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The Rarest Fish in the World is an Anglerfish!

2020-04-17 · explainer · Hank · 3:58 · watch on YouTube

Topic: Science & nature · mode: Explainer · tags: recurring series

In a Bizarre Beasts video, Hank introduces John to the red handfish, an anglerfish of southeastern Australia that walks on hand-like fins, whose babies sink instead of dispersing; arguably the rarest fish on Earth, it may follow the smooth handfish into extinction, and its unknown reason for walking leads Hank to say we do not know almost everything.

What is said

The parts of the video and what is said in each (★ — how much it matters to the video).

00:00:00 — Being stuck to the land; flying, and air and water as fluids

  • ★★ Hank says land animals are stuck to the ground; flying adds a third dimension, and water is a denser fluid that its animals fly through. (playful) — 00:00:00
  • ★ Hank says the top-performing human can get about eight feet off the ground unassisted, only to come right back down. (playful) — 00:00:00

00:00:33 — The red handfish: walking on hand-like fins, two tiny populations, guarded eggs, babies that sink instead of dispersing

  • ★★ Hank says the red handfish can swim but almost never does; when it moves it walks across the ocean floor on modified, upsettingly hand-like fins. — 00:00:33
  • ★★ Hank says handfish, a kind of anglerfish, live in only one place in the world, southeastern Australia, and are not doing great. — 00:01:02 · Australia
  • ★★★ Hank says the red handfish is arguably the rarest fish on Earth. (hedged) — 00:01:02
  • ★★★ Hank says there are only two red handfish populations, each with fewer than 50 adults. — 00:01:02
  • ★★ Hank says handfish mothers guard their eggs from marauders for weeks, never leaving them until they hatch. — 00:01:02
  • ★ Hank says each time a clutch of red handfish eggs hatches, the world population of red handfish literally doubles. (playful) — 00:01:02
  • ★★ Hank says most fish use hatching for dispersal: the larvae become planktonic and let the ocean carry them, most to poor places, some to places where they thrive. — 00:01:31
  • ★★ Hank says, oddly, handfish babies are just smaller handfish with no swim bladders, so they simply sink to the bottom. — 00:01:31

00:02:00 — Extinction risk: the IUCN's single extinct marine fish, the smooth handfish, the Handfish Conservation Project

  • ★★★ Hank says the babies fall to the ground in the two isolated pockets where red handfish remain, which is not great for the species' survival. — 00:02:00
  • ★★ Hank says, to his amazement, the IUCN has classified only one marine fish as officially extinct. — 00:02:00
  • ★★ Hank says this does not mean no other marine fish have gone extinct; it reflects how little is known about the ocean. — 00:02:00
  • ★★★ Hank says the smooth handfish is known from a single museum specimen collected 203 years ago and, despite many surveys, has not been seen since. — 00:02:30
  • ★★ Hank says the red handfish could possibly share the smooth handfish's fate. (hedged) — 00:02:30
  • ★★ Hank says the Handfish Conservation Project is raising hatchlings in captivity to add genetic diversity to the two isolated populations and potentially reintroduce them to new habitats. — 00:02:30
  • ★★ Hank says there is a reason these little anglerfish walk instead of swimming, but we do not know it. — 00:02:30

00:03:13 — We do not know almost everything; facts are discovered by people; sign-off and thanks

  • ★★★ Hank says we do not know almost everything; we feel we do because of a tremendous bias toward the known, since we cannot know what is unknown. — 00:03:13
  • ★★★ Hank says making Bizarre Beasts reminds him that every astounding fact about nature was discovered or figured out by people, the most bizarre of beasts. — 00:03:13 · Bizarre Beasts
  • ★ Hank thanks the Handfish Conservation Project for help and footage and asks viewers to check out their work at handfish.org.au. — 00:03:44

In the description and comments

  • ★★ The description adds that surveys show handfish do not leave a 10-meter area in any given year of their life. — video description

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Mentioned

Central: handfish · red handfish

Also: anglerfish · Australia · biological dispersal · Bizarre Beasts · Handfish Conservation Project · Intellectual humility · International Union for Conservation of Nature · smooth handfish

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