Animal Diversity Web

Ge­o­graphic Range

Loligo forbe­sii is found on all British and Irish sea coasts, the Mediter­ranean Sea, the Red Sea, the East African coast, through­out the At­lantic Ocean around many is­lands, and es­sen­tially in all open coast areas. Mi­gra­tion is sea­sonal among the species and cor­re­sponds to the breed­ing sea­son. (Grz­imek, 1972; Wil­son, 1999)

• Biogeographic Regions
• atlantic ocean
  • native

Habi­tat

Long-finned squid are found in ma­rine habi­tats, usu­ally near sandy and muddy sea bot­toms, but also quite often in clean, coarse sand on the ocean bot­tom. Loligo forbe­sii live in wa­ters with a nor­mal oceanic salin­ity con­tent, usu­ally near-shore re­gions with warm and rarely cool water, never very cold water. (Grz­imek, 1972; Wil­son, 1999)

• Habitat Regions
• temperate
• tropical
• saltwater or marine

• Aquatic Biomes
• coastal

• Range depth

  10 to 500 m

  32.81 to 1640.42 ft

Phys­i­cal De­scrip­tion

These cephalopods have eight "nor­mal arms," along with a pair of re­trac­tile arms with clubbed suck­ers on the ends. Their tor­pedo-shaped, stream-lined bod­ies with ter­mi­nal fins often ap­pear some­what blunter and wider as their depth in­creases, and en­close a thin mem­bra­ne­ous in­ter­nal shell. The two fins com­prise a length of ap­prox­i­mately two-thirds of the or­gan­ism's body and pro­duce a di­a­mond-shape when seen from the dor­sal view. These squid have well-de­vel­oped heads with large eyes that are use­ful in pre­da­tion. These squid pos­sess col­ors and stripes; col­ors change dur­ing the es­cape mech­a­nisms to a pink, red, or brown hue. ("Squids, cut­tle­fishes, oc­to­puses", 1967; Ban­is­ter and Camp­bell, 1985; Wil­son, 1999)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Range length

  12 to 90 cm

  4.72 to 35.43 in

• Average length

  40 cm

  15.75 in

De­vel­op­ment

The yolky eggs un­dergo di­rect de­vel­op­ment with­out the pres­ence of a true lar­val stage. The eggs are laid in large col­or­less cap­sules dur­ing the night. The swollen cap­sules shrink as the em­bryos de­velop and, after ap­prox­i­mately thirty days of em­bry­onic de­vel­op­ment, the young hatch, re­sem­bling minia­ture adults, about 5 to 7mm in length. The young main­tain a ver­ti­cal body struc­ture for a pe­riod of time, float­ing and drift­ing sub­mis­sively through the water. Growth oc­curs rapidly for the young dur­ing the sum­mer, and the species is sex­u­ally ma­ture be­tween the months of June and Oc­to­ber. After 1 to 1.5 years, the adults die, com­plet­ing the life cycle. (Grz­imek, 1972)

Re­pro­duc­tion

Re­pro­duc­tive be­hav­ior and spe­cific mat­ing rit­u­als are lim­ited to the act of con­gre­gat­ing on the bot­tom of the sea be­fore fer­til­iza­tion. For re­pro­duc­tion, mem­bers of Loligo have fused, un­paired go­nads lo­cated at the pos­te­rior ends of their bod­ies. Spe­cial­ized glands of the fe­male pro­vide sub­stances for egg cov­er­ings and open into the man­tle cav­ity. This species col­lects in large num­bers on the ocean bot­tom and pro­duces huge masses of gelati­nous spawn. The spawn are at­tached to solid ob­jects on the ocean bot­tom.

