Abstract

The zebra shark or Indo-Pacific leopard shark, Stegostoma tigrinum, is widely distributed across the Indo-West Pacific but is functionally extinct in the Raja Ampat archipelago. The Stegostoma tigrinum Augmentation and Recovery (StAR) Project was initiated in 2020 to recover endangered zebra sharks, beginning with the population in Raja Ampat, Indonesia.

Through a large multinational partnership, eggs produced through ex situ breeding of healthy, genetically-appropriate adults at association-accredited aquariums (AZA or ZAA) are shipped to Indonesia for hatching and rearing at two custom-built hatcheries. The hatcheries are run by local, trained partners and built using local materials from designs provided by TJP Engineering. Eggs were first transported from Australia in August 2022 and the United States in November 2022. As of writing, three pups have hatched and are doing well. They will be moved to sea-pens until they meet criteria for release into the adjacent marine protected area. Post-release monitoring will include surgically-implanted acoustic telemetry. Based on a Population Viability Analysis, this is anticipated as a 10-year project with cycles of transports, rearing, and releases to develop a healthy, self-sustaining population of zebra sharks in the wild.

Animal care resources developed through the planning process by veterinary and husbandry working groups include an Animal Care Manual with egg transport procedures, egg assessment, and disease risk analysis. The latter of which identified two specific hazards: systemic vibriosis and invasive scuticociliates, along with associated mitigation measures. There have been many challenges and lessons learned through the process to date. Fewer eggs have been shipped than initially planned, partly due to an unexpectedly high proportion of parthenotes, and possibly associated with the older age of many of the genetically-suitable breeding females in the partner populations. The resources and lessons learned will be used by the ReShark collective (ReShark.org) to develop a model for restoring other chondrichthyes around the world.

Acknowledgments

We would like to acknowledge all StAR Project partners, but the word count prohibits it. In particular, we want to thank Conservation International, West Papua Provincial Government, Indonesian Ministry of Marine Affairs and Fisheries, National Research and Innovation Agency, Raja Ampat Research and Conservation Centre, and Misool Foundation.

*Presenting author