Eric and I have been busy with lots of early morning field work recently. As we were walking on a beach in Marin County this morning, I looked down to see a Blue Buoy Barnacle (Dosima fascicularis) attached to a By-the-wind Sailor (Velella velella).
Blue Buoy Barnacles are pelagic (offshore) barnacles that float at the surface of the ocean. They are unusual in northern California and can be indicators of warm-water conditions, or water that's normally farther offshore coming closer to the coast. I'll have to check my notes, but I think the last time we saw one in our area was ~10 years ago (back in 2016).
With the high numbers of Velella washing ashore at this time, the chances of finding Dosima are greater as this barnacle often attaches to Velella floats.
We're interested in other observations of Blue Buoy Barnacles in northern California, so keep your eyes open and if you happen to come across one, I'd love to hear about it!
P.S. For an introduction to Blue Buoy Barnacles, see the post called "Blue buoys!" on 31 August 2014. And more information (and a great video!) can be found in the post called "Driftin' blues" on 23 September 2014.
