Spatiotemporal dynamics of dolphinfish (Coryphaena hippurus) in the western Atlantic Ocean

Abstract

— Dolphinfish ( Coryphaena hippurus ) are caught throughout the western Atlantic Ocean over varying spatial and temporal scales. Prior attempts to quantify the population dynamics of dolphinfish in this region have been inhibited by an inability to model the spatiotemporal dynamics of this stock. We fit a seasonal vector autoregressive spatiotemporal (VAST) model to quantify the spatiotemporal dynamics of western Atlantic dolphin-fish, to estimate standardized relative indices of abundance during 1986– 2022 at regional scales, and to estimate changes in spatial distribution. The magnitude of abundance was greatest during spring and summer in northern spatial strata and was comparable over seasons in southern spatial strata. Abundance of dolphinfish appeared to be stable during 1986–2018 and then declined during 2019–2022. This trend occurred in all regions, except for in Atlantic waters from Cape Hatteras, North Carolina, to the southern border of Georgia, where abundance remained stable during 2019–2022. No shift in the distribution of the population was detected, but regional patterns of abundance provide insight into changes in the timing of availability. This study resulted in the first standardized index of relative abundance to capture the spatiotemporal dynamics of western Atlantic dolphinfish. These results have increased our understanding of the population dynamics of this species in this region and should prove useful in future attempts to manage the population at different spatial and temporal scales