Longfin Squid
The longfin squid (Doryteuthis pealeii), often called the “Woods Hole squid” by locals, has been helping scientists reveal the mysteries of neuroscience for decades. These animals are colorblind, but have special pigment and reflector cells in the skin (known as chromatophores) that can rapidly change color to camouflage. They have three hearts, two gills, and an ink sac.
Dorytheuthis grow quickly and die young. They reproduce right before they die (around six to eight months). The species spawns all year round, with peak production in the winter and summer. The female lays fertilized egg capsules that contain about 150-200 eggs in clusters that they attach to the ocean bottom. A typical female squid lays between 3,000 and 6,000 eggs, which go on to hatch between 11 and 26 days later depending on water temperature.
They are aggressive hunters, can consume fish larger than themselves, and are known to cannibalize other squid.
Type: Cephalopod
Habitat: Sandy sea floor
Range: From Newfoundland to the Gulf of Venezuela. In the northwest Atlantic Ocean, they are most abundant between Georges Bank and Cape Hatteras, North Carolina
Life Span in the Wild: six to nine months
Size: Usually around 12 inches in mantle legnth, with large individuals reaching up to 19 inches
Diet: Plankton, crustaceans, small fish, and other squid
Status: Species of least concern
Squid, like most other cephalopods, are quick. They move by sucking water into their mantle, squeezing the mantle and pushing the water out — basically, they’re jet propulsion-powered cephalopods. Partly controlling this action is a very large axon in the squid’s nervous system called the “squid giant axon,” which are long cable-like motor neurons that run from a specialized nerve bundle called a ganglion to the muscles in the mantle. Unlike the more complicated nervous systems in vertebrates, which are usually made up of billions of small neurons and axons, the squid giant axon can be up to 1.5 mm in diameter (though they’re typically around 0.5mm), making them an ideal way to study cellular neuroscience.
Doryteuthis pealeii, often called the “Woods Hole squid” by locals, is a longstanding model for cellular neuroscience, beginning with Nobel Prize winning research on nerve impulses in the 1950s. Studies with Doryteuthis pealeii have led to major advances in neurobiology, including description of the fundamental mechanisms of neurotransmission.
At the MBL, the longfin squid is used as a model organism to understand adaptive coloration, development, vision, and behavior. Like other cephalopods, Doryteuthis pealeii has the ability to extensively recode its own genetic information within messenger RNA. In summer of 2020, scientists at the MBL used CRISPR Cas-9 to knock out a target gene in Doryteuthis pealeii — a first for any cephalopod.
