management that protects vulnerable life stages (e.g., pregnant females and newborns) and places (e.g., nursery grounds). To date, this information has been elusive in the case of highly migratory sharks in the wild. Here, we report on the deployment a of novel intrauterine satellite tag implanted in two highly mobile apex predators, the tiger shark ( Galeocerdo cuvier ) and the scalloped hammerhead ( Sphyrna lewini ), that remotely documented the location and timing of birth by a highly migratory oceanic animal in the wild. This novel technology will be especially valuable for the protection of threatened and endangered shark species, where protection of pupping and nursery grounds is a conservation priority.

The successful use of a submersible ultrasound to confirm pregnancy on free swimming bull sharks, Carcharhinus leucas, in a provisioned shark site

“…Whether the gravid bull sharks analyzed in this study travel to Chetumal Bay (approximately 360 km from Playa del Carmen) requires further investigation via other methodologies (Sulikowski and Hammerschlag, 2023). Regardless, the results of the current study emphasize the importance of developing and linking emerging technologies with ecotourist sites for the conservation of elasmobranch species.…”

“…Over the course of the two 20 minute dives, individual sharks made several passes and based on the analysis of the Aquanaut video, three sharks were identified to be gravid (Figure 4) by the presence of identifiable embryos within the uterus (Sulikowski and Hammerschlag, 2023). Proprietary software measurements from still images indicated the embryos measured were approximately 4 cm in circumference.…”

“…The use of ultrasonography as a non-invasive methodology has proven to be a useful tool for the study of reproductive aspects in both captive and wild caught sharks (Walsh et al, 1993;Daly et al, 2007;Sulikowski et al, 2016;Inoue et al, 2022;Santos et al, 2022;Sulikowski and Hammerschlag, 2023). However, the use of this technology adapted for use underwater on free swimming wild animals is scant, with only one published study to date on whale sharks (Matsumoto et al, 2023).…”

“…Each scan lasted between one to three seconds. Collected video saved on the Aquanaut were used to create still images of observed embryos (Sulikowski and Hammerschlag, 2023). Stills from the video were then used to measure (via proprietary software pre-installed on the Aquanaut) pup diameter (cm) along the transverse axis (Sulikowski et al, 2016).…”

Top predator status and trends: ecological implications, monitoring and mitigation strategies to promote ecosystem-based management

“…Animal-borne electronic devices (Ropert-Coudert and Wilson, 2005) allow the remote collection of a vast array of high-resolution quantitative data on individual distribution, movement, behavior, trophic and social interactions, and internal state (McConnell et al, 1992;Weimerskirch et al, 2012;Watanabe and Takahashi, 2013;Banks et al, 2014;Andrzejaczek et al, 2022;Papastamatiou et al, 2022;Sulikowski and Hammerschlag, 2023;Watanabe and Papastamatiou, 2023). These tools can also be used to estimate atsea species distributions (e.g., Aarts et al, 2008;Louzao et al, 2011c;Carter et al, 2022).…”