Development of Sperm Cryopreservation Protocols for Sharks and Rays: New Tools for Elasmobranch Conservation

Elasmobranchs are one of the most endangered vertebrate groups on planet, but despite this situation use reproductive techniques in elasmobranch conservation strategies has been scarce. Among these techniques, sperm preservation is a potential tool for ex situ and aquaria sustainability. However, there no widespread protocols sperm, shark cryopreservation never achieved before. Here we present establishment successful tested several species. We have formulated extender that can be used different species, capable maintaining motility weeks. Additionally, by previously diluting it our supplementing with combinations cryoprotectants. The effects methanol dimethyl sulfoxide as permeating cryoprotectants were evaluated, well egg yolk non-permeating cryoprotectant. Sperm quality was assessed studying membrane integrity post-thawing, demonstrating its effectiveness 10 species tested, including two which considered Critically Endangered. This first time reported, broadening knowledge applied to elasmobranchs laying foundations cryobanks ray sperm. Outcomes from study will useful efforts developed public aquaria. A regular supply frozen reduce problems result transport specimens, inbreeding or lack synchronized cycles captivity.