Back to the mangrove creeks for today’s work – we were taking a step into the future and using a drone to survey wildlife there. As an emerging technology, lots of work remains to be done in order to assess the accuracy of aerial drone surveys. One way of measuring this is to send a drone over the creek, then wade up it in person to see if human searchers can spot the same wildlife as the drone.
We launched the drone, which was flown by Dr Nathan Robinson, and it followed its pre-programmed route up the creek. When it returned, we took to the water – viewing the drone footage would have to wait until we were back on campus.
It was low tide, so this creek was much shallower than the one where we caught stingrays – knee rather than waist or chest deep. It was also far clearer, so we could see all the tiny fish flitting around. Checkered puffer fish were so numerous that one swam into my foot, and a couple of blue crabs hid amongst the mangrove roots.
Sending the drone up again, we spotted a juvenile lemon shark on the screen. It cruised around, completely oblivious to the buzzing gadget. A few people splashed out to meet the shark in person, spotting a further two.
Back on campus, we wanted the footage from the drone survey. A lone barracuda flitted across the scene – drones had triumphed over humans at wildlife spotting in this case! We learnt that species such as bonefish and houndfish, a strange, slender creature with a long mouth full of teeth, are far too timid to be seen by human researchers and so are best assessed by drone.
In the afternoon, we loaded our bikes with flippers and snorkels and cycled to a place called The Saddle. Diving on the reef was a very different experience after yesterday’s talk – a few live corals, yes, but also areas of rubble and algae. There were fewer fish here, BUT…
“Ray, ray!” The shout went up. Six magnificent spotted eagle rays cruised below us, slender tails trailing behind them. We were also treated to a sighting of a black-tipped reef shark and an enormous loggerhead turtle. We couldn’t believe our luck!
The second reef was a ray of hope, with sea fans and live corals with their polyps out as they should be. Vibrant purples and yellows dominated, rather than the muted blues and greens I’d come to expect. It was amazing seeing a place so alive… here were all the colourful fish you would expect from a coral reef, as well as long-spined sea urchins which I hadn’t seen on our other dives. On this reef, they were everywhere – nearly every crevice had long, black spines poking out.
Wetsuits still dripping, we mounted our bikes and cycled back triathlon-style. This evening we watched videos made by past students – while we are here, we will plan and carry out a research project, then create a video to explain it to the public. Watching the old videos gave us plenty of ideas!