Slugs in the nud’

At Dalton Koss HQ we come up with some creative names to describe some of the more interesting creatures that can be found in our marine front yards.

Slugs in the nud’  are nudibranchs. Nudi what? Nudibranchs.

Nudibranchs are oceanic snails, do not possess a shell and are mostly brightly coloured.

To break it down, Nudi = nude and branchs = gills. As these snails do not have shells for protection, their gills are nude and exposed (see image below).

Without a shell covering, the nudibranch's gills can be found on the top part of its body and exposed to the water.
Without a shell covering, the nudibranch’s gills can be found on the top part of its body and exposed to the water.

Nudibranch Facts

1. The bright colours of nudibranchs are used as defence mechanisms to avoid predators.

2. Many are able to camouflage with their surrounding environment, such as corals and sponges.

nudi3 fixed
3. Nudibranchs do not make a tasty meal. In fact, they are toxic and poisonous to eat. This is because nudibranchs feed on the stinging cells of sea jellies, anemones and corals.

4. Nudibranchs can be found at different depths in both warm and cool ocean waters.

WA July 2005 041

Although not in the same size category of many other sea creatures, they do create a level of excitement for DKHQ when spotted under water.

Seahorses & Seadragons

Amongst Dalton Koss HQ’s favourite animals and plants are the enigmatic seahorses and seadragons.

Are they real? Do they really exist?”, DKHQ is often asked.

 Yes, they are real and live in both tropical and cooler oceans across the globe.

Regarded by most as resembling half horse half fish, these gentle oceanic creatures spend their time slowly cruising amongst seagrass meadows, seaweed gardens and coral looking for small shrimp to eat.

Both seahorses and seadragons belong to the bony fish family, Syngnathidae, which also includes pipefish and pipehorses (a DKHQ marine fact for another day) .

Seahorses tend to have an upright vertical position while stationary or moving,  while seadragons tend to have a horizontal stationary and moving position. Although seahorses and seadragons look different, they are closely related.

There are some AMAZING facts about seahorses and seadragons.

FACT 1: The seahorse and the seadragon are the only animals in the world where the male gives birth to the babies. Yes, you read correctly! The only animals in the world where the male gives birth. Female seahorses deposit their eggs into the male seahorse pouch where they are then fertilised. The male seahorse will carry the growing babies in the pouch until they are born, which is why some male seahorses look like they have a very big belly. This reproduction approach is very similar for seadragons, however,  the male seadragon will carry the babies in pouches that are attached to their tail rather than in their belly.

FACT 2: Seadragons can only be found in the cooler waters across southern Australia and no where else in the world. The Weedy seadragon is Victoria’s marine state emblem, while the Leafy seadragon is South Australia’s marine state emblem.

FACT 3: If you have an opportunity to dive amongst the tropical reefs of South East Asia, keep your eye out for the pygmy seahorse. No bigger than an average sized thumb, pygmy seahorses will only live on specific types of coral.

A pygmy seahorse attached to coral in the beautiful reefs of Malaysia. Image by Dr Elizabeth Strain.
Spot the pygmy seahorse attached to coral located in the beautiful reefs of Malaysia. Image by Dr Elizabeth Strain.

The next time you are snorkelling or diving amongst seaweed gardens, seagrass meadows or coral reefs, keep your eyes open for a beautiful seahorse or seadragon.

OUR GRASSY OCEAN MEADOWS

“Grass that grows in seawater?”, Dalton Koss HQ is often asked. Yes, grass that can grow in and withstand seawater. But how?

Seagrass is similar to land-based grass, having leaves, veins and roots. The leaves grow from the base of the leave and reproduce with flowers and seeds. Many individual seagrass plants found growing together is termed a seagrass bed or seagrass meadow. Seagrass meadows can be found across the globe, usually in coastal areas close to shore where sunlight can penetrate the water column. Like all plants, seagrass needs sunlight to grow.

The different parts of the seagrass, Amphibolis antarctica, or commonly known as the sea nymph.
The different parts of the seagrass, Amphibolis antarctica, or commonly known as the sea nymph.

Although seagrass meadows may not look like much to the casual observer, they play an incredibly important role in supporting not only the health of our coasts and oceans, but also to humans. There are so many incredible facts about seagrass that DKHQ would like to share with you.

Did you know that seagrass meadows are nurseries for baby sea animals, providing shelter and protection from bigger animals and food to help them grow? Most of the fish we buy to eat would have spent some of their younger years living and growing in seagrass meadows before swimming to the oceans as adults.

An eleven arm seastar (Coscinasterias muricate) and small mussels (Electroma georgiana) living in swan grass (Zoestera muelleri).
An eleven arm seastar (Coscinasterias muricate) and small mussels (Electroma georgiana) living in swan grass (Zoestera muelleri).

Due to the amazing root network of seagrass, they are able trap and stabilise soft sediments, sand and other very small items floating in seawater. This means seagrass plays an important role in protecting our shorelines from erosion and helps improves seawater clarity.

