PORT PHILLIP BAY


Southern Keeled Octopus 

Octopus berrima Stranks & Norman, 1992

View scientific description and taxonomy

Scientific Details

Eight circumoral appendages; eight arms, ventrolateral tentacles absent. Mantle cavity with one opening to exterior. Arms with numerous suckers, without horny, toothed rims. Fins absent. Dorsal border of mantle fused with head. Moderate sized species. Arms of moderate length, two to four times mantle length. Lateral arms longest (typically 3=2>4>1). Webs deep, deepest to 30% of arm length. Web deepest on lateral arms, shallowest between dorsal arms. Suckers biserial; enlarged suckers absent. Gills with seven to eight lamellae per demibranch. Funnel organ VV-shaped, limbs approximately equal length. Funnel locking apparatus absent. Ink sac present. Right third arm of males hectocotylised, length 70 to 100% of opposite arm length. Ligula large, tapering, 11 to 16% of arm length. Calamus of moderate size, 15-20% of ligula length. Hectocotylized arm with 66-78 suckers Eggs large, length 10 to 14 mm.
Colour cream to mottled orange-brown. Transverse pair of large white spots present on dorsal mantle. White bar present between eyes. Skin texture of regular and small rounded patches. Scattered small, unbranched papillae over dorsal surfaces. Single small papilla over each eye. Skin ridge around lateral margin of mantle ("lateral ridge") present.
Maximum mantle length 105 mm, total length to around 360 mm.

Taxonomy

Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Coleoidea
Order:
Octopoda
Suborder:
Incirrata
Family:
Octopodidae
Genus:
Octopus
Species:
berrima

General Description

Moderate-sized, muscular octopus. Body oval-shaped and rimmed around the sides by a raised skin ridge or keel. Colour generally cream to mottled orange-brown with a transverse pair of large white spots on the dorsal mantle and a white bar between the eyes. Skin covered in regular small low bumps. Fingers of skin (papillae) can be raised above the eyes and over the body. Maximum mantle length 11 cm, total length to around 36 cm.

Biology

This octopus emerges at night to forage over the sand for crabs and other crustaceans. During the day it buries in the sand or hides in shells or human refuse (such as discarded bottles). When buried it can raise one eye like a periscope above the level of the sand to check for predators before emerging. The common name of this octopus refers to the ridge of skin around the edge of the body, which may aid in gliding the octopus under the sand when it buries. This octopus buries close to the sand surface so that it can still draw clean water in to its gill cavity in order to gain oxygen. Courtship consists of males standing on their arm tips and flaring the webs as they approach females. They quickly grab the females and use their long thin modified arm tip on the third right arm to pass sperm packages into the female's oviducts. Females lay large single eggs that are attached singly to hard surfaces such as shells or human refuse. The young are well developed at hatching and immediately start foraging on the sea floor. This octopus is caught in low quantities in baitless pot fisheries in bays and inlets in South Australia and Victoria. It is sold for human consumption and as bait.

Habitat

Sand and mud substrates in coastal waters to depths of at least 250 m.

Soft substrates

Distribution guide

Southern Australia.

Species Group

Octopuses and allies Octopuses

Depth

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

Water Column

On or near sea floor

Max Size

36 cm

Diet

Carnivore

Harmful

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

Commercial Species

No

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, Southern Keeled Octopus, Octopus berrima, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 25 Sep 2017, http://portphillipmarinelife.net.au:8098/species/4006

Text: creative commons cc by licence