Sepia apama

Geographic Range

Sepia apama , known as the Australian giant cuttlefish, derives its common name from its geographical origin and nativity, Australia. More specifically, it lives in the coastal waters and bays extending from Ningaloo and Pointes Cloates in Western Australia, across Australia’s southern coast, and northward along the eastern coast to Shoalwater Bay in Queensland. Outside Australian waters, the cuttlefish is also native to the east Indian Ocean, and islands within the southwest Pacific Ocean.

• Biogeographic Regions
• indian ocean
  • native native
• pacific ocean pacific ocean
  • native native

Habitat

Sepia apama inhabits coral reefs, rocky reefs, kelp forests, seagrass meadows, muddy and sandy areas. In general, cuttlefish live in shallow seas where sunlight is abundant and biomass of primary production is high.

• Habitat Regions
• tropical tropical
• saltwater or marine saltwater or marine

• Aquatic Biomes
• benthic benthic
• reef reef
• coastal coastal

Physical Description

Sepia apama has a bulky body, with 10 appendages (8 short, heavy arms, and 2 larger extensible tentacles), highly developed eyes, and a reddish-brown skin with white spots on the arms and mantle. Along each side of the body, a long, pale lateral fin extends the length of the mantle; these fins are used in maneuvering. Cephalopods’ bodies are streamlined, making them efficient at swimming. In addition to their swimming abilities, they have the ability to change colors by the means of contracting or expanding pigments in special cells called chromatophores, located in the skin.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Development

The development of S. apama is exhibited through two alternative life cycles for both females and males. One life cycle encompasses 7 to 8 months to reach maturity during the first summer; during this time, rapid juvenile growth takes place. In contrast to the first life cycle, the second alternative involves slower juvenile growth during the summer; instead of reaching maturity within 7 to 8 months, the cuttlefish reaches maturity within the second year.

Reproduction

Reproduction in the giant cuttlefish is promiscuous, characterized by large spawning aggregations, multiple mating and paternities, potential sperm competition, and female choice. Males elaborately use their color changing abilities to attract female males by flashing their chromatophores. Less dominant males disguise themselves by assuming female coloration and can "hide" among females until they find an opportunity to mate when the dominant males are distracted (the "sneaker male" reproductive phenomenon).

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

As in all cephalopods, fertilization is internal, with the male transferring spermatophore packets into the female's mantle cavity using a specially modified arm called the hectocotylus. A female may mate several times with multiple males during a spawning aggregation. As the female spawns, the eggs are fertilized by sperm from the spermatophores that the male has attached near her oviduct, inside her mantle cavity. Cuttlefish do not feed during the breeding season, and after breeding, individuals die.

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

After the egg capsules have been laid, the female cuttlefish abandons them and dies shortly after, so there is no further parental investment.

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

Lifespan/Longevity

This species is a terminal spawner. Individuals mature in one year and die after breeding, though there are reports of individuals having lived 2 years.

Behavior

Many aspects of the giant cuttlefish’s behavior can be observed through its dynamic ability in changing colors and patterns. While S. apama is generally solitary, they interact with conspecifics during mating season, when males attract females by flashing their chromatophores. Though cuttlefishes are colorblind, they can camouflage themselves in total darkness within seconds. This instantaneous skill is possible by blending simple colors in order to form a great variety of hues in conjunction with a layer of cells called leucophores, which reflect white light. The leucophores allow cuttlefishes to blend in with their environment by precisely matching the ambient light level and color without the animal even needing to use their eyes to detect the color environment around it. This species may display an innate curiosity towards SCUBA divers.

Radiotracking studies of this species reveal that individuals spend more than 95% of the day resting, which suggests that they do not actively forage for food, but instead are lie-and-wait predators.

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• solitary solitary

Home Range

Individuals do not seem to migrate daily or seasonally, except to return to their spawning grounds. Radiotracking studies revealed that one individual moved 65 km to return to the spawning aggregation in Spencer Gulf.

Communication and Perception

Sepia apama is usually a solitary animal, but they communicate with other cuttlefishes during mating season. Even though a giant Australian cuttlefish has highly developed eyes, individuals are color blind. However, they communicate by contracting the chromatophores in their skin. Their perception of their surroundings is unmatchable due to the chromatophores and leucophores in their skin.

• Communication Channels
• visual visual
• tactile tactile

• Other Communication Modes
• mimicry mimicry

• Perception Channels
• visual visual
• tactile tactile
• vibrations vibrations
• chemical chemical

Food Habits

Small fish and crustaceans form the diet of this cuttlefish. When cuttlefishes are catching prey, they approach slowly and stealthily. When they are within striking distance, they thrust out their two tentacles (which are tucked away in a pouch located under their eyes) and seize their food in a fast, rapid motion. The tentacles then contract, bringing the prey item to the mouth, where the cuttlefish's arms enclose it. Cuttlefish also use their beaks to crack the shells of prawns and crabs, and their radula, lined with teeth, scrapes tissue so it can be swallowed.

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

• Animal Foods
• fish
• aquatic crustaceans

Predation

The unparalleled camouflaging ability of cuttlefish is their primary defense against predators. Not only are cuttlefish masters of color manipulation, but they also excel at changing the textural appearance of their integument. Unsurprisingly, this talent goes hand-in-hand with their ability to change body color, but they take their disguises to the next level by changing their body shape. Contraction of circular muscles in the integument allows the animal to “sculpt” their skin into different textures that resemble seaweed, debris, and other elements of the background environment, making the outline of their bodies less conspicuous. Nevertheless, they can fall prey to seabirds and marine mammals such as bottlenose dolphins.

