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Experts: Watch out for the whales with season underway

Last migration season saw record entanglements

A mother and baby humpback whale frolic in the waters off Puamana in January. — The Maui News / MATTHEW THAYER photo

As Maui heads into whale season, researchers and conservationists will be on the lookout for whales in distress after a record season of responding to entanglements.

Throughout the “extremely busy” two-month 2022 migration period in Hawaii earlier this year, more than 3,200 feet of gear was removed from entangled whales — including over 2,400 from one animal — which is the most ever in one response season.

All nine confirmed cases represented potentially life-threatening entanglements, said Ed Lyman, sanctuary natural resource specialist, during NOAA’s Hawaiian Islands Humpback Whale National Marine Sanctuary pre-whale season webinar on Wednesday night.

Of the total entanglements in the last season, eight of the animals were adults and one was a calf. The first confirmed large whale entanglement report of the season was Jan. 16, while the last was March 15.

Specifically, there were four reports off of Maui, three off Hawaii island, one report from Kauai and one from Oahu, Lyman said. Three cases involved mouth entanglements, two cases involved wraps around the head, two otherwise forward on the body and two involved the tailstock.

A humpback slaps its tail near a tour boat in February. — The Maui News / MATTHEW THAYER photo

Stationary traps, or pots, typically used to catch crustaceans, have been the most popular gear type found in entanglements since 2002 at 38.2 percent of all cases, with nearly half originating from Alaska and British Columbia, he said.

Longlines make up 24.7 percent of the gear found, followed by debris (16.9 percent) and monofilament (10.1 percent), with the remaining being fishing gear, gillnet, scientific equipment and other nets.

This season also had the largest use of drones, Lyman said, which helps staff to respond to and record entanglement reports.

Since 1999, there have been 499 reports (240 confirmed) cases of entanglements. Since 2002, the Hawaii Network has freed 39 large whales from life-threatening entanglements, removing more than 15,000 feet of lines and netting.

To add to the data collection, there were 85 reports representing entangled, ship-struck and other compromised-reported animals this season. Ten reports were whale-vessel contacts — five self-reported and five were documented later with wounds.

Since 1979, there has been an overall increase in whale-vessel collisions, with the majority being calves or sub-adult whales (66.1 percent), Lyman said.

Since 2002, more than 1,100 records have been received and logged within the Animal in Distress database.

Injury and mortality from collisions with vessels is considered a major threat to whales worldwide. However, reports involving collisions between vessels and humpback whales on their breeding/calving grounds around Hawaii have fallen over the past decade, Lyman said, which could be for several reasons.

Some examples include changes in whale presence on the breeding grounds, especially calves, reductions in vessel traffic due to the pandemic, and greater awareness from increased outreach and engagement, he said.

Lyman said recommendations on reducing contacts between vessels and whales include reducing vessel speeds to 6 knots or less when within 400 yards of a whale; maintaining speeds of 15 knots or less during whale season, which runs from November to May; and minimizing sudden or unnecessary maneuvers and speed changes when near whales, he said.

Humpback whale season in Hawaii typically runs from November through May, with the greatest abundance reported between January and March, but longtime monitoring and a collection of data from marine scientists and researchers show major fluctuations in the whales’ behaviors.

This could make the 2023 season unpredictable.

Marc Lammers, sanctuary research ecologist, on Wednesday night discussed results from key acoustic monitoring efforts, vessel surveys and tagging work to understand whale behavior over the years.

The data shows that there’s been a lot of “fluctuation and variability” on the chorusing levels of singing whales over the past eight years, beginning with the 2015 migration year, which yielded the highest chorusing level and a longer lasting breeding season amid a marine heat wave, also called the “blob,” Lammers said.

During 2021-22 field season, which ran from October 2021 to May 2022, the team conducted acoustic monitoring of whale singing activity. Five ecological acoustic recorders were deployed in waters around Maui (Olowalu), Molokai, Lanai, Kahoolawe and Oahu at locations ranging in depth between 49 and 656 feet.

In 2020 around Maui, data showed whale singing activity peaking late and lasting later in the season while in 2018 and 2022, activity peaked early in the season and ended early.

The 2020 migration season occurred during the COVID-19 pandemic, but Lammers said that the changes in whale behavior could just be coincidence.

“I’d like to think that whales and migration patterns are not upset by human activities, but it is an interesting coincidence that the migration season lasted longer than almost every other season,” he said. “All of this is to say that the fluctuation that occurred since the blob has continued in some way.”

Chorusing and whale presence also differs per island — Oahu and Kauai recorded drops in singing activity this past season.

Lammer said whale presence in Hawaii is “largely driven by their need to feed” and how much fuel they have to return to the islands to breed.

During the upcoming 2023 season, the sanctuary will be partnering with Syracuse University to better understand how juvenile whales learn to vocalize and sing. The team will tag whales using drones, which is a less invasive tagging method, Lammers said.

“We’re excited about this possibility,” he said.

Researchers have also spent time studying the density of whales in the waters off Maui and the timing of the season.

The sanctuary has conducted transect surveys as part of their health and risk assessment monitoring since 2016 when there are changes in whale sightings. The team placed 27 vessel-based transects representing more than 164 kilometers covering Maalaea Bay and the southeastern area of the ‘Au’au Channel.

Since 2020, the density of whales occurring in the West Maui area has remained stable, but the timing of the season has fluctuated over the past four years, which is “significant,” said Eden Zang, Marine Mammal Response Network assistant and research specialist.

Results indicated that humpback whale abundance in Hawaii increased from mid-December and peaked in late January.

Zang said the goal is to eventually “completely rely on acoustic monitoring for whale density estimation” because it is cost effective and allows researchers to monitor without physically having to be out on the water 24/7.

As whale season gets underway, NOAA advises that anyone who sees an entangled whale should not approach it closely or attempt to free it.

Freeing a 40-ton whale is “extremely dangerous” for the animal and the rescuer. Only trained, authorized and well-equipped responders are permitted to disentangle whales.

If an entangled whale is spotted, maintain at least 100 yards’ distance, obtain imagery and call the NOAA Fisheries’ Marine Wildlife Hotline at (888) 256-9840.

* Dakota Grossman can be reached at dgrossman@mauinews.com.

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