Noosa River biodiversity in big trouble: report
A SHOCKING new report on the health of Noosa River's sub-species of marine animal life has turned on its head contemporary thinking on its management.
The interim report, commissioned by the Noosa Biosphere Research Foundation, titled Biodiversity in the Noosa River system - Assessment of the status and options for recovery of prawns and estuarine biodiversity in the Noosa River shows a massive drop in the number of polychaete, bivalve and amphipod species across a range of locations in the river system.
These creatures are the main food supply for higher food-chain species.
Total abundance from surveyed sites, compared to similar research carried out by the state government's Environment Protection Agency in 1998, indicates a 85-per cent decline in marine animal life in the upper river between lakes Cooroibah and Cootharaba, from 1422 identified in 1998, down to 212 in 2018.
Downriver, at the entrance to Lake Cooroibah, a 83-per cent decrease was discovered (4496 down to 760).
The mid-river opposite Lake Doonella showed a 87-per cent decline from 1133 to 151, while a lower river shallows location identified a 76-per cent reduction over 1998 from 2208 to 539.
The findings cast a shadow over the methodology of the annual Healthy Waterways reports, which has been the benchmark for riverine health measurement, and where Noosa River has consistently scored a higher water health rating against other river systems in the the region.
NBRF chair Dick Barnes suggested a wider set of water measurements may have to be included in future such reports.
He said NBRF's biodiversity interim report was just that - an interim report - and a full report would be forthcoming later this year.
He said the report shed light on what was a critical situation regrading the food chain supporting fish, crabs and prawns, and while it was important to identify the cause and/or causes, he sought to focus on "what we must do" to rectify the problems.
Report co-author, Associate Professor Greg Skilleter of the Marine and Estuarine Ecology Unit at the School of Biological Sciences at University of Queensland, said he was "concerned given the substantial declines in biodiversity we documented".
"But we will have a greater understanding once the additional samples have been processed and analysed," he said.
"Given some of the initial findings, we included additional sampling and work, at no additional cost to NBRF and these samples are the reason we are now working beyond the actual contract period."
Bring Back the Fish project partner Simon Walker said the decline over 20 years warranted further assessment.
"The initial assessment completed by the UQ team is substantial and in my opinion holds substantial weight," he said.
"UQ has completed another round of sampling late in 2018 and are currently processing samples to confirm the first round results presented in their progress milestone report."
Noosa Mayor Tony Wellington said small organisms were integral to the river's biodiversity, "and could arguably be considered as indicative of the river's overall health".
"Although Skilleter's final report is some weeks away, the interim results are extremely disturbing.
"Having taken samples in 1998, and then performed the same sampling in the same locations last year, a comparison is being made between the two sets of data.
"As the interim report notes, the total number of species has declined by between 75 and 85 per cent over the 20-year timeframe," Mayor Wellington said.
"Such findings would appear to indicate that the Noosa River is in significant decline in terms of its biodiversity.
"Plainly this research rings alarm bells for our community and has implications for council's Noosa River Plan as well as our current investigations into sustainable fishing in the river system," Cr Wellington said.