256 
Fishery Bulletin 108(3) 
58* N- 
-58°N 
56*N- 
-56° N 
■60'N 
144°W 
140”W 
1 
136°W 
132*W 
144 °W 
140“W 
i 
136°W 
1 
132’W 
Gulf 
of Alaska 
0 62 5125 
250 
375 
500 
l Kilometers 
Canada 
Figure 2 
Completed survey transects and sightings (circles) of harbor porpoise ( Phocoena phocoena ) during 
the 1997 aerial survey in the Southeast Alaska stock region. 
decisions by NMFS. This quantity was calculated for 
each stock from the completed abundance estimates as 
N ■ =Ne 
y min 
-0.842 Vlnd+CV ( AO 2 ) 
where N = estimated abundance; and 
CV(N) = the estimated coefficient of variation of N. 
Results 
The 1997 line-transect aerial survey was conducted 
from 27 May to 7 June and 10-28 July 1997 in the 
inside waters of southeastern Alaska, Yakutat Bay, Icy 
Bay, and in offshore waters from Dixon Entrance to 
Cape Suckling (Fig. 2). Necessary repairs on the survey 
plane resulted in an unplanned month-long break in the 
survey, and adverse weather prevented a second survey 
of offshore waters. A total of 9844 km were surveyed. 
The 1998 survey was conducted from 27 May to 28 July 
1998 in Prince William Sound, the western Gulf of 
Alaska (from Cape Suckling to the west side of Kodiak 
Island), and Shelikof Strait (Fig. 3). Gaps in the survey 
effort occurred on account of inclement weather, primar- 
ily off the Kenai Peninsula and the southern side of the 
Alaska Peninsula west of Kodiak Island. A total of 9486 
km were surveyed. The 1999 survey was conducted 11 
June to 4 July in Bristol Bay and associated bays. In 
addition, an area south of the Alaska Peninsula west of 
Chignik Bay was surveyed that was not completed in 
1998 (Figs. 3 and 4). A total of 8490 km were surveyed. 
The 1999 data for the Gulf of Alaska was included with 
the 1998 data to estimate abundance of harbor porpoise 
for the Gulf of Alaska. 
Sightings of harbor porpoise for each region (Figs. 
2-4) were more common in nearshore areas, but oc- 
curred throughout the depth range surveyed during all 
three surveys. High densities of harbor porpoise were 
found in Yakutat Bay and near Wrangell (Fig. 2), be- 
tween Prince William Sound and Cape Suckling, on the 
southeast side of Kodiak Island, southwest of Chignik 
Bay (Fig. 3), and in a few small bays on the northern 
side of Bristol Bay (Fig. 4). 
Corrections for species misidentification 
and for under-counting group sizes by belly observers 
A cursory examination of the discrepancies in species 
identification between side and belly observers from 
the 1997 and 1998 seasons indicated that discrepan- 
cies occurred primarily when inexperienced observers 
were at the belly window and had fewer than 10 days of 
