Biophysical assessment of reefs in Keppel Bay: a baseline study (April 2007)

Abstract

The Keppel Islands are a group of 16 continental islands lying 18 km off the coastal town of Yeppoon in the southern Great Barrier Reef. Located in the shallow basin to the north of Keppel Bay, the islands are host to a patchwork of fringing reefs in various forms of development. Coral communities are abundant in some locations, and coral cover is high (60 to 70%) relative to the average at sites surveyed by the Australian Institute of Marine Science’s Long-Term Monitoring Program (~35%), and are often dominated by extensive stands of branching Acropora that extend into shallow water. These ‘staghorn’ corals are vulnerable to impacts caused by environmental stresses such as elevated sea temperature (causing coral bleaching events), degraded water quality (associated with hyposaline floods events) and physical damage (from cyclones, storms and anchoring). The Fitzroy River, one of the largest catchments in Queensland, is about 40 km to the south of the Keppel Islands. Large flood plumes occur approximately every 10 years, and the soft riverine sediments are regularly re-suspended in the shallow bay by wind and tide action causing high turbidity. Heavy rainfall also affects the shallow reef flat habitats, with reported incidences of coral mortality caused by heavy rain at times of extreme low tides