NMML Harbor Porpoise Vessel Survey, SE Alaska, Spring 1991
Citation
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://doi.org/10.15468/3hsqf6 accessed via GBIF.org on 2024-09-01.Description
Original provider: National Marine Mammal Laboratory Dataset credits: National Marine Mammal Laboratory Abstract: 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. Supplemental information: This dataset and associated effort data were updated on September 8, 2005. Those who downloaded them before that date should renew them.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.Sampling Description
Study Extent
NASampling
NAMethod steps
- NA
Additional info
marine, harvested by iOBISTaxonomic Coverages
Scientific names are based on the Integrated Taxonomic Information System (ITIS).
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Phocoenoides dallicommon name: Dall's Porpoise rank: species
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Phocoena phocoenacommon name: Harbor Porpoise rank: species
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Megaptera novaeangliaecommon name: Humpback Whale rank: species
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Orcinus orcacommon name: Killer Whale rank: species
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Balaenoptera acutorostratacommon name: Minke Whale rank: species
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Lagenorhynchus obliquidenscommon name: Pacific White-sided Dolphin rank: species
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Cetaceacommon name: cetaceans rank: order
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Cetaceacommon name: cetaceans rank: order
Geographic Coverages
Southeast Alaska,Bristol Bay,Cook Inlet
Bibliographic Citations
Contacts
Kimberly Goetzoriginator
position: Primary contact
Duke University
email: ktg4@duke.edu
Janice Waite
originator
position: Primary contact
National Marine Mammal Laboratory
email: Janice.Waite@noaa.gov
OBIS-SEAMAP
metadata author
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu
OBIS-SEAMAP
distributor
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu
Kimberly Goetz
owner
position: Primary contact
Duke University
email: ktg4@duke.edu
Janice Waite
owner
position: Primary contact
National Marine Mammal Laboratory
email: Janice.Waite@noaa.gov
Kimberly Goetz
administrative point of contact
position: Primary contact
Duke University
email: ktg4@duke.edu
Janice Waite
administrative point of contact
position: Primary contact
National Marine Mammal Laboratory
email: Janice.Waite@noaa.gov