Cuttlefish

Most people associate cuttlefish with domesticated budgies (the bird, not the male swimsuit). This is because budgies are given cuttlebone, a long ovulated white structure, to sharpen their beaks. This beautiful cuttlebone is an important feature of the cuttlefish; it controls their buoyancy while swimming in the ocean at various depths.

Cuttlefish can be found across the globe. They belong to a group of animals termed cephalopods, which also includes the octopus, squid, chambered nautilus and argonauts. Scientifically, cuttlefish belong to the Class Cephalopoda in the Phylum Mollusca. This means cuttlefish are invertebrates and have no backbone.

Cephalopods are considered amongst scientists to be the most intelligent out of all invertebrates; they learn quickly, are able to solve problems, communicate via complex visual communication and can quickly adapt to their local environment. Like chameleons on land, cuttlefish are experts at adapting to the colour and patterns of the environment around them.

Cuttlefish, as well as the octopus, contain special organs in their skin termed chromatophores which are little elastic bags filled with colour pigment. By expanding and contracting, chromatophores display a particular colour. They can be turned on and off which allows the cuttlefish to create a particular set of colours and patterns with its skin. Additionally, skin flaps, termed papillae, can be pushed or shaped to mimic their surroundings, for example, seaweed or coral. These colour and pattern changes are used for: mating and courting rituals, mate-guarding and camouflage to hide from predators.

Here are some more fascinating facts about cuttlefish:

Fact 1: Cuttlefish have very well developed eyes and acute vision. They are colour blind but respond to differences in light intensity rather than differences in wave length (which vertebrates, like humans, use to determine colour).

Fact 2: Cuttlefish are carnivores, that is, they eat meat. They are active nighttime predators feeding on fish, crustaceans, shellfish and worms.

Fact 3:  During mating, the male passes packets of sperm to the female using its modified arm termed the hectocotylus. The females can immediately fertilise their eggs or are able to store the sperm in special receptacles inside their body for periods of time until they want to fertilise their eggs.

Fact 4:  Females attach the fertilised eggs to the seafloor either on or under hard surfaces such as rocks. Young cuttlefish develop with no parental assistance and many hatchings are carried around in surface ocean currents over long distances.

Fact 5:  Cuttlefish have 8 arms and 2 feeding tentacles. All arms have suckers along the length of the arm except for the feeding tentacles which have suckers only on the tip, termed clubs. The feeding tentacles can be pulled back into the mouth.

The Giant cuttle, Sepia apama, is found in southern temperate Australia extending from Western Australia to New South Wales. This species of cuttlefish can be identified by the three flat skin folds behind the eye and adults are often very curious.
The Giant cuttle, Sepia apama, is found in southern temperate Australia extending from Western Australia to New South Wales. This species of cuttlefish can be identified by the three flat skin folds behind the eye and adults are often very curious.

Fact 6: A cuttlefish’s mouth contains a hard beak, similar to a parrot’s beak. The beak is used to kill and paralyse the prey by injecting a poisonous saliva. The beak also breaks the prey into pieces and then it is further broken down with a row of very small sharp teeth.

Fact 7: When scared or irritated, cuttlefish squirt ink into the water column which can be shaped to be the same size as its body. This ink sac sits inside the body near the anus. Cuttlefish are also able to bury themselves under sand, with only the eyes remaining visible, when they want to hide.

Fact 8: Cuttlefish use their funnel and fins to swim. The fins extend out from its mantle (the back part of its body) enabling rapid or slow propulsion.

Many larger marine animals such as seals, whales and large fish eat cuttlefish, however, they are rarely caught in fisher nets. Perhaps this is indicative of their intelligence and being able to problem solve in difficult situations?

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What the devil……?

Every venture into our amazing marine world provides me with an opportunity to learn something new and to interact one-on-one with some wonderful creatures.

During one dive in Port Phillip Bay, located in Victoria, Australia, the Southern Blue Devil’s iridescent blue colours immediately caught my eye.  Scientifically known as Paraplesiops meleagris, this beautiful fish is endemic to southern Australia. The Southern Blue Devil can only be found in the beautiful waters between Perth in Western Australia to Port Phillip Bay in Victoria to a depth of up to 45m.

