India harbours over 32 00 freshwater and marine fish species, many of which are increasingly threatened by habitat degradation, overexploitation, and climate change. In this context, the implementation of ex situ conservation strategies is critical for ensuring the sustainability of aquatic biodiversity. Embryo cryo banking offers a viable approach for long-term preservation of genetic material, thereby supporting biodiversity conservation and enabling genetic rescue through reintroduction of genetic diversity into endangered or inbred populations. However, u nlike sperm banking , the major impediments in embryos cryopreservation of fish include structural complexities such as multi-compartmental structure of fish eggs, large yolk content, low membrane permeability, and high chilling sensitivity.
In current investigation, we conducted a pioneering feasibility investigation on the cryopreservation of fish embryos from carps and catfish species. Multiple embryonic stages were evaluated, and the toxicity of varying concentrations of several cryoprotectants was assessed. Key parameters investigated included embryonic developmental stage, chorion permeabilization, exposure duration and cryoprotectant concentration . Our results demonstrated that specific developmental stages exhibited increased tolerance to cryoprotectant stress and low temperature freezing. These findings provide a foundational framework for developing standardized protocols for fish embryo cryopreservation in India, with significant implications for biodiversity conservation and genetic resource management.