NMML Harbor Porpoise Vessel, SE Alaska, Summer 1993
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Dataset creditNational Marine Mammal Laboratory
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AbstractIn summer 1993, the Alaskan panhandle and Prince William Sound were surveyed for harbor porpoise (Phocoena phocoena) from the NOAA John N. Cobb using line transect methodology. The shipboard platform was 28.36 m (93 ft) in length with a bridge height of 4.27 m (14 ft). To obtain data on seasonal movements of porpoise, a limited number of transects were made in areas of known porpoise concentrations. When a sighting was made, the following variables were recorded: time, angle, number of reticles to the sighting, radar distance (nm) to the shoreline at the same angle of the sighting, the species, the count of the porpoise seen (best, high, and low), and the animal(s) direction of travel. Search effort was recoded by noting the time and location of the ship at the beginning and end of each transect.
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PurposeAlthough 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. The ability of the observers to sight porpoise was sensitive to environmental conditions. As expected, when conditions deteriorated the number of porpoises observed declined. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Supplemental informationThis dataset and associated effort data were updated on September 8, 2005. Those who downloaded them before that date should renew them.
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AttributesOverviewAttributes described below represent those in the original dataset provided by the provider. Attributes in dataset provided
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OBIS-SEAMAP ID | 151 |
Seabirds | 0 |
Marine mammals | 614 |
Sea turtles | 0 |
Rays and sharks | 0 |
Other species | 0 |
Non spatial | 0 |
Non species | 2 |
Total | 616 |
Date, Begin | 1993-06-07 |
Date, End | 1993-06-19 |
Temporal prec. | 111111 |
Latitude | 54.80 - 59.01 |
Longitude | -136.93 - -131.04 |
Coord. prec. | 5 decimal digits |
Platform | Boat |
Data type | Animal sighting |
Effort | YES (ID: 180) |
Traveled (km) | 1,252 |
Effort hours | 110 |
Registered | 2004-08-09 |
Updated | 2004-08-09 |
Status | Published |
Sharing policy![]() | CC-BY-NC (Minimum) |
Also availalbe from | iOBIS |
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See metadata in FGDC XML | |
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