Looking for Nassau Groupers in Grand CaymanLatest update January 25, 2019 Started on February 7, 2018
In February 2018 with the generous loan of a Trident from OpenROV we searched for a spawning aggregation of Nassau Groupers on the eastern end of Grand Cayman. Rough seas and strong currents limited our field time but we did manage to locate a small number of fish. This new expedition is to continue that search on the eastern end to try and determine the size of that spawning population as well as to look at other sites around the island.
We were finally able to get out today and get the Trident in the water for a refresher dive on the north coast. All of Zack's training from last February came flooding back and we had a great dive. Didn't see any Nassau Groupers but did see a few Barracudas, Bermuda Chubbs, Black Groupers, and lots of Black Durgons and Creole Wrasse.
Hopefully tomorrow will bring better weather and we can make it to the aggregation site.
It's here! Our Trident arrived last week just in time for the full moon today and we're gearing up to start. A huge thanks to National Geographic and OpenROV for supporting this research.
Unfortunately, a cold front swept in last night bringing strong winds and rough seas on the north and east sides of Grand Cayman where the aggregation site is. It should settle later in the week and allow us to get out but in the meantime we'll take it out for a refresher dive in calmer conditions and try to visit a few other sites of interest on the calmer side of the island.
This is the evolution of a previous expedition which we ran in February 2018 and had success with (link below). The aim is to determine the size of the spawning population of Nassau Grouper at the traditional site on the eastern end of Grand Cayman. This is one of several sites throughout the Cayman Islands where groupers have aggregated to spawn, but this particular site has proven difficult because of its depth, strong currents, and smaller number of groupers. We found some groupers during the last expedition but the location and timing wasn't ideal and it wasn't a significant amount so we are hoping to get a better shot at finding the main aggregation of fish.
The fish normally aggregate on the edge of the 'wall' or drop-off and at this site this varies from 150ft to 180ft: well outside the range of traditional SCUBA. We tried using a drop-camera previously, but because of the depth of water and strong currents pulling the camera and cable, it relied on a great deal of luck to get the camera in the right location and pointing in the right direction. The addition of the Trident ROV to this project has improved our efforts significantly by giving us control over where we go and what we look at.
The fish normally aggregate around the full moons in either January of February (depending on the timing of the moon) so we will begin our search in early 2019. Check back closer to that time for updates.
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