by Jeni Bone
The first round of results from water quality testing in the south of Moreton Bay, Brisbane shows some positives outcomes for the health of the Bay and its aquatic flora and fauna.
Moreton Bay silting - only really bad in the north.
The Department of Environment and Resource Management (DERM) has found that the flood plume which loomed over much of Moreton Bay has not affected salinity and turbidity levels - key ecosystem heath parameters for the southern sections of the Bay.
This means that the impact on the seagrass beds of the southern part of the bay is not likely to be as significant as first expected. Experts say that while the seagrass throughout the northern bay is heavily impacted, wildlife such as dugongs and turtles will have alternative food south in the south.
Healthy Waterways has established a Flood Response Taskforce to coordinate a collaborative program that will assess and report on the short, medium and long term impacts of the recent flood on the health of our waterways and Moreton Bay.
Initially, there were fears that tonnes of silt and other rubbish washed down the Brisbane River and into the Bay during January's floods, would kill off the sea grass the dugong relies on to survive and where some species of fish breed.
Biologists from the University of Queensland recently teamed up with Sea World, Sydney Aquarium and Taronga Western Plains Zoo to assess the health and reproductive status of wild dugongs in Moreton Bay.
The team has taken samples of the population, which involved lifting wild dugongs out of the water and putting them on board Sea World's research vessel to take a comprehensive series of blood and other tissue samples. The samples are used to measure clinical health parameters and levels of pollutants, including heavy metals.
Sea World director of marine sciences, Trevor Long says the work they have done so far has been very encouraging. Recently, the team pulled five animals on board, among them two pregnant females and one of the biggest dugongs they had ever pulled out of Moreton Bay!
Most of the animals have been in very good condition, with only about two in what Trevor called 'slightly poor condition'.
'There was a lot of concern, even amongst ourselves, about what would be the outcome for this population, considering the amount of silt that came out of the Brisbane River,' he says. 'It was a concern when we had the floods because we had floods in 1991 in Hervey Bay and we lost a lot of animals there – probably over half of the population.'
The Hervey Bay dugong population has still not recovered, and Trevor and the team will be heading there again soon to see if there are any signs of improvement. But, he says, the number of pregnant dugongs in Moreton Bay has been encouraging because they only have babies once every three to four years and their calves stay with them for about 18 months to two years.
Long is concerned that boaties and fisherman in the area still need to adhere to the go-slow laws in place.
'We've raised a lot of awareness and from that marine parks have put go-slow zones in to protect the animals from boat strike,' he says. 'But some boaties still go through those zones flat out. It's one thing to create a law, it's another to police it.'