As extinction rates accelerate due to habitat loss and climate change, ex-situ programs are becoming increasingly important for species conservation. Recent advances in broodstock surrogacy offer promising tools for the conservation of endangered marine fishes; however, their application has so far been limited to teleost species. In broodstock surrogacy, germ cells (GCs) isolated from an endangered species are transplanted into a host of a closely related species. These cells migrate to the host’s gonads, proliferate, and eventually develop into functional sperm or eggs.
Found only in Macquarie Harbour (TAS), where environmental degradation poses a critical threat to its survival, the Maugean Skate (Zearaja maugeana) is one of the world’s most endangered elasmobranchs. This study investigates whether broodstock surrogacy can be adapted for use in elasmobranch conservation, using the Maugean skate as a model.
In this talk we will present an overview of the program and early results. A protocol for the isolation and cryo-preservation of elasmobranch gonad tissue has been developed, allowing the establishment of a cryo-bank of Maugean skate genetic resources. Furthermore, we present a method for the isolation and transplantation of germ cells into embryonic and juvenile skate hosts, using umbilical and intraperitoneal injections respectively. The incorporation of xenogenic cells was tested by labelling donor cells using PHK26, a fluorescent marker. Cells have been successfully detected in the host gonads 3-4 weeks after transplantation. Successful cell incorporation was observed across a range of conditions like donor sex and state of maturity, host sex, and the use of fresh and frozen donor cells. These early results show promise for the viability of broodstock surrogacy in an elasmobranch model. Combined with assisted reproduction, cryo-banking, and conservation genomics, these technologies hold significant promise for elasmobranch conservation and could help protect and restore vulnerable populations worldwide.