Entangled humpback whale’s sad fate has researchers calling for action on fishing nets
A juvenile humpback whale has been spotted in the Antarctic entangled in fishing gear, leading to calls from conservationists for better protections along migration corridors.
The sighting last Wednesday by scientists aboard the Crystal Endeavour occurred at Mikkelsen Harbour on Trinity Island, on the western side of the Antarctic peninsula.
The researchers from the Colombian Antarctic program, PhD candidate Logan Pallin and Dr Natalia BoteroAcosta, approached the small whale to take a skin biopsy to help determine its genetic origin, sex, cortisol levels and diet.
Pallin noticed the whale’s dorsal fin was missing, and it was trailing fishing gear and several buoys that had become wrapped around the fluke – the tail – where it was causing abrasions and cutting into the skin.
The whale’s age is unknown but it is estimated to be about 18 months. As it was likely on its first migration alone, it had likely carried the gear over thousands of kilometres down the South American coast.
It was last seen labouring to swim and is considered unlikely to survive.
With humpback whale numbers now rebounding after being decimated by whaling, and climate change affecting the availability of food, the animals are increasingly moving through areas with higher levels of human activity.
Simon Miller, an Australian Marine Conservation Society fisheries expert said it was difficult to tell what sort of net had entangled the whale and whether it was active or a “ghost net” that had been abandoned, broken or cut loose.
“If they become wrapped up in a net like this juvenile, they are effectively dragging an anchor behind them which spells an untimely end unless they are freed,” Miller said.
While it is possible to cut away the fishing gear, the process requires specialised equipment and trained teams as the manoeuvre is dangerous for both those carrying out the task and the whale. These are generally unavailable in the Antarctic.
A report of the entanglement was circulated to other vessels in the area in an effort to monitor the whale, but Prof Ari Friedlaender of University of California Santa Cruz’s ocean sciences department said more needed to be done to stop a repeat in the future.
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“My hope is that the more this type of situation is brought to light, the more can be done to minimise these interactions from happening,” he said. “Because nobody wants to see whales harmed like this, nobody wants to see people who fish have their livelihood dragged away as well.”
Friedlaender said entanglements can be reduced with modifications to fishing gear to make it less likely to become caught, tangled and dragged and more information for fishers to better time operations.
Miller said the incident shows the “vast reach impacts like fishing can have on threatened species”.
“Whale entanglement can be avoided to an extent by not setting high risk fishing gear like lobster pots with long head ropes or gillnets in the areas through which humpbacks are known to migrate and congregate,” Miller said.
“As humpback migration patterns and timings are regular, fishers should know where and when not to set their nets.”