Barlow and Forney: Abundance and population density of cetaceans in the California Current ecosystem 519 



Table 3 



Trackline detection probabilities, giO), estimated with the conditionally independent observer method for delphinids, large 

 whales, and Ball's porpoises. Values of ^(0) were derived from the estimated probability density functions evaluated at zero 

 distance, /'(O), for sightings made by primary observers («,) and independent observers (n.,1 *Eq. 4). Coefficients of variation (CV) 

 are given for/(0) andg(O) values. Delphinids include all species except killer whales and are stratified into small (<20) and large 

 (>20) groups. Large whales include killer whales and all baleen whales, except minke whales. 



Species groups and group size strata 



Primary observers 



, /"(Oi CVf{0) 



Independent observers 



/•(O) 



CV/'(0) g(0) CVg(O) 



Delphinids (truncation distance = l kmi 

 Group size <20 

 Group size >20 



Large whales (truncation distance=2.5 kml 

 All group sizes 



Dall's porpoises (truncation distance=l kmj 

 All group sizes 



115 



1.34 



0.09 12 



2.30 0.34 0.822 0.101 



