Thesis
Understanding the health of an estuary for the restoration of shellfish reefs: is the environment suitable to sustain a new population of oysters?
Southern Cross University
Master of Science (MSc), Southern Cross University
2022
DOI:
https://doi.org/10.25918/thesis.222
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Abstract
The global decline of once prolific oyster reefs is well recognised. Destructive fishing methods, overharvesting, increased sedimentation, disease and poor water quality have all contributed to their demise. As the importance of the ecosystem services provided by oyster reefs is becoming globally recognised, conservation and restoration activities are increasing. However, prior to embarking on shellfish reef restoration projects, it is important to assess the suitability of potential sites, including historical reef sites. Historically, the Pumicestone Passage in Queensland (Qld), Australia was well known for its prolific oyster reefs. This study examined five locations historically known to support oysters within the Pumicestone Passage, to ascertain if remnant oysters persist and if sediment conditions could be suitable for oyster reef restoration. No live oysters were found in the intertidal zone at any of the sites despite remnant shell at the Avon and Ningi Creek. Sedimentation and shifting sand banks, in addition to the presence of mud and fine grain sand, may be important factors contributing to the absence of live oysters in the intertidal zone. Oysters are filter feeding organisms, so will be exposed to elements and nutrients in the sediment and water column. Oysters also depend on the availability of microalgae including diatoms, as a food source. Significant spatial and temporal variation in the elemental composition of sediment and benthic diatom communities was confirmed in the Pumicestone Passage. Multivariate modelling revealed significant relationships between the diatom communities and the elemental composition in the sediment. Sites with high metal concentrations tended to be depauperate in diatoms at some time points. Further monitoring of elements, nutrients and diatoms in the Pumicestone Passage could provide important insights into the suitability of sites for oyster reef restoration. This will assist in making an informed decision for future restoration projects, particularly in relation to an adequate food source for proposed oyster populations.
Details
- Title
- Understanding the health of an estuary for the restoration of shellfish reefs: is the environment suitable to sustain a new population of oysters?
- Creators
- Karen Maree Wingett
- Contributors
- Kirsten Benkendorff (Supervisor) - Southern Cross UniversityDebra Stokes (Supervisor) - Southern Cross UniversityKathryn H Taffs (Supervisor) - Southern Cross University
- Awarding Institution
- Southern Cross University; Master of Science (MSc)
- Theses
- Master of Science (MSc), Southern Cross University
- Publisher
- Southern Cross University
- Number of pages
- xii, 138
- Identifiers
- 991013052713802368
- Copyright
- © KM Wingett 2022
- Academic Unit
- Faculty of Science and Engineering
- Resource Type
- Thesis