Much as I enjoy the beach between Cronulla and Merries Reef it can be hard going when you’re forced to walk in the soft sand by the high tide. It wasn’t made easier by the long piles of flotsam heaped along the tide line. My vague irritation with all the obstacles receded as I slowly realised that the flotsam included lots of wildlife. Admittedly dead wildlife, but fascinating nonetheless.
Many of the bodies along the tide line were pelagic organisms, species that spend their lives at the surface of the open ocean. Currents, wind and waves had combined to sweep less mobile pelagics, occupants of the largest habitat on earth, onto the beach. They were mostly members of the ‘purple brigade’, a diverse collection of floating organisms whose common feature is colours of blue to violet.
Prominent amongst the purple brigade were Blue Bottles and Sallee Sailors. Blue Bottles, complete with float and scalding sting, are familiar sights on the Sydney coast. Sallee Sailors are equally common but often overlooked as they look a bit like a squashed Blue Bottle. They have vertical sail that protrudes above the water to catch the wind.
A tree stump amongst the flotsam was draped in Goose Necked Barnacles. The barnacles attach themselves to the surface of a floating tree, coconut, lump of pumice or sundry rubbish. They have a symmetrical pair of shells but are actually a crustacean rather than a mollusc, using their legs to scoop particles of food into their mouths. The shelled body of the Goose Necked Barnacles is attached to its float by a thin stalk of translucent flesh.
The final member of the purple brigade was the most unusual, as species of gastropod (snail) that floats at the ocean surface under a raft of mucus bubbles. Violet Sea Snails are surprisingly beautiful despite all the mucus, their elegant shells a subtle pastel violet and the individual bubbles of the raft almost crystalline in appearance. The ones on the beach were obscured by sand, so I picked one up, gave it a wash and propped it on a boulder on the reef for a photograph.
The pelagics weren’t the only stranded wildlife. The largest body on the beach was a mature Rusa Deer. This feral deer is common south of the Hacking River. The presence of a carcass on the beach was probably down to the species’ habit of swimming across creeks and rivers to access new grazing. In winter they can become exhausted in the cold water and drown.
There were several Porcupinefish up on the beach. They are commonly seen while diving around Sydney. They aren’t strong swimmers and often end up on the beach after a big storm.
Merries Reef provided the expected variety of waders and seabirds. Trudging back I realised that the main interest for the day had come from the crowded tide line, that small glimpse into the alien world of the open ocean.
The following day we went walking in Royal National Park. The first of the spring flowering had started, and the dominant flowers were the boronias. Pure coincidence, but their gorgeous shades of purple provided a nice point of continuity across the weekend.
Odds and sods