The Southern Blue Devil loves to live under ledges and in crevices and caves. They are fiercely protective of their territory, especially during breeding season. My first encounter with the Southern Blue Devil was during breeding season. The male of this species can be a little aggressive if you get too close to their territory, especially if you have any blue colours on your SCUBA kit or wetsuit. My SCUBA mask at the time was made of clear perspex and rubber lined with bright blue rims around the eyes. Thinking I was a competitor for it’s territory, this male Southern Blue Devil told my SCUBA mask in no uncertain terms that it wasn’t welcome.

Southern Blue Devil 1: Dalton Koss HQ SCUBA mask 0.

The Southern Blue Devil on the defensive mode due to my blue rimmed SCUBA mask coming across as a potential competitor.
The Southern Blue Devil on the defensive due to my blue rimmed SCUBA mask appearing to be a potential competitor.

Although quite a visually funny story, here are some other interesting facts about the Southern Blue Devil.

Fact 1. Similar to human finger prints, adult Southern Blue Devils can be individually identified and monitored due to their unique pattern of markings on the lower part of their gill cover.

Fact 2: Adult pairs will stay together during the breeding season, protecting their eggs that are usually laid on rock surfaces in narrow crevices.

Fact 3: The Southern Blue Devil is protected by law across Australia as they are endemic, that is, they are not found anywhere else in the world.

Fact 4: Known to be curious, the Southern Blue Devil will usually interact with SCUBA divers even during non-breeding season.

Fact 5: The Southern Blue Devil loves to eat small crustaceans, snails, worms and sometimes other small fishes.

If you ever have an opportunity to SCUBA across Australia’s southern oceans, look out for the Southern Blue Devil. In fact, it will probably find you first.

The Southern Blue Devil loves living in and around crevices, ledges and caves.
The Southern Blue Devil loves living in and around crevices, ledges and caves.

Estuaries

Taking inspiration from my paper that was published this week, this week’s Dalton Koss HQ Marine Fact takes a look at estuaries.

Estuaries are fascinating systems that are often forgotten natural spaces. This is because they are neither freshwater nor seawater, rather they are a mix of the two. One of Dalton Koss HQ’s favourite sayings is to be in a liminal state meaning that the subject is never in one state of being. This is true for estuaries where saltwater from the open sea mixes with freshwater that flows down from uprivers and streams. As the chemical makeup of saltwater is more dense compared to freshwater, the saltwater will sit under the freshwater layer. This saltwater layer usually decreases in depth as you move up the estuary away from the ocean. Additionally, sediments from both land and ocean meet and mix in the estuary.

Hawkesbury Estuary, New South Wales, Australia.
Hawkesbury Estuary, New South Wales, Australia.

Due to this unique combination of water and sediments, estuaries are incredibly naturally productive places that provide protection from the rough seas. Fish use estuaries for migrating and reproduction, birds feed and nest on the side of estuaries and there is even documented evidence that suggests larger mammals such as whales and larger fish species such as sharks use estuaries as reproductive areas.

As estuaries are directly linked with the ocean they are often influenced by tides. Some estuaries are devoid of water at low tide making it very easy to walk across from one side to the other. Estuaries provide humans with a number of services that contribute to our health and wellbeing. In the field of environmental economics this is called ecosystem services as the natural system (ecosystem) is providing us (humans) some type of service that contributes to our health and wellbeing. Here are some examples of estuary ecosystem services:

1. Humans take out fish and shellfish from estuaries as food to eat.

2. Many of the mangroves, coastal shrub and salt marsh that grow along estuary shores remove pollutants from the air providing us cleaner air to breathe. These same plants can trap sediments amongst their roots which decreases erosion and soil run off into the water. This in turn provides stability to houses and human made infrastructure built along the estuary.

3. For those who visit or live along an estuary, looking and experiencing beautiful natural landscapes can create feelings of relaxation, pleasure, peace and enjoyment.

4. Estuaries contribute to the traditions and cultures of Indigenous peoples across the globe.

Within Australia, there are over 1000 estuaries of different forms and types. In fact, over 60% of Australia’s population live along estuaries, for example, Melbourne and Port Phillip Bay, Hobart and the Derwent River Estuary and Fremantle and the Swan River Estuary.  Globally, there are thousands more. As human populations continue to grow, greater pressure will be placed on our estuaries. How to balance population growth, city planning and impacts on our natural environment needs in depth consideration by governments and citizens across the globe.

Whale Rock, Tidal River Estuary, Wilsons Promontory National Park, Victoria, Australia.
Whale Rock, Tidal River Estuary, Wilsons Promontory National Park, Victoria, Australia.

