Remarkable recovery for Hawaii's humpbacks

Published: Jun. 28, 2012 at 1:43 AM HST|Updated: Jun. 29, 2012 at 4:12 PM HST
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Lisa Van Atta
Lisa Van Atta
Manny Duenas
Manny Duenas

HONOLULU (HawaiiNewsNow) - An estimated 21,000 humpback whales are swimming in the North Pacific. Decades ago, overhunting caused the humpback population to plunge to about 1,400 in the region. Scientists are now worried about more ship strikes, entanglements, and other potential problems. Some people are even wondering whether the animal still needs to be on the endangered species list.

A pair of humpbacks thrilled spectators in January by swimming around Honolulu Harbor. According to experts, the whale population is up, especially in Hawaii's waters.

"It really shows that species can thrive and recover in our waters and that the Endangered Species Act is doing its job," said Lisa Van Atta of the NOAA Fisheries Pacific Islands Regional Office.

But having more whales in the ocean also increases the threat of ship strikes and other issues. Response teams help cut free humpbacks that become tangled in fishing lines.

"People from Hawaii are up in Alaska right now helping us out with disentanglements and getting people trained," said John Moran of the NOAA Fisheries Alaska Science Center, who has been studying the feeding ecology of humpback whales in the Gulf of Alaska.

The whales migrate from their feeding grounds in Alaska to Hawaii to mate and give birth, but the recovery is also raising concerns about the potential impact on Hawaii's fishing industry. During his presentation at the Fishers Forum on Wednesday night, Moran indicated that humpbacks are "generalist" feeders that consume a variety of prey, including zooplankton, forage fish such as herring, and adult pink salmon. According to him, the rise in the humpback population is already resulting in impacts in parts of Alaska through direct consumption and other behavioral changes of fish as a consequence.

In addition to Moran's information about the changing situation in Alaska, NOAA officials are also starting to receive more reports from fishermen in Hawaii who have seen humpbacks blowing bubbles and behaving as if they are feeding. The reports are unconfirmed, but Moran said at the forum that he would not be surprised if the whales opportunistically eat while in the islands based on their generalist feeding behavior. Some local fishermen are worried about the potential impact on fish stocks if the whales learn to occasionally feed in Hawaii.

"If these whales are consuming 500 pounds of fish a day, what would that do to the opelu population? What would that do to the akule population? What do that do to other fish populations around the islands?" questioned Manny Duenas of the Western Pacific Regional Fishery Management Council.

The fishermen would like to have scientists research whether the whales are currently feeding while in Hawaii. If the humpbacks are feeding here, the fishermen want to know what the whales are eating and the quantities being consumed.

"We love the whales. We're not out to kill them, however, we need our fish around our communities and our islands to continue to survive," Duenas said.

As for the endangered species status of the animal, NOAA's National Marine Fisheries Service convened a team of scientists to study the humpbacks worldwide. They'll decide whether to break the population down into smaller segments.

"Depending on the outcome of a status review, that status of endangered could be changed to a lesser status of threatened or even not warranted, which means they would be taken off the Endangered Species Act list," explained Van Atta.

If a petition is filed to have the humpbacks delisted, then NOAA is held to a statutory deadline. The experts are supposed to come out with a proposed rule with one year of the petition being filed if it is warranted. If no petition is filed, as in the current case with the status review, then there is no timeline.

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