Friday, April 7, 2017

Farewell to our whale friends

A humpback whale breaching. (NOAA photo)
At the end of March, 2009, we went on a boat dive to Molokini. One of the divers complained on the way back that he hadn't seen any whales. The boat captain said the whales already left. To this the man exclaimed angrily: "The chamber of commerce said they are here until April first!" I guess the whales just didn't look at their calendar that year.

We enjoyed our whale watching season this year. Every December an estimated that 60 percent of the North Pacific humpback whale population migrates to Hawaii's waters. In spite of numerous studies, no one knows how the marine giants manage to cross open ocean from Alaska to Hawaii never veering off course by more than one degree.

The waters around Maui, Lanai and Molokai provide the perfect protected waters the whales need for their great social gathering. The channel between Maui and Lanai turns into one big nursery when the pregnant humpbacks give birth to their 2,000 pound calves. The newborns measure about 12 to 15 feet. A Humpback mother and newborn calf will stay close to shore while nursing. The calf will consume about 100 gallons of his mother's fat-rich milk a day.

The adult whales, including mothers, don't eat while they are here. The water is relatively nutrient free and too warm to support enough of the humpback's food to sustain them, so they live off their blubber.

The calf can double in length during his first year and learns whale behaviors from its mother. We would often see the mother whale breach followed by a clumsy attempt from the baby whale. We also noticed the mother and baby were often accompanied by a "teenaged" whale that seemed to be acting as an escort or bodyguard.

Male humpbacks hang around and sing. Their songs are complex and can last up to 20 minutes and can be heard up to 20 miles away. Since December, with our heads underwater, we could hear the songs and sounds of whales. No one knows exactly why, but recent studies show that male songs actually attract other males, rather than females. The male whales face the singer during the song. These encounters are usually brief and friendly. Maybe they just want to brag about their new calves.

Songs are just one of the ways whales communicate. Humpbacks emit other sounds referred to as social sounds. In addition, they use breaching, tail slapping, and fin slapping to attract attention, which works on whales and humans alike.

Breaching seems like an act of pure joy. (NOAA photo)
Last weekend, on April first, we saw a whale breach. It was beautiful and poignant because we knew it would most likely be the last one of the season.

But with the whales gone, another friend has returned. We don't know why, but while the whales were here, we spotted fewer dolphins. Maybe they can't put up with the whale's singing. Until next December, the dolphins will delight us and keep everyone company.

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