Loligo pealeii

Geographic Range

Loligo pealeii is found from Newfoundland to the Gulf of Venezuela, migrating to different places to spawn. Among other places, these squid migrate to the Cape Cod area during the Spring and are also known as Woods Hole squid because they are studied at the Marine Biological Laboratory in Woods Hole, Massachusetts (Marine Biological Laboratory,2000).


This species lives in the waters along the eastern continental shelf of North America, and in the Gulf of Mexico. In comes into shallow waters near shore to lay eggs. (Marine Biological Laboratory, 2000)

Physical Description

These medium-sized squid grow to about 50 cm long. Like all squid, they have ten arms (eight of which are the same length, and one pair used for grabbing prey are longer) and three hearts (two close to their gills) so that they "can pump oxygen to the rest of the body easily." Their speed and maneuverability have earned them the description of "invertebrate athletes" (Squids,2000; Ellis, 34).


Males court females (there is much communication by flashing skin colors), and if accepted by a female, use a modified arm (called a hectocotylus) to transfer a package of sperm called a spermatophore to the female. Females produce packets of about 200 eggs, and stick them to the sea floor in large groups with other females. Sometimes "sneaker" males lurk around the eggmasses, darting in to add their sperm as females lay their eggs. (MBL 2000)


Among other things, one of the most interesting behaviors studied in Longfin inshore squid is their celebrated ability to change color and color patterns instantly. It is thought that as well as using this color/pattern transformation as a defense mechanism, it is also a communication technique which may be employed in courtship.

Food Habits

Loligo pealeii is carnivorous. Its diet includes chaetognaths, crustaceans, decapod shrimp, fishes, polychaetes, other squid, and euphausids.

Economic Importance for Humans: Positive

This species of squid is very important to fishing industries throughout the world, including the United States, where a big market exists for this animal in both commercial and recreational fishing. In commercial fishing, Longfin inshore squid are sold to restaurants and other stores. In recreational fishing they serve as bait to catch to fish such as Mahi-mahi, Swordfish, and Marlins (Cadrin 2000, von der Linden et al. 1998).

Loligo pealeii is also used as specimen in neurobiology research. Its neurons, one thousand times larger than their counterparts in humans, have provided scientists ample opportunity to study such things as sodium and potassium ion pumps. The study of these neurons has helped scientists better understand heart disease, cancer, Alzherimer's Disease, and kidney disease (Marine Biological Laboratory, 2000).

Conservation Status

This species is vulnerable to overfishing, and the U.S. National Oceanic and Atmospheric Administration's Northeast Fisheries Center has helped establish catch limits to protect the population (Cadrin 2000).


Martha Rodriguez (author), Fresno City College, Jerry Kirkhart (editor), Fresno City College.


Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


the nearshore aquatic habitats near a coast, or shoreline.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

native range

the area in which the animal is naturally found, the region in which it is endemic.


Cadrin, S. "Longfish Inshore Squid" (On-line). Accessed April 3, 2001 at

Ellis, R. 1998. The Search for the Giant Squid. New York: The Lyons Press.

Feldman, G. "Squid: Variations on a theme" (On-line). Accessed October 25, 2000 at

Hickman, Jr., C., L. Roberts, A. Larson. 2001. Integrated Principles of Zoology, 11th Edition. New York: McGraw-Hill Companies.

Lackner, C. "Squids" (On-line). Accessed October 25, 2000 at

Marine Biological Laboratory, "Loligo pealei: the Long-finned Squid" (On-line). Accessed April 3, 2001 at

Marine Biological Laboratory, March 12, 2000. "Scientists study nerve cells of squid to learn more about a crucial cellular machine" (On-line). Accessed October 25, 2000 at

Morris, R., D. Abbott, E. Haderlie. 1980. Intertidal Invertebrates of California. Stanford, CA: Stanford University Press.

Vecchione, M. 1996. "Loligo Lamarck 1798" (On-line). Accessed April 3, 2001 at

Wood, J. 2001. "The Cephalopod Page" (On-line). Accessed April 3, 2001 at

von der Linden, B., P. Farrand, G. Myers. October 30, 1998. "Use and Exploitation of Marine Invertebrates" (On-line). Accessed November 2, 2000 at