Dove MC and O’Connor WA (2009) Reproductive behaviour of Sydney rock oysters, Saccostrea glomerata, selected for faster growth. Presentation given at the 10th International Congress on Medical and Applied Malacology, 25 – 29 August 2009, Busan, Korea.

Summary

Since 1990, Industry and Investment New South Wales’ (NSW) Sydney rock oyster  breeding program has successfully improved oyster growth rates. But, some oyster growers have observed that selected oysters from this program condition at a different rate and to a different extent compared to naturally caught oysters grown under similar conditions. The reproduction cycle of fifth generation Sydney rock oyster s selectively bred for fast growth was investigated by collecting monthly samples at a northern, mid and southern site in NSW between June 2005 and July 2006. Non-selected wild oysters farmed under the same conditions were also sampled at the same time. Overall, selected and non-selected oysters developed and spawned at each at the same time, however, selectively bred oysters, in most instances, had a lower condition index, different meat conditioning cycle and less gonad area than their non-selected counterparts. Although selective breeding for fast growth hasn’t changed reproductive timing, the variation in meat condition is consistent with oyster grower’s observations and has encouraged further research to better understand the environmental responses of selected oysters and improve reproductive condition in Sydney rock oysters through breeding.