Environment SA News

Endangered Murray hardyhead breeding in big numbers

A recent Riverland fish survey found the endangered Murray hardyhead (Craterocephalus fluviatilis) breeding in substantial numbers.

Endangered Murray hardyhead breeding in big numbers
Endangered Murray hardhead, like the one pictured, have been discovered breeding in large numbers in a Riverland lagoon.

Department for Environment (DEW) Wetlands Project Officer Stephanie Robinson said 2,519 Murray hardyhead of different sizes, including smaller juveniles and large adults, were caught recently, compared to just 80 in last year’s survey.

“We are so fortunate to have these populations of Murray hardyhead and to be able to help sustain them and monitor their progress,” she said.

“These little fish are critically endangered due to many threats such as river regulation (disconnection from the main river channel), water diversion and competing fish species such as the European carp.”

In March 2019 the species were discovered in a local lagoon during surveys conducted by Aquasave–Nature Glenelg Trust.

Since discovering the Murray hardyhead population at the lagoon last year, management of the site has been focused on triggering a breeding event.

During spring 2019, Nature Foundation SA delivered water for the environment (provided by the Commonwealth Environmental Water Holder) through Central Irrigation Trust infrastructure to ensure fresh water would reach the lagoon in time for a breeding event.

Nature Foundation SA and DEW worked closely with Berri Barmera Landcare to monitor salinity at the site and keep it to a level suitable for Murray hardyhead eggs.

Ms Robinson said the partnership is a great example of how well a critically endangered species population can do when everyone works together to manage the environment.

The Murray hardyhead is a small-bodied native fish that grows to approximately 9 cm in length.

They are an omnivorous species, eating micro-crustaceans, aquatic insects, and algae and have evolved to become salt tolerant.

The species is found in more saline wetland environments containing a wide range of aquatic vegetation and snags, which are used for habitat and breeding.

The DEW Wetlands Team has worked closely with Nature Foundation SA, the Commonwealth Environmental Water Holder, Berri Barmera Landcare and Central Irrigation Trust as part of a collaborative partnership to manage the Murray hardyhead population in this particular lagoon.

The project is supported through funding from the Australian Government’s National Landcare Program and Natural Resources Management levies.