PORT PHILLIP BAY


Luminous Bay Squid 

Uroteuthis noctiluca (Lu et al., 1985)

View scientific description and taxonomy

Scientific Details

Ten circumoral appendages, eight arms and two ventrolateral tentacles. Mantle cavity with three openings to exterior. Arms and clubs at the tips of the tentacles with numerous suckers, each armed with a horny, toothed rim. Tentacles contractile but not retractile, no pockets between arms III and IV. Mantle edge near mantle cartilages with small projections or 'angles'. Fins united at posterior end of mantle. Dorsal border of mantle free (unfused) from head. Non-hectocotylised arm sucker arrangement biserial. Left ventral arm of males hectocotylised along entire length, suckers modified into conspicuous elongate interconnected papillae with minute apical suckers. Tentacle club with four suckers in transverse rows. Internal shell straight, feather-shaped, chitinous.
Colour pattern of large black, brown and orange chromatophores over a transparent background.
Mantle length to 90 mm, total length to 130 mm.

Taxonomy

Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Coleoidea
Order:
Teuthida
Suborder:
Myopsida
Family:
Loliginidae
Genus:
Uroteuthis
Subgenus:
Aestuariolus
Species:
noctiluca

General Description

Small squat, cylindrical, free-swimming squid. Two large rounded fins on sides of body encompassing the rear half of its length. Fins joined at rear tip to form overall heart shape. Colour pattern of large black, brown and orange dots (chromatophores) over a transparent background. Mantle length to 9 cm, total length to 13 cm.

Biology

This small squid is very tolerant of low salinities allowing it to forage in estuaries and brackish water. It is most active at night hunting for crustaceans and fish. The common and scientific names of this squid refer to its light-producing abilities (bioluminescence). Within its gill cavity it has two special light organs that contain living bacteria. The bacteria are fed sugars by the squid in return for producing light. The squid uses this light to hide its silhouette when it is swimming around at night. It lets out just enough light to match the background moonlight or starlight, effectively hiding it from fish predators waiting below. Little is known of reproduction in this species. The adult male has a special modified lower left arm where the suckers have been replaced by rows of fingers of skin. This arm may help pass sperm packages to the female or may be used to remove the sperm of previous males. This squid is caught incidentally in inshore trawls, at least in north-east Australia. It can be confused with the juveniles of the larger more commercial squid species. It is short-lived (at least in northern Australia), living only 70 days.

Habitat

Shallow coastal habitats particularly around seagrass beds to depths of around 50 m.

Seagrass meadows

Distribution guide

Eastern Australia.

Species Group

Octopuses and allies Squid

Depth

Shallow (1-30 m)
Deep ( > 30 m)

Water Column

Midwater

Max Size

13 cm

Diet

Carnivore

Harmful

Potential to bite, especially if handled. Venom status unknown.

Commercial Species

Yes

Global Dispersal

Native to Australia

Identify

Conservation Status

  • DSE Advisory List : Not listed
  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not listed

Author

article author Finn, J.K.

Dr. Julian Finn is a Senior Curator of marine invertebrates at Museum Victoria.

Author

article author Norman, M.

Dr. Mark Norman is Head of Sciences at Museum Victoria.

citation

Cite this page as:
Finn, J.K. & Norman, M., 2011, Luminous Bay Squid, Uroteuthis noctiluca, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 19 Oct 2017, http://portphillipmarinelife.net.au:8098/species/7305

Text: creative commons cc by licence