Gorgeous Giant Isopods! Episode 1

Come one and come all, to the first official episode of Weird Fish of the Week! Our first contender isn’t even a fish at all, please welcome the giant isopod!


INTRODUCTION:
The giant isopod (Bathynomus giganteus) was discovered in 1879 in the Gulf of Mexico by Alphonse Milne-Edwards, and scientists haven’t learned much about them since then. This interesting creature resembles other isopods found on land, such as wood lice or a rolly polly. And for good reason too, giant isopods share a distant relative to the crustaceans living away above water. These massive bugs live along the deep sea floor in the ocean’s benthic zone, from 170 m to 2140 m below the surface, and in most areas of the world.

Giant Isopod in the Gulf of Mexico, 2017. By the NOAA Office of Ocean Exploration and Research. From Flickr.

ANATOMY/PHYSIOLOGY:
The giant isopod sports an armored back seen in other crustaceans, meant to protect the creature from potential predators. They use their specialized tail called a uropod and their pleopod legs to swim around the depths. And living in such dark depths where there’s no light to be found, this 14-legged arthropod comes equipped with massive compound eyes containing 3,500 ommatidia, in addition to their long antennae used to feel their surroundings and hooked claws to grab onto the sea floor. Like their landlocked cousins, they possess the ability to curl up if frightened. What gives the giant isopod the ‘giant’ in its common name is the sheer size, larger specimens can range from 14-16 inches in length! This is thought to be a perfect example of deep sea gigantism, where creatures grow to exorbitant lengths the farther down they live. The largest of this genus and/or species can be found the deeper you go.

FOOD:

Deep sea isopods are carnivores, and like most deep sea creatures, scavenge on anything they can get (I’ve received reports that they may even eat slow moving live food!). However, due to the scarcity of food in the deep, these animals can survive extreme lengths of time without food (one isopod lasted 5 years!) in order to conserve energy. In turn, they’re prone to gorging themselves on food when they do find some, since it’s unknown when their next meal is. The typical giant isopod diet includes marine snow, decaying matter falling from the ocean’s surface, whale falls, crabs, fish, sponges, and sea cucumbers.

Isopods feast on an alligator corpse. Shot in the Gulf of Mexico by Louisiana Universities Marine Consortium

PERSONAL REVIEW:
I am a HUGE fan of these guys, I have a giant isopod plushie at home. They’re one of the first creatures that got me into deep sea biology specifically. I was enamored by this massive little bug creature swimming around the ocean floor without a care in the world. There’s something about the way they swim that is fascinating, and their size is nothing short of impressive. I give the giant isopod a solid 10/10!


That’ll be all, if you liked what you saw today be sure to do your own research and fall down the rabbit hole of giant isopods, you’ll be fascinated with what you see. See you next week!
(502 words)


References:

Monterey Bay Aquarium. (n. d.). Giant Isopod. Monterey Bay Aquarium.
https://www.montereybayaquarium.org/animals/animals-a-to-z/giant-isopod

Aquarium of the Pacific Online Learning Center. (n. d.). Giant Isopod. Aquarium of the Pacific. https://www.aquariumofpacific.org/onlinelearningcenter/species/giant_isopod

Krulwich, R. (2014, February 22). I Won’t Eat, You Can’t Make Me! (and They Couldn’t). NPR. https://www.npr.org/sections/krulwich/2014/02/22/280249001/i-wont-eat-you-cant-make-me-and-they-couldnt

Chamberlain, S.C., Meyer-Rochow, V.B. and Dossert, W.P. (1986), Morphology of the compound eye of the giant deep-sea isopod Bathynomus giganteus. J. Morphol., 189: 145-156. https://doi.org/10.1002/jmor.1051890205

Osterloff, E. (n.d.). Giant isopods: Curious crustaceans on the ocean floor. Natural History Museum. https://www.nhm.ac.uk/discover/giant-isopods-curious-crustaceans-on-the-ocean-floor.html