More than half a million prawns released into Perth rivers

Thursday, 08 May 2014

Reigniting the once popular pastime of prawning on the Swan and Canning rivers has become a reality following large-scale releases of western school prawns into Perth’s iconic estuary.

Challenger Institute of Technology’s Australian Centre for Applied Aquaculture Research (ACAAR) director Greg Jenkins said more than 635,000 juvenile river prawns had been released this breeding season.

The release was made possible following a scientific breakthrough in 2013 which saw a world-first achieved with the development of techniques to culture river prawns in ACAAR’s Fremantle laboratory.

“The release numbers we achieved this season has been a huge win for the people of Perth,” Mr Jenkins said.

“In the first year, we had to overcome a number of breeding and culture hurdles and as a result only managed to release 1,000 river prawns into the Swan and Canning rivers.

“We have had a lot more success this year through fine tuning the culture protocols and up-scaling our production facilities.”

Mr Jenkins said the ultimate measure of the project’s success would be its ability to reignite prawning on the Swan and Canning rivers but already it was securing a number of wins in the laboratory and within the community.

“We were still challenged by the low number of eggs produced by river prawns, which on average is under 30,000, compared with other species such as the western king prawn that can produce up to 650,000 per individual,” Mr Jenkins said.

“This reality meant that large numbers of broodstock had to be collected to meet our target and this was achieved through the Swan River Trust’s citizen science program Prawn Watch.

“Community volunteers worked side by side with scientists to collect gravid (egg-bearing) females from November to March and their assistance was a boost for this project and was critical to increasing our production.”

Mr Jenkins said broodstock collection would begin again in November and in the interim scientists would continue to work to unlock the secrets of the river prawn.

“Murdoch University is still monitoring prawns in the river to try and determine the factors inhibiting their natural recruitment and ACAAR will continue to fine tune our procedures to ensure large-scale releases of the river prawn continue,” Mr Jenkins said.

This project was made possible by the Swan River Trust, Challenger Institute of Technology and the Recreational Fishing Initiatives Fund and is supported by Recfishwest and the WA Department of Fisheries.

PHOTO CAPTION: Fisheries Minister Ken Baston releases a batch of juvenile Swan River prawns during the project.​

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