highdesert50, on 19 February 2013 - 12:11 PM, said:
It is unfortunate that we do not know more of dolphin behavior nor the evolutionary patterns that might translate to a more immediate understanding of the event. But, if we perhaps extrapolate to other migratory events across species, we see that these are driven by the need to feed, breed, or deal with climate change. Regardless, they are all linked to survival, and that certainly should raise some concerns.
Dolphins are mentally complex beings. We probably shouldn't assume that everything they do is necessarily connected with their immediate survival needs. What is happening near San Diego could be the dolphin equivalent of a mass meeting, social, or spiritual gathering.