Over the past several months we've been monitoring one of the only documented Nassau grouper fish spawning aggregations in Puerto Rico. This project, funded by the NOAA Section 6 Endangered Species Recovery grant, is a three-year project that we designed to promote the continued recovery of the species.
We aim to strengthen the recovery of Nassau grouper through active aggregation monitoring, searching for new aggregations, characterizing habitat preferences, exploring genetic connectivity, and improving communication channels with enforcement agencies.
The latter objective was the primary focus of the first year of the project, whereby our team coordinated meetings and strategic planning opportunities with the NOAA Office of Law Enforcement, Dept. of Natural and Environmental Resources, and the US Coast Guard to explain the regulations around Nassau grouper (no-take, $5000 fine if caught in possession) and provide an overview of the areas of particular concern where their enforcement efforts should be focused. With limited funding and personnel for local enforcement, and thus few opportunities to intervene in illegal fishing, this became a top priority for our project so that we could help these agencies identify the timing of enforcement presence that would be the most beneficial.
We also took the opportunity to educate by providing free copies of our Grouper Guide which highlights key grouper species with fishing regulations, along with a map of seasonally closed areas on the west coast and their closure dates. We have received very positive feedback about these guides, and the Caribbean Fishery Management Council even funded our production and printing of the guides to feature USVI fishing regulations so that they can be expanded to other parts of the US Caribbean.
Aside from our communication coordination with enforcement agencies, we have also been enhancing our sample collection of Nassau grouper DNA in order to eventually assess the genetic connectivity between the various populations of this species around the island. Juvenile Nassau grouper, like many other juvenile fish, find solace in the protective blades of seagrass beds and rocky rubble reefs where their coloration can quickly hide them from predators. As we receive reports of grouper sightings from our reporting app and from local fishers, we investigate these areas searching for juvenile Nassau grouper. When found, we take small clips of their fins which we use to extract DNA for the genetic analysis. Check out the video below, produced by our colleague HJR Reefscaping, that highlights the quick process.
During the winter months, we focused our efforts on monitoring one of the last known Nassau grouper spawning aggregations in Puerto Rico. This aggregation is part of a long-term monitoring effort that has spanned over a decade. We continue to visit this site so that we can observe the fish, take estimates of their sizes, and get an estimate of the number of fish present. Although weather is always tricky during this season, we were able to monitor each month of the spawning season and complete this objective for the first year of the project.
Now as we continue into the summer months, our efforts shift from aggregations to habitats. Another aspect of the project is to characterize the critical habitat used by Nassau grouper during the various phases of their life. For example, this fish like many other fishes, recruit to shallow areas of rocky rubble surrounded by seagrass beds. We identified, from a past project, some general characteristics of habitats on the east coast of the island where Nassau grouper tend to be found. This summer, we will be expanding on that pilot study to continue the search and characterization. This step is critical because it provides us with a more robust understanding of what habitats this fish prefers so that we can help management agencies generate appropriate protection measures for the entire life cycle of Nassau grouper. It's not enough to protect just the spawning aggregation - because without the juveniles, there will be no adults.. without the adults.. well, you get the idea.
Follow along here as we continue this project and report on the initial findings. We also educate about the various aspects of our projects (experimental design, purpose, equipment used, etc.) on our social media accounts to help explain what we do in common language so our community can understand and appreciate the science.