Transcript 1

INVESTIGATING THE CREATURES ON ROCKY SHORES

Hi my name is Jason Morton I’m a marine scientist from Avondale University

College and I've been investigating rocky shores

like this one at Bateau Bay on the Central Coast of New South Wales

for over 20 years.

Lots of people visit sandy beaches but if you want to investigate marine

species there is no better place to do so than rocky shores.

There are lots of creatures that live here they are easy to find as they are either

stuck to the rocks or move very slowly.

All you need is sun protection some sturdy shoes a rocky shore with

good protection from the waves, a low tide and a good field guide that

will help you identify the things that you find.

One of the main things evident on a rocky shore is

Zonation- that is as you move from the higher to the lower parts of the shore

there are distinct bands or zones that contain species called

indicator species.

These indicator species are generally restricted to specific zones.

On steep shores these zones are often compressed into only a couple of meters

but on flat platforms like this one at Bateau Bay these zones can be spread out over many

tens of meters.

The Supralittoral Zone is the highest zone on the rocky shore

In this zone it's above the highest of the tide so it's often called the splash

or the spray zone-.

Up here it's home to very few hardy species and those that are here are often very

Abundant indicator species in this zone are small snails called blue periwinkles, which have a smooth shell and Noddie Winks which have a bumpy shell both species

feed on lichens and microscopic alga.

Growing on the rock surfaces as they receive only occasional wave splash

they must have various adaptations for survival in this hottest

and driest of rocky shore environments.

One of these adaptations is to be a light colour which helps reflect sunlight and prevent

them from heating up too much.

The highest of the intertidal zones is the Upper Littoraal Zone. Here the creatures spend a

lot of time out of the water so they either have to store water

or retreat to crevices or pools.

Indicator species in the upper literal zone include Honeycomb Barnacles, Rose

Barnacles and Striped Mouth Connie Winks.

Moving down the shore we next reach the Mid Littoral Zone.

Here we find high abundances of Zebra Periwinkles, Black Nerites, Oyster Borers

and many species of limpets including Variegated Limpets We also find the first seaweeds including Neptune's Necklace and Sea Lettuce.

The lowest level on the rocky shore is the Lower Literal Zone

In this zone we move from an area that was dominated by

animals in the mid and the upper to now an area that's dominated by seaweeds,

including Lacerated Sargassum, Coraline Algae and Sea Velvet.

Species found here do not tolerate drying out very well so even during low tide they may rely on waves regularly washing over them animals to be found here include Sea Squirts

or Cunjevoi, which are often indicator species of this zone as well as Purple Urchins, Gloomy

Octopuses and predatory snails such as Spengler's Tritons and Cartrut shells.

The Lower Littoral zone is the zone where you'll find most animals but you do need a very low tide and a day when the waves are small. You also need to take great care and

keep your eyes on the ocean as there is always the possibility of an unsuspecting wave washing through this lowest of intertidal zones.

In this zone you are likely to be rewarded with finding less common species such as

Nudibranchs, Umbrella Shells, Bubble Shells, Sea Hares, Elephant Snails

and Keyhole Limpets.

As well as having preferences for certain zones, most rocky shore species also have micro

habitat preferences.

Micro habitats are smaller habitats found on the rocky shore. The main ones

are flat rock surfaces, crevices, pools and cobbles.

Flat rock surfaces are the most exposed of the micro habitats.They are exposed to intense sunlight, drying winds and the impact of waves.

Many species require special adaptations to live here including the ability to store water

when the tide is out, tolerance to heating up and the ability to avoid being dislodged by waves.

Creatures living on the flat rock surfaces (especially those higher on the

Shore) must wait for the incoming tide before resuming their daily activities

including feeding.

Crevices provide a place to retreat when the tide is out. They are often shaded. They commonly hold water and they're protected from the waves

Crevices may even be flush with water when the tide is out allowing creatures

that live here to continue feeding even during low tide

Species common in crevices include Green Anemones, Sand Anemones, Orange Tunicates, various crabs such as Purple Clawed Shore Crabs and snails such as Oyster Borers.

Pools provide an oasis for many rocky shore species that otherwise live lower on the shore. Common species to be found in pools include Bell Shells, Gloomy Octopuses, fishes,

Purple Urchins, Eight-armed Sea Stars and many seaweeds.

These seaweeds in turn provide homes for Warreners, Leaning Limpets, small Brittle Stars and amphipods.

The seaweeds offer these creatures protection from drying out from waves and from predators which are looking to eat them.

These predators include birds when the tide is out and fishes when the tide is in.

Exploring beneath cobbles provides rewarding opportunities to find rarely

seen rocky shore creatures. One reason is that waves don't impact beneath the cobbles

so sediment can accumulate underneath them which provides a home to various species including Peanut Worms and Brittle Stars that feed on organic matter within the sediment.

So here we've got lots of fire worms and we also have a flat worm. Down here also

a Keyhole Limpet and various types of Chitons. Other species living beneath the cobbles

include crabs and shrimps various Chitons.including the Australian Black Chitin, Giant Turban Shells, Elephant Snails, Sea Hares, Spiorbid Worms, Five-armed Sea Stars and barnacles such as the Tessellated Barnacle and Purple Barnacle.

Just remember when you're exploring the cobble area that you lift rocks very very gently

because lots of the creatures are very very sensitive and also sensitive to sunlight and so

once you've done your exploring it's important to very gently but quickly return the rocks to their original position.

The cobbles are also a micro habitat where blue ringed octopuses are likely to be encountered

as well as other creatures that can cause harm including Orange Fireworms.

You now know where to find creatures on the rocky shore so what are you waiting for.

It's time to go out and explore!