I arrived in Little Cayman to join the Department of Environment Grouper Moon Team Friday after school. So today was my first official day with the team and underwater with the Nassau grouper! The seas were a bit rough today, but what a day we had! Each day there are three dives – a morning dive that leaves the dock at 8 am, an afternoon dive at noon, and an evening dive at 4:30 pm. 

 

There are three main tasks for the team of divers on each dive. The first is a research method called ‘Fish Faces.’ This year instead of physically tagging the grouper to obtain an estimate of the population size, researchers are obtaining images of individual grouper ‘faces’ or the sides of the grouper. Each grouper has a pattern that is unique to only him or her, sort of like our fingerprints! Using a GoPro on a long selfie stick, we take videos of as many fish as we can so that the researchers can use AI software to identify each fish. Today there were many fish, in the thousands! Some were up in the water column against the edge of the coral reef wall. Other grouper were resting at the bottom of the reef along the sea floor. Today we had three buddy teams, so a total of six divers, doing ‘Fish Faces.’

The second task that a buddy team of divers is assigned to is ‘Stereo Video.’ The Stereo Video is a specially designed device to take length measurements of the grouper. It is essentially a long stick with a GoPro on each end. This device is used to measure the length of different Nassau grouper at the spawning aggregation site. Length data is important because the larger the fish are, the more eggs the fish will have. Also, the fish get bigger as they get older, so this is one way to determine how the population of fish is growing.

The third research method that we are using is a ‘Video Pan.’ This is probably the most exciting! Two divers are propelled through the water on underwater scooters and dive the entire length of the band of fish, sometimes this can be longer than 100 yards, the length of a football field! 

We are expecting the peak spawning to either be on Sunday or Monday, so stay tuned for tomorrow’s post!