Modeling Hotspots of Jellyfish Blooms in Light of Climate Change in the Northern Gulf of Mexico

With increasing magnitudes of anthropogenic forcing and climate change, outbreaks of gelatinous zooplankton have received mounting foci due to deleterious consequences on coastal ecosystems. While extensive studies have outlined the potential drivers associated with bloom-forming, the intrinsic mechanisms of jellyfish blooms remain elusive. In the present study, we developed an individual-based bioenergetic model including a full life cycle of a common jellyfish species (Aurelia aurita) to examine the population dynamics of the species in the northern Gulf of Mexico during the period of 2003-2012. Our simulations highlighted a significant bottom-up effect in triggering the presence of jellyfish swarms. In addition, compared to the inter-annual variability of jellyfish abundance, biomass seemed more sensitive in response to environmental change. Spatially the south Texas coast, the Louisiana coast, and the Mississippi Bight were considered as historical bloom areas. The year 2003 was identified as a severe bloom year in terms of the remarkable density and widespread distribution of the species in the study area. Seasonally Aurelia aurita in 2003 displayed the peaks in abundance and biomass which mostly occurred in September-October, and October-November, respectively. When targeting on a “hotspot” in 2003 near the Mississippi River plume, our simulations showed inconsistencies in bloom timing and duration defined either by abundance or biomass. Given a lack of a clear definition of jellyfish blooms, we further explored the implications of the mismatch of bloom timing in terms of jellyfish ecology and the mechanisms driving the jellyfish blooms in light of environmental change.