Underwater World

Short-finned Squid

North American Atlantic coast

At a glance | Vital stats | Curiosities | Closeup | Feeding off each other

At a glance

The lifespan of the Short-finned squid may not be long, but in the space of 12 months this strange-looking cephalopod sure gets around. The squid travels great distances in search of warm spawning grounds—journeying from the Gulf Stream to the continental shelf and southward—fending off predators and competitors along the way.

Vital stats

Scientific name:
Illex illecebrosus
Taxonomy:
Cephalopod
Region:
North and South Atlantic coast —from Newfoundland and Labrador to Florida

Curiosities

Short-finned squid live for only one year. Their whole reason for being is to reproduce. Both males and females die when their roles in spawning are complete.

Closeup

About the Short-finned squid

Many people are familiar with the image of the Short-finned squid: large eyes (these creatures have good vision), eight arms and two retractable tentacles. Not including the arms and tentacles, the squid's body—called the mantle—is about 30 centimetres long. Females are typically larger than males.

In the early part their lives, Short-finned squid inhabit the Gulf Stream and feed on small crustaceans. As they grow and move onto the continental shelf, they add deep-sea fishes and Lantern fish to their diet. By the time they reach inshore areas these squid also eat Atlantic cod, Arctic cod, Atlantic herring and Sand eels. Short-finned squid eat more in the first four months of their lives than they do for the rest of their lives.

Lifecycle and reproduction

Although Short-finned squid may reproduce (or ‘spawn') at any point in the year, most do so during winter in the waters of the continental shelf south of Cape Hatteras. The minimum sea temperature for a Short-finned squid embryo to develop is about 13 degrees Celsius—but waters of 20 to 26 degrees Celsius are preferable.

Male squid insert packages of spermatophors into a female's body near the gills. The spermatophors are long spindles or bundles of sperm. Once the male has released its sperm, it dies.

The female carries the spermatophors with her for up to a few days. When the time is right, she expels her eggs through a funnel on her belly—the same funnel used to expel air to help her jet away from predators when threatened. As the eggs move through the funnel, the female uses here arms and tentacles to form one to three jelly-like masses. Each mass is a metre across and contains approximately 100,000 eggs. Like the male, when the female is done spawning, she dies.

The squid's fertilized egg mass is buoyant, meaning it floats in the water column. The Gulf Stream carries the mass northeast, away from the spawning area.

When first hatched, infant squid are called paralarvae. Unable to move on their own, they are easy prey for other species: the death rate among squid paralarvae is high.

Squid paralarvae are shaped like elephant trunks. They feed through this trunk until their body grows and their arms and tentacles separate—at which point they are able to move independently and begin their journey to the continental shelf.

The underwater world of the Short-finned squid

These animals play the roles of both predator and prey during their short lives. Atlantic cod and other squid species (such as the Long-finned squid) compete with the Short-finned squid for food. Atlantic cod also prey on them, as do swordfish, Bluefin tuna, various sharks (mostly the Dogfish shark), and pilot or pothead whales. While the Atlantic cod eats the squid early on, the squid becomes a predator of this species and, in turn, preys on its young.

Feeding off each other

As short-finned squid grow, their food needs increase. And if other sources are sparse, they eat each other.

Climate change

Changes in the conditions of the ocean as the result of recently rising temperatures and other environmental conditions have pushed large populations further north than they have been found in the past.

Revised: October 2009