Male squid gather sperm into a sper­matophore car­ried on a spe­cial­ized ten­ta­cle, called a hec­to­coty­lus. This ten­ta­cle is used to trans­fer the sper­matophore to the fe­male's man­tle cav­ity, and is pos­si­bly bro­ken off there. The an­te­rior por­tion of the sper­matophore has a gelati­nous sub­stance that dis­charges ex­plo­sively upon con­tact with the fe­male glan­du­lar stuc­ture. The sperm are then re­leased into the man­tle cav­ity to pur­sue the rather large, yolky eggs. ("Squids, cut­tle­fishes, oc­to­puses", 1967; Ban­is­ter and Camp­bell, 1985; Grz­imek, 1972)

• Mating System
• monogamous

Fe­males lay up to 100,000 eggs at­tached to sea floor sub­strates. Sex­ual ma­tu­rity is reached about one year after hatch­ing. Al­though it is pos­si­ble for squid to re­pro­duce more than once, they most often don't be­cause of their lim­ited lifes­pan.

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • internal
• oviparous

• Breeding interval

  Breeding occurs yearly.

• Breeding season

  Loligo forbesii breed from autumn through spring.

• Range number of offspring

  1000 to 100000

• Average number of offspring

  5000-32000

• Range age at sexual or reproductive maturity (female)

  11 to 14 months

• Range age at sexual or reproductive maturity (male)

  11 to 14 months

Fe­males pro­vide their eggs richly with yolk. There is no fur­ther parental in­vest­ment.

• Parental Investment
• pre-fertilization
  • provisioning
• pre-hatching/birth
  • provisioning
    • female

Lifes­pan/Longevity

The long-finned squid lives ap­prox­i­mately 1-2 years in or out of cap­tiv­ity, three years at the most. Nat­ural causes are the com­mon cause of death; adults usu­ally die after a mere year and a half. It is very com­mon for squid to be eaten by preda­tors, ex­plain­ing why num­bers in schools of squid are dra­mat­i­cally re­duced dur­ing and after mi­gra­tion, falling prey to their preda­tors. Can­ni­bal­ism is also a very com­mon cause of death of in­di­vid­u­als. The large num­ber of eggs pro­duced more than com­pen­sates for the high mor­tal­ity rate. (Wil­son 2001, Grz­imek 1972)

• Range lifespan
  Status: wild

  1 to 3 years

• Average lifespan
  Status: wild

  1-2 years

• Range lifespan
  Status: captivity

  1 to 3 years

• Average lifespan
  Status: captivity

  1-1.5 years

• Typical lifespan
  Status: wild

  1 to 2 years

• Average lifespan
  Status: wild

  1-1.5 years

• Typical lifespan
  Status: captivity

  1 to 3 years

• Average lifespan
  Status: captivity

  1-2 years

Be­hav­ior

Loligo forbe­sii moves through the water by ad­just­ing buoy­ancy through gas ex­change, as well as by using jet propul­sion through man­tle con­trac­tions. Loligo forbe­sii leads a rather soli­tary life, only in­ter­rupted dur­ing breed­ing sea­son and when they form large schools to mi­grate. Mass con­cen­tra­tions of long-finned squid near coasts are spawn­ing mi­gra­tions. These in­ver­te­brates, like oth­ers in the class Cephalopoda, demon­strate an abil­ity to learn. (Grz­imek, 1972)

• Key Behaviors
• natatorial
• motile
• migratory
• solitary

Com­mu­ni­ca­tion and Per­cep­tion

Lit­tle is known of com­mu­ni­ca­tion among Loligo forbe­sii, yet the most pre­dom­i­nate com­mu­ni­ca­tion and per­cep­tion chan­nel is vi­sual, using their large, well-de­vel­oped eyes to rec­og­nize sexes for mat­ing, prey for eat­ing, and so forth. (Nichols and Cooke, 1971)

• Communication Channels
• visual
• tactile

• Perception Channels
• visual
• tactile

Food Habits

Loligo forbe­sii usu­ally feeds on or­gan­isms smaller than it­self, in­clud­ing her­ring and other small fish, crus­taceans, other cephalopods, and poly­chaetes, among oth­ers. Can­ni­bal­ism is also com­mon among the species. ("Ceph­Base", 1998-2001; Wil­son, 1999)

