Prawns be­ing gob­bled up

GOBBLEGUTS PREY­ING ON JU­VE­NILES

Cockburn Gazette - - BUSINESS -

MUR­DOCH Univer­sity sci­en­tists in­volved in a pro­ject to re­stock the Swan and Can­ning rivers with Western School Prawns have iden­ti­fied a key preda­tor of the ju­ve­niles and are us­ing their re­search find­ings to max­imise prawn sur­vival rates.

Dr James Tweed­ley from the School of Ve­teri­nary and Life Sci­ences and a team of re­searchers have been mon­i­tor­ing prawn num­bers, their breed­ing habits and which preda­tors eat the newly-re­leased prawns since Oc­to­ber 2013.

Their find­ings have shown that the lit­tle known but aptly-named “gob­ble guts” fish is tak­ing most of the ju­ve­nile prawns in their field ex­per­i­ments.

Dr Tweed­ley said the lo­ca­tions and tim­ing of the lat­est re­leases of 400,000 prawns at the start of the month had been care­fully se­lected be­cause of preda­tors like the gob­ble guts.

“Hav­ing re­searched the en­vi­ron­men­tal pref­er­ences of the prawns and iden­ti­fied the fish species that eat them, we are able to se­lect the best places to re­lease the prawns to en­sure max­i­mum sur­vival,” Dr Tweed­ley said.

“As gob­ble guts pre­fer dense sea­grass and are more abun­dant and ac­tive at night, we are re­leas­ing the prawns dur­ing the day into mainly sandy ar­eas.

“The prawns are noc­tur­nal too and so when we re­lease them dur­ing the day they swim to the bot­tom and bury them­selves, which hides them from preda­tors.

“Our find­ings sug­gest that, con­trary to pop­u­lar be­lief, the dreaded blow­fish is not a sig­nif­i­cant preda­tor of the ju­ve­nile prawns.

Th­ese di­etary in­sights have been re­vealed by Mur­doch Univer­sity PhD re­searcher Brian Poh, who found around 300 prawns in the gut of a sin­gle gob­ble guts which was only 45 mm long.

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