5 mistaken identities along SA’s beaches

Before enjoying your next beach walk, smarten up your seaside knowledge with these five commonly mistaken finds.

There are lots of interesting creatures and plants that wash ashore on South Australia’s beaches. But some are regularly misidentified – with the misinformation often flowing down from generation to generation.

To set the record straight, here are the facts about five commonly mistaken finds along SA’s coastline:

1. Jelly sack

Jelly sacks are not jellyfish. Instead they are an egg mass laid by moon snails. The eggs are encased in a clear, moon-shaped, jelly-like substance. So when you are squishing them between your toes remember you are actually squishing tiny moon snails.

Jelly sack (image courtesy of Port Phillip Baykeeper)

A moon snail (image courtesy of S.Reynolds)

2. Sponge

This little guy is often mistaken for a plant, but is actually an animal.

Sponges are simple animals. They have a skeleton made up of a fibrous material called spongin. Sponges pump water through pores to extract food and expel wastewater through larger holes called oscules.

Sponges can be washed ashore shaped like wine glasses, fingers, balls or flat, spiky mats.


3. Seagrass wrack

Seagrass wrack regularly washes up along our shores. It is often mistaken for seaweed, which is an algae. Seagrass wrack is actually a plant with roots and leaves.

Read up on seagrass wrack versus seaweed.


4. Sea tulip

Another treasure that washes up along our beaches and is mistaken for seaweed is the sea tulip. Sea tulips are actually from the animal kingdom. They are filter feeders, meaning they pump water in and out of their siphons (tube-like structures) and extract the plankton.

Sea tulip

Sea tulip underwater (image courtesy of S.Reynolds)

5. Velella

Velellas are often mistaken for the venomous stinger jellyfish known as the bluebottle. Luckily bluebottles are not generally found in SA. Although they’re not venomous, it’s best not to touch them.

Each velella has a disc-like float with a transparent sail, which the animal uses to drift around the ocean surface. Sometimes you will find large numbers of them washed ashore.


Discover more about the fascinating things that wash up onto our beaches by downloading SA’s beachcombing guide.

Want to know more about what’s lurking below the surface? Check out some of our weirdest-looking creatures and the quirky facts that go with them. 

This story was originally posted in May 2017.

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