July 4, 2004
The McArthur II spent July 4th off the Queen Charlotte Islands in Canada, and therefore displayed both the American flag and the Maple Leaf. Our traditional 4th of July barbeque was held outside on the fan tail, despite somewhat ominous skies.
After chatting with Dr. Barlow during our barbeque, I have a better understanding of why our cruise has been employing both the traditional "line transect" survey technique, such as is outlined in the work of Jon Calambokidas, and the photo ID and capture-recapture methods. Dr. Barlow explained that classic line transect surveys are most appropriate for populations that are geographically dispersed, as the "random" lines have an equal probability of encountering whales. For humpbacks, which tend to be distributed in "clumps," photo ID and capture-recapture may be a more robust method of estimating population size. The combination of these two techniques allows us to cover a wider area in our "on effort" line transects, but build our catalogue of photographs while pursuing the "off effort" photo ID collection.
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