Phenology of penaeid shrimp nursery habitat use: trends and environmental drivers over four decades

White shrimp Penaeus setiferus and brown shrimp P. aztecus are key predators of benthic infauna and important prey resources for higher trophic levels in coastal waters of the southeastern USA. Both species rely on estuaries as nursery habitat and are subject to the dynamic environmental conditions typical of these ecosystems. Understanding the phenology of juvenile penaeid shrimp estuarine habitat use, detecting changes in phenology over time, and linking interannual variability in phenological metrics to environmental conditions will provide an improved understanding of the degree to which global change is impacting the life history of these key members of estuarine communities. We analyzed nearly 4 decades of catch data (1984-2022) from a tidal creek in South Carolina, USA, comparing the timing, synchrony, and duration of juvenile shrimp habitat utilization across years to identify shifts in phenology. We then investigated linkages between environmental and climatological conditions and shrimp phenology to understand potential drivers of interannual variation in these metrics. Brown shrimp phenology showed no directional change over time; however, salinity and winter water temperature were strong predictors of variability in all 3 phenological metrics. Conversely, white shrimp nursery habitat use has become less synchronized and occurs over a longer interval, but no single environmental variable strongly predicts all 3 metrics. Differences in life history strategy and environmental tolerances likely contribute to the variation in phenological responses observed for these species. Our findings demonstrate that climate-change-related shifts in phenology will be species- and life-history-specific.