Tinkers l.gp 



Tinkers Lower 

 A Ledge 



Sandy I.E& 



Spruce I. 



Tinkers Upper 

 Ledge A 



44°58' 



*^ * / * * 



* / / / / 



Black 

 Rock ^ 



Casco 

 Bay I 



44"57 



44 56 



E. Quoddy 

 Head 



1/2 mile 



Scott Head 



Knowlton 



FIGURE 1. — Experimental survey transects through Head Harbor Passage are indicated by the dotted lines. Flags indi- 

 cate the observation stations on each side of the passage. 



overlap in viewing fields of 10°. Observ- 

 ers were changed after each transect to reduce 

 fatigue. Navigation was accomplished by the use of 

 radar and triangulation with landmarks. Vessel 

 speed was 9 ± 2 kn, its variability caused by the 

 strong tidal currents in Head Harbor Passage. 



Aircraft transects were flown at an altitude of 229 m 

 at 90- 100 kn. Two experienced aerial observers and a 

 recorder participated in each flight. Navigation and 

 sighting locations were accomplished by triangula- 



tion on landmarks, including large orange markers at 

 each land station. Visual survey techniques were 

 similar to those employed in standard aerial surveys 

 (Scott and Gilbert 1982). Because observers were 

 looking specifically for harbor porpoise and because 

 the survey area was limited by land masses, observ- 

 ers' search scans were restricted to within 630 m of 

 the transect line. On two days of the experiment, 

 observers noted the right angle distance of each 

 sighting from the transect line by a handheld Suunto 



911 



