Whale disentanglement off Bluff a first

The successful freeing of a southern right whale off the Bluff coast was a ‘‘particularly complex’’ operation, the Department of Conservation says, as new details of the first-of-its-kind rescue emerge.

The tohorā whale was freed from entanglement in a blue cod pot line in a complex and technical operation - the first time this species, a taonga for Ngāi Tahu, had been disentangled in New Zealand waters.

On Tuesday, Doc, with the support of southern right whale experts, launched a rescue mission to free the whale after assembling a team of trained responders from across the country.

The whale had been reported trapped on Saturday.

The 9m-long whale, thought to be a subadult male, was successfully freed off the coast of Bluff just after 4pm on Tuesday, following a multi-day ordeal.

‘‘Tohorā are among the most difficult whale species to disentangle,’’ Doc Rakiura operations manager Jennifer Ross said in a statement.

‘‘They are large, extremely strong and incredibly mobile - this makes any attempt to free them particularly dangerous.’’

Fishers first reported the entanglement to Doc on Saturday morning.

Doc staff confirmed the whale’s location and on Monday attached a satellite tracking buoy to keep track of its location while the safest course of action was determined.

A welfare assessment by Massey University professor Karen Stockin identified the whale was showing some signs of distress and there was risk of infection from the wound where the rope was tangled around its tail.

A southern right whale disentanglement had never been recorded in New Zealand before and required an advanced level of expertise, Ms Ross said.

‘‘Tohorā can change direction quickly, roll 180 degrees and swim backwards.

‘‘They’re more unpredictable than other whale species. A whale disentanglement is never straightforward, but this one was particularly complex.’’

On Monday, the tracker showed the whale was on the move, heading towards Bluff. It had broken free of the pot, but still had four buoys and around 100m of rope coiled and draped from its tail.

On Tuesday morning, Doc’s whale disentanglement team had arrived at the Bluff ferry terminal ready to cross Foveaux Strait to Stewart Island, when they asked the crew on the RealNZ ferry if they could make a short detour to the tracker’s last known location.

‘‘Because of that detour we were able to get eyes on the whale, and save crucial hours in the day,’’ Ms Ross said.

The team was able to successfully release the whale’s tail just after 4pm and it was last seen swimming normally into the sunset.

While this operation was successful, it was a reminder to fishers to only set as much line as they need for depth - the longer the lines, the more chance of entanglement, Ms Ross said.

‘‘At this time of year, many whale species are migrating, which increases the risk. They are also at risk of vessel strike; southern right whales don’t have a dorsal fin, so they can be harder to spot in the water.

‘‘This is a timely reminder to take care on the water and share our coasts. Slow down to 5 knots within 300m of any marine mammals, keep 50m away from whales and do not enter the water with them.

‘‘We’d all been hoping for the best outcome for this whale and we thank everyone who has offered their support,’’ Ms Ross said.

‘‘Whale disentanglement is extremely dangerous and should never be attempted by anyone without the right training and gear, but people reporting sightings quickly has meant we’re able to get the right people in place to try and free the whale.

‘‘It’s truly been a team effort.’’

- Allied Media