After heavy rain that continued on throughout the night, we awoke to sunshine and a calm blue ocean – it was a perfect day for surveying fish. Jordan Goetze (a PhD student from the University of Western Australia) and Sam Moyle (Western Australia Fisheries) meticulously check the gear and calibrate cameras carefully before we headed out, as mistakes can be costly in science.
Once the two cameras are ready and mounted on the frame the survey work is not hard. It simply involves swimming along the edge of the reef, holding the camera as steady as possible. At each site, we do six 50m transects recording underwater video. The surveys themselves take only 20 minutes, but Jordan tells me that each video from each site takes him a whole day to analyse.
Back in the laboratory he has to set up two televisions to watch both videos simultaneously, so that he gets a three dimensional view of the reef in front of him. From each video he records all the species of fish on the video, and their sizes. I learned that this technique has greater accuracy than using divers counting fish under the water, and he actually has a paper coming out with our Director Dr. Stacy Jupiter, to prove this.
Throughout the course of the day, we surveyed reefs both inside and outside a large community tabu area that Nauouo village has set up inside the lagoon. The reefs form a patchwork of reefs in the sandy lagoon. We saw a wide range of reefs from those teaming with live corals, to more degraded reefs covered with lots of algae. With just the eye, it was hard to judge how much the tabu areas had recovered from their last harvest, though I did notice a lot of juvenile parrotfish and wrasses.
We really won’t know the answer until Jordan finishes analysing all those video tapes. With nine sites surveys, that is nine full days of work he has ahead of him. We are lucky to be working with Jordan, who really wants to make sure his research makes a difference to people on the ground in Fiji.
By Sangeeta Mangubhai on Day 2 of the Periodic Harvest survey
Check out the Day 1 blog