© 2016 by Select Oyster Co P/L.Last update June 2019

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Frequently asked questions 

Q. How is the Select Oyster Company stock bred?

A: Initially NSW DPI Fisheries approached farmers from four of the major oyster growing estuaries (Wallis Lake, Port Stephens, Hawkesbury R. and Georges R.) and asked them for their best oysters. We then bred those oysters and for each successive generation we selected over two hundred of the best and then bred from those. We do not modify the genetics of the oysters, there are no new genes introduced, we simply look for oysters that naturally grow faster and that are hardier than the others.  We do this by selecting those oysters that grow and survive the best on farms using normal farming techniques. Over the past 10 years as the program has developed, we've incorporated additional wild oysters from several estuaries including Clarence River, Nambucca, Camden Haven, Hastings, Port Stephens, Wallis Lake, Hunter, Hawkesbury & Georges River, Shoalhaven, Turros and Merimbula. Incorporating stock from a diversity of estuaries throughout the course of the program's history to date is an important factor in assuring genetic diversity while capturing key commercial traits. Oysters that are incorporated into the breeding program have been selected for specific traits of commercial significance including weight gain, QX and Winter Mortality disease resistance, shell shape, and meat condition. 

Q. How do I order stock?

A: You can call any of the hatcheries or nurseries listed on our website to put in an order. You can order smaller or larger quantities, and different sizes of spat according to your needs and spat availability. You can also request a line type. 

Q. Which line is right for my farm?

A: It depends on which trait you're interested in. For example, you might prefer an oyster line that's been selected for its higher resistance to QX disease in which case you'd make this known to your hatchery. SOCo will provide the best broodstock to the hatchery in order to provide stock with this trait.  

Q. Are oysters 100% resistant to diseases?

A: No. Resistance is relative. Each generation of selection gets stronger, in that more oysters will survive than the previous generation provided that the handling and environmental conditions are the same. This also applies for gains in other traits. Condition will improve at each generation among those families that have been selected for condition, but it's always relative to level of condition of the parents.   

Q. What is the difference between mass selected lines and family lines?

A: The Sydney Rock Oyster breeding program is transitioning from mass selection to multi trait, single pair mated families breeding program. Mass selection is a process whereby a population of oysters are selected for one or two traits, for example fast growth and QX disease resistance. Each year, survivors of QX disease, and fast growing animals will be selected from the population and induced to spawn. The progeny form the next mass selected population, and the process repeats whereby survivors and fast growers within the next generation are selected for spawning. This technique has made substantial gains in growth and disease resistance over the past 20 years (see Science and Extension). However, there is little control over which male fertilises which female, and therefore after several generation the risk of inbreeding increases. By contrast, family breeding is multi trait, full sibling model. Oysters are managed in their separate families, and controlled fertilisations allow us to know which family is used to select a male and a female to cross. This model allows us to capture pedigree information of each family, and therefore control inbreeding. It also allows us to incorporate multiple traits, and quantify the heritability of each trait through time using quantitative genetic tools. We are selecting Sydney Rock Oysters for weight, QX disease resistance, WM resistance, condition, and shell shape. The gain in each trait at each generation is quantified using an Estimated Breeding Value (EBV) and therefore we can accelerate gains by selecting families with the best EBVs. Family breeding is used in salmon, cattle, wheat, merino sheep, and the poultry industries to name a few.   

Q. What is SOCo's role?

A: SOCo manage, and improve broodstock. We manage several family lines and some mass selected lines, and make them available to hatcheries for spawning on request. We communicate on behalf of industry to government agencies in regards to research priorities, and breeding program decisions. We facilitate extension work including hatchery training and Hatchery Hub programs, field days, conferences and workshops.  


Q. If I bring Select Oyster Company stock into my estuary will they breed with the local oysters.?

A. Yes, they are "normal" oysters and as they get older and mature they will spawn, however, this does not mean they will become dominant in your area. While we don’t know how many wild oysters there are in every river, some surveys have been made. For instance, there is estimated to be more than 1 billion wild oysters in the Shoalhaven River.  If we took all of the Select Oyster Company stock ever produced and put it all in the Shoalhaven R. at the same time, it would form less than 0.1% of the total population and is unlikely to influence the genetics of the local stock.


Q. Are these oysters GMO’s (genetically modified organisms)?

A. No. the genetic material of the oyster has not been modified. These oysters are simply a subset of the normal oyster population.


Q. How can I be sure that I get the numbers of spat I order?

A. All Select Oyster Company approved nurseries have strict protocols for counting spat to ensure you receive your full order, however it is not that difficult to confirm your count and it does not require particularly expensive equipment. Select Oyster Company has simple protocols to help you. These are downloadable in written form (link to document but not available yet), or as a DVD of a workshop which was held by the NSW industry and NSW DPI. If you would like a copy of the DVD please contact us.