In areas of seagrass meadows there are less toxic algal blooms. Seagrass is amazing at absorbing a whole lot of different nutrients, that often contribute to algal blooms, and using it as food to grow.

The seagrass plant is like a small cosmos to itself. It provides a solid surface for other small seaweeds, sponges and animals to grow.

A meadow of Southern strapped (Posidonia australis) in Corner Inlet Marine National Park, Victoria.
A meadow of Southern strapped (Posidonia australis) in Corner Inlet Marine National Park, Victoria.

Worried about high carbon levels in the atmosphere? Seagrass is able to absorb and store large quantities of carbon in their leaves and roots. Let’s protect seagrass so it can be a wonderful and natural way to address our high carbon lifestyles.

If you ever have an opportunity to snorkel in a grassy ocean meadow, do not pass it up! You might just be surprised with what you find.

A beautiful and vibrant red sponge growing in the Southern strapweed.
A beautiful and vibrant red sponge growing amongst the Southern strapweed.

Sea Anemones of the Southern Ocean

At DKHQ we are constantly asked whether some of the facts portrayed on Finding Nemo are true, specifically the much difficult to pronounce Sea Anemone. Pixar did a wonderful job raising the profile of tropical reefs, although to the detriment of Clown Fish who, if the facts are correct, were being flushed down toilets by young children wanting to release ‘Nemo’ back into the ocean.

This aside, the often asked sea anemone questions at DKHQ are: a. can sea anemones sting, and b. can their poison kill humans? The answer to a. is yes and to b. is no. This public fascination with sea anemones inspired today’s DKHQ Marine Fact, with a focus on southern sea anemones.

Unlike the large sea anemones of our tropical reefs systems found across the globe’s equator line, the sea anemones of the southern ocean are comparatively smaller but just as beautiful and colourful. Here are some interesting facts:

1. Southern sea anemones always occur as solitary individuals usually in intertidal and subtidal areas.

2. All sea anemones have one opening, function both as its mouth and anus (this fact usually elicits some funny facial and noise reactions). Sea anemones are carnivores, on other animals.

3. The sea anemone body is supported by water pressure, which means when not in water their body and tentacles become floppy.

4. The tentacles of all sea anemones radiate from the mouth in one or many rows and are hollow. These tentacles contain stinging cells known in marine science as nematocysts. Each nematocyst contains a pressurised coil that can be pushed out to capture prey or used as self defence. The sea anemone use the nematocysts to stun, and in some cases, kill the prey.

5. Nearly all southern ocean sea anemones grow attached to a rock or some other type of hard structure. The exception to this rule (and when it comes to Mother Nature, there is usually one exception to the rule) is the Swimming anemone known by its scientific name as Phlyctenactis tubercles. (See image below). The Swimming anemone can move through the current or crawl along hard structures.

The Swimming anemone, Phlyctenactis tuberculosa.
The Swimming anemone, Phlyctenactis tuberculosa.

So why can’t sea anemones sting us? Our skin is too thick to be penetrated by its stinging cells, unlike many sea creatures with very thin skin. In the case of Clown fish, they have adapted over a long time for their skin to not be affected by the stinging cells and use the sea anemone as a place of protection from enemies.

DKHQ hopes you enjoyed these sea anemone facts and will leave you to enjoy the beautiful colours of some of the southern ocean’s sea anemones.

This beautiful sea anemone is known as Phlyctenanthus australis and can be found along Australia's intertidal shoreline that is exposed to ocean waves.
This beautiful sea anemone is known as Phlyctenanthus australis and can be found along Australia’s intertidal shoreline that is exposed to ocean waves.
This gorgeous red sea anemone is known as the Waratah Anemone and it's scientific name Actinia tenebrosa. This lovely Waratah Anemone can be found along the intertidal shoreline, often looking like a red blob at low tide.
This gorgeous red sea anemone is known as the Waratah Anemone and it’s scientific name Actinia tenebrosa. This lovely Waratah Anemone can be found along the intertidal shoreline, often looking like a red blob at low tide.
This fun orange and white stripped sea anemone is known as Anthothoe alboctinia and can be found under rocks or underhangs along Australia's intertidal shoreline that is exposed to ocean waves.
This fun orange and white stripped sea anemone is known as Anthothoe alboctinia and can be found under rocks or underhangs along Australia’s southern intertidal shoreline that is exposed to ocean waves. There are two variations to this sea anemone, white and orange stripes and brown and green stripes.

What are those round smooth shells you find on the beach?

At DKHQ the creative talents of individuals who use natural elements in their art often fascinate us. This holds true when we see shells made into jewellery or used as decorative placements in homes and businesses.

When DKHQ was asked to identify a bowl full of white round shells used for decoration purposes, we realised its potential as a new marine fact.

This round white item (see image above) is officially known as an operculum. Attached to the upper surface of the snail’s foot, it functions as a door to the snail’s shell. Like the door to your house, the snail uses the operculum to keep unwanted visitors out.

Unfortunately, sometimes our doors do not keep pesky visitors out. When you find an operculum washed up on the shore, it usually means the snail experienced an unwanted guest and is no longer alive.