Tiny chip tracks fish movements

Scientists at Dalhousie University are developing research tools that could reveal secrets that might mean the difference between life and death for some fish.

The research is taking place in a swimming-pool-sized tank called the Aquatron.

If you look at the fish swimming there, you'll notice immediately that they are wearing computers. Those computers track their every movement.

Researcher Fran Broell says there is a lot to be learned about schools of fish in the deep ocean from the way they move. "They move as if they are one, but they don't. There is one fish that starts moving, and all the other ones respond to that movement, but we can't see that because it happens so fast," she said.

Broell and her research partners have created a circuit board the size of a postage stamp that can record 500 movements a second. The circuit board is built from 20 dollars worth of parts, from plans available through open source on the Internet, so there aren't even any royalty fees to pay.

"Like a Lego kit for people who are interested in electrical engineering" said Broell.

"We were interested in those really, really fast movements of the animals, but there is no technology that can measure it," she said.

For example, a little fish swimming next to a big fish has to move its tail much more quickly, to keep up at the same speed. By measuring the number of movements over several months, they can track the growth of the fish.

"We know due to the frequency of the tail beat, that fish must be 15 inches long," she said. By measuring movements associated with eating, the researchers can answer questions about how often and where the fish eat.

"If we could find out where certain animals are eating, we could protect those areas," said Broell.

A similar technology applied to seals could determine how many cod the seals are eating, and when and where they are eating them. To be able to track such detailed information will require an evolution in the equipment they use. Currently, they retrieve the information by removing a card from the computers, much like the card in your digital camera. But improved gear will allow fish to transmit the information from the deep ocean to a computer on land.

"Yeah, it talks to you," said Broell. "It's like a fish that is carrying an iPhone."