• Primary Diet
• carnivore
  • piscivore
  • eats non-insect arthropods

• Animal Foods
• fish
• mollusks
• aquatic or marine worms
• aquatic crustaceans
• other marine invertebrates

Pre­da­tion

Long-finned squids have a mus­cu­lar bag be­hind the head which con­tains the or­gan­ism's gills that pro­vide rapid jet-propul­sion used to es­cape preda­tors. When the squid re­tracts back­wards by use of the jet-propul­sion, the body quickly changes to a much lighter color, and a bag of pig­ment opens into the man­tle cav­ity that emits a large black cloud, con­fus­ing the preda­tor. (Berg, et al., 1999; Nichols and Cooke, 1971)

• Known Predators

  • toothed whales (Odontoceti)
  • sharks and rays (Chondrichthyes)
  • penguins (Spheniscidae)
  • larger fish (Actinopterygii)
  • seals (Phocidae)
  • other squid (Cephalopoda)

Ecosys­tem Roles

Squid are im­por­tant as a food base for oceanic preda­tors, as well as being im­por­tant preda­tors of smaller ma­rine ver­te­brates and in­ver­te­brates.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Aside from the ob­vi­ous use of squid as food, re­search, and ed­u­ca­tion, an un­usual use of these squid is for jew­elry: many prim­i­tive tribes use the hooked rings of the species' suc­tion cups for rings. Loligo forbe­sii is also used as fish bait and fish-meal pro­duc­tion in the Mediter­ranean. (Grz­imek, 1972)

• Positive Impacts
• food
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

This species is very com­mon dur­ing spe­cific times of the year in nearshore wa­ters and may prey on small fish and her­ring im­por­tant to nearshore fish­eries. How­ever, squid are also eco­nom­i­cally im­por­tant to hu­mans. (Grz­imek, 1972; Nichols and Cooke, 1971)

Con­ser­va­tion Sta­tus

Loligo forbe­sii is abun­dant and is not threat­ened.

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Rae Tay­lor (au­thor), South­west­ern Uni­ver­sity, Stephanie Fab­ri­tius (ed­i­tor), South­west­ern Uni­ver­sity.

Ref­er­ences

1998-2001. "Ceph­Base" (On-line). Ac­cessed Sep­tem­ber 14, 2001 at http://​www.​cephbase.​utmb.​edu/​spdb/​speciesc.​cfm?​CephID=229.

1967. Squids, cut­tle­fishes, oc­to­puses. Pp. 93-94 in The Larousse En­cy­clo­pe­dia of An­i­mal Life. Lon­don: Mc­Graw-Hill Book Com­pany.

Ban­is­ter, K., A. Camp­bell. 1985. Mol­lusks. Pp. 255-270 in The En­cy­clo­pe­dia of Aquatic Life. New York, NY: Facts of File Pub­li­ca­tions.

Berg, L., D. Mar­tin, E. Solomon. 1999. Bi­ol­ogy. Or­lando, FL: Har­court Brace Col­lege Pub­lish­ers.

Grz­imek, B. 1972. Mol­lusks. Grz­imek's An­i­mal Life En­cy­clo­pe­dia, Vol. 3: Mol­lusks & Echin­o­derms. New York, NY: Van Nos­trand Rein­hold Com­pany.

Nichols, D., J. Cooke. 1971. The Ox­ford Book of In­ver­te­brates. Ox­ford: Ox­ford Uni­ver­sity Press.

Wil­son, E. 1999. "Mar­LIN: The Ma­rine Life In­for­ma­tion Net­work for Britain & Ire­land" (On-line). Ac­cessed Sep­tem­ber 14, 2001 at http://​www.​marlin.​ac.​uk/​species/​Loligoforbesii.​htm.