When not trapping and tagging fish, we’re busy searching for those already marked. Not an easy task, given the size of the reef and the number of fish around! To assist with this effort we use a hand-held receiver that listens for pings emitted from tagged fish. We swim around, sweeping the receiver back and forth, until it picks up a signal. Weak at first, we move towards the signal until the receiver indicates the fish is nearby. External tags placed on each fish help us visually locate the fish once the hand-held brings us to its neighborhood.

Once spotted, we spend five to fifteen minutes videotaping the fish to capture footage of its behavior. Sounds simple enough. But in fact it’s quite a challenge. To help you imagine what it’s like to videotape fish take your video tape recorder and place it in a shoebox. Cut a hole the size of a stamp out of the back. Look thru that into the camera’s tiny viewfinder. Oh, and remember, you are doing this with a mask on and a regulator in your mouth. So actually you can only get the shoebox about five inches from your face. Now keep the camera steady as you swim – you don’t want to make your viewers seasick! And make sure you keep track of you’re air supply (you don’t want to run out!) and your buoyancy (you don’t want to bump
into the coral!) and don’t lose your buddy!!!

Keeping track of your buddy while videotaping is especially important on a saturation mission. Because you always need to be able to find your way back to the habitat – surfacing is not an option. Your buddy’s job, while you are attending the simple task of filming fish, is to keep track of the way home. We’ve been trained to do that using reels attached to a system of excursion lines that lead back to the habitat (breadcrumbs won’t work down here). We tie our line to the excursion line and venture forth, unwinding our line as we travel. Thus, when it is time to go home, we can follow our line back to where we started. This is critical, because it is amazing how lost you can become chasing a fish in circles while looking into a hole in a shoebox!

James and I employed this method today while using the receiver to search for a black grouper. The receiver indicated that the fish was in deep water, so we swam off into the deep, dark, cold water. Visibility was poor and the current strong, so without our reel, we would have had a very hard time finding our way back! As we searched, I found myself looking back at the line, disappearing into the haze. Every so often I’d give it a tug, just to reassure myself that it was still attached! Our efforts were rewarded – we found the grouper, tagged seven days ago, swimming around and appearing healthy. Having confirmed that, we turned around and happily followed our reel home!