Back to Search Start Over

Estimating upper bounds for occupancy and number of manatees in areas potentially affected by oil from the Deepwater Horizon oil spill.

Authors :
Martin J
Edwards HH
Bled F
Fonnesbeck CJ
Dupuis JA
Gardner B
Koslovsky SM
Aven AM
Ward-Geiger LI
Carmichael RH
Fagan DE
Ross MA
Reinert TR
Source :
PloS one [PLoS One] 2014 Mar 26; Vol. 9 (3), pp. e91683. Date of Electronic Publication: 2014 Mar 26 (Print Publication: 2014).
Publication Year :
2014

Abstract

The explosion of the Deepwater Horizon drilling platform created the largest marine oil spill in U.S. history. As part of the Natural Resource Damage Assessment process, we applied an innovative modeling approach to obtain upper estimates for occupancy and for number of manatees in areas potentially affected by the oil spill. Our data consisted of aerial survey counts in waters of the Florida Panhandle, Alabama and Mississippi. Our method, which uses a Bayesian approach, allows for the propagation of uncertainty associated with estimates from empirical data and from the published literature. We illustrate that it is possible to derive estimates of occupancy rate and upper estimates of the number of manatees present at the time of sampling, even when no manatees were observed in our sampled plots during surveys. We estimated that fewer than 2.4% of potentially affected manatee habitat in our Florida study area may have been occupied by manatees. The upper estimate for the number of manatees present in potentially impacted areas (within our study area) was estimated with our model to be 74 (95%CI 46 to 107). This upper estimate for the number of manatees was conditioned on the upper 95%CI value of the occupancy rate. In other words, based on our estimates, it is highly probable that there were 107 or fewer manatees in our study area during the time of our surveys. Because our analyses apply to habitats considered likely manatee habitats, our inference is restricted to these sites and to the time frame of our surveys. Given that manatees may be hard to see during aerial surveys, it was important to account for imperfect detection. The approach that we described can be useful for determining the best allocation of resources for monitoring and conservation.

Details

Language :
English
ISSN :
1932-6203
Volume :
9
Issue :
3
Database :
MEDLINE
Journal :
PloS one
Publication Type :
Academic Journal
Accession number :
24670971
Full Text :
https://doi.org/10.1371/journal.pone.0091683