Naomi Edwards Is Creating Happy Beaches

Naomi Edwards lives on the Gold Coast, a popular Queensland coastal strip on the east coast of Australia. Naomi’s passion and drive translates into a number of diverse roles including: Young Social Pioneer for the Foundation for Young Australians, National Landcare Ambassador, Founder and Researcher for Happy Beaches and a Griffith University student and coastal community advocate and expert.

Naomi chats with Dalton Koss HQ about her passion for beaches and her drive to empower the people around her to have ownership of their dreams.

I always wanted to be a pilot. The idea of flying through the clouds enchanted me. But during my high school years at Keebra Park SHS, I went to Queensland’s south-west outback for 10 days on a science school trip to work alongside Peter McRae, a lifetime campaigner and conservationist for the endangered bilby. Peter inspired and transformed me to live a life with purpose where sustainability is at the heart. His passion for world sustainability led me to study environmental science and post-graduate degrees in international and community development, and coastal cultural studies to refine my purpose. I preferred to be outdoors, volunteering and looking after coastal environments. It didn’t take long to discover that my purpose was to inspire communities to care for beaches and influence coastal management decisions having grown up along Gold Coast’s beaches.

My journey really began with volunteering at my local beach with watering native dune seedlings during south east Queensland’s decade-long drought. The Friends of Federation Walk have been restoring the dunes at The Spit for over 15 years and my experiences volunteering with them changed my life – again. As one member made quite an impression on me by stating, Naomi, it is up to you what you want to do with your life but why not create a masterpiece.” And there I was standing on a sand dune creating a masterpiece. What was once a bare sand dune is now a thriving coastal rainforest, a beautiful ecosystem for native biodiversity.

Yet, I recognised that only a small group of dedicated people volunteered and wonder what difference we could make if more people supported the cause – perhaps more positive outcomes for the sustainability of the coast. I shared the possibility with my fellow science students and academics at Griffith University. What started as four university friends turning up to volunteer, evolved into twenty undergraduate students consistently volunteering every month, planting trees and keeping up with the restoration maintenance. We called ourselves Griffith University Science Maintenance Team to help support the small group of volunteers. Despite the less-than-engaging name for the group, this was the launching of my first coastal community project – without even realising. Then all of sudden I saw plenty more gaps, patched them up and inspired and supported other’s to do so too.

After completing my Bachelor of Environmental Science, I planned to study an Honours vegetation ecology, specifically, carbon sequestration. However, I was having too much fun on the beach working with volunteers and in between researching various forest structures measuring over 15,000 trees for the Program for Planned Biodiversity and Ecosystem Research (PPBio) project. It was these experiences that opened a world of opportunity, fuelling my passion for community wellbeing and the environment – particularly, beaches and dunes.

As I believe where there is a need, there is an opportunity, where there is passion, there are people, and where there is a dream, there is hope. My dream is to transform the sustainability of beaches to be happy beaches, so there is hope for the coast and the future of beaches and coastal communities around the world.

I have never really considered myself to be a leader, rather an instigator for progressive change for the environment, particularly beaches. There has been a lot of learning along the way; there was no strategy and there is no strategy. Luckily, I had wonderful support and mentoring to guide my spontaneous acts of action. As I just did things, didn’t wait and thought about it later.

I would probably put myself in the change maker category. As our future is today’s experiences and if want to see change we have to be in action. That means we are always setting ourselves up for the next thing even if we fell like we are in limbo.

Every possibility presents an opportunity to act.

The five key words I use to describe effective and successful leadership include:

1. Passion – Passion is the key driving agent for all change makers. It fires up the heart and soul and keeps you grounded and focused. It is important for leaders to have a passion to drive energy, a vision, ignite others, influence and open opportunities.

2. Plan – I was fortunate to be guided early on by leading change makers in my community. They encouraged me to package my dreams and desires for every idea – too many ideas – into an achievable plan. This has also helped others and myself stay on track and work towards common goals and objectives to achieve and complete projects and lasting successes.

3. Integrity – Integrity is the foundation of leadership. Yet it can be overlooked or not recognised as it shown through the small actions. This involves keeping your word and helping others without expecting something in return, and always living by your values. People will believe and support you when you have integrity. Do not compromise your values.

4. Commitment – You have to be accountable, do the hard work and create a community full of leaders in their own right, which takes commitment.

5. Consistency – Consistency helps you get over the line to reach success. It helps establish your reputation. It also makes you relevant, and maintains and helps you refine the freshness of your message.

