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In 1991, Just 5,000 Humpback Whales Went to Hawaii. Now, They’re Rebounding.

When a call comes in about an entangled whale in Hawaii’s waters, Edward Lyman sends out a “code yellow” alert to his team. 

On the phone, he asks the caller questions and determines if the whale is seriously threatened. If it is, then he green-lights a rescue mission — and his team assembles.

Lyman is the natural resource specialist for the Hawaiian Islands Humpback Whale National Marine Sanctuary. Based on Maui, he monitors and protects humpback whales and is the lead coordinator for entanglement response efforts.

It may take one to two hours for his team to get to its boat and then to the whale, so the community often jumps in to help. Tour boats already on the water that heard the call radio each other and take turns tracking the whale from a safe and legal distance until Lyman’s team arrives.

Entanglements are just one of the ongoing threats to whales, along with ship strikes, climate change and even noise pollution. Whales twisted and trapped in fishing lines or gear can be dragged around for months over thousands of miles and are at risk of drowning and starvation due to limited movements.

Beyond removing all of the trash in the ocean, there isn’t really another way to prevent this from happening. “A lot of it is fishing gear, but not all, so that’s the thing. Just our very existence, I mean, it’s kind of a sad statement, but our very existence poses a threat to many species,” Lyman tells SFGATE.

A tight wrap of line and a large bundle of marine debris around a humpback whale’s head.

The Hawaiian Islands, particularly the area between Maui, Molokai, Kahoolawe and Lanai, are the breeding grounds for North Pacific humpback whales and have been designated as a national marine sanctuary to protect this important habitat. The whales travel to the islands from Alaska every year during the months of November to April to mate, give birth and nurse their young. 

The NOAA response team uses a long pole with a specially designed knife on the end to cut the wrap around a humpback whale’s head.

In the 19th and 20th centuries, the humpback whale population was nearly decimated by commercial whaling, so they were put on the list of endangered species in 1970. Since then, data has shown that their populations have rebounded.

From 1991 to 1993, an estimated 5,000 whales were making the trip to Hawaii. In 2004 to 2006, that number was over 10,000. Each year, the number increased by at least 5%. By 2016, data showed that their population continued to rise, and that’s when the Hawaii population segment of humpback whales was taken off the endangered species list.

“They are recovering, but we haven’t quite taken the step to say they are recovered,” Lyman says.

A humpback whale, now free of her entanglement, swims off with her calf.

Scientists aren’t waiting for the whale population to reach a specific number to proclaim the species’s recovery. Rather, they’re waiting for the whales to reach their “carrying capacity,” or the point when their population has reached the maximum number the environment naturally allows.

When they reach carrying capacity, whales will start slowing down the number of calves they birth. There will also be a higher mortality among the younger and older animals as competition for resources grows. These are the type of indicators scientists are watching out for, and Lyman thinks they’re getting close.

“It is one of the success stories. You know, it’s good to be taken off the endangered species list, that the numbers are high, but the caveat here is it doesn’t mean our job’s done,” he says.

An entangled humpback whale, with the bow of a response vessel in the foreground.

When Lyman and his team arrive at the scene of the entangled whale, they jump into an inflatable raft to get closer and inspect what needs to be done. Using modified whaling techniques, they tag it with a tracker, in case it takes longer than the day to cut it loose. They also use grappling equipment and buoys to slow the whale down until they are finished cutting it free.

When the freed whale is finally able to swim away, Lyman’s work isn’t complete. Later, he’ll piece together what they gathered off the whale and try to figure out where the marine debris came from. If he’s lucky, he’ll figure out who to call to let them know what happened and how to possibly prevent it in the future.

“You’re not going to eliminate all the threats unless we somehow are off the face of the earth,” Lyman says. “So you’re mitigating — you’re trying to reduce the threats at the individual level.”

Source : SFGATE