Cuttlefish

Sepia spp

Cuttlefish update – news from the cross-agency Cuttlefish Working Group

Cuttlefish update - Issue 1: 24 April 2013 (PDF 343.4 KB pdf)

Cuttlefish decline at Point Lowly information

Find out what is being done to determine the cause for the decline in the Giant Cuttlefish population at Point Lowly.

Cuttlefish information

What are they?
Habitat
Movement
Feeding
Predators
Reproduction
Fishing
Closures
Catch limits and legal lengths

What are they?

Cuttlefish belong to a group of animals known as cephalopods. Cephalopods are a sub group of a much broader group of animals known as molluscs. Most molluscs possess an external shell consisting of one or two parts, such as oysters, abalone, scallops and snails. The shell in most cephalopods has been reduced in size (or completely lost) and shifted to the inside of the body to form a structure more like a backbone, and it is this cuttlebone which is often seen as cuttlefish wash up on the beach.

The Giant Australian cuttlefish is one of the largest cuttlefish species in the world, and can reach up to 60cm mantle length and weigh up to 5kg.

A closure for the taking of cuttlefish exists in the area known as False Bay near Whyalla.

Habitat

The Giant Australian Cuttlefish (Sepia apama) occurs in all coastal waters and bays from Ningaloo in Western Australia across the southern coast of Australia to Port Jackson in New South Wales and some parts of Tasmania.

Movement

Cuttlefish have two methods of swimming. They can jet propel themselves backwards by sucking water into their body cavity and then expelling it through a funnel. This produces a very rapid backward movement, which is usually reserved for escaping predators.

Hovering and normal swimming is achieved by gentle undulations of their lateral (side) fins. In addition, gas can be passed into small spaces within the cuttlebone to change their buoyancy and move up or down in the water column.

Feeding

The main diet of cuttlefish consists of small fish and crustaceans (such as prawns and small crabs). When they feed, the cuttlefish shoot out two tentacles, which are usually tucked away in pouches under their eyes. This is done in a rapid whip-like action to seize their prey, then holding their prey within their arms while they consume it. If they are feeding on a hard-shelled animal, they use their strong beaks to crack open the shell and their tooth lined tongue for rasping away at the food.

Predators

When attacked, cuttlefish can produce a cloud of black ink just like a squid, which probably confuses the predator and allows the cuttlefish to swim away. Cuttlefish also pose the ability to camouflage themselves to hide from their predators – an ability that is also used to ambush their prey. This camouflage can be seen in the changing of colours and patterns, caused by a layer of tiny elastic pigment sacs found just under the skin.

Reproduction

Cuttlefish are solitary animals, but close to spawning time they are known to form localised aggregations with one known mass spawning ground located in False Bay near Whyalla.

Spawning usually occurs in the winter months and in shallow inshore rocky reefs, in less than 10 metres of water. They start appearing at their spawning ground around the first week of May and disappear towards the end of August.

Eggs are laid individually within protective casings, and are attached to the underside of flat rocks in tight hard to reach spaces. The eggs hatch within three to five months, depending on the water temperature, with hatchlings looking similar to their adult form, and seen in early September.

It is not known where the giant cuttlefish spawning aggregations near Point Lowly migrate from, or where juveniles travel after hatching.  Further research is required to determine these factors.

Giant cuttlefish populations are characterised by high natural variations from year to year, linked to changes in environmental conditions. The biomass of the subsequent year largely depends on successful recruitment from the previous year. The inter-annual variation in recruitment can be vary significantly.

Fishing

A small commercial fishery for the giant Australian cuttlefish did exist in South Australia prior to 1998. Historically Cuttlefish constituted a small bait fishery where reported catches rarely exceeded four tonnes per annum, however, in the mid-1990s, commercial fishing pressure increased.

In response to this increase, in 1998 the state government introduced a giant cuttlefish fishing closure in and around Point Lowly. The closure covers an area where 92-98 percent of the total state-wide catch was historically taken. Since this closure was implemented, the state-wide catch of cuttlefish has been minimal. An additional area adjacent to Point Lowly in Fitzgerald Bay was also closed to fishing for giant cuttlefish earlier in 2012.

There is no strong evidence to suggest that fishing is impacting on the Giant Cuttlefish population.

Closures

A cephalopod fishing closure exists within the area of False Bay near Whyalla to protect the spawning area.  As a result, it is unlawful for any person to target or take any species of cephalopod (i.e. cuttlefish, squid and octopus) within the closed area at any time.

This includes all waters of Spencer Gulf enclosed by a line from the lighthouse at Point Lowly to the southern end of the Point Bonython jetty, then in a south westerly direction to the southern end of the Onesteel wall near Whyalla, then follow the high water mark along the shoreline in an easterly direction to the point of commencement at the lighthouse.

The area remains open to recreational and commercial fishers targeting other fish species.

In March 2013, the Government announced an additional, temporary closure to Cuttlefish fishing in northern Spencer Gulf. Find out more and view map

Catch limits & legal lengths

Minimum legal length: Not applicable A Cuttlefish

 Catch limits apply to a combined catch of cuttlefish and squid
Personal daily bag limit: A total of 15 (including cuttlefish and squid)
Combined daily boat limit: A total of 45 (including cuttlefish and squid)
Closed area: The taking of all cephalopods (squid, cuttlefish and octopus) is prohibited at all times in the waters of False Bay and areas in Fitzgerald Bay near Whyalla. See map
  A temporary Cuttlefish fishing closure is also in place in northern Spencer Gulf until 27 March 2014. Find out more and view map