Anyone looking forward to summer and cooling off with ice cream🍦 may look to algae with thanks 

The thick brown, flexible and strong algae we 🏊🏼‍♀️ & 🏄🏼‍♀️ with, the Bull Kelp (Durvillaea potatorum), forms the basis of important ecosystems.

Living up to 8 x years, it is one of the fastest growing algaes, able to grow to lengths over 30 m. Providing shelter from predators and strong currents, the forests create important nursery areas and sanctuaries for many species of fish, crustaceans, suspension feeders, and other invertebrates, including sea urchins, sea stars and crabs.

Being a good source of trace minerals it also contains Alginate, a compound found within the cell walls of brown algae, that causes liquids to gel, and therein used in ice creams (amongst many other uses, both traditional and current).

Usually found in areas with high nutrient levels, such as where deep-water upwellings of nutrients occur, it only grows in cooler waters.

Happy summer Marine Monday exploring day to you 😀

With the commencement of December, I’ll be looking forward to writing more Marine Monday’s in Jan 2020.

  • Rebecca Hosking

Part fish and part shark, the Callorhinchus milli is unique, being a Chimaera.

The Elephant Shark/Fish/Ghost Fish has a skeleton of cartilage like sharks and rays, they have only one gill opening, are minus denticles, and their teeth are fused into plates.

Their habitat is on the continental slope in deep water, and it uses it’s unique trunk-like ”snout” to probe the sea floor for invertebrates and small fish. Given that, how do we on the Surf Coast encounter them?

After the females reach 16 years x they are able to reproduce. They make a journey towards the shore, needing the shallow waters of bays and estuaries, to lay one of two eggs, then they return to their deeper waters. They reproduce only every two years if not caught by fisherman during the journey in shallower waters.

The egg case is fantastically shaped to settle just below the sand.

The pups need to be in their egg case for eight months before they are ready to hatch. Occasionally we may see a fresh egg case, like this one, or the remains of a darker brown coloured case, once the pup has hatched, washed ashore after big swell during winter.

If you find one that is still occupied, gently return it to the ocean. (I often find a rip to place them in to give the best chance of it being taken behind the breaking waves.)
Happy Marine Monday exploring day to you

-Post and Image by Rebecca Hosking @ FERMS

Adding to the trend of “going nude” at the beach, is one of my favourite creatures, the Nudibranch.

As per those at the Whites Beach and the Pt Addis area, “Nudi’s” come in all shapes and sizes; with some being microscopic, far smaller than the tip of a finger nail and well camouflaged, and those being brightly coloured and up to around 2 cm’s (for those around here).

Derived from the Latin nudus (naked) and branchia (gills), as the name suggests, there is a naked component to these wonderful opisthobranchs.

They are members of the mollusc family, yet the adults are minus a shell and their gills are exposed. Without a shell to protect them they have very interesting means of protecting themselves from predation.

The chemical diversity in Nudi’s is extensive. Whilst the majority manufacture their own pigment others are fantastic recyclers. Having highly specialised diets, they re-use the colour pigments from their diet by incorporating them in their skin. Others capture and ably retain the active stinging cells of their food source, some “farm” elements to become “solar powered”, whilst others again alter defensive compounds to enhance them, for their personal defence mechanisms. Fancy being able to utilise the toxins from what one eats for one’s own protection. Super neat.

They are thought to live for only 1 x year, and with their species specific eating habits, they are sensitive to any disruption to their food source.

This weeks post shows the Nudi Rostanga calumus. Given the strong red colour of this Nudi it is likely it dines on red sponges. (Phone footage, Aireys Inlet, 2014.)

  • Rebecca Hosking @ FERMS

What looks like a mini seaweed purse but is more exciting? It’s likely to be an egg case that has washed ashore from certain sharks, or from skates and chimaera, after the young has hatched, much like this one last week.

There are a few reproductive methods for the approx 500 species of sharks, with around 40% laying eggs. Oviparity involves the process of egg laying, where the young hatch outside of the female. This example is thought to belong to a rusty cat shark.

The cases are thin and strong, being made from the same substance as human hair and fingernails; collagen and keratin.

Finding an egg case is always a treat as it indicates there are breeding females.

A female may spend a long time laying her eggs, ensuring they’re securely fixed in a safe place, as the process of the young developing, ranges from around 6 – 12 months, species dependant.

