2019 TAS Broodstock
Year Class in Review
58 2019 families were produced at IMAS Taroona from 24/09/2019 - 31/10/2019 using 2016, 2017 and 2018 broodstock. The 2019 breeding season was difficult due to issues in the IMAS-ASI Biosecurity Facility (or as known as the “ASI hatchery”) for the first time in many years. This resulted in a lower number of families being produced and a later than anticipated deployment. This was due to a large number of ciliates entering the IMAS bag system, which affected the ASI spat survivability. Despite these issues we were still able to produce 58 families, which were deployed from mid-January 2020 for POMS exposure trials at Pittwater.
A thorough review of the problems encountered has been conducted by IMAS including recommended changes for the upcoming season, including incorporating better hygiene measures in the algae room. Currently, 92,378 oysters have been measured with more performance test data (meat condition, shape, and growth) underway in the coming months over multiple sites.
EBV + Inbreeding Values
The top ten POMS resistant families were made available for commercial allocations in November 2020.
There were three POMS trials deployed in upper Pittwater. The environmental conditions over the summer period with relatively cool temperatures resulted in very low level and sporadic POMS activity in upper Pittwater. We were able to get a mild POMS hit on one 2019 ASI trial. The first trial, 19PW1, did not appear to get a POMS hit and we should assume the mortality was not caused by POMS. That is based on the low heritability and the absence of any correlation with this trial and other 2019 trials, or any other trials.
The second and third trials appear to have had what we called a “light POMS hit” based on the terminology we used last year’s trials. These trials had a moderate heritability, which was lower than all last year’s trials, and that will impact on gains. The result is that we have been able to calculate POMS EBV’s for this year class using 19PW2 and 19PW3 although the low-level POMS activity means that we do not have heavy within family selection.
It is important to note that the EBV reflect POMS mortality only and are not intended to show losses due to other causes. Therefore, other potential losses must be factored in (added) to give an overall expectation of survival.
The button below takes you to a separate CSIRO website which allows hatcheries to calculate inbreeding/EBV values. For further questions, please refer to FAQ's page or contact the General Manager, Matt.
Broodstock Pictures
2019 SA Broodstock
Allocation information
58 2019 families were produced at SARDI from 30/10/2019 - 27/11/2019 using 2017 and 2018 broodstock. The spat performed very well in the early phases until early January. Unfortunately, there was a chiller failure at SARDI which coincided with a heatwave. The result was that the spat were subjected to 30+ degree Celsius water until the problem was observed. This caused a significant mortality event in the spat and a delay in deployment whilst the surviving animals recovered from the heat stress.
A decent amount of spat was recovered and deployed with on average approx. 2000 spat were deployed per family. ASI has put in place measures to prevent this happening in the future. Spat were first deployed to the field from mid-March 2020 for SA survival exposure trials at Coffin Bay and Cowell. Currently, 27,113 oysters have been measured with more performance test data (meat condition, shape, and growth) underway in the coming months over multiple sites.
EBV + Inbreeding Values
2019 in SA are pending commercial allocations.
Spat survival trials were deployed at 3 sites but initial results suggest that there has been significant mortality in the spat which can be attributed to compromised health at deployment. We have recently completed a major revision of SA survival collected throughout the life of the ASI program. We have measured survival at multiple time points for 30 trials over 12-year classes (from 2005 to 2017) and for 449 families. When the data was analysed in this way we were pleasantly surprised by the results.
When we combine all the data, we see a much better result than when we look at individual trials or year classes. The heritability of this trait tells us that we can significantly improve survival if we were to concentrate on this trait in the SA population. If we were able to gain further improvements in the way we measure the trait by incorporating spat survival trials we would be able to accelerate gains further, this would be a game changer for the SA industry.
It is important to note that the EBV reflect POMS mortality only and are not intended to show losses due to other causes. Therefore, other potential losses must be factored in (added) to give an overall expectation of survival.
The button below takes you to a separate CSIRO website which allows hatcheries to calculate inbreeding/EBV values. For further questions, please refer to FAQ's page or contact the General Manager, Matt.
Broodstock Pictures