I have experienced a number of key successes and challenges in my leadership journeyBeing creative, having fun and working with the right people has led to many successes in my life. I can’t really pinpoint any specific key successes rather I simply acknowledge the entire journey. In the beginning the biggest challenge was overcoming the overwhelming state of the environment when learning about climate change, marine debris impacts, species extinction etc. You can’t let the negative side of things get to you or else they will bring you down. You have to maintain a positive outlook and act on what you can do. 

I don’t really believe in failures as every action and project occurs the way it is suppose to be. It is about learning from every experience and building your experience bank for next time to do it better, bigger and most likely more innovative. “And whether or not it is clear to you, no doubt the universe is unfolding as it should” (Max Ehrmann, Desiderata: A poem for a Way of Life).

My success is attributed to inspiration and support. I am continually inspired by others, from Peter McRae at the beginning of my journey to the many community champions I come across in my work. I love hearing about other people’s ideas, dreams and hopes and where I can offer my experience and support. Without my support base I wouldn’t be where I am today. I am thankful for the support my family, friends and close networks.

I have been fortunate to live a life where as one door closes another one opens. I think staying true to my passion, being committed and consistent has laid a fun and creative journey filled with endless possibilities!

I apply a holistic approach to maintaining my mental and physical health and wellbeing. I am happy, positive and optimistic and stay true to my passion. I support my support network and encourage others around me to live a powerful life, a life they love. I go to the beach – a lot! I enjoy eating wholesome food but also indulge in sugary sweets when I want. I enjoy walking my dogs and exercising.

You have to think and act beyond your own capabilities to grow, learn and reflect. This begins with dreaming up boundless possibilities and opportunities, sharing them, and then inspiring others to follow and be part of the journey as anything is possible! Leadership is helping others to take ownership of their ideas.

Two organisations I recommend for others to join are:

Landcare Australia – there are many opportunities for all walks of life to get involved in caring for the land and sea.

Foundation for Young Australians – delivers a range of initiatives (co)designed with and for young people to deliver change across Australia.

To learn more about Naomi and her Happy Beaches vision, please click on the links below:

Naomi’s blog – http://coastaltangents.com/

Naomi’s latest project – http://www.happybeaches.org/

SEA SQUIRTS

Visits to the coastline are often filled with feelings of enjoyment, relaxation and excitement through discovery and exploration. At Dalton Koss HQ we often see young children and teenagers having fun exploring the beach, especially when they find sea squirts exposed at low tide. The name giveaway here is the squirt of seawater that comes out of this animal when lightly squeezed.

Sea squirts live on the lower areas of intertidal zone (see this link), from rock platforms to human made structures such as groynes and seawalls.

Sea squirts attached to a pylon and sea wall on Hampton Beach, Victoria, Australia. Notice that each individual sea squirt has two siphons for intake and outtake of water and gases.
Sea squirts attached to a pylon and sea wall on Hampton Beach, Victoria, Australia. Notice that each individual sea squirt has two siphons for intake and outtake of water and gases.

Aside from the amusement they provide when squeezed, here are some interesting facts about sea squirts:

FACT 1: Sea squirts, in the adult form, are individual animals that permanently attach themselves to hard structures, such as rock platforms, groynes and sea walls.

FACT 2: Sea squirts are filter feeders meaning they filter their food and oxygen out of the water column. To do this sea squirts have two siphons, one for bringing in the water and one for getting rid of the water. The walls of the siphons are lined with cilia (think of cilia as microscopic arms that wave and move together) that grab plankton and absorb oxygen as the water passes through the intake siphons. Any unwanted matter and carbon dioxide is released from the outtake siphon

FACT 3: Sea squirts along Australia’s southern shoreline have a brown outer colour and a beautiful orange/red inner colour. This brown outer colour allows them to blend in with the seaweeds and hard structures they are attached to.

FACT 4: At low tide sea squirts close their siphons so water cannot escape while providing protection against predators and the elements (e.g. sun and air).

FACT 5: Sea squirts are also referred to as cunjevoi or ascidians (as they belong in the scientific class Ascidiacea).

FACT 6: Sea squirts are mostly hermaphrodites meaning they possess both male and female reproduction organs.

FACT 7: The larvae of sea squirts look like small tadpoles that can swim around in the water. They only stay in this form for a few hours before settling on a hard surface, which signals the start of its transformation into the adult form.

