George Town, Grand Cayman–The Department of Environment (DoE), the Reef Environmental Education Foundation (REEF) and the Darwin Initiative are collaborating on a project  that will help identify the different types of fish species that visit designated spawning sites in the Cayman Islands using specialised underwater devices.

The devices, commonly known as hydrophones, act like microphones to pick up sounds that fish make and convert them into audio signals that are translated into measurable data. Scientists at the DoE and REEF then use the findings to determine the species and number of fish, including Nassau Grouper, which are frequenting the sites. 

DoE Marine Research Officer, Bradley Johnson, explained why this new equipment was necessary. "We have been tracking fish species via in-water monitoring and acoustic tagging for many years now. However, aside from in-water monitoring, we could only track fish that we tagged when they passed by the monitoring stations. With these hydrophones, we can now record underwater sounds at the spawning sites every five minutes which allows us to collect more comprehensive data and ultimately, provide greater in-depth understanding of which species use the sites and their abundance."

The Hydrophones will be deployed for six months at a time, recording sound for 20 seconds every five minutes. Upon collection, the data is interpreted and analysed for species and number of each fish species present at each site. There are currently three hydrophones deployed on Little Cayman and one in Grand Cayman. A fifth will be installed in Cayman Brac within the next few months. 

The equipment was provided through funding from the Scripps Institution of Oceanography and the Darwin Initiative Grant, which is funded through the UK Department for Environment, Food and Rural Affairs (DEFRA). The DoE publically thanks those organisations for their support with continuing projects, and looks forward to working with them on future environmental programmes.


From Ministry of Financial Servies, Commerce and Environment; Cayman Islands Government

Contact: Ariana Rahamut