Mud crabs are given a grade between A and C, with grade A considered to contain the most meat.

“It will allow a fisher or a market stallholder to point this device over a crab’s claw or carapace and determine what grade it is so there is no ambiguity around the meat content,” James Cook University (JCU) senior lecturer Dr Eric Wang said.

“Right now, a lot of grade C crabs are caught which isn’t sustainable for the environment, so this is a way to help filter those out.”

The prototype device uses a near-infrared spectrometer and artificial intelligence to grade live crabs based on their meat content.

It’s hoped it will ultimately replace the current practice of fishers using thumb pressure applied to the carapace.

“The device has a lamp which shines onto the claw of the mud crab, and depending on the chemical composition of the claw, it will reflect or absorb different wavelengths,” Wang said.

“Based on the absorbed wavelengths, the developed AI algorithm can then determine what grade of mud crab it is.”

The Rapid Assessment Unit, a joint JCU and Department of Agriculture and Fisheries (DAF) organisation focused on innovative scientific research, is also involved in the project.

While DAF had already developed the technology being used as a proof-of-concept, Wang said the main challenge was how to make it portable.

“What I’m exploring is how we can make this device affordable, waterproof and easier to carry on the boat, as well as integrate all of the AI algorithms into it,” he said.

“It’s important to get the device to a point where it can eventually be recognised by industry as a reliable tool.”

Depending on the success of the device, there is potential for it to be used to measure other types of seafood, such as fish or prawns.