Evidence of shared trends in juvenile fish recruitment to nearshore seagrass habitats of the eastern Gulf of Mexico

Abstract

Monitoring abundance of juveniles over time is fundamental to effective fisheries management, especially when juvenile abundance may be used to predict future productivity. Yet, the mechanisms underlying variation in fish recruitment remain a source of uncertainty for fully understanding population dynamics. Given the interest in progression from single-species to ecosystem-based fisheries management, tracking multiple species over time and determining overall trends becomes a key component of management. Therefore, we (1) examined potential temporal synchrony among recruitment of juvenile fish species to seagrass habitats along the West Florida Shelf (WFS) in the eastern Gulf of Mexico and (2) sought to identify potential environmental covariates driving shared trends among species. Dynamic factor analysis identified 3 shared trends among catch-per-unit-effort (CPUE) time series of 11 species from a 2008-2018 trawl survey. The first and third trends had similar bimodal patterns with high CPUEs at the beginning of the time series, a decline, and then an increase near the end of the time series. The second trend had increasing CPUEs for the first 2 yr, a stable but variable trend in the middle, and an increase thereafter. Within the annual trends, most species’ seasonal CPUEs mimicked seasonal variability of seagrass biomass. Furthermore, southeast to westerly winds along the WFS 1 mo prior to sampling coincided with increased juvenile fish abundance for multiple species. Although the model is not without its limitations, there is evidence of shared recruitment patterns among fishes, which can inform multispecies survey design, habitat protection and restoration efforts, and management decisions for data-rich and data-limited species.