Wildlife

Humpback whales put on a bubble-net feeding show in Southeast Alaska

A humpback whale breaches in Frederick Sound off of Kupreanof Island north of Petersburg on Saturday, July 21, 2018. (Bob Hallinen / ADN)

OFF KUPREANOF ISLAND — Frederick Sound in Southeast Alaska is a rich feeding ground for humpback whales. A pod of humpbacks was seen bubble-net feeding July 21 north of Petersburg.

Humpback whales bubble-net feed in Frederick Sound. (Bob Hallinen / ADN)

The whales dive and then expel a ring of bubbles. Small fish are trapped in the rising circular curtain of bubbles. The whales come up inside the circle of bubbles with mouths open, capturing the fish.

Humpback whales bubble-net feed in Frederick Sound off of Kupreanof Island. (Bob Hallinen / ADN)

The whales have 240 to 400 baleen plates hanging from the upper jaw that filter out the small fish as they force the water out. Humpbacks also feed on krill.

Humpback whales bubble-net feed north of Petersburg. (Bob Hallinen / ADN)

The whales migrate between Alaska and Hawaii, Mexico and near Japan. They rarely feed during migration or while in southern latitudes. The breeding season occurs while they are in their southern range, and females give birth 11.5 months later.

Humpback whales exhale noisily off Kupreanof Island. (Bob Hallinen / ADN)

Humpback whales grow to 49 feet long and weigh 35 tons, with males being slightly smaller than females. They can live 40 to 50 years. Humpbacks have long flippers that can be up to 30 percent of the body length. They sometimes slap the water with their flippers.

A humpback breaches in Frederick Sound. (Bob Hallinen / ADN)
A humpback breaches off of Kupreanof Island. (Bob Hallinen / ADN)

When whales breach, they power their 35 tons out of the water, sometimes completely out, and crash down on their sides, creating a boom and a huge splash. Humpbacks also slap their tails on the surface. Scientists are not sure why.

A humpback whale sounds near a boat as a pod was bubble-net feeding in Frederick Sound. (Bob Hallinen / ADN)

Humpbacks are commonly seen in Southeast Alaska, the Aleutians and in Southcentral waters between Kodiak and Prince William Sound, including Resurrection Bay.

As people watch from a boat, a humpback whale exhales as the pod was bubble-net feeding in Frederick Sound off of Kupreanof Island. (Bob Hallinen / ADN)
A humpback whale sounds in Frederick Sound. (Bob Hallinen / ADN)
Water flows off a humpback tail in Frederick Sound. (Bob Hallinen / ADN)
A humpback sounds in Frederick Sound as other whales exhale at sunset. (Bob Hallinen / ADN)
In evening sunlight, a humpback sounds in Frederick Sound. (Bob Hallinen / ADN)

Information on the humpback whale is from the Alaska Department of Fish and Game website.

A humpback whale sounds in Frederick Sound. Devils Thumb, in the Stikine Icecap range, is the prominent peak on the horizon. (Bob Hallinen / ADN)