Spider Crabs, Leafys & Cuttlefish

On our 2019 photographic tour of temperate Australia, Mornington Peninsula, Victoria, was our first stop.  The reason…. to witness the iconic giant spider crab moulting aggregation! Between May and July each year, tens of thousands of  spider crabs march into the shallows of Port Phillip Bay to shed their shells.  Once rid of their constrictive outer cases, they can put their energy into growing until their new soft shell hardens.  Whilst moulting, the crabs are more vulnerable to predators.  It seems that they seek safety in numbers and in this case, man-made coverings such as Blairgowrie Jetty.

Seeing thousands of spider crabs covering the jetty was eerie and could have been an alien invasion scene from a sci-fi movie. Massive sting-rays were gliding around, vacuuming up any stray crabs who hadn’t made it to safety. Unfortunately, due to the easily accessible location of the crabs, we also witnessed unprecedented numbers of humans fishing the crabs out of the water as if it were an all-you-can-eat buffet.

Our next stop was Port Lincoln, where we met up with our Leafy & Cuttlefish Photography Workshop participants. Our goal here was to seek out Leafy Seadragons at near-by Tumby Bay Jetty.  After much searching, one of our group found an adult leafy seadragon only a few metres away from the jetty.  The fact that we’d swam past this spot multiple times, is a testament to just how complete the seadragon’s disguise is.   The guys got their much anticipated seadragon photos.

We hit the road again and drove north along the Spencer Gulf to Whyalla. Here is where approximately 130,000 giant cuttlefish aggregate to mate, lay eggs, then die. Because the competition is so intense here, the males put on spectacular displays of macho to attract a female.  They can flash rainbow-like colours and patterns over their skin, alternate between smooth and jagged skin textures, and spread their bodies out to look as imposing as possible. Once they think the have secured a mate, they possessively guard her by blanketing themselves around her whilst flashing dark and light warning signals to keep other males away.

Some males take sneakiness to a new level.  They disguise themselves as a female to sneak past the possessive male, and mate with his girl.  This whole scene makes absolutely compulsive viewing.  It’s a paradise for photographers because there is action going on wherever you look.  The hardest thing is that there is too much choice of what to shoot!

We then headed back around the Spencer Gulf to Rapid Bay Jetty on the Fleurieu Peninsula, again in the hope of finding the elusive leafy seadragon. The great thing about Rapid Bay is that, apart from leafies, the jetty is an incredible dive. The artificial reef structure shelters a multitude of fish – schooling bulls-eyes, old wives, and others. Then….thanks to our guide we found the treasure we were looking for! A perfect little seadragon dancing above a patch of weed. What a treat for our eyes, and a wonderful conclusion to our tour.

Thank you to all the guides & dive shops for their local knowledge and for helping us with dive equipment. Sam from The Scuba Doctor, Leo from The Dive Shop Port Lincoln, Tony from Whyalla Dive Shop, Lisa and the girls from Diving Adelaide & Online Dive Gear. Thanks to all our participants for joining us for the Leafy & Cuttlefish workshop, fantastic to dive with you all.