Bringing Oyster Reefs Back To Oyster Harbour, Western Australia

Date: 
Tuesday 4 June 2019 - 11:00
Location: 
NOC Southampton - Node Room (074/02) (Waterfront Campus).
Speaker: 
Peter Cook

The overall aim of this project was to assess native oyster (Ostrea angasi) survival and growth in Oyster Harbour, Western Australia, and to produce results and observations to inform expanded restoration in future years. Approximately 40,000 juvenile oysters were produced in a hatchery in Albany, from brood stock collected from Oyster Harbour. These oysters were seeded onto a variety of cultch types, and after four weeks in the hatchery, the average density per shell, and estimated abundance of juvenile oysters on each cultch type, was quantified. Before removal from the hatchery, all spat were disease tested and all were found to be negative for the presence of Bonamiaand QF disease (Marteilia sydneyi). The oysters, still attached to shells, were then deployed onto small, experimental reef plots, at various locations in the harbour, shells being spread evenly across each reef. After about 2 years on the reefs, shell length ranged from less than 0.4 cm SL to 7.05 cm SL. Whilst it is certain that the largest oysters were part of the experimental deployment, the origin of the smaller oysters is less certain. Given the large number of oysters in the smallest size class, it is tempting to speculate that these represented a cohort of spat derived from reproduction by the deployed oysters. Without further research, however, this remains only a speculation. If the smaller oysters did result from natural colonization, this would indicate that the deployed reefs are already having their desired effect of acting as a substrate for oyster reef development. Following these initial experiments, the State Government of Western Australia has provided a grant of $1 million for us to continue the project, and this has been supplemented by a further grant of $150 000 from RecfishWest.

 

 

Seminar category: 
POETS Corner
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