Hagfish Day

What the day is

Hagfish Day is kept in late October. It was established by a marine conservation organization with an explicit point to make: conservation attention flows overwhelmingly to charismatic animals, and the unattractive ones are quietly allowed to disappear.

The hagfish was chosen as the test case because almost nobody finds it appealing.

Origin and background

Hagfish are among the oldest vertebrate lineages alive, with a body plan largely unchanged for hundreds of millions of years. They are eel-shaped, jawless, effectively blind, and they feed on the seafloor, including on the carcasses of large animals that sink there.

Their defense is genuinely extraordinary. When threatened, a hagfish releases a secretion from glands along its body that expands on contact with seawater into an enormous volume of slime, thousands of times the volume of the fluid released, within a fraction of a second. A predator that bites one gets its gills clogged and releases immediately. The slime is a composite of mucus and fine protein threads, and materials scientists have studied those threads seriously as a model for strong, biodegradable fibers.

The hagfish also ties itself into a knot and slides the knot down its body to scrape the slime off afterward, and uses the same motion for leverage when tearing food.

They matter ecologically as deep-sea recyclers, processing carcasses that would otherwise sit on the seabed. They are also fished commercially, both for food in Korea and for their skin, which is sold as eel leather, and some populations have been depleted.

How to take part

• Watch a video of the slime. It has to be seen to be believed and takes thirty seconds.
• Look up a genuinely unappealing threatened species and learn why it matters.
• Check whether any eel-skin item you own is actually hagfish. It usually is.
• Support marine conservation work that is not about whales, turtles or coral.
• Take the underlying point seriously: an ecosystem is not made of its photogenic members.