Sydney Cockles Seeded in Flood-Hit Estuaries
The NSW Department of Primary Industries and Regional Development (DPIRD) have released 110,000 juvenile Sydney Cockles into the Tweed River and Wallis Lake since May in a positive step towards restoring populations in the flood effected regions.
DPIRD Senior Principal Research Scientist Dr Matt Taylor said Sydney Cockle (Anadara trapezia) are sensitive to the salinity of estuarine water across their life cycle and freshwater flushes from floods have caused population numbers in some estuaries to decline.
“The Seeding Sydney Cockles project, aims to develop aquaculture restoration techniques for Sydney Cockle populations in estuaries impacted by the February 2022 floods and show how juvenile cockles respond to low salinity”, Dr Taylor said.
“Taking steps to recover the local populations of Sydney Cockle was identified as a priority activity in the Tweed River Cultural Restoration Strategy, developed by the Tweed-Byron Local Aboriginal Land Council (LALC) under the Program.
“60,000 Sydney Cockle were released into the Tweed River last month, with the local Aboriginal Community in attendance”.
Miss Leweena Williams, Tweed Byron LALC CEO said cockles are an important traditional food staple that has largely disappeared from the Tweed estuary because of overfishing, taking undersized stock and environmental factors, such as flood impacts.
“We are excited to integrate our Traditional Knowledge with other scientific research and be a part of working to restore this important missing cultural resource”, Miss Williams said.
“Seeding the cockles into the seagrass areas was both a culturally significant and practical multi-generational activity that will hopefully bring back our ability to continue our cultural practices and sustainable use of this special species.
“Tweed Byron LALC Land & Sea Rangers and community members will be regularly monitoring the site to ensure protection of the new stock for current and future generations”.
DPIRD’s Mollusc Aquaculture Team, led by Senior Research Scientist Dr Laura Parker, have so far produced 110,000 Sydney Cockle at the Port Stephens Fisheries Institute to be stocked into flood effected regions.
Millions of marine and freshwater fish are produced through aquaculture and stocked into estuaries and rivers by DPIRD each year, however, this is the first time we have produced and restocked cockles to depleted beds”, Dr Parker said.
“Beyond producing the cockles, we have also been trying to understand how juvenile cockles respond to low salinity and how we can increase their resilience to future flood events”.
Dr Taylor said the trial releases of Sydney Cockle into these flood-affected estuaries is an important step towards developing strategies to aid ecosystem and fishery recovery following floods, as it is a highly valued species for commercial, recreational and cultural fishers all along the NSW coast.
“DPIRD will continue working with TBLALC and Indigenous Rangers to monitor the seagrass beds where the cockles were released, over the coming months”, Dr Taylor said.
“A second release of around 50,000 Sydney Cockle recently occurred in Wallis Lake, after water quality improved following recent flooding events.
“With their creamy white shell and that they are readily found in shallow estuarine waters, cockles are popularly harvested by recreational fishers for bait and are important culturally for Aboriginal communities as a food source.
“As filter feeders, cockles are also important to the health of our estuaries by filtering 1.5 litres of water in an hour”.
https://www.dpi.nsw.gov.au/about-us/media-centre/releases/2025/general/seeding-the-future-for-sydney-cockles-in-flood-affected-estuaries