Calambokidis et al.: Distribution and abundance of marine mammals off the northern Washington coast 



569 



Figure 2 



Locations (by year) for humpback whales (Megaptera novaeangliae) seen during ship 

 surveys off the northern Washington coast between 1995 and 2002. 



2000, Table 4, Fig. 3). The encounter rate of groups 

 (0.046-0.053 sightings per nmi), density (0.034-0.050 

 whales per nmi 2 ), and abundance (85-125 individuals) 

 were similar among these years. These data indicate 

 that about 100 humpback whales used the study area 

 during this period. 



The sighting rate of humpback whales was dramati- 

 cally higher in 2002 than in all previous years and 

 was reflected in the line-transect estimates (Fig. 3). 

 Estimated density (0.23 whales per nmi 2 ) was more 

 than four times higher than any previous year. Apply- 



ing this density to only the reduced area surveyed in 

 2002 (1953 instead of 2505 nmi 2 ) still yielded much 

 higher estimates of abundance (562, CV=0.21) than in 

 any previous year. These higher abundance estimates 

 could not have been an artifact of random variation; the 

 lower bound of the 95% confidence interval for the 2002 

 estimates was well above the upper confidence interval 

 of any of the previous years (Table 4). 



Of the humpback whales photographed during small 

 boat surveys off the northern Washington-BC border 

 between 1989 and 2002, 508 individuals were success- 



