Long-term Assessment of the 2010 Deepwater Horizon Oil Spill Impact on Deep Diving Marine Mammals

Natalia Sidorovskaia1, Kun Li1, Christopher Tiemann2, Azmy S Ackleh1, Tingting Tang1, George E Ioup3 and Juliette W Ioup4, (1)University of Louisiana at Lafayette, Lafayette, LA, United States, (2)R2Sonic, LLC, Austin, TX, United States, (3)University of New Orleans, New Orleans, LA, United States, (4)Univ of New Orleans, New Orleans, LA, United States
Abstract:
Five years have passed since the 2010 BP oil spill. Researchers have explored various aspects of the long term impact of the oil spill, from the oil sinking process to the environmental changes in coastal wetlands, to developing an efficient restoration plan. In this paper we present the data collection and processing strategies that can assist in studying the long-term impact on deep diving marine mammals (sperm whales, beaked whales, and dolphins). The analysis is rooted in using multi-year broadband passive acoustic monitoring data collected in the vicinity of the oil spill. We developed a suite of algorithms first to extract acoustic signals associated with different species of marine mammals from data collected at two sites located 15 and 40 km away from the Deep Water Horizon platform. A statistical method was applied in a population abundance estimation method originally developed by Buckland et al. (2001) for visual observations and generalized by Marques et al. (2009) for acoustic events. Finally, we estimated and compared the abundance of the whales before and after the spill to analyze population trends. Point and interval abundance estimations of sperm whales and beaked whales in 2007 and 2010 have been compared. We observed that, for sperm whales, there was a decrease by factor of 2 at the closest site and an increase at the site farther away on the Western side of the spill. However, the trend observed for beaked whales has shown the increased presence of animals at both locations. The different factors extracted from collected data were also analyzed to assist in interpretation of observed trends. In June 2015, the newly BP/GOMRI funded LADC-GEMM consortium conducted a follow-up PAM monitoring experiments at the same locations. Data collected during the experiment and other acoustic surveys in the area will contribute in future monitoring efforts to assist in better understanding how the spill affected different species long term.
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