Perhaps one of the most interesting facts about sea squirts is their evolutionary link between animals without a backbone (think sea stars, sea jellies, sea snails) to animals with a backbone (such as fish, birds, humans). In the larval stage sea squirts have a notochord, which looks like a rod. The notochord eventually forms into the backbone. However, sea squirts do not form a backbone. When the sea squirt larvae settle onto hard structures, the notochord disappears. This is an interesting phenomenon for evolutionary scientists who study how animals and plants evolve over time.

Sea squirts have a few predators including humans who cut up the sea squirt and use the red part of its body as fish bait. Although we often see how much fun everyone has from squeezing and squirting each other with water from sea squirts, it does cause them a lot of stress while they are exposed to the sun and air at low tide. So while it is tempting to squeeze sea squirts, it is best to leave them in peace as they wait out the turn in tides.

The Intertidal Zone

Over the past few weeks, quite a number of the Dalton Koss HQ Marine Facts have referred to the intertidal zone. Many DKHQ readers have curiously responded with the questions:

  1. Where is the intertidal zone located?
  2. Exactly what is the intertidal zone?

At Dalton Koss HQ we are more than happy to answer these two questions.

The intertidal zone is located along our coastlines, specifically where the sea meets the land. This zone varies all across the globe. It can be made up of rocky shores with many fun rockpools, mudflats or sandflats, mangroves, salt marsh and seagrass beds, sandy beaches and coral reefs. The intertidal zone can be exposed to the rough and tumble of open oceans or located in sheltered places such as bays and inlets. Some scientists refer to the intertidal zone as the littoral zone.

An exposed intertidal rocky shore at low tide along Victoria's Great Ocean Road. Notice the prolific range of seaweeds adorning the rocks.
An exposed intertidal rocky shore at low tide along Victoria’s Great Ocean Road. Notice the prolific range of seaweeds and mussels adorning the rocks.

At Dalton Koss HQ we often refer to the intertidal zone being in a liminal state. This is because the intertidal zone is either covered with ocean waters or exposed to the sun and air due to the constant movement of tides. It is never in one state of being within a 24 hour period; rather it is in continuous flux.

Being exposed to two completely different types of conditions means that as an animal or plant living in this zone, one needs to have some incredibly amazing adaptations to survive. Intertidal plants and animals need to be resilient to wave wash, tides and currents, sun exposure, predators and drying out all while trying to photosynthesise/eat and reproduce.

An exposed intertidal sandy flat located along Cape Conran Coastal Park in eastern Victoria, Australia.
An exposed intertidal sandy flat located along Cape Conran Coastal Park in eastern Victoria, Australia.

This makes the intertidal zone a fascinating area to explore and discover the spectacular range of marine animals and plants. To conserve this amazing zone while you explore, please be careful where you tread/snorkel, place rocks back to their original positions when you examine what is beneath and keep all rockpool animals and plants fully immersed in water to reduce their stress.

An intertidal coral reef exposed at low tide located in Fiji's Coral Coast.
An intertidal coral reef exposed at low tide located in Fiji’s Coral Coast.

Chitons

Visitors to coastal shores often come across unusual looking animals hidden in rock crevices. Here at Dalton Koss HQ we strive to help make sense of these unusual sea creatures by sharing our marine knowledge.

Chitons are one of these more unusual finds that many coastal visitors find on the rocky shoreline. With the Ch pronounced as a k sound, chitons have a fossilised appearance due to their numerous armoured plates. In fact, some people call Chitons the armadillos of the ocean as they are able to curl up into a ball using their armoured plates as protection.

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The armoured plates grow from the head to the foot of their body providing protection and camouflage from predators, hence why this animal is also commonly known as the coat-of-mail. The actual animal grows and lives under these armoured plates and its body is not segmented like its armour.

Here are a few interesting facts about chitons:

1. Chitons can only be found in the intertidal and upper subtidal zone of rocky shores.

2. The majority of chitons are vegetarian, grazing and eating seaweeds using their radula (see earlier What creates those circular holes on seashells? DKHQ Marine Fact to find out more about radulas).

3. Chitons can live from 1-20 years or more.

4. All chitons have a girdle around their body and plates.

5. Chitons prefer to move around during dusk and at night to reduce their chances of being prey to birds and other larger animals.

6. Sexual reproduction is often associated with a particular phase of the moon or with a tide, in some instances both.

The most fascinating and favourite Dalton Koss HQ Chiton fact is their homing ability. Chitons are able to have a night out crawling around rocks and feeding, but they are able to return to exactly the same spot before the sun comes up. Just amazing for a creature that has no eyes!