The Courier-Mail 5 Sep 12;
A SURVEY has shown a significant decline of dugong numbers in the Great Barrier Reef.
"In the southern Great Barrier Reef region the estimated size of the dugong population - about 500 to 600 - was the lowest since surveys began in 1986," Professor Helene Marsh from James Cook University said yesterday.
But the report indicates dugong numbers further south, in Hervey Bay and Moreton Bay, are steady.
Prof Marsh said widespread flooding and Cyclone Yasi in early 2011 had a detrimental impact on seagrass, which is the staple of the dugong's diet.
"The data indicates that Townsville and Gladstone were the dugong mortality hotspots," she said.
"In both these places seagrass was in poor condition."
The report called on the state and federal governments to create larger protected areas for dugongs, and create an indigenous group to co-ordinate responses to major weather events.
‘Lady of the Sea’ under threat
James Cook University Press Release 4 Sep 12;
No dugong calves were seen in the southern Great Barrier Reef in a survey last year, and numbers are the lowest since the mid 1980s, indicating a dramatic decline in the endangered mammal’s population in the region.
The results show a reduction in fertility in response to the extreme weather conditions in 2011, which exacerbated a decline in their seagrass feeding grounds over several years.
James Cook University Distinguished Professor Helene Marsh recently conducted a project to examine the concern: Marine wildlife management in the Great Barrier Reef World Heritage Area.
Professor Marsh said severe weather along the Queensland coast in the summer of 2010/11 had affected the Great Barrier Reef’s endangered dugong population.
“The latest aerial survey by researchers from JCU of dugong distribution and abundance indicates a significant decline in the dugong population of the southern Great Barrier Reef,” she said.
“Although aerial survey estimates of dugong are underestimates, they track trends in the population.
“The recent survey report, estimates a total number of about 3000 dugongs in south-east Queensland’s Moreton and Hervey Bays, similar to the previous aerial survey figure in 2005.
“However it was a different story in the southern Great Barrier Reef region where the estimated size of the dugong population - about 500 to 600 - was the lowest since surveys began in 1986.
“Similarly, while the proportion of dugong calves in Hervey and Morton Bays was within the range expected for normal conditions, no calves were seen in the southern Great Barrier Reef during the 2011 survey, indicating a reduction in fertility in response to the extreme weather in 2011 which exacerbated a decline in their seagrass feeding grounds over several years.”
Professor Marsh said dugong mortalities recorded by StrandNet (the Queensland Marine Wildlife Mortality Database) in 2011 were the highest ever recorded.
“The data indicates that Townsville and Gladstone were the dugong mortality ‘hotspots’. In both these places seagrass was in poor condition.
“The report’s recommendations include several measures to protect dugongs along the coast, including increasing the proportion of protected dugong habitat in Moreton and Hervey bays to support their high density dugong populations.
“They also recommend re-establishment of a regional Indigenous coordinating group to coordinate responses of Traditional Owners to extreme weather events in their Sea Country and the introduction of regional zoning of the East Coast Inshore Finfish Fishery to minimise interactions between fishers and dugongs.”
Professor Marsh said the report also called on the Queensland and Australian Governments to develop policy that favours the establishment of several well managed mega-ports along the GBR coast, which would pose fewer risks to dugongs and their habitats than a larger number of smaller ports.
This research was conducted with the support of funding from the Australian Government’s National Environmental Research Program.
Moreton Bay dugong birth rate falling
Jacinda Tutty 9 News 20 Sep 12;
New research shows the birth rate of dugongs in Brisbane's Moreton Bay has fallen since the 2011 Brisbane floods.
Researchers from the University of Queensland and experts from Seaworld and Sydney Aquarium teamed up to test and assess dugongs in the Moreton Bay area to determine any risks to the population.
UQ research leader, Janet Lanyon, says early observations by the six-day mission show reproduction rates have slowed since last year's flooding.
Since Saturday 15 dugongs have been caught and released after scientists took samples for research - six were females and none of them were pregnant.
"Normally half the females would be pregnant," Ms Lanyon told AAP.
More research will be needed to assess the extent of the problem accurately.
But Ms Lanyon said the initial results were not unexpected given the high rates of mercury and lead pollution in run-off after the flooding.
"I suspect we will get fewer breeding females this year, as we know dugongs suffered from low nutrient content in damaged seagrass after the floods," she said.
A year on, the seagrass beds have begun to return to normal but have not fully recovered.
Ms Lanyon said preserving the seagrass meadows and managing pollution were the keys to sustaining dugong populations and returning reproduction rates to normal.
"We know from dolphins and whales a presence of heavy metals like mercury and lead can lead to reproduction problems," she said.
UQ and Seaworld research groups wrapped up the research project on Thursday.
Dugong blood, urine, semen and weight measurements will be examined to make a thorough assessment of the health and reproduction status of dugongs in the area.
