NMML Harbor Porpoise Aerial Survey, SE Alaska, Replicate 2, 1993
Entry ID:
seamap140
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Summary
Abstract:
On 1 to 26 June 1993, as part of a larger study, Alaska harbor porpoise (Phocoena phocoena) 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 saw-tooth tracklines was flown at an altitude of 152.2 m (500ft) and at an airspeed of 100 kn. 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 = .04) and 4.02 groups/100 km^2
(SE=7.42). 
Purpose:
Although harbor porpoises, Phocoena phocoena, are known to occur throughout Alaska waters (Fiscus et al. 1976; Leatherwood and Reeves 1978; Lawry et al. 1982; Leatherwood et al. 1983), few estimates of abundance exist. In 1991, the National Marine Mammal Laboratory initiated a 3-yr 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. 2) Establish a baseline for detecting changes in abundance through time,
for analysis of trends.
SUPPLEMENTAL INFORMATION: Note: This dataset and associated effort data was
updated on Sept 8, 2005. Those who downloaded them before that date should
renew them. 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.
CURRENTNESS REFERENCE: ground condition
SPATIAL REFERENCE INFORMATION -
GEODETIC MODEL
Horizontal Datum Name: D_WGS_1984
Ellipsoid Name: WGS_1984
Semi-major Axis: 6378137.000000
Denominator of Flattening Ratio: 298.257224
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Description:
Access data from the OBIS and OBIS-SEAMAP websites.
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Geographic Coverage
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Spatial coordinates
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N: 60.34
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S: 54.4
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E: -132.33
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W: -147.17
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Data Set Citation
Dataset Originator/Creator:
National Marine Mammal Laboratory
Dataset Title:
NMML Harbor Porpoise Aerial Survey, SE Alaska, Replicate 2, 1993
Dataset Series Name:
OBIS-SEAMAP
Dataset Release Date:
2004-08-09 16:51:40.622642-04
Dataset Release Place:
http://seamap.env.duke.edu/
Dataset Publisher:
OBIS-SEAMAP
Data Presentation Form:
vector digital data
Online Resource:
http://nmml.afsc.noaa.gov/
Parent DIF
This data set description is a member of a collection. The
collection is described in
OBIS-SEAMAP
Temporal Coverage
Start Date:
1993-06-02
Stop Date:
1993-06-26
Data Resolution
Latitude Resolution:
0.000167 Decimal degrees
Longitude Resolution:
0.000167 Decimal degrees
Horizontal Resolution Range:
1 meter - < 30 meters
Access Constraints
ACCESS CONSTRAINTS: Open public unless otherwise noted.
DISTRIBUTION LIABILITY: Not to hold OBIS-SEAMAP liable for errors in the data.
While we have made every effort to ensure the quality of the database, we
cannot guarantee the accuracy of these datasets. Also please refer to Use
Constraints.
Use Constraints
Not to use data contained in OBIS-SEAMAP in any publication, product, or
commercial application without prior written consent of the original data
provider. To cite both the data provider and OBIS-SEAMAP appropriately after
approval of use is obtained. Also please refer to Distribution Liability.
Data Set Progress
COMPLETE
Distribution
Distribution Format:
Shapefile
Personnel
Role:
TECHNICAL CONTACT
Role:
DIF AUTHOR
Phone:
919-613-8021
Fax:
919-684-8741
Email:
efujioka at duke.edu
City:
Durham
Province or State:
NC
Postal Code:
27708
Country:
USA
Role:
TECHNICAL CONTACT
Phone:
206-526-6554
Email:
Janice.Waite at noaa.gov
Contact Address:
NATIONAL MARINE MAMMAL LABORATORY
7600 Sand Point Way N.E.
City:
Seattle
Province or State:
Washington
Postal Code:
98115-6349
Country:
USA
Publications/References
Intergovernmental Panel on Climate Change (IPCC) (2007), IPCC Socio-Economic Baseline Dataset, Cambridge University, New York, NY, http://sedac.ciesin.columbia.edu/data/set/ipcc-assess-socio-economi... Rosenzweig, C., P. Neofotis, M. Vicarelii, and X. Xing (2000), IPCC Fourth Assessment Report (AR4) Observed Climate Change Impacts Database, NASA Socioeconomic Data and Applications Center (SEDAC), Palisades, NY, http://sedac.ciesin.columbia.edu/data/set/ipcc-assess-ar4-observed-... Yohe, G., E. Malone, A. Brenkert, M. Schlesinger, H. Meij, X. Xing, and D. Lee (2005-2050-2100), Synthetic Assessment of Global Distribution of Vulnerability to Climate Change: Maps and Data, 2005, 2050, and 2100, NASA Socioeconomic Data and Applications Center (SEDAC), Palisades, NY, http://sedac.ciesin.columbia.edu/data/set/ipcc-assess-synthetic-vul...
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date:
2005-05-06
Last DIF Revision Date:
2012-04-13
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