https://doi.org/10.82144/4b562352 https://www.gbif.org/dataset/491a8670-4d9a-4266-a18c-8102042a1d2a https://seamap.env.duke.edu/dataset/131 https://obis.org/dataset/6a854b88-254c-40dc-9a5c-a95b0a76037e Kimberly Goetz Duke University Primary contact ktg4@duke.edu 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

A328 LSRC building Durham NC 27708 US

seamap-contact@duke.edu https://seamap.env.duke.edu distributor Kimberly Goetz Duke University Primary contact ktg4@duke.edu owner 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 and 2 August 1991, as part of a larger study, Alaska harbor porpoise (<i>Phocoena phocoena</i>) abundance was investigated during an aerial survey throughout the coastal waters of Cook Inlet. A Twin Otter was used to fly a single sawtooth trackline across Cook Inlet 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 for Cook Inlet was 1.33 (SE = 0.33) and 0.54 groups/100 km2 (SE = 0.31). 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 Sept 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/131 Oceans,Cook Inlet,Alaska -153.06673 -149.7475 61.42133 58.83467 1991-08-01 1991-08-02 Scientific names are based on the Integrated Taxonomic Information System (ITIS). species Balaenoptera acutorostrata Common minke whale order Cetacea Cetaceans species Delphinapterus leucas Beluga species Megaptera novaeangliae Humpback whale species Phocoena phocoena Harbor 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 Kimberly Goetz Duke University Primary contact ktg4@duke.edu Janice Waite National Marine Mammal Laboratory Primary contact Janice.Waite@noaa.gov NA NA NA Kimberly Goetz owner Janice Waite owner NA zd_131 2025-09-11T12:22:14-04:00 dataset Goetz, K. and J. Waite. 2009. NMML Harbor Porpoise Aerial Survey, Cook Inlet, 1991. Version 1.7.0. Dataset published in OBIS-SEAMAP. https://doi.org/10.82144/4b562352. 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/131 FGDC Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/131/fgdc EML Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/131/eml OBIS-SEAMAP zd_131 zd_131