Cryopreservation helps shellfish breeders

Have a ready source of eggs and sperms from known parental lines means that all sorts of genetic combinations can be made possible. Why do Nick and Serian find this exciting?

Transcript

Nick King ( One of the biggest issues that I still have is how we look after our broodstock. So we end up with these mussels which are like our top performers, our stud mussels or broodstock. And at the moment we’ve got those out in the Marlborough Sounds and we’ve got some in the hatchery. But really, at some point we are going to have a lot of mussels like that. So it’s just figuring out a good way of storing them in one place where they’re going to be safe and they will still be in condition so we can spawn them.

Serian Adams ( What we are doing is trying to freeze the sperm, eggs and larvae so that they can be stored indefinitely. So it’s live storage. And the thing with cryopreservation is it’s not about having them down at that temperature that kills them; it’s getting them to and from that temperature is where they can die. So we play around with different chemicals which help them to survive that process. And then we play around with different cooling rates and holding times to try and get them through that transition zone where they basically will either live or die.

The main reason that we are doing this work is so Nick can store all his family lines and when he finds a superior family, he can go back to a couple of years and cross a particular individual with another one, or even from different years, he can cross different individuals and things like that. So it’s having a library, basically, of all of the families that he has worked with stored so he can go back and use them.

It also means he can do it at any time; he doesn’t have to wait till the shellfish are in season. He could do it in the middle of winter with oysters if he wanted to, and they are usually only ripe in summer. So there is that benefit as well. That is quite important for hatcheries as well, because it means you can produce shellfish year-round without having to condition them [get them ready for breeding].