Lancetfish

May 09, 2023

Inside yesterday’s newspaper I found an article about the “freaky-looking” fish that are washing up on the Oregon coastline.  Several of these fish have appeared on the beaches of central Oregon.  Oregon State Parks has asked beachgoers to take a photo and post it online when they are found.  Ben Frable who manages the Marine Vertebrate Collection at Scripps Institution of Oceanography at the University of California San Diego said it is not uncommon for these fish to wash up on beaches of the California and Oregon coast.  It is unclear what is causing these deep-water fish to wash ashore, or if this is more frequent, or is just being noticed more due to social media.  The slinky bodies of the Lancetfish have sharp protruding teeth and a sail-like fin.  The gelatinous flesh makes the Lancetfish something humans do not wish to eat.

When I looked online, I found Lancetfish are large oceanic predatory fish in the genus Alepisaurus (“scaleless lizard”) in the monogeneric family Alepisauridae.  Lancetfish grow up to 6.6 feet (2 m) in length.  Very little is known about their biology, though they are widely distributed in all oceans, except the polar seas, although they have been recorded as far north as Greenland and Alaska’s Bering Sea.  They are often caught by vessels long-lining for tuna.  The generic name is from Greek meaning a – “without”, lepis meaning “scale”, and sauros meaning “lizard”.  There are two recognized extant species in this genus, the short-snouted lancetfish (Alepisaurus brevirostris) and the long-snouted lancetfish (Alepisaurus ferox).  The anatomic difference between the two species is the shape of the snout (surprise!).  The long-snouted lancetfish is found in the tropical and northern sub-tropical waters of the Pacific Ocean and the short-snouted lancetfish lives in the Atlantic Ocean’s tropics, subtropics, and in the southern sub-tropics of the Pacific Ocean.  A third species (Alepisaurus paronai) is found in the fossil record from the Middle Miocene-aged strata from Italy. 

Reports of finding Lancetfish on the beaches date back to the 19th century and the collection Frable manages contain fishes found on the beach.  This includes a lancetfish who shot out of the water near the institution where he works late in 2021 and was immediately mobbed by seagulls.  It was unclear whether that fish was pursuing small fish as a predator or being pursued by another predator like a sea lion.  Lancetfish swim at depths of more than a mile (1.5+ km) beneath the surface.  The person who found the 4 foot (1.2 m) long specimen on April 28th originally believed it to be a barracuda, but it did not seem right.  When she posted a photo on Twitter, she got an immediate response and identification.  Frable asked people to report any unusual sightings as it could provide researchers useful information.

Thoughts:  While Lancetfish move between the surface and the deep ocean (pelagic) waters, only about 2% of known marine species inhabit the pelagic (no light penetration) environment, or in the deep water column as opposed to organisms that live in or on the sea floor.  Trawling samples indicate lanternfish account for as much as 65% of all deep-sea fish biomass and are among the most widely distributed, populous, and diverse of all vertebrates with an estimated global biomass of 550–660 million metric tons, or several times the entire world fisheries catch.  However, there are only a few commercial lanternfish fisheries, and many regulatory agencies warn against eating these abundant fish.  They are found to feed on the small bits of plastic debris accumulating in the oceans.  Human waste and pollution extend beyond the depth of light.  Act for all.  Change is coming and it starts with you.