42 



41 



40 



39 



38 



37 



36 



35 



34 



33 



32 



31 



30 



29 



28 



27 



26 

 25 



24 



20 19 IS 17 16 15 14 13 12 M 10 9 



Figure 10. — Number of seals seen per hour of effort in each square (areal unit) occupied by a research vessel in 

 November 1967 off Washington. The sides of each square measure 18.52 km. (10 nautical miles). Squares occupied 

 for less than 0.5 hours are marked "X." See table C-2 for detailed data. 



35 



