Cuttlefish. Stony Point, Whyalla. 27 May 2022

Our first dive at the Cuttlefish aggregation site was fantastic! After three years of failed attempts due to bad weather forecasts and COVID19, the drive to Whyalla was well and truly worth it!

Even though the end of May is relatively early in the season there were plenty of Cuttlefish, with mating rituals, threat displays, mating, and egg laying all on view. The males were fronting up to each other, changing colour to dark purple, then exhibiting zebra-striping, side-by-side body alignment, waves of dark colours across the body, and the occasional head-on display with arms spread wide open. We didn't see any physical attacks, although there were plenty of males showing the scars of these fights.

There were very few other fish on view, although I did see a large six-spined Leatherjacket in a cave, with a cleaner shrimp clambering over its side - the first cleaner shrimp I've ever seen!

After eighty minutes we were gettng cold, but torn between staying in the water to watch more of the action, or getting out to warm up. A shallow dive, so Kirsty and I had plenty of air left, and we could have stayed in quite a lot longer, athough our camera batteries would have died...

The Giant Cuttlefish, Sepia apama, is the largest of all Cuttlefish, reaching a length of approximately 1 metre, and weighing as much as 12kg. They live solitary lives, only coming together during spawning aggregations. The major aggregation takes place near Whyalla, South Australia.

Giant Cuttlefish can change colour and can create temporary protuberances all across their body.

Kirsty Batchelor, filming a Giant Cuttlefish at Stony Point, May 2022.

This Cuttlefish is showing a variety of colours, rough surfaces areas and tassles.

When male Cuttlefish have a variety of techniques they use to intimidate rivals. This includes moving black bands of colour across their body.

Cuttlefish can move by undulating their lateral fins, or by ejecting water from their syphon.

Cuttlefish have eight arms (seen here) and two tentacles which are used for capturing prey.

Giant Cuttlefish run through a sequence of stereotyped threat behaviours when confronting another male. They also will suck water into the mantle cavity in order to appear as large as possible.

Another of the threat behaviours involves side-by-side body alignment and rippling patterns being displayed on their body.

Colour, size, and skin texture can change in seconds, making Gian Cuttlefish masters of comouflage.

Another of the threat behaviours involves side-by-side body alignment and rippling patterns being displayed on their body.

Fertilised eggs are laid individually, in cracks and crevices of the reef. Eggs hatch during Spring. Cuttlefish either reach sexual maturity by the following Winter, or grow more slowly, and don't reach maturity until the following year, where they join the aggregation as the largest individuals present. Both males and females die at the end of a successful mating season.

This Six-spined Leatherjacket was spotted at a cleaning station, where a Cleaner Shrimp was removing external parasites. If you look just behind the pectoral fin in this photo you will see a small, transparent, shrimp on the body of this fish.

Mating takes place head-to-head, with one of the male's arms placing a sperm packet to the female's sperm receptacle, located near her mouth. Mating generally takes 2 to 3 minutes. Other males will often wait around for an opportunity to replace the dominant male.

Once mating has taken place, the male will hover over or beside the female., guarding her from other males until she has had the opportunity to deposit her eggs. Only one egg is secured in a crevice at a time, with subsequent eggs being placed in different locations.

Large protruberances and tasssles can be exuded all over the body of the Cuttlefish, appearing and disappearing very quickly.

Even the arms of the Giant Cuttlefish can change colour. We regularly saw the arms become white after mating, when warning off competitors.

We were at Stony Point at the end of May, which is still fairly early in the annual aggregation, but there were lots of Cuttlefish around.

When a male Cuttlefish first sees a competitor they turn a dark purple.

Cuttlefish can make themselves appear much larger than they actually are, by sucking in water, and spreading out their arms.

The shallow waters of Stony Point, near Whyalla, South Australia, abound with Cuttlefish in late Autumn and early Winter.

Divers: Kirsty Batchelor, Peter Batchelor

Weather/Sea: light breeze.
Visibility: 5 - 10 Metres.
Water temperature: 14°C.
Maximum depth: 4.8 metres.
Time of entry: 11:45am
Duration: 84 minutes.