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NMML Harbor Porpoise Aerial Survey, Bristol Bay, Replicate 3, 1991

Dataset homepage

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. https://doi.org/10.15468/hywsz2 accessed via GBIF.org on 2025-05-21.

Description

Original provider: National Marine Mammal Laboratory Dataset credits: National Marine Mammal Laboratory Abstract: From 4 to 13 August 1991, as part of a larger study, Alaska harbor porpoise (Phocoena phocoena) abundance was investigated during an aerial survey throughout the coastal waters of Bristol Bay. A Twin Otter was used as the survey platform and was flown at an altitude of 152.2 m (500 ft) and at an airspeed of 185 km/h. The third of three identical sawtooth track lines was flown along the south side of Bristol Bay. 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 for Bristol Bay was 1.17 (SE = 0.35) and 4.48 groups/100 km2 (SE = 1.38). 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. 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. 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. 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.

Sampling Description

Study Extent

NA

Sampling

NA

Method steps

  1. NA

Additional info

marine, harvested by iOBIS

Taxonomic Coverages

Scientific names are based on the Integrated Taxonomic Information System (ITIS).
  1. Phocoenoides dalli
    common name: Dall's Porpoise rank: species
  2. Eschrichtius robustus
    common name: Gray Whale rank: species
  3. Phocoena phocoena
    common name: Harbor Porpoise rank: species
  4. Lagenorhynchus obliquidens
    common name: Pacific White-sided Dolphin rank: species
  5. Cetacea
    common name: cetaceans rank: order
  6. Cetacea
    common name: cetaceans rank: order

Geographic Coverages

Bristol Bay,Alaska

Bibliographic Citations

Contacts

Kimberly Goetz
originator
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
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