Much like a chook egg, the egg case is a protective capsule which acts as a life-support machine, containing everything that’s needed for the developing young. The embryo absorbs nutrients from a yolk-sac before hatching and emerging as a miniature version of the adult.

If you find one that is still occupied, gently return it to the ocean. (I often find a rip to place them in to give the best chance of it being taken behind the breaking waves.)

  • By Rebecca Hosking @ FERMS

Sometimes we encounter lovely transparent glinting elements washed up on the shore. At times these sparkling forms will be a fabulous creature known as a Salp.

Salps are semi-transparent, barrel-shaped, gelatinous-type creatures. Whilst they possibly look a bit like jellies, salps are actually free-floating tunicates.

They live in the open ocean and propel themselves along by contracting their bands of muscles.

The contractions cause water to pump through their bodies, which they strain, to feed on phytoplankton.

If you look very closely, you can see the contractions with the naked eye.

They can end up washed onto our shore line, and when they do, the individuals tend to be around 1 cm in size. However, if you are fortunate to be out surfing behind the sets, like my partner, it is there that you will see the salps connected in long lines.

These lines are the result of their method of reproduction; they are asexual and the parent produces a chain, of tens to hundreds, of individuals.

Salps are important for their own life, for the fish that eat them, and also for the environment. During their digestive process, they transport tons of carbon from the ocean surface to the deep sea, and keep it from re-entering the atmosphere. Pretty cool!

Their numbers are most abundant in the Southern Ocean, near Antarctica, but are also found in temperate and equatorial seas.

– With Rebecca Hosking @ FERMS

Today’s post features the Sea Hare of the class of Gastropoda and shows the sea hare Aplysia parvula.

I took these photographs in 2014 and 2015, with also seeing many at the end of 2019, at ERMS.

I have had some of my favourite times observing the gentle algae grazing action and interactions of families of sea hares in rock pools in Vic, TAS, SA and WA.

The name Sea Hare derives from their rounded shape and from the two long rhinophores that project upwards from their heads that were thought to somewhat resemble the ears of a hare. Those rhinophores are extremely sensitive chemoreceptors which gives the sea hares the ability to follow the faintest scent, like a super power. (The “scents” detected are chemicals dissolved in the sea water.)

Other identifiable physical traits are the oral tentacles at the front of the head, on either side of the mouth, and the large flaps (parapodia) on their backs that enclose the fragile shell. These large wing-like flaps protect the gills, and some species of sea hares use these flaps for swimming, but generally we see them gliding over rocks whilst feeding on algae.

Being herbivores, they live in seagrass beds, rock pools and other intertidal environments where there is a good amount of healthy algae. As they eat, they take up the pigments in the algae, which influences their colour. This is an effective way of ensuring they camouflage well with their habitat. Overall, they consist of 9 x genera, and size-wise, range from less than 2cm up to 70cm in length.

They tend to come closer to shore when it is time for them to breed. They are hermaphrodites and when it comes to breeding time, they congregate in shallow waters, forming a chain. In due course they lay yellow spaghetti-type eggs. In the intertidal zone they are more vulnerable as they’re prone to being effected by wind and wave action, and can therefore be stranded on the sand. As they have soft bodies, they oft look like a coloured blob of jelly, when unfortunate enough to be washed up onto the sand. Gently collecting them and returning them to the ocean, and watching them restore and take on their true shape, is very rewarding.

The neurophysiology of sea hares is unique and are being used by scientists to assist in research of human neurological diseases due to their observable 20,000 neurons.

They are sweet, very gentle, slow moving creatures, with a defence mechanism being to taste unpleasant, which would be an effective deterrant. They can have a semi-toxic slime layer over their bodies and toxins infused through their tissues (that are usually of no effect to humans). They are also able to emit a coloured dye when stressed to work as a distraction/smoke screen. The colour of the dye is dependant on the pigments in their algae food source. That said, of those I have seen beached in SA and WA, including those being collected by humans as food (in a Marine Sanctuary which made for good teaching material), even though in danger, they had not emitted the dye.

Whilst they have minimum predators due to the above their life cycle is very short.

Along the Surf Coast, I’ve only seen them under rocks at the Eagle Rock Marine Sanctuary, and once further along towards the Fairhaven Surf Club. I’d love to know if and where you’ve seen them along the Surf Coast. 

