Whale trapped in salmon farm moorings is set free

A humpback whale that became entangled in moorings at a salmon farm off the northeast coast of Skye has been freed.

The whale, which was found to have become entangled at Organic Sea Harvest’s Invertote site yesterday morning, was rescued with the help of the Large Whale Disentanglement Team from British Divers Marine Life Rescue (BDMLR), a nationwide charity that rescues marine wildlife including seals, dolphins, and whales.

Organic Sea Harvest (OSH) suspended normal farming operations at Invertote yesterday and focused on trying to free the whale.

Worked tirelessly

A spokesperson for Organic Sea Harvest said: “We’re delighted to confirm that the humpback whale entangled at our salmon farm has been freed.

“Our farm staff, supported by experts from British Divers Marine Life Rescue, have worked tirelessly since discovering the whale just after 7am yesterday.

“This is the outcome we had all hoped for and worked towards.

“OSH staff will continue to monitor the whale’s movements and provide any further assistance to the authorities.

“We sincerely thank everyone involved in the rescue operation, especially the British Divers Marine Life Rescue. We would also like to offer our thanks to other salmon farmers and local seafaring community on Skye for all their offers of assistance.”

Carrying old ropes

The spokesperson added: “During the rescue it became clear that the whale had previously been entangled and was carrying old ropes of a type not used by Organic Sea Harvest. It was this existing entangled rope which caught onto the farm moorings as it swam by. Thankfully the BDMLR team were not only able to free the whale from the salmon farm, but they were also able to free it of the other ropes it had been carrying.”

Martin Boon,  coordinator for the disentanglement team, made the three and a half journey from near Elgin to take part in the rescue, with other members of the six-person team travelling from as far as Devon and Cornwall.

Although the disentanglement team is part of  British Divers Marine Life Rescue, Boon explained that the rescuers don't go into the water, but instead work from a small inflatable boat of a type used by special forces, using an underwater camera to see what's happening under the whale.

"The boat hasn’t got a rigid hull, so you can come up against the animal without risk of scraping or scratching it," said Boon. "Depending on the entanglement, if the whale can dive and you get caught in it, you’re going to go down, so nobody goes into the water. We’ve got specialist knives which we put on poles, and we cut from the surface."

A slow and careful rescue

After assessing the entanglement yesterday, and staying with one of the team's relatives on Skye, the rescuers were on site at 6am today, and after preparations they began the work of freeing the whale at around 8am. It took three and a half hours.

"The problem was that all the rope was really tight around the animal. It was stuck underneath it. Since the footage that we took yesterday, it had got tighter, so we used the underwater camera again, and re-evaluated the situation, making sure we were cutting the right thing – we want to make sure that we’re not cutting a rope to set if free while it’s still got an entanglement on it. We have to cut it systematically, so the final cut is the one where it’s free and we get everything off it," explained Boon.

"The whale was exhausted, it had been tied up for 24 hours, and it was obviously stressful for it.

"We don’t know where the entanglement came from. It’s certainly nothing to do with the fish farm. It was a mooring buoy that it was caught in, and that’s just chains (not rope). It was just a random piece of rope and we don’t know where that’s come from, whether it’s drifted on to the mooring or whether the animal was entangled in it and the entanglement’s caught the mooring chain. We just know that it was heavily wrapped up beneath the animal and tight to the chain."

It is the first time Boon has seen a whale entangled at a fish farm.

"We’ve had fishing gear but not fish farms. And the guys at Organic Sea Harvest have been brilliant. They made it possible, they gave us support boats and RIBs to get us out there as quickly and as safely as possible. They gave us a safe working platform, they did brilliantly, so all thanks to them."

36 whales a year

The Scottish Entanglement Alliance - a collaboration between NatureScot, the Scottish Marine Animal Stranding Scheme, Scottish Creel Fishermen’s Federation, Whale and Dolphin Conservation, Hebridean Whale and Dolphin Trust, British Divers Marine Life Rescue, and the Scottish Association for Marine Science - estimates that around 30 minke whales and six humpback whales become entangled in Scottish waters each year, in fishing gear. 

An academic paper assessing collaborative trials of simple gear modifications to reduce entanglement reported that where entanglement type was known, 83% of minke whales, 50% of humpback whales, and 76% of basking sharks were caught in floating groundlines between creels. 

Researchers who collaborated with fishers on Scotland’s west coast to trial sinking groundline (which lies on the seabed) to assess its practicality reported encouraging results.