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NMML Harbor Porpoise Aerial Survey, SE Alaska, Replicate 2, 1993
Citatie
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. https://marineinfo.org/id/dataset/3330

Toegang tot data

Beschrijving
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. meer

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
Thema's:
Biologie > Zoogdieren
Kernwoorden:
Marien/Kust, I, North Pacific, Cetacea

Geografische spreiding
I, North Pacific [Marine Regions]

Spreiding in de tijd
2 Juni 1993 - 26 Juni 1993

Taxonomic coverage
Cetacea [WoRMS]

Bijdrage door
National Oceanic and Atmospheric Administration; National Marine Mammal Laboratory, meerdata eigenaar
Duke University, meer

Gerelateerde datasets
Gepubliceerd in:
OBIS-SEAMAP: Spatial Ecological Analysis of Megavertebrate Populations, meer

Publicatie
Gebaseerd op deze 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. http://dx.doi.org/10.1111/j.1748-7692.2000.tb00902.x, meer

URL's

Dataset status: Afgelopen
Data type: Data
Data oorsprong: Onderzoek
Metadatarecord aangemaakt: 2012-11-13
Informatie laatst gewijzigd: 2012-11-14
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