Cawthron scientists make significant progress enhancing cryopreservation techniques for Greenshell mussels
Globally aquaculture is one of the fastest growing food production sectors. Over 50% of fish, shellfish, crustacea and aquatic plants in our food supply now come from aquaculture and this trend in growth is projected to continue. Sustained growth of the sector requires hatchery production to underpin the supply of juveniles for on growing. Alongside of this are selective breeding programmes which can make rapid genetic gains as farmers move from wild to selectively bred stocks.
Cawthron Institute are leading-edge researchers in the field of shellfish breeding. We aim to help the seafood industry identify the best qualities in shellfish that make for the highest quality and economic seafood and help industry to breed those characteristics into their stock.
Cryopreservation can be a useful tool for breeding programmes because it provides a backup of germplasm for breeders to go back to, should breeding stocks be lost for any reason (e.g. severe weather events) or should breeding objectives change (e.g. selection for resilience to emerging diseases). Cryopreservation can also be used to create reference lines that can provide a benchmark between different cohorts and measure true genetic gain.
Several New Zealand’s largest commercial mussel producers trust us to help them optimise their operations and enhance their product. Establishing a reliable method of cryopreservation for mussel larvae would be a valuable tool that supported their operations and an important global scientific breakthrough.
In our latest study as part of our Ministry of Business, Innovation and Employment-funded Shellfish Aquaculture Research Programme, Cawthron Institute researchers and collaborators at the Spanish University of Vigo set out to develop a reliable protocol for freezing veliger larvae of GreenshellTM mussels.
Using the developed protocol, over 50% of previously cryopreserved D-larvae were able to survive after 4 days of rearing, compared with 65% in the unfrozen control. More importantly, about one third of thawed larvae were able to swim and feed, and potentially develop further to adulthood. These findings are encouraging and demonstrate that such protocol could be routinely implemented during a breeding run by freezing left-over larvae from a given family. This would provide a back-up of material year-round should breeding stocks be lost due to disease or severe weather events, as well as the creation of reference lines.
While there is still work to be done to ensure cryopreservation can form an integral part of selective breeding programmes for the species, the findings of this study represent a significant step forward.