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NMML Harbor Porpoise Vessel Survey, SE Alaska, Spring 1991
Citatie
Dahlheim, M. E., P. A. White, J. M. Waite. 2009. Cetaceans of Southeast Alaska: distribution and seasonal occurrence. Journal of Biogeography. 36: 410-426. https://marineinfo.org/id/dataset/3323

Toegang tot data

Beschrijving
Data from Southeast Alaska, Cook Inlet, and Bristol Bay surveyed for harbor porpoise (Phocoena phocoena) in spring 1991. meer

In spring 1991, Southeast Alaska, Cook Inlet, and Bristol Bay, was surveyed for harbor porpoise (Phocoena phocoena) from the NOAA John N. Cobb using line transect methodology. The shipboard platform was 28.36 m (93 ft) in length with a bridge height of 4.27 m (14 ft). To obtain data on seasonal movements of porpoise, a limited number of transects were made in areas of known porpoise concentrations. When a sighting was made, the following variables were recorded: time, angle, number of reticles to the sighting, radar distance (nm) to the shoreline at the same angle of the sighting, the species, the count of the porpoise seen (best, high, and low), and the animal(s) direction of travel. Search effort was recoded by noting the time and location of the ship at the beginning and end of each transect. Purpose 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. The ability of the observers to sight porpoise was sensitive to environmental conditions. As expected, when conditions deteriorated the number of porpoises observed declined.

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

Geografische spreiding
I, North Pacific [Marine Regions]

Spreiding in de tijd
20 April 1991 - 3 Mei 1991

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.E.; White, P.A.; Waite, J.M. (2009). Cetaceans of Southeast Alaska: distribution and seasonal occurrence. J. Biogeogr. 36(3): 410-426. https://dx.doi.org/10.1111/j.1365-2699.2008.02007.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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