Come on a journey of discovery with me – from identifying the very big, to the small. 

I’ll tell my tale of through the images below. 

Meet the Humpback Whale BCX1188 nicknamed “Jigger” for the now faint fish-hook shaped scar on her right fluke.

When we saw Jigger in 2009, we noted the barnacle growing on the right top of her dorsal fin. Such barnacles are a distinct species only found on Humpback Whales. The Humpback Whale Barnacle is Coronula diadema (to 5 cm tall and 6 cm wide.

Then, when we saw Jigger in August of 2010, we noted that her dorsal fin looked very different. My research partner from the Marine Education and Research Society, Christie McMillan, and I were worried that it might be an injury so we tried to get a better photo of the dorsal fin.

Here’s what the dorsal fin looked like from behind (photo taken with a telephoto lens and cropped)  When I had this perspective, I thought that what we were looking at might be seaweed growing on the Humpback Whale Barnacle we had seen the year before (note that the barnacles often do fall off between years).

But, it didn’t quite look like seaweed. With patience and good camera lenses, we got a better look.

What on Earth?! They’re gooseneck barnacles growing on the Humpback Whale Barnacle!

Gooseneck barnacles are an order of barnacles that are attached to a hard surface by a long stalk that looks like a goose’s neck. They depend on the motion of the water to feed on plankton as they do not have the “foot” (cirri) that rakes in plankton in many other barnacle species.

That’s when I learned that there is a species of gooseneck barnacle that, in the North Pacific Ocean, most often grows on the Humpback Whale Barnacle!! The species is the Humpback Whale Gooseneck Barnacle, also known as the Rabbit-eared Whale Barnacle (Conchoderma auritum (to 11 cm long).

This is the kind of discovery that causes wonder and euphoria in my world.

To be able to identify a Humpback as an individual is already something of great scientific and educational value.

That this attention to an individual whale leads me to learn that there is a species of gooseneck barnacle that grows almost exclusively on a species of barnacle that only grows on Humpback Whales  = sheer wonder.

I can’t wait to find out what else the Humpbacks are going to teach me!

More detail

From E-FAUNA BC: ELECTRONIC ATLAS OF THE WILDLIFE OF BRITISH COLUMBIA “Conchoderma auritum is most often found attached to the shells of Coronula on the humpback whale; sometimes more than fifty are attached to one shell. “Rarely a specimen is found attached to the base of the teeth of an old sperm whale” (Sheffer, 1939). Gordon C. Pike reports finding specimens of C. auritumon sperm and fin whales taken in British Columbia. In each case the barnacles were associated with a deformation or an apathological condition of the jaws, baleen, or teeth. Each barnacle is usually oriented with the opening facing in the direction the whale swims. The food-laden water passes through the opening and over the feeding appendages, then out through the two “ears” which have tubular openings.”

From the Marine Species Identification Portal: Species is “attached to the whale barnacle Coronula diadema and sometimes Coronula reginae. It seems to be a rule that no Coronula is without a Conchoderma. Whether this is a form of symbiosis has been discussed by Broch (1924b). Specimens from northern waters have been taken from humpback whales (Megaptera novaeangliae ) or from teeth of bottle-nosed whales (Hyperodon spp.). In the Antarctic C. auritum has also been found on baleen plates of whales and on their tails. In tropical and subtropical parts of the oceans it can also be found attached to ships’ hulls and other floating objects, to slow moving fishes or to the tail of a large eel, but never on soft objects.”
From Mike Horan (pers. com January 2022) “I have also seen the stalked barnacle [Conchoderma auritum] on Bottlenosed Dolphins during the die off of 1987 in New Jersey.”

Excerpt from Hakai Magazine’s “What Whale Barnacles Know” (November 2021)

“Individual whales have been known to collect up to 450 kilograms of barnacles. That’s an enormous mass, but relative to a 30-tonne humpback, it would weigh only about as much as an extra layer of clothes. And as far as scientists can tell, the hangers-on don’t particularly bother a healthy whale. They may slightly increase drag as the whale swims, but they may also be helpful as a set of brass knuckles when adult males battle each other over the chance to mate [and when dealing with mammal-hunting Bigg’s Killer Whales]

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. He specializes in studying barnacles that live on other living things.

Studying those symbiotic barnacles that live on sea turtles, dolphins, crabs, and other marine animals has given Zardus some idea of how whale barnacles might hack it. Adults mate on the whale, but rather than take their chances during their host’s oceanic migrations, they likely wait to release their larvae until the whales gather in coastal areas to breed. The larvae then go through several developmental stages, which can take up to two weeks, before they’re ready to settle. “It’s not like the larva is being released from a whale and it’s going to [immediately] attach to the whale next door,” Zardus says.

When a larva is ready, a chemical signal is most likely what tips it off that it’s in the presence of whale skin. This could be a pheromone emitted by already settled adult barnacles—a strategy commonly used by other barnacle species—or it could be some molecule that wafts off the surface of the skin itself. If other barnacles are any indication, the larva probably reaches out with its sensitive antennules to familiarize itself with the epidermis. It squeezes a drop of sticky polymer out of one antennule to adhere itself temporarily, then sticks down a second antennule and releases the first one, swinging it over to another spot. By repeating this process, a larva “ends up walking around on the surface, leaving little gluey footprints,” says Zardus. “These larvae can possibly crawl all over the host until they find the right location where they want to be.”

Where they want to be is generally on the whale’s forehead, its tail, or the leading edges of its flippers. Those are the places on a whale’s body that water flows over most efficiently. That gives the barnacle a front-row seat when the whale swims through a cloud of plankton, which the barnacle also gets to eat. When the larva finds a good place to settle down, it exudes a stronger glue onto the skin and cements itself for the rest of its life, which may last about one to three years.

Much of this is informed speculation, Zardus stresses, because living whale barnacles and their larvae are extremely hard to come by. Collecting them from a living whale is out of the question, since it would require cutting into the whale’s flesh. A dead whale that washes up has to be discovered before its barnacles die of hunger, desiccation, or predation . . ..

Other than whale barnacles, nothing else reliably recorded the month-to-month movements of ancient whales, says Taylor. Bone tissue doesn’t care about the chemistry of the water it grew in; baleen does, but it’s hardly ever fossilized. But a well-preserved whale barnacle is the perfect time-traveling tracking device. “We won’t be able to tell you, ‘This whale hung a left at Malibu,’” says Taylor, “but [we can] get a general sense of where animals might have been moving.” . . .

Sources:

Hakai Magazine, November 2021, What Whale Barnacles Know

Mike Severns, The Life and Times of a Humpback Whale Barnacle

Würsig, Bernd G., J. G. M. Thewissen, and Kit M. Kovacs. 2018. Encyclopedia of marine mammals. Chapter: Barnacles.