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Fishery Bulletin 105(4) 



where L, = the length of on-effort transect lines in 

 region ;'; 

 f(0\zj) = the probability density function evaluated 

 at zero perpendicular distance for group j 

 with associated covariates z; 

 s = the number of individuals of that species in 

 group j; 

 g.iO) = the trackline detection probability of group 

 j; and 

 n, = the number of groups of that species sighted 

 in region i. 



Annual abundances for each species in California 

 (1991-2005) and in Oregon-Washington (1996-2005) 

 were estimated from Equation 2 based on the sightings 

 and search effort for the given year. The California total 

 was the sum of the three California region. Because 

 transects covered only 35 km in calm conditions in 

 the central California region in 2005, that region was 

 pooled in 2005 with the northern California region 

 to estimate abundance for Ball's porpoises and small 

 whales (whose abundance was based only on surveys in 

 calm sea states — see below). Only half-normal detection 



