Fish Sensory Organ Could Improve Underwater Robots

A team of scientists led by the University of Bristol has been studying a fish sensory organ in order to gain insight into collective behavior, which could be used for underwater robots.

The focus of the research was the lateral line organ found in African cichlid fish and almost all other fish species. This organ allows fish to accurately sense water pressure and detect external factors like other fish, changes in water flow, predators, and obstacles.

Lateral Line System in Fish

The lateral line system spans the head, trunk, and tail of fish and consists of mechanoreceptors known as neuromasts. These receptors can be located within subdermal channels or on the surface of the skin.

Elliot Scott of the University of Bristol’s Department of Engineering Mathematics was lead author of the study.

“We were attempting to find out if the different areas of the lateral line — the lateral line on the head versus the lateral line on the body, or the different types of lateral line sensory units such as those on the skin, versus those under it, play different roles in how the fish is able to sense its environment through environmental pressure headings,” he said.

“We did this in a novel way, by using hybrid fish, that allowed for the natural generation of variation.”

The researchers found that the lateral line system around the head has a significant impact on the fish’s ability to swim in a group. A higher number of subdermal neuromasts leads to closer swimming, while more surface neuromasts result in more separated swimming.

Scaling Up Through Simulation 

The mechanisms behind the lateral line system were also shown to work at larger scales through simulation. This could lead to the development of a low-cost pressure sensor for underwater robotics, specifically for swarm robotics, where cost is a major concern.

“These findings provide a better understanding of how the lateral line informs shoaling behavior in fish, while also contributing a novel design of an inexpensive pressure sensor that could be useful on underwater robots that have to navigate in dark or murky waters,” Elliot said.

The team will now look to develop the sensor even further and integrate it into a robotic platform to help a robot navigate underwater.