Trial aerial survey of sea otters in Prince William Sound, Alaska, 1993. Restoration project 93043-2. Exxon Valdez oil spill restoration project final report
We developed an aerial survey method for sea otters, using a strip transect design where otters observed in a strip along one side of the aircraft are counted. Two strata are sampled, one lies close to shore and/or in shallow. The other strata lies offshore and over deeper water. We estimate the proportion of otters not seen by the observer by conducting intensive searches of units (ISU`s) within strips when otters are observed. The first study found no significant differences in sea otter detection probabilities between ISU`s initiated by the sighting of an otter group compared to systematically located ISU`s. The second study consisted of a trial survey of all of Prince William Sound, excluding Orca Inlet. The survey area consisted of 5,017 sq km of water between the shore line and an offshore boundary based on shoreline physiography, the 100 m depth contour or a distance of 2 km from the shore. From 5-13 August 1993, two observers surveyed 1,023 linear km of high density sea otter habitat and 355 linear km of low density habitat.
- Research Organization:
- Alaska Fish and Wildlife Research Center, Anchorage, AK (United States)
- OSTI ID:
- 426707
- Report Number(s):
- PB-96-194683/XAB; TRN: 62392949
- Resource Relation:
- Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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