Population boom for threatened species

Posted 30 November 2020.

The spring monitoring team has discovered an incredible population boom for the threatened Murray hardyhead (Craterocephalus fluviatilis), at one of its Riverland habitat sites recently.

The Murraylands and Riverland Landscape Board’s Wetland Team Leader Darren Willis said normally if you catch around 20-100 Murray hardyhead in a site survey, you’d say …Hmmm that’s low.

“If you caught 100-400 fish, you’d probably think …OK, that’s not unusual. If you caught 500-1,000 fish, you’d be thinking …now we’re talking,” he said.

“So when the board’s Wetlands Program and Aquasave-Nature Glenelg Trust (NGT) survey team found more than 17,000 Murray hardyhead at one site, you can imagine – they got a bit excited.

Aquasave-NGT’s, Dr Nick Whiterod, an expert in native fish in the Murray-Darling Basin, said to his knowledge this bumper catch is the largest observed anywhere in the Murray-Darling Basin for some time.

“The impressive numbers demonstrate how collaborative management efforts can promote favourable habitat to support this endangered freshwater fish,” Dr Whiterod said.

Mr Willis said we’ve been successful in maintaining a few key populations in managed wetlands in the Riverland, which have been specifically managed to support Murray hardyhead for many years.

“Murray hardyhead habitat sites are not what would generally be considered classically beautiful wetlands,” he said

“They are generally more saline wetlands which have been heavily impacted by the millennium drought.

“But the Murray hardyhead is robust in its natural environment and has the ability to tolerate more saline water which is one of the features of its capacity to survive in wild sites.

“It can thrive and reproduce in wetlands were carp and other introduced species don’t like to live.

“In the last couple of years two additional populations have been found in the region and these new population sites are now also being regularly monitored and managed to make sure we sustain the right conditions for the Murray hardyhead,” he said.

Mr Willis congratulated everyone involved in this work and the fantastic collaborative effort.

Murray hardyhead has been listed as an endangered species since 1999 - and currently survives in just a handful of places in northern Victoria, and in the Riverland and Lower Lakes in South Australia.

Its one of four threatened small native wetland fish species that the Murraylands and Riverland Landscape Board’s Wetland Program has a conservation focus on, including the southern purple-spotted gudgeon, Yarra pygmy perch and southern pygmy perch.

This work is a collaboration between the Wetlands Team; Aquasave – Nature Glenelg Trust (who are specialists in threatened native fish management); the Commonwealth Environmental Water Office (CEWO) which provides water for the environment to support these critical wetlands sites; Nature Foundation SA who deliver water to some sites on behalf of the CEWO; and the Berri-Barmera Landcare group.

This project is supported by the Murraylands and Riverland Landscape Board through funding from the Australian Government’s National Landcare Program and the Landscape levies.