The Pentagon is funding research with the ultimate hope of turning real sharks into "stealth spies" capable of gliding undetected through the ocean. It involves placing neural implants in the fish, to transmit their controllers’ bidding.

The research, to be reported in the UK’s New Scientist this week, builds on experimental work to control animals by implanting tiny electrodes in their brain, which are stimulated to induce a behavioural response.

"The Pentagon hopes to exploit sharks’ natural ability to glide quietly through the water, sense delicate electrical gradients and follow chemical trails," says the report. "By remotely guiding the sharks’ movements they hope to transform them into stealth spies, perhaps capable of following vessels without being spotted."
The project is being funded by the Pentagon’s Defence Advanced Research Projects Agency, which pioneered the internet as a platform for robust communications.

Scientists involved in the scheme presented their work last week at a meeting on ocean sciences in Hawaii.

A team at Boston University have implanted electrodes into the brain of a spiny dogfish in a shallow tank.

The implants stimulate either the right or left side of a brain area dedicated to smell, causing the fish to flick around in that direction in response to the signal.

The next step will be to take this device outside the laboratory. Blue sharks implanted with the gadget are to be released off Florida.

Communications with the fish will be made through US Navy acoustic towers capable of sending sonar signals to a shark up to 300km away.

Other DARPA-funded researchers are working on using implants to record brain activity in sharks in order to understand which neurons are fired by scents, electrical or magnetic fields.

These signals help the fish to navigate and offer the reward of food, and could thus in theory be manipulated for surveillance work.

Most will agree that the DARPA work is controversial but says that work with animal implants could also have a benefit for medicine.

In the meantime, it can provide inspiration for producers of B-movie sequels.