https://doi.org/10.82144/6e251322 https://www.gbif.org/dataset/12689b74-4989-4c00-875d-82b7f7f09e52 https://seamap.env.duke.edu/dataset/140 https://obis.org/dataset/ff972223-5015-4ea6-bafa-6dd05d3f4f13 Janice Waite National Marine Mammal Laboratory Primary contact Janice.Waite@noaa.gov OBIS-SEAMAP Marine Geospatial Ecology Lab, Duke University

A328 LSRC building Durham NC 27708 US

seamap-contact@duke.edu https://seamap.env.duke.edu OBIS-SEAMAP Marine Geospatial Ecology Lab, Duke University

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seamap-contact@duke.edu https://seamap.env.duke.edu distributor Janice Waite National Marine Mammal Laboratory Primary contact Janice.Waite@noaa.gov owner 2025-09-11 eng Original provider: National Marine Mammal Laboratory Dataset credits: National Marine Mammal Laboratory Abstract: On 1 to 26 June 1993, as part of a larger study, Alaska harbor porpoise (<i>Phocoena phocoena</i>) 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). Occurrence GBIF Dataset Type Vocabulary: http://rs.gbif.org/vocabulary/gbif/dataset_type.xml Observation GBIF Dataset Subtype Vocabulary: http://rs.gbif.org/vocabulary/gbif/dataset_subtype.xml Marine Biology Visual sighting Aircraft Sightings harbor porpoise Phocoena phocoena abundance aerial survey marine mammal survey survey marine mammal cetacean N/A This dataset and associated effort data were updated on September 8, 2005. Those who downloaded them before that date should renew them. This work is licensed under a Creative Commons Attribution Non Commercial (CC-BY-NC) 4.0 License. https://seamap.env.duke.edu/dataset/140 Oceans,Southeast Alaska -147.17217 -132.32733 60.33967 54.40383 1993-06-02 1993-06-26 Scientific names are based on the Integrated Taxonomic Information System (ITIS). species Balaenoptera physalus Fin whale order Cetacea Cetaceans species Megaptera novaeangliae Humpback whale species Orcinus orca Killer whale species Phocoena phocoena Harbor porpoise species Phocoenoides dalli Dall's porpoise Although harbor porpoises, <i>Phocoena phocoena</i>, 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: <br> 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 <br> 2) Establish a baseline for detecting changes in abundance through time, for analysis of trends. <br><br> 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. notPlanned Janice Waite National Marine Mammal Laboratory Primary contact Janice.Waite@noaa.gov NA NA NA Janice Waite owner NA zd_140 2025-09-11T12:24:33-04:00 dataset Waite, J. 2025. NMML Harbor Porpoise Aerial Survey, SE Alaska, Replicate 2, 1993. Version 1.7.0. Dataset published in OBIS-SEAMAP. https://doi.org/10.82144/6e251322. 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 Science16(1):28-45. OBIS-SEAMAP Dataset Page UTF-8 Interactive map https://seamap.env.duke.edu/dataset/140 FGDC Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/140/fgdc EML Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/140/eml OBIS-SEAMAP zd_140 zd_140