Nassau grouper form large spawning aggregations where thousands of fish come together to spawn annually. While adult Nassau grouper typically rarely move more than a few hundred meters to feed and find shelter, they migrate hundreds of kilometers to spawning sites. Through this project we will understand how adult migrations link home ranges and spawning sites throughout The Bahamas.
For over 10 years we have tracked Nassau grouper movement in The Bahamas using acoustic telemetry. We surgically implant a small transmitter into fish that has a unique code and have receivers set up to listen for these transmitters along the reef. When a fish swims by a receiver it detects the transmitter, identifies the fish and logs the time. To date we have tracked over 70 Nassau grouper, with most fish tracked for several years.
We also implemented a tag-recapture program with over 100 Nassau grouper marked with an externally visible tag. Fishermen capture tagged fish and report which fish was caught as well as where and how big the fish was. This provides additional information on movement patterns and tracks growth of individual fish.
This information provides key information on how fishing in one area affects populations in other parts of the archipelago. It also lets us develop more effective marine protected areas and other fishery management measures to rebuild Nassau grouper stocks. Healthy Nassau grouper populations in The Bahamas will support reef ecosystem health, build a sustainable fishery, and replenish stocks regionally.