Close Encounter with Humpback Whales

(In February 2008 I spent four wonderful mornings diving with the Mike Severns Diving outfit in Kihei, Maui. Here's a writeup of one of our memorable wildlife encounters, which happened before I even got my gear on!)

During Captain Andy’s introduction talk aboard the Pi’iili Kai, he went over all the usual safety stuff, pointed out various features of the boat – the side gates we would giant-stride out of, the stern ladders we’d use to get back onto the boat at the end of the dive -- and ran through what the day would probably be like. Then he said our first dive would be out at Molokini crater. “Usually it takes us 15 minutes to motor out there,” he said. “But this is humpback season, so it could take us a lot longer!”

Whales have right of way around Maui, which is the center of the Humpback National Marine Sanctuary. Also, since the humpback is both on the Endangered Species List and protected under the Marine Mammal Protection Act, people are supposed to give the humpbacks a wide berth – 100 yards, by law. “Sometimes these guys pop up right in front of the boat with no warning and I have to slam on the brakes,” Andy warned us. “It’s like having a three-year-old run out in front of your car.”

So it was no surprise to any of us that, five minutes into our cruise between Kihei boat ramp and Molokini, we were veering off course to avoid a small pod comprising mom, calf, and escort. Our veer took us closer to another pod, though, just as one of them started doing pectoral slaps. Andy cut the engine and we drifted, watching the 40-something foot long beast roll back and forth on the calm surface of the ocean, repeatedly flinging one 15-foot-long front flipper skyward and then bring it down on the water with a resounding smack. White water fountained up around the graceful pectoral fin each time it plunged into the sea, and cascaded off it again as the pec rose for another slap.

The long pectoral fins are relatively narrow and look thin compared to the animal they are attached to. Dark on the upper side, white beneath, they are rounded at the tips and have a lacy crenellation around the edges, which often carry barnacles the size of a toddler’s fist.
After a few slaps another pec – this one belonging to another 40-something-foot-long leviathan – rose into the air and smacked down, doubling both the sound and the whitewater fury of the display. The first humpback brought its second pectoral fin into play, rolling rapidly back and forth, smacking down first one, then the other, as though to outdo its competition. The only other sound was the occasional blast of a humpback expelling a breath at 300 miles per hour through the paired blowholes, or nostrils, on top of its head.

We drifted for five or ten minutes, and the pectoral slapping display showed no signs of abating as Andy started the engine and turned us again towards our dive spot. Researchers suspect the slapping is a form of communication between humpbacks – the sound carries for quite a distance both above and below water – but what it really means is for the whales to know and us to wonder.