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Restock helps fishers and ecosystem
University of New South Wales   
Thursday, 20 November 2008
kingprawns.jpg
One-year old eastern king prawns from
Wallagoot Lake.
Image: Dr Matthew Taylor

Eastern king prawns are back on the menu after a seven-year absence at Wallagoot Lake, near the NSW south coast town of Merimbula, following a prawn-restocking program that is yielding wins for prawners and the environment.

Prawners are reporting catches of up to three kilograms an hour and recreational anglers who use them as bait have had excellent fish catches. The eastern king prawn is an iconic and popular prawn species heavily targeted by NSW prawners. The species accounts for more than 80 per cent of NSW recreational prawn catches.

Beginning 18 months ago, eight million juvenile eastern king prawns were stocked in the Wallagoot and Back lakes near Merimbula. Another three million are due for release at Wallagoot Lake from 1-5 December. Since restocking began, individual prawns have bulked up from about 5 milligrams in weight to an average 30 to 40 grams - an increase of between 6000 to 8000 per cent. To date, the largest specimen recorded weighed 54 grams and measured 20 centimetres.

This phenomenal growth is occurring because the prawns are confined to the estuary system. Prawns only spawn when they enter the sea so the energy that would have been diverted into reproduction is being conserved for growth.

The restocking program has been a triumph for prawners, according to project leader, UNSW biologist Dr Matt Taylor: "Before the release program, eastern king prawns hadn't been captured in Wallagoot Lake for more than seven years. We have tracked their growth and survival rates, and for the first time we will tag prawns with acoustic pingers. This will help us understand what is driving the prawns' movements and food foraging activities so that we can target our release numbers to levels that the ecosystem can support."

The restocking program is part of a three-year collaborative project between the University of New South Wales and the NSW Department of Primary Industries, funded by the Recreational Fishing Trusts and the Australian Research Council.


Editor's Note: Original news release can be found here.
 

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