ANYWAYS, the lad asked .. MOM.. how do barnacles breed?
I said "I THINK, they release their eggs and sperm into the water, kinda like other fishy type critters do...but I'd have to look it up to be sure". This led of course to other questions about how animals breed... such as frogs, worms, and such like. I told him I"d look it all up, make a blog post of it so that it was all right at hand for him in the morning.
So... JUST HOW do barnacles breed? Well here's a video of them doing it.... No sound, just barnacles breeding.
From Washington Ed, this fascinating fact. "To be successful barnacles must have a strong stretchable penis. This means that all barnacles are hermaphrodites; both male and female at the same time. After mating season the penis is thrown away, and a new one is developed the next year. The eggs and sperm are stored in separate cavities months before fertilization. After fertilization occurs, the eggs hatch and the larvae stay with the mother until there is enough plankton in the spring."
Other interesting places to learn about barnacles
Barnacles of British Columbia.
I also learned the answer to another question the lad had. If you take a barnacle off mom, can it get back again? The answer is no. Once removed from whatever surface it is on, it cannot reattach itself.
and here's a short video on what barnacles look like when feeding.