NMML Small Cetacean Aerial Survey 1998

Roderick Hobbs

doi:10.15468/9bza9z

NMML Small Cetacean Aerial Survey 1998

Citation

Hobbs R, OBIS-SEAMAP (2021). NMML Small Cetacean Aerial Survey 1998. OBIS-SEAMAP. Occurrence dataset https://doi.org/10.15468/9bza9z accessed via GBIF.org on 2024-12-11.

Description

Original provider: National Marine Mammal Laboratory Dataset credits: National Marine Mammal Laboratory Abstract: Researchers from NMML's Cetacean Assessment and Ecology Program conducted the line transect aerial surveys for harbor porpoise and Dall's porpoise from 27 May to 28 July 1998 in the Gulf of Alaska (offshore waters from Cape Suckling to Unimak Pass), Prince William Sound, and Shelikof Strait. Surveys were conducted from a NOAA Corps DeHavilland Twin Otter, flown at an altitude of 152.5 m (500 ft) and an airspeed of 185 km/hr (100 knots). Sawtooth lines were designed to cover the offshore waters from Cape Suckling to Unimak Pass (offshore of Kodiak Island) and included lines extending 15 nmi seaward, or to the 50 fathom line, whichever was farthest from shore and lines extending to the 1,000 fathom line. In Shelikof Strait a series of zigzag lines were designed between the Alaska Peninsula and Kodiak Island. Larger inlets and bays were also included in the survey. The survey in Prince William Sound consisted of two lines: one covering the central waters and one along the coast with extensions into selected inlets. Two primary observers surveyed from a bubble window on the left and right sides of the plane. An independent observer was positioned in a belly window. This observer surveyed the trackline directly below the plane to record animals missed on the trackline by the primary observers. Purpose: A 3-year survey began in 1997 to complete a new abundance estimate by 1999. This survey will also include an abundance estimate for Dall's porpoise (Phocoenoides dalli). Once the 3 years of surveys are completed, the data will be used to estimate annual abundance of harbor porpoise and Dall's porpoise, which is one of the key pieces of information needed to manage marine mammal-fishery interactions, as required under the Marine Mammal Protection Act. Inclement weather restricted the completion of the entire planned survey. Survey lines were completed in Prince William Sound and an adequate number of survey miles were completed offshore from Cape Suckling west along the Kenai Peninsula, offshore of Kodiak Island, west to Sutwik Island (Alaska Peninsula), and in Shelikof Strait. A total of 49.09 survey hours were flown, with sightings of 69 harbor porpoise, 60 Dall's porpoise, 13 killer whales, 46 humpback whales, 25 fin whales, 1 Cuvier's beaked whale, 11 unidentified dolphins/porpoises, 31 unidentified whales, 21 harbor seals, 18 Steller sea lions, and 8 unidentified pinnipeds. These numbers do not include the independent bubble window observer sightings.

Purpose

A 3-year survey began in 1997 to complete a new abundance estimate by 1999. This survey will also include an abundance estimate for Dall's porpoise (Phocoenoides dalli). Once the 3 years of surveys are completed, the data will be used to estimate annual abundance of harbor porpoise and Dall's porpoise, which is one of the key pieces of information needed to manage marine mammal-fishery interactions, as required under the Marine Mammal Protection Act. Inclement weather restricted the completion of the entire planned survey. Survey lines were completed in Prince William Sound and an adequate number of survey miles were completed offshore from Cape Suckling west along the Kenai Peninsula, offshore of Kodiak Island, west to Sutwik Island (Alaska Peninsula), and in Shelikof Strait. A total of 49.09 survey hours were flown, with sightings of 69 harbor porpoise, 60 Dall's porpoise, 13 killer whales, 46 humpback whales, 25 fin whales, 1 Cuvier's beaked whale, 11 unidentified dolphins/porpoises, 31 unidentified whales, 21 harbor seals, 18 Steller sea lions, and 8 unidentified pinnipeds. These numbers do not include the independent bubble window observer sightings.

Sampling Description

Study Extent

NA

Sampling

NA

Method steps

NA

Additional info

marine, harvested by iOBIS

Taxonomic Coverages

Scientific names are based on the Integrated Taxonomic Information System (ITIS).

Balaenoptera physalus
common name: Fin Whale rank: species
Callorhinus ursinus
common name: Northern Fur Seal rank: species
Eumetopias jubatus
common name: Steller Sea Lion rank: species
Megaptera novaeangliae
common name: Humpback Whale rank: species
Orcinus orca
common name: Killer Whale rank: species
Phocoenoides dalli
common name: Dall's Porpoise rank: species
Phocoena phocoena
common name: Harbor Porpoise rank: species
Phoca vitulina
common name: Harbor Seal rank: species
Cetacea
common name: cetaceans rank: order
Cetacea
common name: cetaceans rank: order
Ziphius cavirostris
common name: Cuvier's Beaked Whale rank: species

Geographic Coverages

Oceans

Bibliographic Citations

Contacts

Roderick Hobbs
originator
position: Primary contact
National Marine Mammal Laboratory
email: Rod.Hobbs@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

Roderick Hobbs
owner
position: Primary contact
National Marine Mammal Laboratory
email: Rod.Hobbs@noaa.gov

Roderick Hobbs
administrative point of contact
position: Primary contact
National Marine Mammal Laboratory
email: Rod.Hobbs@noaa.gov