The entanglement of two humpback whales on the NSW coast has highlighted the man-made threats marine life face at an increasing rate.
On Saturday, a humpback whale was being monitored at Seal Rocks, south of Forster on the mid-north coast, after becoming snared by ropes and five buoys.
Further north at Ballina, a juvenile whale was detected in the Richmond River on Sunday, also being hampered by buoys and netting around its body.
Marine rescuers were unable to disentangle the whales before losing sight of them.
In a strange twist of fortunes, incidents like these entanglements are a reflection of a healthy and increasing whale population using the “humpback highway” along the Australian east coast each year.
Organisation for the Rescue and Research of Cetaceans in Australia (ORRCA) second vice-president, Jools Farrell, said we could expect to see more entanglements.
“Because the population is increasing we will, unfortunately, see more situations of whales becoming entangled,” she said.
The 2019 whale migration started in April this year, and promised to be one of the “busiest yet”.
Entanglement similar to a human ‘dragging a car’
While the humpback whale population is growing, so too is the amount of marine debris that poses a risk to the mammals.
The Tangaroa Blue Foundation is a not-for-profit organisation involved in the clean-up and cataloguing of marine debris from coastlines around Australia.
Managing director Heidi Taylor said the problem had never been so great.
“When it really started to come to the forefront about 15 years ago we knew there were around 276 species being impacted by marine debris and now the statistics are up around 800 species,” she said.
Whales face a range of threats from marine debris like nets and ropes, often referred to as “ghost nets”, but most common is entanglement, as seen in the past few days at Forster and Ballina.
“Entanglement can cause them not to feed properly. In some cases they can’t breathe and they can’t resurface,” Ms Taylor said.
“Eventually they just get worn out, it would be like a human walking around dragging a car behind them.”
Ms Farrell said the humpback whale spotted at Seal Rocks on Saturday was again seen about 80 kilometres south at Hawks Nest on Sunday afternoon.
“It’s really hard to say [how fast it’s travelling] because it’s dragging five buoys, and we’re not sure how long these buoys have been on this whale for, and the longer that it’s trailing them, the more tired and slower it’s going to get,” she said.
Waste is not necessarily local
The marine debris that entangled the whales on the NSW coast may not have even originated in Australian waters.
The work of the Tangaroa Blue Foundation has found that fishing waste, such as ropes and nets, found along the east coast can come from regions to the north of Australia, or further east in the Pacific.
“I think that this is a larger problem we’ll keep facing, purely because the world keeps getting bigger and we keep creating and using more stuff so there’ll be more and more of it ending up in our oceans until we stop it at the source,” Ms Taylor said.
More whales will mean more deaths
Up to 35,000 humpback whales are expected to migrate north this year.
Marine wildlife project officer with National Parks and Wildlife, Andy Marshall, said humpback whale numbers were increasing by 10 to 11% each year.
But as young whales came through, there was also the natural progression of increasing deaths of whales.
“While the increase in whales is normal, the other end of the lifecycle is also normal; so seeing dead whales, unfortunately, will be a larger part of this migration each year,” he said.
“While it’s sad, it’s an inevitable part of the movement of a big population of animals as the population ages.”
The NSW Office of Environment and Heritage said last year there were 22 recorded whale entanglements in NSW waters. There have been seven recorded so far in 2019.