The World Wetland Day Yabby Festival was a huge success on Sunday, February 26 as Western Murray Land Improvement Group (WMLIG) took a group of locals and visitors out to Pollack Swamp. 

The Pollack Swamp is a 700ha flora and fauna nature reserve in the Koondrook-Perricoota Forest. Historically occupied by the Barapa Barapa people, the swamp has become a model of how locally driven projects can collaboratively engage community members, farmers and traditional owners to enhance environmental outcomes. Far from ‘lock up and leave’, active management and the strategic application of water has demonstrated what can be achieved with a bottom-up approach.

After a safety briefing by Emma Searle of WMLIG and a Welcome to Country by Barapa Barapa elder Ron Galway, Josh Campbell of NSW Local Land Services gave an introduction to the day.

“World Wetlands Day is an international day recognising the importance of wetlands, focusing on public awareness and awareness of the benefits of wetlands, but also promoting the conservation and wise use of wetlands,” said Mr Campbell.

“The theme for this year’s World Wetlands Day is wetland restoration and highlighting the importance and urgent need to prioritise our wetlands and restoration of wetlands.

“One of the reasons for this is 64 per cent of the world’s wetlands have disappeared since 1900, it’s estimated to be 87 per cent of the world’s wetlands that have disappeared since the 1700s.

“Some of the reasons for this is humans have obviously populated across the world, which altered landscapes.”

With the groundwork laid out, freshwater fish researcher Dr John Conallin spoke about the humble yabby.

“Yabbies are an important part of a wetland, so we thought we’d have a theme around yabbies, the importance of yabbies to the people and then the importance of them to the ecology of the system.

“The species name is Cherax destructor, and there’s a reason why that destructor part is there, they really are formidable,” said Dr Conallin.

“They are able to live in a wide range of environments, from cold to warm water, and they prefer around 22 to 28 degrees. They can breed two to three times a year. 

“If they live up north around Grafton, they’ll actually grow for 11 months of the year. Down here at Narrandera Fisheries, they found that they only grow for five months of the year. Once you get below 15 degrees, they stop growing.

“They can live five, six-plus years. In the first year of their life, mortality is around 98-99 per cent.”

Dr Conallin explained that survival rates dramatically increase after the first year as their list of predators dramatically drops as they obtain some size about them and explained that their diet is an opportunist one.

“They’re opportunists, they’ll eat anything.

“When they’re really small, they actually feed off zooplankton.

“That’s why you won’t have a good survival of yabbies if you don’t have good zooplankton populations.”

Environmental consultant Dan Hutton, who conducts regular monitoring of the site, then explained the importance of the yabby to the current bird breeding.

“At this site at the moment, there has been a large waterbird breeding colony here for the past four months.

“The yabby populations have been seriously depleted; we’re not finding as many as we usually do.”

Dan went on to talk about the large population of long neck turtles around the site and the risks that foxes pose to turtle nests.

A brief walk led the tour to a series of ponds in which traditional owners had used water regulation to increase food production. Dan explained that dating of the aboriginal mounds had placed them at over 3,000 years old. The mounds were formed through the deposits from cooking, using charcoal heating clay bricks to cook the food. The clay bricks were strategically chosen from the pond they wished to deepen, ensuring a more abundant water supply.

A check of the nets in the water by Dr Conallin highlighted the impacts the current carp population is having throughout the system. Over 90 per cent of the total catch was carp and Dr Conallin explained that all the nutrients that went into growing the large pile of carp robs other beneficial species of a food source.

Kids both young and old then enjoyed a yabby and turtle race, and while it wasn’t a win over the hare, the turtle kept his winning form, romping it home in front of the yabbies.

By lunch time, all the walking, learning and catching had worked up quite the appetite and the participants had a chance to sample the ‘destructor’ back at the Murray Connect offices. 

The day was made possible by the partnership of Landcare, NSW Government, NSW DPI, NSW LLS Forestry NSW, WMLIG, the Joint Indigenous Group and Tanya and Graham Heffer.

This article appeared in The Koondrook and Barham Bridge Newspaper, 2 March 2023.