Tony Moore Brisbane Times 20 Jan 12;
Coral reefs in Moreton Bay’s no-fishing zones are recovering from last year’s flood faster because fish eat damaging algae, scientists can demonstrate for the first time.
Lower levels of the algae, which prevent coral regenerating, have allowed the reefs in no-fishing zones to recover quicker than those in other parts of the bay, researchers from the Australian Rivers Institute have discovered.
No-fishing zones were controversially added when the Moreton Bay Marine Park was reviewed in 2009.
Now researchers can say the no-fishing zones have helped coral recover faster after the January 2011 flood.
However, the flood has badly damaged 40 per cent of the seagrass beds in Moreton Bay, the same research shows.
Rod Connolly, who works for Griffith University, said the results followed 12 months of tests after ‘‘unusually fresh water’’ washed hundreds of millions of tonnes of sediment into Moreton Bay.
This sediment affected the coral reefs running in an arc from Mud Island, to St Helena, past Peel Island and near Myora Creek on North Stradbroke Island.
Professor Connolly said the massive amount of fresh water and dirt washed into the bay stressed the coral reefs.
‘‘Within eight weeks of the flood, substantial amounts of the coral had bleached,’’ he said.
‘‘And what we have just found out is that largely since the coral has recovered.”
The Australian Rivers Institute believed the recovery was due to fish eating the algae which effectively killed the organism causing the colour in the coral, Professor Connolly said.
‘‘There was huge contention three years ago when they put in new ‘green zones’ [no-fishing areas] in Moreton Bay,’’ he said.
“That has resulted in larger populations of bream and rabbit fish in the green zones.
‘‘And they are out there in generally bigger numbers in these green zones.
‘‘The algae tends to inhibit the recovery of the coral, so where you get the high rate of grazing, you get the better rate of recovery of the corals.’’
He said while the finds were ‘‘of great interest scientifically’’, to the general public they were proof that the scheme allowed nature to take its course.
‘‘The point is that we sometimes bag the green zones for being a limit on our freedoms, but there are some good signs out of it,’’ he said.
However, the flood badly damaged seagrass beds on the Moreton Bay side of North Stradbroke Island.
Seagrass beds are crucial feeding beds for dugongs, turtles and fish.
‘‘All of them depend on seagrass to some extent and seagrass bed health is in effect an early warning sign for things further up the food chain,’’ Professor Connolly said.
The Australian Rivers Institute research has measured energy stores in the seagrass beds, by looking at the amount of carbohydrate in seagrass plants since the flood.
Curiously, they found seagrass beds in poorest condition, furthest from the mouth of the Brisbane River.
‘‘What we found is that the seagrass beds on that side of Moreton Bay are not used to flood waters,’’ he said.
‘‘And this year what we found is that while the flood waters were worse on the western side of the bay [near the mouth] the seagrass there was used to that experience a bit more.
‘‘However on the Stradbroke Island side, they are not used to poor water conditions at all.’’
The outcome is that 40 per cent of Moreton Bay’s seagrass beds near Stradbroke Island are now in poor condition.
‘‘They are not all dead over at Stradbroke, but they are low in reserves for this time of year,’’ he said.
‘‘And if there was a further stress, most likely another flooding event, that would be the one that we would be worried about.’’
Moreton Bay still recovering from flooding
Bayside Bulletin 19 Jan 12;
No-fishing zones implemented to protect the Moreton Bay ecosystem have proven their worth in light of last year's flooding, however the coral reefs and seagrass habitats are still at risk.
This is according to ongoing research by scientists at Griffith University's Australian Rivers Institute.
In partnership with the Department of Environment and Resource Management, flood monitoring work has revealed that substantial bleaching of the coral occurred but that it has since undergone some recovery.
"There was a massive impact from the huge slug of sediment that arrived in the Moreton Bay ecosystem," research leader Professor Rod Connolly said.
"Corals nearer to the Brisbane River mouth have been affected historically by past flooding.
"Unfortunately this has resulted in reduced diversity but the remaining species tend to be better adapted and have managed to cope with the flood water pulses they were subjected to.
"Most importantly we have discovered their ability to recover is improved where the algae doesn’t overgrow the coral. This is evident from our research within the bay's green zones.
"Having a small number of select areas where fishing is not permitted results in higher numbers of fish grazing on algae, which in turn maximises the chance for corals to recover.
"These green zones were highly contentious when first implemented three years ago, but we can now confirm real benefits in the face of the flood impacts," Prof. Connolly said.
The ARI research has also monitored energy reserves within seagrass plants which shows that seagrass meadows near Stradbroke Island are in poorer condition than expected at this time of year as a result of the flood.
Moreton Bay corals ‘still at risk’
Griffith University Science Alert 31 Jan 12;
No-fishing zones implemented to protect the Moreton Bay ecosystem have proven their worth in light of last year’s flooding however the coral reefs and seagrass habitats are still at risk.
This is according to ongoing research by scientists at Griffith University's Australian Rivers Institute.
In partnership with the Department of Environment and Resource Management, flood monitoring work has revealed that substantial bleaching of the coral occurred but that it has since undergone some recovery.
"There was a massive impact from the huge slug of sediment that arrived in the Moreton Bay ecosystem," said research leader Professor Rod Connolly.
"Corals nearer to the Brisbane River mouth have been affected historically by past flooding. Unfortunately this has resulted in reduced diversity but the remaining species tend to be better adapted and have managed to cope with the flood water pulses they were subjected to.
"Most importantly we have discovered their ability to recover is improved where the algae doesn't overgrow the coral. This is evident from our research within the Bay's green zones.
"Having a small number of select areas where fishing is not permitted results in higher numbers of fish grazing on algae, which in turn maximises the chance for corals to recover.
"These green zones were highly contentious when first implemented three years ago, but we can now confirm real benefits in the face of the flood impacts," Professor Connolly said.
The ARI research has also monitored energy reserves within seagrass plants which shows that seagrass meadows near Stradbroke Island are in poorer condition than expected at this time of year as a result of the flood.
"These meadows are along the eastern side of the bay where the plants are rarely exposed to river water and they are now vulnerable to any major flooding this summer," Professor Connolly said.
"Seagrass habitat is critical food for dugongs, turtles and fish. With the unfortunate spike in dugong and turtle deaths reported during 2011, we are continuing to closely monitor this situation."
