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The Inter-tidal Zone Revealed

Friday, 26 February 2016 03:39 Written by  Lisa Leslie
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As we gathered around Judy Dixon and her treasured box full of the remains of creatures found washed ashore over the years, a full apricot-coloured moon rose above the horizon, Illuminating the length of shoreline which stretched before us. A large jackal buzzard swooped past and made its way towards the lofty fossilised dunes which rise up sharply alongside this beachscape.

We were all here ready to embark on Judy’s renowned Moonlight Meander, an educational walk (which she has been conducting for 18 years), toward one of this region’s most prized, and popular natural assets: Gericke’s Point. But before heading off onto the moon lit beach, Judy spent a good amount of time discussing these various washed up remains, giving us insight into the fascinating life cycles and incredible adaptations of the many creatures that can be found thriving within the intertidal zones of our Garden Route coastline. A marine biologist and accredited field guide, Judy exudes a real passion and love for the sea’s complex web of life. Her knowledge is spell binding.

“Does anyone know what this is?”, she asked, holding up the fragile piece of what is commonly known as a ‘sand collar’. Many of us had seen it during a beach jaunt, but not one of us knew what it was. We learned that the sand collar consists of the gelatinous egg masses of the moon snail. The collar is made by the female and consists of sand grains cemented together by a gelatinous medium, with eggs embedded within it. Each collar contains thousands of capsules, each housing one or more live embryos.
She went on to describe another common object found on our beaches; egg cases known fondly as a mermaid’s purse, which is the casing that surrounds the fertilised eggs of several sharks and skate species. The various different shapes, colours and sizes of each casing gives an indication of the large variety of different species that exist.
She then brought out a large paper nautilus specimen, which is certainly one of the most cherished and rare finds for beach combers. These delicate objects are, in fact, not a nautilus (a pelagic marine mollusc) at all, but in fact the paper-thin egg casing of a type of pelagic female octopus called an argonaut. It is definitely a matriarchal world with this particular species and the fate of the male - which is much smaller in size than the female - is rather unfortunate. The male argonaut has an altered third tentacle which is called a hectocotylus, which is used for copulation with the female. Trouble is, after the act of procreation, the hectocotylus falls off and the male dies. Certainly not the stuff of fairy tales.

As we headed off down the beach towards Gericke’s Point, we stopped often along the way to chat about the various creatures that we saw. What appeared before us to be merely sculpted rocky outcrops, under her guidance they suddenly became living, complex eco-systems of highy adapted and interdependent life forms.
Evening, spring low tides provide the perfect opportunity to observe the various species of life found within these myriad tidal pools. During the day, many are hidden away in nooks and crannies to avoid predation, but at night they appear in all their glory. The tidal pools teem with life of all shapes and colours; spiny starfish, octopus, crabs, purple urchins, plum anemones, giant periwinkels, orange nudibranch and a variety of fish. Judy gives fascinating commentary about this most enchanting tidal pool spectacle.

With the sound of the waves colliding with the shore, the smell of sea salt in the air, and the moonlight washing over this dynamic marine environment, you will be left with a profound appreciation of the wonders that exist here. It is, without a doubt, a richly rewarding experience.

“The only reason I do this is to make people aware”, Judy explained to me on the walk back to the car park, “because aware people care and it is often said that we cannot protect that which we don’t understand.” Enough said.

Judy conducts two tours a month during the spring tides: Moonlight Meander during full moon, and the Starlight Trail during the new moon.
For more information, email: This email address is being protected from spambots. You need JavaScript enabled to view it. or call: 072 390 6667

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