Final Technical Report: - Southwest Fisheries Science Center - NOAA

overwhelming majority of “Bryde’s or sei whale” sightings in the ETP region are Bryde’s
whales.
Include sightings of “Kogia spp.” in the Kogia sima model because the majority of Kogia
sightings unidentified to species in the ETP are believed to be K. sima.
Do not include Beaufort sea state as a predictor variable in the spotted dolphin models
because the primary visual cue for Stenella attenuata sightings is flocks of birds flying
overhead.
Incorporate latitude and longitude, or a latitude/longitude/SST interaction term in the eastern
spinner model to differentiate eastern spinner from whitebelly spinner habitat.
Include islands in the distance-to-shore computation to improve the prediction accuracy of
the bottlenose dolphin encounter rate models in particular.
Select simple models for the final models, unless strong support exists for the alternative
complex model.
Use geographically stratified estimates of density rather than predictions derived from
cetacean-habitat models for sperm whales, killer whales (Orcinus orca), and coastal spotted
dolphins.
Image Quality Analysis (IQA; Wang et al. 2004), a quantitative, spatially-explicit method
for comparing two images, was implemented as an additional model evaluation technique, but it
was not used in final model selection because we found that people had difficulty interpreting the
resulting statistics. Nevertheless, the IQA approach seems promising and future work into
making the results accessible to a non-expert audience would be valuable.
Density Estimation
The values for the line-transect sighting parameters f(0) and g(0) used to compute
population density in the ETP analysis came from published reports, as summarized by Ferguson
and Barlow (2001). For species in which the f(0) values were stratified by group size, selection
of the appropriate group size stratum for determining which value of f(0) to use was determined
by the group size predictions from the preferred group size model for the species.
Similar to the California Current analysis, the value of Beaufort sea state used to compute
the final encounter rate and group size predictions for the SDSS was set to the average Beaufort,
weighted by survey effort, of all segments used to build the models. The f(0) values for all
beaked whales and Kogia were computed from data collected during Beaufort sea states from 0
to 2. Therefore, computation of weighted average Beaufort for beaked whales and Kogia
predictions included only segments with average Beaufort conditions of 2 or less.
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