Seasonal occupancy and population trends of juvenile permit (Trachinotus falcatus) in Texas estuaries

As tropicalization alters marine communities in the Gulf of Mexico, flats fisheries are likely to be impacted. Permit ( Trachinotus falcatus ) (Linnaeus, 1758) are a popular flats species and are commonly targeted in Florida (USA) and the Caribbean. Much of the research on permit has been conducted in Florida and, in the western Gulf, such research is lacking. This study aims to provide an insight into the permit population in Texas (USA), including abundance, distribution, seasonality, and associated environmental conditions. We used long-term fishery-independent data from bag seine and gill net samples (1983–2024) to assess population trends and used Boosted Regression Trees (BRT) to determine the environmental variables that most predicted permit presence. Small juveniles sampled in bag seines (12–208 mm TL) increased significantly over the timeseries, but larger juveniles sampled in gill nets (127–519 mm TL) and adults did not. Permit were distributed in higher densities on the mid and lower coast, specifically around Gulf-estuary passes. Observations of permit occurred from April to December, a shorter seasonality than recorded in Florida, but one that coincides with the estimated spawning season. Environmental conditions associated with permit include moderate salinities (20–40 ppt) and high temperatures (> 25 °C), and permit presence increased with increased dissolved oxygen and decreased turbidity. This research is novel as it is the first study of permit populations in Texas and should provide a foundation for future management strategies.