> Two years later, Killingley had worked with Scripps biologist William Newman (affectionately known to colleagues as Barnacle Bill) to come up with the e = mc2 of barnacle biochemistry: an equation that relates the ratio of oxygen isotopes in a shell layer to the temperature and composition of the water it grew in. Because different parts of the ocean have unique temperature and salinity profiles, explains Taylor, measuring these isotopes could theoretically allow you to figure out roughly where in the ocean each layer had formed. “The basic idea is that there are these chemical tracers in the environment,” he says. “The barnacle puts some of those tracers in its shell and thereby keeps a kind of growing record of places that it’s been.”
I used to really dislike barnacles every time I saw a whale photo with them - never imagined that they are implicitly collecting metrics in their shell.
>“Here’s what we don’t know about whale barnacles, at least with any certainty: just about everything else. Like, how do their larvae, no bigger than a grain of salt, find a migratory whale to grab onto in the first place? Once they locate one, how do they navigate around its gargantuan body—hundreds of thousands of times larger than theirs—to find their permanent homestead? “It just seems preposterous,” says John Zardus, a marine biologist at the Citadel in Charleston, South Carolina.”
Further, the article points out that certain types of whale barnacles are shown to prefer certain types of whales. Nature is amazing.
Whale lice don't have swimming larvae. Like kangaroos they have pouches to incubate the eggs and hold the larvae, until they are able to live alone. They can move to other whales when whales mate
EDIT: Nope, I'm mistaking one type of parasite for another, my bad. Barnacles use most probably chemistry to find other whales.
Is interesting that they don't even mention the most interesting aspect of the whale barnacle life. Whale barnacles and whale lice are the fingerprints of the whales. You can identify one particular whale for years and years mapping the head patches made by its barnacles. Those islands of parasites are exclusive from each specimen in extension, number, shape and color. Is incredibly useful for studying them.