step on the slugs!
rock with onch slugs
make a good 'first station' to sensitise visitors to the fact that
every inch of the shore is alive.
What are slugs?
Have you ever seen a slug? How about a snail? Yes, almost everyone
knows what a snail looks like. Slugs are like naked snails! Snails
Slugs belong to a group of animals called molluscs. Other molluscs
include snails, clams, octopus, squids and cuttlefishes!
A closer look at slugs
look at this Onch slug! You can almost always find some
kind of onch on a rocky shore, even on sea walls. You can do this
even in a shelter during rainy weather or while waiting for the
tide to go down.
many onchs can you find? "I can see 5, can you
see them? See how well camouflaged they are, so watch your
step when you walk on the stones."
do you think the onch eats? "Yes, it eats this
fuzzy stuff that grows on the rocks. This is tiny seaweed.
See the bare patch where it has grazed the seaweed. And see
the trail of 'processed seaweed' behind it!"
I dropped the onch. Let's pick it up and put it back where
it was. Slugs are slow and if we leave it there it
might not be able to get back where it is safe, or it might
get washed away when the tide comes in.
We've found a nudibranch! (Pronounced 'noo-dee-brank'
to rhyme with 'bank'). Nudibranch means 'naked gills'. After explaining
some of its features, put it back exactly where it was and explain
why this is important. Many nudibranchs only eat a particular
kind of food (usually a sponge or other immobile animal).
do you think nudibranchs are so pretty and colourful? These
naked slugs don't have a shell to hide in. Many protect themselves
with chemicals that taste bad, or with stinging cells. They advertise
their unpleasant nature by being very striking.
myths to dispel
- Slugs should
not be kept in home aquariums. Many only eat a particular kind
of food. If you can't provide them the food, they will die. Or
they may eat up their tank-mates. Some produce powerful toxins
that can wipe out the entire tank.
Where to find slugs? Onch slugs are common on big boulders,
sea walls, even some jetty pilings. Especially those covered
with algae. They are more active during a cool day.
Be gentle! Onchs can be very slippery. If one falls
it may not be able to creep back to where it's safe. Pick
up any dropped onchs and put them back where you found them.
Explain why you are doing it.
Don't disturb slugs: Try to point out slugs in their
original location. You can show how conspicuous or well camouflaged
they are. If you took them away, put slugs back exactly where
you found them. Many only eat a particular kind of food. Their
mother would have laid her eggs on the food. If removed, they
may not be able to find their food and may die.
Don't encourage people to handle slugs Many slugs are
delicate. They may drop off parts of their body when they
are stressed. Don't pinch the edges of slugs or pick them
up by their edges. The slug may break off that part of their
Some slugs may also release unpleasant chemicals that can
cause irritation to the skin or eye.