Our Changing World: The tricky work of disentangling whales

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When a whale gets entangled in fishing gear it's bad news. It can get trapped in place causing it to starve, or rope wounds can get infected.

However, trying to free a 40-tonne water-based animal in distress is incredibly dangerous business.

It's why the Department of Conservation (DOC) trains and maintains two whale disentanglement teams. In October Our Changing World travelled to Kaikōura to meet the lead of the South Island team.

As DOC's compliance boat Tītī skips across the water on a calm, sunny October day, marine ranger Zac Penman is confident in spotting some whales. "This time of year, it's not rare for there to be 50 humpback whales coming through."

They migrate past Kaikōura on their way south, to the big summer feed in Antarctica, but lately there are some juvenile humpback whales that have been sticking around all year round. On the morning of our trip, four have already been spotted nearby by whale watching tourism operators.

Here, with boats, planes and helicopters all on the lookout, if a whale happens to get entangled in fishing gear it's likely that the alarm will be sounded swiftly.

But that's not the case elsewhere, says Zac.

"People always think it's really easy to find whales because they're so big. The issue is the ocean's even bigger. So sometimes it's like looking for a needle in a haystack."

As the lead of the South Island's large whale disentanglement team, it's Zac who will get the call if a whale is spotted wrapped up in fishing gear.

In remote areas it's often commercial fishermen who are picking up the phone. Sometimes the team simply won't be able to help - if the whale is too far offshore or there is bad weather preventing them from launching.

But for those sighted closer to the coast or locked in place by nets or craypot lines anchored to the seafloor, the team will get called into action.

How to disentangle a whale

Since Zac started in the role, just over a year ago, he's been involved with two successful disentanglement efforts.

The first step, he says, is to find the whale and to keep an eye on its location. To do this, they use a grapnel hook to attach a satellite tracker buoy to the entanglement.

Once they've got an eye on where it is, the second step is to plan. This is key, says Zac, to keeping both the team and whale safe.

If the whale is anchored in place, it makes their job easier. If it's mobile, they will try to get next to it by using a small boat and pulling themselves close to the whale using one of the entangled ropes, which they dub their 'working line'. They'll sit and study the entanglement, or they'll use either a drone or a camera on a stick to try to get a visual, because choosing which rope to cut first is really important, says Zac.

"It's kind of like defusing a bomb ... If you cut the wrong line, we can lose our working lines straight away. Or we might cut away something that's anchoring the whale to the bottom and then we've got a mobile whale with a small amount of entanglement there. It's really hard to get to and that can cause open wounds ... that can lead to death in these whales later on."

Cutting the lines involves a team of three. The boat skipper oversees the operation, the cutter stands at the front of the boat wielding a specialised long-handled rope cutter with a curved hook to avoid harming the whale, and a third person holds the cutter as they lean out to do their work.

The team trains in Kaikōura by dragging a fake whale tail through the water, but it's not like the real deal says Zac.

In June, he lead the team in a successful effort to free a Southern Right Whale that was trapped in craypot lines off Rakiura.

Southern Right Whales are considered to be the trickiest of the large whales to free, Zac explains, "They get really big and they got really big pec(toral) fins, like massive, big wide things. They can turn on a dime, complete 180 degrees, they can swim backwards ...They're a little bit more boisterous."

It was the first recorded Southern Right Whale disentanglement in Aotearoa.

An international effort

The teams' training and work follows agreed International Whaling Commission guidelines and principles. These were drawn up in the wake of the tragic loss of Kaikōura local Tom Smith, when he tried, as he had before, to help a humpback whale by getting in the water with it.

He was struck by the whale's tail and his body was never recovered.

Among other recommended protocols and safety gear, the standard operating procedure of working from a boat only is designed to keep the disentanglement community safe, says Zac.

It also aligns their effort with what others are doing around the world.

In New Zealand the teams get about six calls per year, but their colleagues in Australia are much busier, says Zac, with callouts increasing on the East Coast due to their resident, and growing, populations of humpbacks.

"They have the added issue of shark nets that they have in lots of places around New South Wales and Queensland. And it makes a real big mess when you get a humpback whale wrapped up in one of those. But they can be reporting to seven a week sort of thing, just in that sort of south eastern coast of Australia."

The international disentanglement teams also exchange information frequently, says Zac, about entanglements they've had and what went well or not. Plus, trying to find new tools and methods that can make the work easier and safer.

And while it is dangerous work, it is also very rewarding says Zac, "Nothing makes you feel as good as saving a whale."

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