• Anti-predator Adaptations
• mimic
• cryptic cryptic

Ecosystem Roles

The Australian giant cuttlefish is a secondary and tertiary consumer in the neritic ecosystem; their feeding activities help regulate the populations of their fish and crustacean prey. The cuttlefish in turn serves as prey for sea birds, sharks, dolphins, and pinnipeds.

Sepia apama is known to host dicyemid parasites (phylum Rhombozoa : Dicyemida ) within the organs of its renal system.

Economic Importance for Humans: Positive

The main economic utilization of S. apama is as food and bait. They are caught incidentally as by-catch in trawl fisheries, and on a small-scale using jigs, hooks, and spears. The inner shells ("cuttlebones") are used in the pet trade; captive birds like parakeets, parrots ( Psittaculidae ) and canaries (genus Serinus ) use the soft, calcareous material to clean and sharpen their beaks. The spawning aggregations that occur annually in Spencer Gulf, South Australia attract hundreds of divers, scientists, and ecotourists to view this spectacular event.

• Positive Impacts
• food food
• body parts are source of valuable material
• ecotourism ecotourism

Economic Importance for Humans: Negative

There are no known adverse effects of Sepia apama on humans.

Conservation Status

Sepia apama is characterized as "near threatened" by the IUCN, with a decreasing population. This is due to intense fishing in a few areas that have significantly decreased the population. While localized, since this species lives for only a couple years, and dies shortly after reproducing, the stability of their species could be significantly impacted if too many cuttlefish are removed. To combat this, the locations where S. apama aggregates to spawn annually in northern Spencer Gulf, South Australia, have been under management protection since 1998, when the area was closed to fishing.

Additional Links

Encyclopedia of Life

Contributors

Dianne Aglibot (author), San Diego Mesa College, Paul Detwiler (editor), San Diego Mesa College, Angela Miner (editor), Animal Diversity Web Staff.

References

Aitken, J., R. O'Dor, G. Jackson. 2005. The secret life of the giant Australian cuttlefish Sepia apama ( Cephalopoda ): behaviour and energetics in nature revealed through radio acoustic positioning and telemetry (RAPT). J. Exp. Mar. Biol. Ecol , 320: 77-91.

Barratt, I., L. Allcock. 2012. " Sepia apama " (On-line). The IUCN Red List of Threatened Species. Version 2014.2. Accessed July 26, 2014 at http://www.iucnredlist.org/details/162627/0 .

Beeton, R. 2011. "Advice to the Minister for Sustainability, Environment, Water, Population and Communities from the Threatened Species Scientific Committee (the Committee) on Amendment to the list of Threatened Population under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)" (On-line pdf). Accessed October 20, 2013 at http://www.environment.gov.au/biodiversity/threatened/species/pubs/69365-listing-advice.pdf .

Catalano, S. 2013. Five new species of dicyemid mesozoans ( Dicyemida : Dicyemidae ) from two Australian cuttlefish species, with comments on dicyemid fauna composition. Systematic Parasitology , 86/2: 125-151.

Hansford, D. 2013. "Cuttlefish Change Color, Shape-Shift to Elude Predators" (On-line). Accessed October 10, 2013 at http://news.nationalgeographic.com/news/2008/08/080608-cuttlefish-camouflage-missions.html .

Karleskint, G., R. Turner, J. Small. 2013. Introduction to Marine Biology, Fourth Edition . Belmont, CA: Brooks/Cole, Cengage Learning.

Martin, N. 2010. "Species Spiels: Giant Australian Cuttlefish ( Sepia apama )" (On-line). Accessed November 13, 2013 at http://www.fishabout.com.au/news/article/species-spiels/giant-australian-cuttlefish-sepia-apama-by-nick-martin/ .

Naud, M., R. Hanlon, K. Hall, P. Shaw, J. Havenhand. 2004. Behavioural and genetic assessment of reproductive success in a spawning aggregation of the Australian giant cuttlefish, Sepia apama . Animal Behaviour , 67/6: 1043-1050.

Norman, M., A. Reid. 2000. A Guide to Squid, Cuttlefish and Octopuses of Australasia . Victoria (Collingwood): CSIRO Publishing.

Norman, M. 2000. Cephalopods - A World Guide . Germany (Hackenheim): ConchBooks.

Norman, M. 2007. "Species Bank" (On-line). Accessed September 22, 2013 at http://www.environment.gov.au/cgi-bin/species-bank/sbank-treatment2.pl?id=69365 .

Payne, N. 2010. Approaches to Understanding the Population Dynamics and Behaviour of Sepia apama in Northern Spencer Gulf . University of Adelaide, South Australia: Unpublished thesis. Accessed December 12, 2013 at http://digital.library.adelaide.edu.au/dspace/bitstream/2440/69711/1/02whole.pdf .

2013. "BBC Nature - Giant cuttlefish videos, news, and facts" (On-line). Accessed September 22, 2013 at http://www.bbc.co.uk/nature/life/Australian_Giant_Cuttlefish .

2013. "Fisheries | Cuttlefish" (On-line). Accessed September 10, 2013 at http://www.pir.sa.gov.au/fisheries/recreational_fishing/target_species/cuttlefish .

Department of the Environment and Water Resources. Molluscs of commercial, recreational, cultural and ecological significance. 4.12. Kingston, Tasmania: Commonwealth of Australia. 2006. Accessed December 12, 2013 at http://www.researchgate.net/publication/235223445_The_south-west_marine_region_ecosystems_and_key_species_groups_Report_prepared_for_the_National_Oceans_Office/file/60b7d51584b149ae62.pdf#page=259 .