Ocean Ambassador Dr Brian Luckhurst - previously head of Fisheries in Bermuda and originally a student at UWC Atlantic College - sends us a short report and images showing his efforts to protect Grouper fish through monitoring spawning aggregations - amazing natural events that are important for the success of certain species.
Many species of commercially important groupers and snappers form spawning aggregations at specific sites and times in order to enhance spawning success. When these locations and times (based mainly on lunar phase) become known these sites become vulnerable to high mortality rates as fishermen target them intensely. Unless these sites are managed and protected they can be fished down very quickly and sometimes disappear altogether.
The best way of tracking the movements of fish to these sites is to tag them and record their movements to and from the site. This can be done remotely by surgically implanting sonic tags in a number of fish and deploying sonic receivers at the site to detect their presence. These data can then be used to actively manage aggregation sites by adjusting seasonal closure periods. More information about spawning aggregations globally can be found at www.scrfa.org.
Step 1: A Black Grouper is caught by handline
Step 2: Tagging in a cradle
Step 3: Spaghetti tag inserted
Step 4: Release the Grouper. Its movements will be monitored to allow the protection of future spawning aggregations.