Monitoring fish populations and behaviours has taken off globally, thanks to agreed protocols on acoustic telemetry.

Understanding how fish move around and use our marine environment is vital to conserving ocean life. GPS does not work underwater so different tools are used. One way to follow the movements of fish underwater is to use sound waves transmitted by small tags on fish, which travel very effectively through water and can be picked up by receivers or loggers. This is acoustic telemetry. Marine scientists around the world have been using acoustic telemetry to remotely track the movements of fish and other marine and freshwater species for many years.

Tags attached to marine creatures by scientists transmit sound through a sequence of pulses at high frequency or pings. Unique to that tag on that fish, these can be picked up by loggers or receivers on the seabed as the fish swim by, recording their movements and presence at a particular location and time. The tags can be surgically...