https://doi.org/10.82144/5a6a05c9 https://seamap.env.duke.edu/dataset/117 https://www.gbif.org/dataset/5c488b46-101b-470d-8b2b-ccf279488c04 https://obis.org/dataset/0124b64b-16f3-40ec-b1a1-d8e9b2b7171f Roderick Hobbs National Marine Mammal Laboratory Primary contact Rod.Hobbs@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 Roderick Hobbs National Marine Mammal Laboratory Primary contact Rod.Hobbs@noaa.gov owner 2025-07-31 eng Original provider: National Marine Mammal Laboratory Dataset credits: National Marine Mammal Laboratory Abstract: The National Marine Mammal Laboratory (NMML) conducted an aerial survey for small cetaceans from 5 June to 4 July, 1999 in Bristol Bay and along southwestern Alaska Peninsula (out to the 1,829 m [1,000 fm] depth contour). A total of 8,522 km were surveyed in a Dehavilland Twin Otter at 152.5 m (500 ft) altitude and 185 km/hr (100 kts). Two overlapping sawtooth lines were designed along the coastline of Bristol Bay. Both sides of each sawtooth were approximately 37 km with a 46 km base. Large bays were also included in the survey. Primary observers searched through bubble windows on the left and right sides of the aircraft and reported sightings to a computer operator. To estimate a perception bias correction factor for this study, an independent observer was added at a belly window position to determine the number of animals in the immediate vicinity of the trackline that were missed by the primary observers. There were 215 sightings of harbor porpoise (260 individuals), 12 Dall's porpoise (24 individuals), and 16 Pacific white-sided dolphins (170 individuals) while surveying tracklines. Additional cetacean sightings included 12 gray whales (13 individuals), 18 humpback whales (29 individuals), 8 minke whales (13 individuals), and 3 killer whales (11 individuals). 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 aerial survey survey arial cetacean porpoise Aircraft Sightings N/A This work is licensed under a Creative Commons Attribution Non Commercial (CC-BY-NC) 4.0 License. https://seamap.env.duke.edu/dataset/117 Oceans,Alaska,Gulf of Alaska,Southeast Alaska,Bristol Bay,Bering Sea -164.7692 -157.0705 59.071 53.9342 1999-06-11 1999-07-04 Scientific names are based on the Integrated Taxonomic Information System (ITIS). species Balaenoptera acutorostrata Common minke whale order Cetacea Cetaceans species Eschrichtius robustus Gray whale species Eumetopias jubatus Steller sea lion species Lagenorhynchus obliquidens Pacific white-sided dolphin species Megaptera novaeangliae Humpback whale species Odobenus rosmarus Walrus species Orcinus orca Killer whale species Phoca vitulina Harbor seal species Phocoena phocoena Harbor porpoise species Phocoenoides dalli Dall's porpoise The current study (1997-1999) will provide new abundance estimates for each stock of harbor porpoise and Dall's porpoise. Although the previous harbor porpoise surveys (1991-1993) used a vessel platform for the inside waters of southeast Alaska (Dahlheim et al. 1992, 1993, 1994), the current survey was conducted entirely from aircraft. However, a concurrent vessel survey in a selected portion of southeastern Alaska and a calibration study with the survey vessel. We report here the results from the third year of surveys (1999). References: Dahlheim, M., A. York, J. Waite, and C. Goebel-Diaz. 1992. Abundance and distribution of harbor porpoise (<i>Phocoena phocoena</i>) in southeast Alaska, Cook Inlet and Bristol Bay. Annual report to the MMPA Assessment Program, Office of Protected Resources, NMFS, NOAA, 1335 East-West Highway, Silver Spring, MD 20910. Dahlheim, M., A. York, J. Waite, and R. Towell. 1993. Abundance and distribution of harbor porpoise (<i>Phocoena phocoena</i>) in southeast Alaska, Kodiak Island, and the south side of the Alaska Peninsula, 1992. Annual report to the MMPA Assessment Program, Office of Protected Resources, NMFS, NOAA, 1335 East-West Highway, Silver Spring, MD 20910. Dahlheim, M., A. York, J. Waite, and R. Towell. 1994. Abundance and distribution of harbor porpoise (<i>Phocoena phocoena</i>) in southeast Alaska and the offshore waters of Dixon Entrance to Prince William Sound, 1993. Annual report to the MMPA Assessment Program, Office of Protected Resources, NMFS, NOAA, 1335 East-West Highway, Silver Spring, MD 20910. notPlanned Roderick Hobbs National Marine Mammal Laboratory Primary contact Rod.Hobbs@noaa.gov NA NA NA Roderick Hobbs owner NA zd_117 2025-07-31T14:05:25-04:00 dataset Hobbs, R. 2013. NMML Small Cetacean Aerial Survey 1999. Version 1.0.0. Dataset published in OBIS-SEAMAP. https://doi.org/10.82144/5a6a05c9. OBIS-SEAMAP Dataset Page UTF-8 Interactive map https://seamap.env.duke.edu/dataset/117 FGDC Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/117/fgdc EML Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/117/eml OBIS-SEAMAP zd_117 zd_117