Ecotone Vol32 No4 - CAFNEC

THE RIVER FLOWS TO THE REEF
BY YVONNE CUNNINGHAM
I have lived alongside the Johnstone River for forty-two
years and watched the river run red every time heavy rain
falls. Lately, I have noticed it needs less and less rainfall to
cause the river to run red. (see Photo1)
all coral cover. For some time there has been conclusive
evidence to demonstrate the link between nutrient runoff
and escalating crown-of-thorns starfish infestations.
The evidence of the link between crown-of-thorns starfish
outbreaks and nutrient run-off was first revealed at the
Catchment-to-Reef conference in June 2004.
I asked Martin Cunningham, a fisherman and my son,
what is happening to the coral. Martin told me ’Coral
along the headlands and around the inshore islands is
gone. The fringing reefs are all but completely gone.
Reefs 20 miles offshore are also in terrible shape. The near
reef shoals such as Gouge Banks, Arthurs Patches and
Surprise Shoal have a distinct red stain to the surrounding
sediment and the coral cover would be less than ten per
cent. The mid shelf reefs are in poor shape.’
To investigate the cause of all this additional sediment
that seems to be coming down the river these days I
went with Victor Cassidy a local aboriginal Elder and keen
fisherman, up the North Johnstone River. (see Photo 3)
At the mouth of the Johnstone River the mangrove forest
has died. It is thought that the sediments carried by the
river contain many chemicals including herbicides. When
these sediments are deposited, by the action of the river
around the mangroves, herbicides slowly leach out and
kill the mangroves. (see Photo 2)
We left the town wharf and immediately saw riparian
vegetation had been removed completely in front of
some subdivisions along the river. Elsewhere gaps have
been made in the vegetation to view the river. There was
severe erosion on the riverbank adjacent to these riverside
developments. (see Photo 4)
The Australian Institute of Marine Science (AIMS) has
reported the Great Barrier Reef has lost half its coral
cover over the past 27 years. Much of the blame for coral
loss has been placed on the effects of storms and coral
bleaching. However, sediment and nutrient runoff from
agriculture and coastal development are believed to have
a far greater impact on the reef-ecosystem and affect the
reef’s ability to naturally regenerate after storm events.
One of the impacts of storms is the re-suspension of
bottom sediments, reintroducing buried pollutants from
earlier days.
High background populations of crown-of-thorns starfish
are reaching plague proportions every decade and are
believed to be responsible for the loss of 42 per cent of
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