Functional connectivity of habitat networks for Permit (Trachinotus falcatus) in the Florida Keys

Functional connectivity among habitat types shapes the spatial ecology and management of species that move between habitats for reproduction and foraging. Many marine fish species aggregate offshore to spawn while relying on nearby inshore habitats (seagrass flats) for foraging, creating connectivity networks between habitat types. We used acoustic telemetry to characterize functional connectivity linking offshore aggregation sites and nearshore flats, using Permit ( Trachinotus falcatus ) across the Florida Keys as a case study. Using tracking data from 45 Permit across three regions (Lower, Middle, and Upper Keys) between 2017 and 2021, we quantified habitat use and connectivity between aggregation sites and flats across seasons. Middle Keys fish (n=5) occupied the largest spawning-season areas (median 138 km 2 ), though this estimate should be interpreted cautiously given the small sample, followed by Lower Keys (n=30, median 35 km 2 ) and Upper Keys (n=10, median 6.6 km 2 ). Non-spawning areas were larger across all regions, averaging 4.8 times spawning-season areas, indicating that Permit concentrate space use around aggregation sites during reproduction. Connectivity networks revealed direct transitions from aggregation sites to nearby flats during the spawning season, and community detection recovered each region's geographic structure without any spatial information. These results show that the functional habitat network of a spawning marine fish extends beyond aggregation sites to nearby foraging habitats, and that this link is most intense during a narrow window of the spawning season, highlighting the need for spatially explicit, seasonally targeted fisheries management. More broadly, pairing telemetry with network analysis offers a transferable approach for identifying when and where space use contracts around critical life-history events, to inform protections elsewhere.