Abstract:
Aerial surveys was conducted in 1997 progressing from east to west,
to estimate abundance of the Southeast Alaska (SEA, 9,844 km survey effort),
Gulf of Alaska (GOA, 10,127 km survey effort), and Bering Sea (BS, 7849 km
survey effort) harbor porpoise stocks. In addition, 1355 km of survey effort
during a Cook Inlet beluga survey were analyzed to add to the coverage for the
GOA stock. Data from an
... independent observer concentrating on the trackline was
used to estimate perception bias. Significant differences in g(0) and effective
strip width (ESW) were found between the survey conducted in 1997 and the 1998
and 1999 surveys, therefore 1997 was treated separately. In both analyses, g(0)
was dependent on visibility reported by observers, and in the 1997 data ESW was
dependent as well. The 1997 survey included the inland waters of southeastern
Alaska and the eastern Gulf of Alaska from Dixon Entrance to Cape Suckling 
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.
SUPPLEMENTAL INFORMATION: 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.
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
