People have occasionally glimpsed tailless whales in western North America, but a recent spike in sightings has troubled scientists. This year alone, at least three flukeless gray whales have been spotted near California. Ship collisions or killer whale attacks probably aren’t to blame for the injuries; entanglement in fishing equipment is likely the cause.
National Geographic reported that when whales are feeding in areas with debris, man-made objects or fishing gear, nets or ropes can get stuck at their tail’s base, slowly sawing off their flukes. Ropes and nets can also cut off blood circulation, causing a whale’s tail to wither away. Entangled whales may not survive, according to National Oceanic and Atmospheric Administration‘s (NOAA) California stranding network coordinator Justin Viezbecke. “The majority of them — if not all of them — are going to most likely die from these injuries,” Viezbecke said.
Losing a tail makes life difficult for whales. Feeding becomes a challenge; the limb serves as a propeller as they navigate to the seafloor and seek out crustaceans. The long migration from Mexico birthing grounds to Arctic feeding grounds can also be hard without a tail. Flukeless mother whales are less capable of defending their babies from killer whales.
According to whale biologist Alisa Schulman-Janiger, some whales can adapt to the handicap. Brooke Palmer — who posted a YouTube video of a tailless whale near Newport Beach, California earlier this year — said in the video description that the whale was doing “seemingly well as it adapted to the loss of an integral limb. It is sad, but inspirational how resilient and adaptive these beautiful mammals can be.”
The increase in tailless gray whale sightings matches up with what National Geographic called a general increase in whale entanglements. There was an average of 10 incidents a year between 2000 and 2012, but in 2017, there were 31 incidents, according to NOAA whale disentangler Pieter Folkens. Folkens said the reason behind the rise is unknown, although it could be possible that people are better at spotting the whales.