On March 29, 2023, off the coast of Cape Cod in the Atlantic Ocean, observers at the Center for Coastal Research in Provincetown, Massachusetts, USA, spotted a right whale entangled in a rope, dragging a string of fishing ropes tens of meters long behind it.
Source: Northeast Fisheries Science Center
In fact, this is not the first time that this right whale has been trapped, and the research center has noticed it a month ago, when the sea rescue team helped it remove some of the ropes, but there are still some fishing ropes that have been deeply strangled into the skin and are difficult to remove by conventional means, and the rescue team can only install tracking equipment on the rope, grasp its dynamics in real time, and wait until the weather conditions and the whale's position allows, and then remove the remaining ropes.
A special throwing hook with a cutting function that can be used to remove most of the fishing rope dragged out of the whale's mouth Source: The Florida Fish and Wildlife Conservation Commission
This is not uncommon. Globally, fishing gear placed in the sea can cause "accidental" harm to marine life that would not otherwise be in target, from turtles to sharks to sea lions, seals and other marine mammals.
But big guys like right whales seem to be easier to get caught —
According to research data, more than 80% of right whales living in the North Atlantic have been entangled in fishing ropes or nets at least once in their lives.
Twilight for large cetaceans
Since humans shed their fear of cetaceans, all that has been revealed is endless greed.
North Atlantic right whales often swim slowly close to the coast, making them easy to encounter near the coast, and unlike most whales, their carcasses often float on the surface rather than sink into the water after death, making it easier for whalers to access blubber and baleen plates, so whalers have been a primary target for centuries.
Right whales nearly disappeared in the icy North Atlantic before whaling was banned Source: NOAA Photo Library
This vigorous "whaling hunt" campaign lasted until the end of World War II, when it became clear that the number of cetaceans, including right whales, had deteriorated, and eventually the overfishing of whales led to the conclusion of two international conventions for the protection of whales: the Geneva Convention for the Control of Whaling (1931) and the International Agreement on the Regulation of Whaling (1937), which began to regulate whaling.
In the decades since, the North Atlantic right whale population has recovered at a rate of 1 to 2 percent per year until it peaked in 2010 at about 500 individuals. It looks like the species is moving in a good direction, albeit slowly.
Figure 4 Source: earth.org
However, the number of right whales living in the South Atlantic is growing at a rate of 7 to 8 percent per year, with an estimated population of 15,000. Such disparities in numbers have led scientists to realize that there must be a serious existential threat to right whales in the North Atlantic.
The "power" to change the oceans
At the end of the 20th century, a news report reported the discovery of a whale carcass in waters off New Jersey, the whale died because a taut fishing rope cut deep into its skin and fat layer from the mouth to the back, and as the whale swam, the fishing rope would constantly "slide" backwards, basically "peeling" the whale's skin little by little while it was still alive.
After entering the 21st century, more and more right whales with fishing ropes began to appear, and at the same time, there were fewer and fewer newborn calves, which was due to the excessive energy consumed by female right whales in the entanglement with fishing ropes, which extended the fertility preparation period from three years to six or even ten years, which in turn led to the population of North Atlantic right whales not increasing but declining, and there are currently less than 360 left.
Source: The New England Aquarium
With the hard truth in front of them, scientists began to search for why North Atlantic right whales got entangled in fish ropes. Before the 90s, stories of right whales entangled with fishing ropes were almost unheard of, and an important reason for the connection between the two was climate change.
High temperatures drive copepods, the main food source for right whales, further north. When the whales followed the herds of zooplankton north, they broke into the lively snow crab fishing ground, where nets were set up for snow crabs, but collided with uninvited guests from afar.
Figure 6 The rope on this crab trap is heavier, harder and more dangerous to get entangled Source: CC BY-NC 2.0
In the end, right whales are "shackled" on their backs, and fishermen lose their crab cages, snow crabs or the biggest beneficiaries.
As the habitat of right whales changes, they are also more exposed to the busiest shipping lanes in the North Atlantic, through which giant ships transport cargo across the Atlantic, and whale-ship collisions have begun to increase, so many large cargo ships also have observers to keep an eye on the location of right whales, but with little success, because even trained observers can hardly distinguish black right whales moving below the surface.
What can we do?
U.S. and Canadian maritime rescue teams help the whales untie their fishing ropes when the waves are calm and the whales are more cooperative, but after dragging long "attachments" through the water for weeks or even months, they often lose patience to be rescued, and even become agitated when the rescue boat approaches, quickly stirring the whirlpool and retreating into the sea.
图七 图源：the Florida Fish and Wildlife Conservation Commission
On the other hand, "ropeless fishing tackle" has begun to appear in fishing grounds everywhere, which can remotely recover fishing gear through sound signals, fishermen can send signals through handheld devices on the boat, and then set underwater fishing traps will release compressed air and return it to the surface, which directly reduces the possibility of fishing ropes encountering whales.
Figure 8 Source: CC BY-NC 2.0
However, for many fishermen, changing ancient fishing techniques that have lasted for thousands of years is too radical for most to accept.
But at least methodologically, we see a new dawn.
Bibliography:
1.Monitoring North Atlantic right whale Eubalaena glacialis entanglement rates: a 30 yr retrospective. Mar Ecol Prog Ser 466:293-302.
https://doi.org/10.3354/meps09923
2.Entanglement is a costly life-history stage in large whales
https://doi.org/10.1002/ece3.2615
United Nations Audiovisual Library of International Law
https://legal.un.org/avl/pdf/ha/icrw/icrw_c.pdf
3.How we all kill whales
https://doi.org/10.1093/icesjms/fsu008
4.Slow adaptation in the face of rapid warming leads to collapse of the Gulf of Maine cod fishery
DOI：10.1126/science.aac9819
Author: Yuyu
Winner of the Silver Award for Excellent Popular Science Works of China Popular Science Writers Association
Lovers of various fish heads, such as steamed fish heads and spicy fish heads
Editor-in-charge: Gollum
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