The Science and Innovation Awards for Young People in Agriculture are coordinated by the Australian Bureau of Agricultural and Resource Economics and Sciences, on behalf of the Department of Agriculture.

Danswell Starrs has been awarded $19K by the Fisheries Research and Development Corporation (FRDC) to explore if Computed X-ray Tomography (CT scanning) can be employed to examine the growth rings inside fish earstones, to reveal age and growth rates of fishes. This is a neat progression from his PhD research, which explored the microstructural and chemical properties of fish earstones.

A chance meeting with researchers talking about Computed X-ray Tomography (CT scanning) led Australian National University fish biologist Danswell Starrs to wonder if there was an easier way to work out the age of a fish.

About two million fish are aged every year by looking at their ear stones—called otoliths—which hold information about how old a fish is in a similar way to measuring growth rings on a tree trunk.

To age a fish, researchers currently have to euthanase the animal, remove the otoliths, mount them in a block of hard resin, slice the block into sections with a saw and look at a thin sliver under a microscope. Current techniques are time consuming!

But Danswell hopes to make that process a whole lot easier by investigating whether CT scanning can be used to determine the age of fish without having to section the otoliths.

Future developments in CT scanning could even mean there is the potential to find out how old a fish is while keeping it alive. The collection of age and growth data is central to fisheries management.

“With this information you can work out the effects of fishing,” he said.

“If you’re overfishing a population, for instance, you might find that their age profile is changing, so you no longer have as many older fish.”

Danswell said he grew up on a farm south of Canberra and was interested in the fish and crustaceans swimming in the creek from a very young age.

He came up with the idea of employing CT scans on otoliths during his doctoral research into age and growth processes in native freshwater fish.