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



571 



in the proportion of these whales that had also 

 been seen off California and Oregon (7 of 136 

 whales or 5%). This difference falls just short 

 of statistical significance (j 2 = 3.71, P<0.10) but 

 is in the reverse direction from what would be 

 expected if immigration from the south were to 

 increase over time. 



Between 1989 and 2002, 15 different mothers 

 were seen with 16 calves (one mother seen with a 

 calf in two different years). Mothers with calves 

 represented 4.2% of the individual whales iden- 

 tified each year ( 15 of 356 unique annual iden- 

 tifications. Table 2). For each year only a small 

 proportion of the calves were identified because 

 calves raise their flukes less often. 



Killer whales 



One other large cetacean species (killer whales) 

 was also seen every year; there were a total of 

 14 sightings of 124 animals from ship surveys 

 (Table 3). Three of these sightings were of large 

 groups between 20 and 35 animals, and the 

 rest were in groups fewer than ten (14 sight- 

 ings, mean = 8.9, SD = 11.2). Killer whales were 

 widely distributed across different habitats; there 

 were sightings of animals both close to and far 

 from shore and in fairly shallow and deep water 

 (Fig. 5). 



All three ecotypes of killer whales (namely, 

 1) southern and northern residents, 2) transients, and 

 3) offshore residents) were observed off the northern 

 Washington coast. Of the 15 groups identified pho- 

 tographically between 1989 and 2002, there were 

 sightings of animals from the southern resident (2 

 groups), northern resident (3), transient (5) and off- 

 shore (3) groupings (Table 7). Other sightings appeared 

 to be northern residents (1) and offshore (1) animals 

 but the quality of the photographs were too poor for 



■B 80<r 



i 1 



5 

 ■D 



2091 



X % y % \ x % x \ \ \ \ % 



Year 



Figure 4 



The proportion of humpback whales (M. novaeangliae) seen 

 in more than one year during annual surveys off northern 

 Washington from 1989 to 2002. 



us to be certain. Large groups of killer whales (20-40 

 animals) were seen on five occasions during small boat 

 surveys. 



Dall's porpoises 



Dall's porpoises were the most frequently sighted small 

 cetacean; there were 115 sightings of 406 animals and 

 Dall's porpoises were observed every year (Table 3). No 



