SEALS PER HOUR 



21 



^ 



20 19 18 17 16 15 14 13 12 II 10 9 



Figure 12. — Number of seals seen per hour of effort In each square {areal unit) occupied by a research vessel in 

 January 1968 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-4 for detailed data. 



37 



