Exploring Trends in Abundance of Young‐of‐the‐Year and Age‐1 Atlantic Croaker, Black Drum, Spot, and Weakfish in Relation to Salinity, Temperature, and Large‐Scale Climatic Signals in a Mid‐Atlantic Estuary

Abstract

AbstractAtlantic Croaker Micropogonias undulatus, Black Drum Pogonias cromis, Spot Leiostomus xanthurus, and Weakfish Cynoscion regalis have shown species‐specific, varying trends in abundance despite general declines in commercial landings throughout the Delaware River estuary. Identifying how environmental factors and climatic processes affect fishes at multiple life stages is needed to enhance the precision of regulatory actions for managed species. Species‐, area‐, and age‐specific indices were compared with depth, salinity, temperature, the Atlantic Multidecadal Oscillation (AMO), and the North Atlantic Oscillation (NAO) to explore potential relationships as well as temporal and spatial parameters. Our results demonstrate that station (15 indices), salinity (14 indices), the AMO and NAO (13 indices each), and depth and temperature (12 indices each) served as important components for models of abundance for 17 species‐, age‐, and area‐specific combinations from 1991 to 2016. Significant time series trends were detected in six of the modeled indices of abundance, including baywide indices of age‐1 Weakfish (decline) and age‐0 Atlantic Croaker (increase); age‐0 Atlantic Croaker (increase) and Weakfish (decline) in Delaware; and age‐1 Spot (decline) and Weakfish (increase) in Delaware. Our results demonstrate how multiple fixed‐station surveys can be combined to quantitatively assess environmental and climatic effects correlated with species‐, age‐, and area‐specific levels of abundance, suggesting that climatic signals are affecting smaller‐scale environmental variables that in turn affect relative abundance.