Researchers at the University of Illinois in the US have developed an artificial version of the lateral line sense organ
of fish to be used for underwater robots.
The lateral sense organ present in most fish detects minute changes in water pressure to detect obstacles. It is thought to be particularly useful in situations where fish cannot rely on vision such as in murky water or at large depths, and will also be useful to detect objects that are too close for sonar. The researchers hope that the new sensor will prevent future underwater vehicles from becoming trapped by unseen obstacles.
Check out the article
or some more detailed non-scientific info at the New Scientist