Many sailors on SF Bay have likely noticed an increase in sightings of Harbor Porpoise. These small and usually solitary animals are found up and down the CA coast. But their presence in SF Bay since WW II was limited. Now, likely because of cleaner water, they have returned.
But there is possibly another, darker, reason for Harbor Porpoise in SF Bay. Right here off Capitola, and elsewhere off the Central CA Coast, gangs of juvenile Bottlenose Dolphins are attacking the smaller Harbor Porpoise and killing them with blunt force. Dozens of dead Harbor Porpoise have washed ashore in the last few years, and there is now video of these attacks.
What this all means is uncertain. Bottlenose Dolphins are usually found in warmer waters to the south. Are Harbor Porpoise seeking refuge from these "porpicide" attacks in SF Bay? Fascinating stuff.
http://www.sfgate.com/news/article/P...es-2309298.php
http://www.youtube.com/watch?v=VBul5j30V98