Quantitative ecological risk assessment of accidental oil spills on ship routes nearby a marine national park in Brazil

Abstract

ABSTRACTFernando de Noronha (FN) is a marine protected area off the coast of Brazil. The study of risks caused by nearby ship routes is new to authorities concerned with preserving FN. We identify nearby ship routes that cause FN to be potentially exposed to oil spills from tankers. A coral species is chosen as a bioindicator of the ecosystem's health, which aids quantitative approaches. We simulate oil leakage scenarios with pessimistic occurrence frequencies and corals' mortality in case of accident. A metapopulation coral model is integrated to quantify measures of ecological risk under the potential occurrence of accidental scenarios. The categorization of risk results according to the International Union for the Conservation of Nature quantitative criteria shows that risks are negligible. Due to the considerable uncertainty in the results, we propose a more conservative categorization of risks based not on total metapopulation extinction, but on half loss. As a result, risks were considered not acceptable. The presented methodology and results are useful in supporting authorities in their preservation efforts such as the prioritization of sources of hazard as well as selection of the best cost-effective conservation measures for maintaining good environmental health on a realistic budget, using this methodology as an exploratory tool.