I was at one of my favourite dive sites on Australia’s Gold Coast. The Seaway is one of very few shore dive sites in this popular region, and never fails to provide surprises. Being a tidal site, fish life is always abundant; divers also see stingrays, eagle rays, shovelnose rays and the occasional dolphin.
One of the reasons I enjoy diving the Seaway is the chance to indulge in some muck diving. I get to see a cool collection of critters including sea horse, nudibranch, shrimp, crab, octopus, stonefish, ghost pipefish, leaf scorpionfish, cockatoo waspfish, velvetfish, and cuttlefish.
On this particular dive, I was looking for high-crown sea horses (Hippocampus procerus) which are great macro subjects and endemic to this part of Australia. After an hour underwater I couldn’t find any of these well camouflaged sea horses, but had found plenty of other subjects for my camera.
Heading back to shore I suddenly came across a mourning cuttlefish (Sepia plangon) hidden amongst the seaweed in only 5m. This small cuttlefish species is endemic to the east coast of Australia and grows to a mere 130mm in length.
The mourning cuttlefish is a very common species that I have regularly encountered in New South Wales and Queensland. They obtained their unusual common name from their sad looking eyes, which look the same as all other cuttlefish eyes to me.
These cute cuttlefish generally reside in shallow water, especially around estuaries and sea grass beds, where they find their favourite food of shrimps, crabs and small fish. They are wonderful macro photography subjects, as they will boldly sit out in the open, sometimes with two tentacles held high, allowing you to get very close. They have the ability to change colour and skin texture in the blink of an eye to match their surroundings using pigment cells under their skin called chromatophores, which means you have a fantastic subject that is always changing appearance.
I snapped a few frames of this wonderful cuttlefish before I realised that there was another mourning cuttlefish close by. As I continued to shoot, the two cuttlefish moved closer, allowing me to capture them in the same frame. Cuttlefish will sometimes lift their tentacles and flash colours as a warning to leave them alone, or jet off in a cloud of ink, but this duo was thoroughly nonchalant about my presence.
As I continued to fire away, one cuttlefish inched away so I concentrated on the closest cuttle. I was about to snap a shot when I noticed that the other cuttle had turned a creamy colour and elongated itself. Suddenly it darted forward and wham, rammed smack into the side of the first cuttle before beating a hasty retreat.
This side slam happened so quickly and unexpectedly that I didn’t get a shot, but I soon realised that the aggressor was closing in for another run. This time, I was ready. The cuttle repeat
ed it three more times
– with each round being gentler and slower. What I thought was a cuttlefish fight turned out to be, well, rough foreplay!
Things got even more exciting – on the next round of contact, one cuttle flung its tentacles wide open and the other followed suit and before you knew it they were locked in a mad embrace of intertwined tentacles. It lasted less than ten seconds, but it was thankfully enough time for me to fire off three images. Then the cuttlefish drifted apart, like nothing had happened, leaving me wide eyed and amazed, and extremely happy to have observed the bizarre incident.
That night when I got home, I delved into the sordid depths of cuttlefish sex. All cephalopod (cuttlefish, octopus and squid) males delivered sperm in a package into a pouch beneath the female’s mouth with a modified tentacle. The female then moves to a safe place, removes the eggs from her cavity, passing them over the sperm to fertilise them. Where the female lays her clutch of eggs varies between the species, with cuttlefish and squid depositing their eggs in coral, sponges, sea weed and in caves, but leaving their eggs unattended, while octopus females retire to caves and ledges to guard their eggs. How they care for their eggs, and mate, obviously varies between the families.
The octopus matings I have observed were gentle, with the male slowly following the female around the reef, lovingly touching the female with his tentacles, until he gently probed with one tentacle to deposit his sperm. Not the wham-bam that these mourning cuttlefish had performed.
The most famous gathering of mating cuttlefish also happens in Australia each year, when thousands of giant Australian cuttlefish (Se
pia
apama) gather off Whyalla in South Australia. These cuttlefish, which grow
to a metre in length, are quite a tourist attraction, with divers flocking to
Whyalla each winter (May to August) to witness this amazing aggregation.With so many cuttlefish in one spot the males have to fight for the right to mate with the smaller females, they pulsate colours and perform elaborate dances around each other. Up to seven males may display to each other until the top dog is established. However, the top male has to be careful, as smaller males, posing as females with similar body colouring, can sneak in and mate while he is busy showing off who is boss. After the dominate male has been established he then gets to mate with the female by gently locking tentacles, again no wham-bam involved.
I couldn’t find any information about cuttlefish ramming before sex, so phoned my good friend Neville Coleman to describe the violent mating behaviour between the two mourning cuttlefish. He confirmed that I was very fortunate to have observed a very private moment between two consummating cuttlefish, but added that it was not typical for this species.
Male mourning cuttlefish also have to compete for the attention of available females. They usually display white wavy lines across their backs as a warning for other males to stay away. The males will parade their stripy body colours until the dominate male is determined. But in the ramming incident I witnessed no wavy white lines where used as there was no other male around, so they just went for it!
Neville then pointed out, in a rather bizarre twist, that it was the female that was doing the ramming! Maybe he was a little shy and needed some encouragement from the female. Or maybe he wasn’t interested unless he had another male to show off to first. Sex in the sea can be very strange.