No, you can't actually call the fish and ask them if they fancy a bite but you can find out where they are.

South Korea's SK Telecom has come up with a waterproof transmitter that attaches to the end of a fishing line and sends out ultrasonic pulses to gauge the density of fish in the surrounding water. This information is sent back to a receiver plugged into a cellphone and software on the handset displays this information along with additional data, such as water temperature. With enough of these we might even be able to find Nessie.