Density, abundance, survival, and ranging patterns of common bottlenose dolphins (Tursiops truncatus) in Mississippi Sound following the Deepwater Horizon oil spill
After the Deepwater Horizon (DWH) oil spill began in April 2010, studies were initiated on northern Gulf of Mexico common bottlenose dolphins (Tursiops truncatus) in Mississippi Sound (MSS) to determine density, abundance, and survival, during and after the oil spill, and to compare these results to...
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Published in | PloS one Vol. 12; no. 10; p. e0186265 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Public Library of Science
20.10.2017
Public Library of Science (PLoS) |
Subjects | |
Online Access | Get full text |
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Summary: | After the Deepwater Horizon (DWH) oil spill began in April 2010, studies were initiated on northern Gulf of Mexico common bottlenose dolphins (Tursiops truncatus) in Mississippi Sound (MSS) to determine density, abundance, and survival, during and after the oil spill, and to compare these results to previous research in this region. Seasonal boat-based photo-identification surveys (2010-2012) were conducted in a section of MSS to estimate dolphin density and survival, and satellite-linked telemetry (2013) was used to determine ranging patterns. Telemetry suggested two different ranging patterns in MSS: (1) inshore waters with seasonal movements into mid-MSS, and (2) around the barrier islands exclusively. Based upon these data, dolphin density was estimated in two strata (Inshore and Island) using a spatially-explicit robust-design capture-recapture model. Inshore and Island density varied between 0.77-1.61 dolphins km-2 ([Formula: see text] = 1.42, 95% CI: 1.28-1.53) and 3.32-5.74 dolphins km-2 ([Formula: see text] = 4.43, 95% CI: 2.70-5.63), respectively. The estimated annual survival rate for dolphins with distinctive fins was very low in the year following the spill, 0.73 (95% CI: 0.67-0.78), and consistent with the occurrence of a large scale cetacean unusual mortality event that was in part attributed to the DWH oil spill. Fluctuations in density were not as large or seasonally consistent as previously reported. Total abundance for MSS extrapolated from density results ranged from 4,610 in July 2011 to 3,046 in January 2012 ([Formula: see text] = 3,469, 95% CI: 3,113-3,725). |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Competing Interests: The authors declare no competing interest. Authors TM and FH are employed by Western EcoSystems Technology, Inc., a commercial company contracted with NOAA through Industrial Economics, Inc. (a commercial company) to assist with analysis of data collected during this study and the larger NRDA effort in general. The contract provided salary and overhead support only. No patents, products in development, marketed products, or other intellectual property were generated or claimed by these authors. All authors adhere to the PLOS ONE policies on sharing of data and materials. |
ISSN: | 1932-6203 1932-6203 |
DOI: | 10.1371/journal.pone.0186265 |