TRIPLOID

A triploid oyster is one that has one more set of chromosomes than a usual or normal diploid oyster, three sets instead of two, this is a hatchery process not a genetic modification.
It is suggested that because a triploid oyster is almost sterile it will not waste energy producing eggs or sperm and will therefore grow faster and not become too “milky”.
From our research and feed-back from growers we know that this is not necessarily the case, the triploid oyster needs a very good grow-out site to be able to sustain the faster growth.
If conditions are not perfect and many sites are far from it, the triploids can be prone to poor growth or mortality, and we have heard lots of sayings like “they don’t seem any different than normal gigas” or “they never really fattened up” and “the jury is still out”.
If you have serious problems with milky oysters and a very good site and are prepared to pay more for the triploid seed it may be worth trying, but we are not convinced yet.
Most batches are far from 100% triploid and this can also be a problem, however it is now possible to produce 100% triploids by crossing tetraploids (4 sets of chromosomes) with diploids.
We are currently working towards having a stock of tetraploids, so we can breed from them in the eventuality that the growers should require triploid oysters at some stage in the future.
Since producing a few batches some years ago we have taken the position of wait and see and have concentrated our efforts on producing diploid gigas oysters as cost effectively as possible and this meant not spending time and money producing something the industry may or may not want.

Male & female broodstock oysters seperated during spawning