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Fishery Bulletin 106(3) 
70° 40' W 70° 30' W 70° 20' W 70°10'W 70° 00' W 69° 50' W 
42° 10' N 
42° 00' N 
41° 50’ N 
41° 40’ N 
70° 40' W 70° 30’ W 70° 20’ W 70°10'W 70° 00' W 69° 50' W 
Figure 2 
Aerial survey track lines for the Cape Cod Bay right whale (Euba- 
laena glacialis ) monitoring program (black lines: 15 east-west 
lines at 1.5 nautical mile (2.7 km) intervals and a sixteenth 
line paralleling the eastern shore of the Cape approximately 3 
nmi from shore). Also shown are the area boundaries for the 
sightings per unit-of-effort analysis (shaded gray). 
Materials and methods 
Aerial surveys 
Aerial surveys were conducted from a Cessna 337-A Sky- 
master, a twin-engine, high wing aircraft with retract- 
able landing gear. The aircraft was flown at a standard 
altitude of 229 m and a ground speed of approximately 
185 km/h, and survey methods were those developed for 
the Cetacean and Turtle Assessment Program (Scott 
and Gilbert, 1982) and adapted for right whale surveys 
(Brown et al., 2007). The aircraft was flown in sea con- 
ditions up to and including sea state 4 on the Beaufort 
wind scale, but were aborted in Beaufort sea state 5 or 
when visibility decreased below two nautical miles (3.7 
km) in fog, rain, or snow. 
Surveys were conducted in winter and spring (Janu- 
ary through mid-May) of 1998-2002. Additional surveys 
were conducted in December of some years (for the 
purpose of this paper, a given year or season includes 
December of the previous calendar year.) The standard 
survey design consisted of 16 track lines (Fig. 2). Fif- 
teen east-west track lines were flown at 2.8-km inter- 
vals from the mainland to the eastern Cape Cod Bay 
shoreline. Analysis of the right whale survey data indi- 
cated that the effective total survey swath of a Cessna 
337 was 4.2 km (Kenney et al., 1995); thus the 2.8 km 
track line spacing of the standard survey plan was 
designed to provide 100% coverage of the sea surface 
in the study area to maximize the potential to detect 
right whales. 
An additional 65-km track line was flown parallel 
to the outer coast of Cape Cod from the eastern end of 
the northernmost track line to a point east of Chatham, 
Massachusetts, at an approximate distance of 5.6 km 
from shore (Fig. 2). The entire survey (approximately 
568 km of track line distance) was completed as often 
as conditions permitted (ca. 2 surveys/week), and ad- 
ditional track lines to the north of the standard survey 
design were occasionally added to address management 
concerns outside the bay (e.g., whale distribution in the 
shipping lanes). 
Analysis of survey data 
To quantitatively assess right whale distribution and 
minimize bias caused by uneven distribution of survey 
effort, we used the sightings per unit of effort (SPUE) 
