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University of Puget Sound

Publication Date

Fall 2019

Program Name

Australia: Rainforest, Reef, and Cultural Ecology

Abstract

Oysters are hard shelled bivalves that aggregate over time to create structures in estuarine systems, known as oyster reefs. These reefs are important for the promotion of estuarine biodiversity by supporting many species of fish, invertebrates, and plants. They also act as a key contributor to water health by using active suspension feeding mechanisms and selective feeding to remove nutrients and water borne pollutants from estuarine systems. They have been touted as possible bio-remediators. They also effect rates of sedimentation in estuaries.

Oyster reefs have historically been threatened by anthropogenic influences such as overharvesting, destructive fishing practices, water pollution, CO2 emissions and sediment runoff, prompting focus on efforts to restore and rehabilitate oyster reef ecosystems to restore their natural processes. This study aims to investigate how location, positioning and seasonal variation affect selective feeding behavior of the Sydney Oyster (Saccostrea glomerata) in New South Wales, Australia. Video of oysters on the edge and centre of Port Hacking (n=39), and Towra Point (n=30), as well as the centre of Hunter River (n=7) were taken in order to observe feeding behavior in these locations. Observations of the length of time each oyster occupied 2 states, open or closed, were used to determine differences between oyster sites and locations. Data from Port Hacking was used to examine seasonal variation of oyster feeding behavior.

Oysters spent significantly more time feeding on the edge of a given reef, however this difference did not depend on whether an oyster was found on Port Hacking or Towra Point. This is likely due to the physiological differences between the reef edge and centre. Oysters located at Hunter River spent significantly less time actively feeding than oysters at Port Hacking and Towra Point. This is likely due to the physiological differences between the sites, such as higher speed of water flow, and larger concentrations of suspended sediment at Hunter River.

There were significant differences in feeding behavior at Port Hacking based on month. The month of March experienced 7x more rain than April, and more than 2x the rain of August. These precipitation differences likely increased nutrient runoff to Port Hacking, increasing algal concentrations which would have decreased the amount of time oysters needed to spend actively feeding.

Disciplines

Aquaculture and Fisheries | Climate | Environmental Monitoring | Environmental Studies | Marine Biology | Oceanography | Research Methods in Life Sciences | Terrestrial and Aquatic Ecology

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