Genetic tracing fish offspring outside Kimberley no-take sanctuaries proposed

DNA tracking has been used to monitoring the effect of marine sanctuaries on stocks at nearby fisheries.

James Cook University marine biologist Prof Geoff Jones says the method could be easily used to study the impact of the new no-take zones at Camden Sound Marine Park off the Kimberley coast.

“The purpose of the study was to basically work out whether or not there were added benefits of having marine sanctuaries for restocking fish populations outside reserves,” he says.

“We’ve known for a long time that adult numbers build up in reserves, so there’s obviously some sort of conservation benefit within the reserve boundary.

“What people really wanted to know is ‘does that do any good for the fishery outside?’.”

He said there had never been a previously-agreed method for tracing the dispersal of baby fish from their parents.

“We put a lot of thought into that and we came up with a DNA technique.

“We now have the ability to find juvenile fish, sample the DNA of adults and then work out who belongs to whom.

“We did the proof of concept of this, years ago, using clown fishes.

“We not only did the DNA but we were able to tag eggs using a chemical marking technique - and we had almost 100% correspondence between the two different techniques.

Professor Jones and his colleagues applied the technique to coral trout breeding in three marine sanctuaries at Great Barrier Reef’s Keppel Islands.

“We were just amazed [at] how many small baby fish that we found that we could relate to parents back at the reserves,” he says.

“What astounded us really was that a lot of them were within one or two and up to 10 or 20 kilometres away from the reserve.

“I think it’s important to repeat the kind of work that we did on other species in other places just to see how this unfolds in terms of being a general concept.”

He says it would be well worth applying the method to a study of fish populations in and near the two no-take zones declared earlier this year at the new Camden Sound Marine Park, off the Kimberley coast.

“You can take a lot of conservation actions and you don’t really know if it’s beneficial for many years down the track—but for reserves you can see within two or three years something has happened.”