The final global stronghold for the critically endangered freshwater sawfish has seen numbers dramatically decline after at least 40 sawfish were found dead last December.
The deaths were reportedly due to high temperatures and declining water levels in two pools at Blina Creek at Liveringa Station, a Kimberley cattle station owned by Gina Rinehart.
Murdoch University’s Freshwater Fish Group and Fish Health Unit headed a response by attempting to relocate any surviving sawfish.
Only two survived and were relocated to Uralla Creek.
The Unit reported that the sawfish likely entered the Blina Creek floodplain during the wet season and returned to Uralla Creek during the dry season as water levels declined.
However, the pools became unsuitable later in the dry season due to extreme heat waves and the report concluded that the sawfish most likely died due to exposure to constant high temperatures and the resulting warmer water temperatures.
CEO of environmental organisation Environs Kimberley Martin Pritchard said while low rainfall and climate change has played a part in the water decline, there are also concerns about the role irrigation is playing in the deaths of so many sawfish.
“To have such a large number of sawfish that have died in one event is unprecedented, as far as we’re aware, in the Kimberley,” Mr Pritchard said.
“They are obviously in distress already and we don’t know what the role of irrigation has played in that so far.”
Mr Pritchard said he is concerned that Gina Rinehart wants to take 325 billion litres of water out of the Fitzroy River.
The CEO said the impacts of such a huge loss is still unknown to the broader environment, but for the freshwater species itself it is a “major catastrophe.”
“If they’re dying here [in the last global stronghold] then they’re in serious trouble … as a species,” Mr Pritchard said.
In April 2019, questions were asked in WA State Parliament to the Minister for Regional Development Alannah MacTiernan and the Minister for Water Dave Kelly about the mass sawfish deaths.
The questions revealed the State Government was aware the freshwater sawfish was listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999 but did not report the mass deaths to the Commonwealth as the “Department’s assessment of the event showed no relationship between the event and the taking of water.”
Minister MacTiernan also said no water had been extracted from the same freshwater system as the one the sawfish died in and that the site was not downstream of any dams, weirs, or other obstructions that hindered water flow.
Although a range of questions were answered about the sawfish deaths, Mr Pritchard said he is not satisfied with the answers.
“We want a full investigation, and clarity around the role of water extraction from Snake Creek for irrigation, and then we want to make sure it doesn’t happen again.”
Mr Pritchard said the government has not answered how pumping at Snake Creek may have had an impact or could have future impacts on situations like these.
“There needs to be a management plan going into the future to protect the sawfish,” Mr Pritchard said.
By Hannah Cross