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Monitoring Cairns section fringing
reefs
Surveys of inshore reefs of
the wet tropics coast
Introduction
A monitoring program
in the Cape Tribulation area was commissioned by the Great
Barrier Reef Marine Park Authority in 1985 to look at the
effects of sediment run-off from a newly constructed dirt
road. Sites at Cape Tribulation were grouped in three
"locations" (numbered 1 to 3 from south to north). There
were four sites per location. The sites were surveyed
annually from 1985-88 and again from 1994-2001.
A more
general survey of 17 Cairns fringing reefs was made in
1994-95, and in 1997, long-term monitoring using fixed
transects was established on two of these reefs: Snapper
Island and the Frankland Islands. Annual surveys were made
at three sites on each of the exposed and sheltered aspects
of these islands. All Frankland Island sites, the north
Snapper Is sites and eight of the 12 Cape Tribulation sites
were surveyed in March/April 1998 to document the effect of
the 1998 coral bleaching event. These surveys estimated the
percentage of bleached corals on the transects.
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All monitoring was by
Sea Research under contract to the Great Barrier Reef
Marine Park Authority (GBRMPA). A detailed report by Ayling and Ayling (2002) can be requested from
www.gbrmpa.gov.au
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Figure 1. Map of surveys sites monitored by GBRMPA.
Click on the orange dots to view monitoring data from that
location.
Methods
The fringing reef studies were based on sampling "sites",
where groups of five 20m transects were laid haphazardly
within an area about 60 x 10m. Transects usually ran along a
depth contour and were straight unless the reef topography
decreed otherwise. The transects at each site were usually
2-5m below low tide spring level, and were positioned below
the algal-dominated fringe if one was present. .
Permanent
transects were marked with five 100 cm long 15 mm
reinforcing rod stakes driven deep into the reef structure
at 5 m intervals. Each site was mapped and to assist in
relocating transects. During each survey a fibreglass tape
was stretched tightly between the 5 marker stakes and
percent cover was estimated using the Line Intercept
Transect technique (English et al, 2000).
The following
organisms, or groups of organisms, were measured: the brown
macroalgae Sargassum spp.; all turfing algae grouped;
all sponges grouped; Millepora spp.; Heliopora
spp.; all hard corals to genus level, or to structural
growth form grouping if more appropriate eg Acropora
staghorn, Acropora tabulate etc.; all soft corals to
genus level.
Contact
Dr
Hugh Sweatman, Team Leader
Telephone: (07) 4753 4470.
Facsimile: (07) 4772 5852.
Email:
h.sweatman@aims.gov
December 18, 2008
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