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NMML Harbor Porpoise Aerial Survey, SE Alaska, Replicate 2, 1993
Citation
Dahlheim, M., A. York, R. Towell, J. Waite, and J. Breiwick. 2000. Harbor porpoise (Phocoena phocoena) abundance in Alaska: Bristol Bay to southeast Alaska, 1991-1993. Marine Mammal Science. 16(1):28-45

Access data
Availability: Creative Commons License This dataset is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Description
Data from an aerial survey from Prince William Sound to Dixon Entrance to study the Alaska harbor porpoise (Phocoena phocoena) in June 1993. Replicate 2. more

On 1 to 26 June 1993, as part of a larger study, Alaska harbor porpoise (Phocoena phocoena) abundance was investigated during an aerial survey from Prince William Sound to Dixon Entrance. Employing a Twin Otter as the survey platform, the second of three identical sawtooth tracklines was flown at an altitude of 152.2 m (500 ft) and at an airspeed of 185 km/h. Line-transect methodology was used, and only those observations made during optimal conditions were analyzed. Density of harbor porpoises was calculated using line transect estimates based on perpendicular distances of sightings to the cruise track of the airplane. On average, porpoise group size and density from Prince William Sound to Dixon Entrance was 1.22 (SE = 0.04) and 4.02 groups/100 km2 (SE = 7.42). Although harbor porpoises, Phocoena phocoena, are known to occur throughout Alaska waters, few estimates of abundance exist. In 1991, the National Marine Mammal Laboratory initiated a 3 year study on Alaska harbor porpoises. The objectives of this program were to: 1) Obtain minimum population estimates in coastal waters using line transect methodology with a coefficient of variation for density estimates of less than 30% for each survey area, and 2) Establish a baseline for detecting changes in abundance through time, for analysis of trends. During the present study, it was not fiscally possible to survey all areas of the state in any one year. Accordingly, we selected sections of the state to survey in consecutive years to maximize the likelihood of including all of the animals for a particular area surveyed while minimizing the likelihood of significant movement between areas among survey years.

Scope
Themes:
Biology > Mammals
Keywords:
Marine, I, North Pacific, Cetacea

Geographical coverage
I, North Pacific [Marine Regions]

Temporal coverage
2 June 1993 - 26 June 1993

Taxonomic coverage
Cetacea [WoRMS]

Contributors
Duke University, more National Oceanic and Atmospheric Administration; National Marine Mammal Laboratory, moredata owner

Related datasets
Published in:
OBIS-SEAMAP: Spatial Ecological Analysis of Megavertebrate Populations, more

Publication
Based on this dataset:
Dahlheim, M. et al. (2000). Harbor porpoise (Phocoena phocoena) abundance in Alaska: Bristol Bay to southeast Alaska, 1991-1993. Mar. Mamm. Sci. 16(1): 28-45. hdl.handle.net/10.1111/j.1748-7692.2000.tb00902.x, more

URLs

Dataset information:

Dataset status: Completed
Data type: Data
Data origin: Research
Metadatarecord created: 2012-11-13
Information last updated: 2012-11-14
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