Impacts of the Deepwater Horizon oil spill evaluated using an end-to-end ecosystem model

Abstract

We use a spatially explicit biogeochemical end-to-end ecosystem model, Atlantis, to simulate impacts from the Deepwater Horizon oil spill and subsequent recovery of fish guilds. Dose-response relationships with expected oil concentrations were utilized to estimate the impact on fish growth and mortality rates. We also examine the effects of fisheries closures and impacts on recruitment. We validate predictions of the model by comparing population trends and age structure before and after the oil spill with fisheries independent data. The model suggests that recruitment effects and fishery closures had little influence on biomass dynamics. However, at the assumed level of oil concentrations and toxicity, impacts on fish mortality and growth rates were large and commensurate with observations. Sensitivity analysis suggests the biomass of large reef fish decreased by 25% to 50% in areas most affected by the spill, and biomass of large demersal fish decreased even more, by 40% to 70%. Impacts on reef and demersal forage caused starvation mortality in predators and increased reliance on pelagic forage. Impacts on the food web translated effects of the spill far away from the oiled area. Effects on age structure suggest possible delayed impacts on fishery yields. Recovery of high-turnover populations generally is predicted to occur within 10 years, but some slower-growing populations may take 30+ years to fully recover.

Changes in Reef Fish Community Structure Following the Deepwater Horizon Oil Spill

“…These species can have limited (<10 m 2 ) home ranges 87 , are heavily reliant on local resource pools, and would incur the highest cost associated with emigration. These traits not only increase the probability of exposure-related mortality but also mortality associated with resource limitation 66 . Impacts on pelagic production 88,89 , increased trophic position 68,69 , and greater reliance on benthic resources 63 suggest small demersal reef fishes experienced increased resource competition and higher predation immediately following the DWH.…”

“…Individuals present after the DWH probably consisted of few residents that survived acute exposure and resource limitation along with new immigrants seeking more favorable conditions 93 . The fact that guilds comprised of mobile reef species (i.e., generalist carnivores and piscivores) showed little indication of recovery suggests a large number of individuals were either permanently displaced, perished (either from starvation or exposure 66 ), or basal resource pools remained insufficient to support pre-DWH densities.…”

“…The fact that reef fish density remained low for a number of years following the DWH suggests indirect food web effects have played an important role as well 66 . Consumption of swarming zooplankton by red snapper declined markedly following the DWH, a possible reflection of an initial reduction in pelagic production 66 . The reduction in zooplankton was balanced by increased foraging on demersal fishes and invertebrates 63 .…”

Index‐based approach for estimating vulnerability of Arctic biota to oil spills

“…Toxicity of oil to fishes and invertebrates has been studied widely (Albers 1998), but their behavior in oiled environment has received little attention. As another example, physical sensitivity is sensitive to changes in loss of prey but collecting data on it would be expensive and demanding or would require use of detailed ecosystem models (see, e.g., Ainsworth et al 2018 for using ecosystem model Atlantis in evaluating the population-level impacts of the Deepwater Horizon oil spill). However, no such ecosystem model has yet been calibrated for the true Arctic as they require vast amount of data.…”

Potential influence of the Deepwater Horizon oil spill on phytoplankton primary productivity in the northern Gulf of Mexico

“…Using state-structured models, Girard et al (2018) suggested that the complete recovery of corals will take up to three decades (depending on the initial level of impact). As for the food web, the oil spill may have led to a significant decrease of the fishery yield which could take more than 30 years (especially for some slowly-growing populations) to recover fully (Ainsworth et al 2018). Tatariw et al (2018) found that the salt marsh denitrification capacity (over the moderate and heavy oiling areas) had not yet recovered six years after the DwH oil spill.…”