Strengthening recovery of the Nassau grouper in Puerto Rico: This project focuses on implementing specific action plans for the management, monitoring and enforcement of the only known spawning aggregation in Puerto Rico. The project is designed to greatly expand on previous monitoring and identification of critical habitat for Nassau grouper while also identifying potential areas of larval settlement and nursery sites and better understanding habitat use by Nassau grouper through ontogeny. Knowledge gaps in species biology will be addressed, aided by the incorporation of citizen scientists to report sightings of Nassau grouper and build a map of distribution by size class. Ongoing. Funded by NOAA Section 6.

Identifying critical habitats of juvenile Nassau grouper (Epinephelus striatus) in Puerto Rico: This study was designed to identify the habitats used by juvenile Nassau grouper and provide a population estimate for the area surveyed as well as increase the awareness and outreach regarding the status of this species and other groupers in Puerto Rico. At the largest spatial scales, juvenile Nassau grouper habitats include seagrass beds, patch and linear reefs. At smaller spatial scales, they occupy hard substratum surrounded by unconsolidated sediment colonized by seagrass. At the finest spatial scale, these habitats can be defined as patch reefs colonized by macro- and turf algae, and bare substratum (rubble, pavement, or sand) located within 25 m or less from continuous/dense seagrass beds. Completed 2022. Funded by CFMC. Final Report.

In situ Tagging of Nassau Grouper Using Closed-Circuit Rebreathers: This study introduced a novel application of in situ tagging using closed-circuit rebreather (CCR) technology at mesophotic depths, specifically targeting Nassau grouper at a spawning aggregation off Puerto Rico's west coast. Conducted at depths of 40-50 m across six dives, the procedure involved tagging 10 fish with minimal stress or physiological impact, achieving a 100% post-surgery survival rate over short-term tracking up to 347 days. This methodology, leveraging CCR efficiency, enhances survivorship and reduces bias in acoustic telemetry studies, contrasting with traditional surface implantation methods. Completed 2016. Funded by CFMC and NOAA SK. Publication

Spatial and temporal dynamics of a Nassau grouper fish spawning aggregation located on an isolated seamount in Puerto Rico: Acoustic telemetry was employed to study Nassau grouper spawning dynamics at Puerto Rico's only documented spawning aggregation located at a seamount and seasonally closed marine protected area. Over three spawning seasons, 26 tagged fish revealed the formation of three to four aggregations per season, closely tied to lunar cycles from January to April. The study highlighted high visitation rates to the aggregation site, significant variability in timing of arrivals and departures, and occupancy of a relatively small staging and courtship area. Findings suggest that the current seasonal closure, ending in April, may insufficiently protect the spawning population, recommending an extension until the end of June. Completed 2022. Funded by CFMC. Publication.

Home range, space use, and vertical distribution of Nassau grouper during non-spawning times: The study used acoustic telemetry to analyze non-spawning spatial patterns of Nassau grouper at Bajo de Sico seamount, a seasonally closed marine protected area in Puerto Rico. Twenty-nine groupers were tagged, with fourteen tracked continuously over three years, revealing high site fidelity to home reefs and consistent small home range sizes. Vertical distributions were discrete among individuals sharing home reefs, with occasional visits to the spawning site outside of the spawning season and instances of home reef relocation. Results underscore Bajo de Sico's importance as critical habitat for Nassau grouper, suggesting adjustments to MPA management to enhance protection for the non-spawning population and maintain ecological roles. Completed 2022. Funded by CFMC. Publication.