QERM alum, Kiva Oken, will be presenting at the UW School of Aquatic and Fishery Sciences (SAFS) Quantitative Seminar on March 1. She currently holds a post-doc position in SAFS. See the Quantitative Seminar page for more information about the series.
Date/Time: March 1, 2019, 12:30pm-1:30pm
Location: FSH 203
Title: Quantifying and explaining nearshore species assemblages’ response the Deepwater Horizon oil spill
The Deepwater Horizon oil spill released approximately 210 million gallons of oil into the Gulf of Mexico. There was a clear signal of oil exposure in individuals across taxa, experiments have shown oil to be a stressor that leads to physiological responses, and there were changes observed in lower trophic level communities. Combined, this indicates a strong potential for population declines of commercially and recreationally valuable fishes and aquatic invertebrates. First I will briefly present work using spatiotemporal models to analyze years of monthly monitoring data around the Mississippi Delta to quantify potential impacts of the oil spill at the population scale. Both our study and others have shown little evidence of population declines. Several hypotheses have been proposed to explain this apparent paradox. Two possibilities include a fishing moratorium following the spill and changes in predation pressure following predator die offs. Using food web models, we quantified how much species would be expected to increase given only a fishing moratorium or predator die off without any oil mortality. Predicted increases of a magnitude much greater than what was observed indicate evidence for some other source of population mortality; we hypothesize this source is likely oil exposure. We emphasize that oil spills are one influence within a large socio-ecological system, and understanding oil spill impacts requires consideration of this complexity.