Market Squid, Doryteuthis opalescens
Market Squid Squid, Doryteuthis opalescens. Traditional product readily available for purchase at most of the of large food markets within Mexico. An exceptional bait utilized for bottom fish and flylinned on the surface. Length: 14 cm (5.5 inches).
Market Squid, Doryteuthis opalescens. An interesting catch with a cast net off one of the piers in Puerto Adolfo Lopez Mateos, Baja California Sur. Length: 12 cm (4.7 inches). Very large tentacles, produced an excessive amount of black ink, and underwent a significant number of color changes.
Market Squid, Doryteuthis opalescens. Caught from coastal waters off Long Beach, California, January 2019. Photograph and identification courtesy of Chris Wheaton, Fullerton, California.
Phylogeny: The Market Squid Doryteuthis opalescens (Barry, 1911), is a member of the Loliginidae Family of Pencil Squid. The genus Doryteuthis is one of ten genera in this family, and there are eight species in this genus. Market Squid are also known as the Common Squid, Pacific Loligo Squid and the Opalescent Inshore Squid and in Mexico as Calamar Comun.
Morphology: Market Squid have an elongate body, eight arms, two tentacles, large eyes, and an internal shell, know, as a gladius or pen. The pen is made of chitin and provides rigidity to the body, as well as an attachment point for muscles. The tentacles are modified arms that are longer than the arms, are retractile, and terminate in wide, flat lobes (tentacular clubs). The only suckers on the tentacles are located on the tentacular clubs. They have two rows of suckers along their arms, and four rows on the tentacular clubs. Fins are attached to the mantle and may be used for swimming, hovering, or maneuvering. Their bodies taper to a point, and are about 4 to 5 times longer than they are wide, and about 2.5 times longer than their arms. Their fins run about half the length of their body and unite posteriorly. The head has a tentacle pocket. Market Squid lack eyelids and instead have a transparent membrane covering the eye. They vary greatly in color, changing from translucent bluish white to gold, brown, or red. They can change color, and color patterns almost instantly. Squid are usually measured by mantle length, because it is so difficult to measure the tentacles accurately. Males are slightly larger than females, and have a mantle that is 19 cm (7.5 inches) in length.
Habitat and Distribution: Market Squid are generally pelagic, ranging from the surface to depths of 500 m (1,640 feet), with some sources extending this depth to 1,000 m (3,280 feet). They are strong vertical migrators, spending the day in deeper water and the nights near the surface. Once a year, they move, as large groups, into shallow water to spawn. Market Squid are a temperate Eastern Pacific species. They have a limited range in Mexican waters, only being found along the entire west coast of the Baja Peninsula. They are most common north of Punta Eugenia, Baja California Sur. They are absent from the Sea of Cortez. Market Squid paralarvae have been found in the Sea of Cortez as far north as Bahía de los Ángeles, Baja California.
Diet: Larval Market Squid feed on copepods and other plankton. Mature squid feed on amphipods, euphausiids, fish, shrimp and other squid.
Predators: Market Squid are preyed upon by sea birds, fish, toothed whales, sea lions, seals, and Sunflower Stars, Pycnopodia helianthoides. For defense mechanisms, they utilize camouflage, water-jet propulsion, and squirting ink.
Reproduction: Market Squid are gonochoric (male or female for life). They reproduce sexually. In male Pencil Squid, one of the arms is modified to carry sperm in an open groove. This arm is known as a hectocotylus. The male inserts this arm under the mantle of the female during reproduction, delivering packets of sperm (spermatophores). The female lays the fertilized eggs on to the sea floor substrate, in finger-like clusters. The male and female both die within weeks or months after mating.
Ecosystem Interactions: Market Squid are known to host endoparasitic bacteria and nematodes. There is no documentation of commensal or symbiotic relationships for this species. Market Squid are an important link in the food web from lower to higher trophic levels.
Human Interactions: Market Squid are highly sought after by commercial and recreational fishermen. They are the subject of one of the largest commercial fisheries in California. In the 2023 calendar year, more than 52 million pounds of market squid were landed in California, generating approximately $33 million. Those squid which survive predation and fishing activities die soon after spawning with their entire populations being replaced once a year. With high reproduction rates and rapid growth they are able to maintain healthy population levels. From a conservation perspective they are currently considered to be of Least Concern with stable widely distributed populations.
Synonyms: Loligo opalescens and Loligo sternsii.