CSI Missing Manatee The Steps to Search for a Manatee (Or its Tag) Imagine that you've been tracking a manatee with a satellite tag, the then the satellite data stops. What do you do? Where is the manatee now? Is it hurt? Is the tag missing or broken? How would you go about searching for one of your tagged manatees in waters as big as an ocean? The general approach is sort of like CSI-or rather, CSM (Crime Scene Manatee)--it's an investigation. As with any investigation, you have to start with the last information you had about the manatee, and then work from there. For manatees that are tracked, the last information you will have with be the tracking data before the signals stopped With that last location signal, the next steps will generally be to start with broad information and then progressively narrow your search in the field with more specific location data, and even visual searching, until you hopefully find the manatee. The Search Starts in Space--Satellite Data Scientists begin with the last location coordinates from the Argos satellite system, and travel to that general area in the field. The Next Step--VHF Signals in the Field Once there, they listen for VHF signals from the tag to either narrow down the location of the manatee, or to find it's location for the first time. Scientists are usually in boats to do this and use antennas and radio receivers tuned to the specific VHF frequency assigned to that specific manatee's transmitter. Sometimes they can even listen for VHF signals when they are flying an aerial survey too. Take a look and listen to a signal receiver detecting a transmitter's VHF signal. This is what it sounds like! Listen to the VHF Signals Audio Clip (.aif format) or (.wav format) Step Three--Listening for Sonic Beacons Underwater If scientitsts get the VHF signal and it is very strong, they then narrow their search even more, and turn to listening underwater for the sonic beacons from a sonic transmitter that actually is on the belt that is strapped around the manatee's peduncle. To do this they use a hydrophone (an underwater microphone) which they lower in the water. When they hear the sonic beacons with the hydrophone, they will know the direction the Manatee is located. At this point using the sonic beacons, the Manatee is usually within 50 to 100 feet away, and the scientists watch for the Manatee's tag in the water. But what if you don't have satellite signals or VHF signals to start with, and you have to use only the sonic signals? CSI Manatee: What Damaged the Transmitter? If the scientist's search in the field locates only a tag and no manatee, the focus turns to what might have caused the tag to be damaged and detached from the manatee. There are many possibilities and the evidence usually give many clues. Take a look at these tags and the damage you see. This damage is from an alligator-you can see the teeth marks This damage is propeller damage-you can see the clean slice from the blade Copyright 2004 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form