Happy sea hare day to you.

?

(I’ve included some other photos of those taken in Aireys Inlet, Robe and Beachport in SA, and Gnaraloo in WA, showing differences and similarities, on my photography page if interested.)

Welcome to Marine Mondays. ??

Today’s post features the Waratah Anemone (Actinia tenebrosa)

The Waratah Anemone is from the Phylum of Cnidaraians.

It is endemic to rocky shores and is part of a community of many different anemones living in the tidal zone. (I’ll cover some more in other posts). They are fun to spot due to their distinctive strong red to reddy-brown colouring and are a fixture of many peoples visits to our coast and a part of delightfully leisurely days/times at the beach exploring the intertidal zone.

You’ll notice that their habitat is usually in crevices, on the undersurfaces of rocks, on semi-protected and exposed rocky shores, clumping together in areas of shade, in the mid littoral zone. You may see a line of of juveniles lining the rock pool fissures which are always fun to see. The reason for their oft appearing in large groups is due to the method of reproduction, which involves the adult brooding the young (in the coelenteron, which is the area used as a stomach, an excretory organ and as a primitive vascular system), and releasing the small but fully developed offspring through it’s mouth. The offspring then attach to the nearest rock surface available.

They are visually made up of a column (the body) which is a rich red colour, a central oral disk which is lesser red in colour, and tentacles which are also bright red. Therefore a colourful feature of our rock pools. (Tentacles are tactile feelers, whilst some are chemoreceptors, where they are able to taste chemicals in the water.)

Whilst they seem to be sessile, meaning they live in the one place throughout their lives, using their basal disc to fix to a substrate, they actually are able to move and relocate by very slowly gliding.

There are two forms that we see the Waratah Anemone in. Open or closed. This refers to when the feeding tentacles are open (like a flower) or closed. It draws it’s tentacles in when it is out of the water, on low tides, to minimise it’s exposure to the air and drying out. They breathe by the method of diffusion through the thin membrane like skin which must be kept moist (by mucus).

Cnidarians are simple two celled layered organisms with jelly like support tissue called mesoglea between these layers to give them structural support and adaptive shape (hydrostatic skeleton).

Waratahs catch and immobilise their prey, of plankton and small fish by using their tentacles, each of which contains hundreds of stinging cells called nematocysts. If you very gently offer some seaweed to the tentacles you will see these tentacles move, bending into the middle of the central oral disk, where it’s mouth is located. If you were to touch these tentacles, you will feel a slightly sticky tickling feeling. That sticky sensation is when you have been harpooned by the nematocysts, but as our fingers are not their intended food source, this harpooning is of no harm to us.

As we know, life on the rocky shores can be competitive so as an adaption for survival/habitat/real estate mogul-ing, these family oriented anemone’s, have tentacles which they can use to attack a neighbour if they discern that they are not a direct relative, and are too close/are a threat to their habitat and the habitat of their direct family.

They have few predators but on a high tide are vulnerable to fish and crab predation.

Their distribution range is Vic, SA, NSW, TAS and across to southern Western Aust and NZ.

Happy Waratah Anemone day to you 

-Rebecca Hosking

?? Following on in the steps of Fossil Friday and Wildlife Wednesday is Marine Monday, where I’ll share marine related finds from along our beautiful coastline. Hidden mainly from view, below the surface of the sea, in the rock pools, under the waves, there is much “going on” underneath.

Today’s post features the Blue Blubber Jelly or Jelly Blubber (Catostylus mosaicus)

A jelly encounter

The sea jelly is made up of 95% water with only 5% being a solid matter, which is why they are lovely to watch in the ocean but then appear blob-like when washed up upon the shore. Jellies are not fish, and therefore no longer referred to as the good old jelly fish, but are sea jellies (or Cnidarians).

They don’t have a backbone (being invertebrate animals), and the general anatomy of jelly’s includes the bell, the tentacles, and the oral arms. Jellies are composed of three layers: an outer layer (epidermis), a middle layer made of a thick, elastic, jelly-like substance called mesoglea; and an inner layer (the gastrodermis). They have limited control over movement, but can use their muscles (the hydrostatic skeleton) to accomplish movement through a pumping action, contraction-pulsations, of the bell-like body, to propel themselves through the water. (Some species of jellies actively swim most of the time while others are passive much of the time.)

Their habitat is the water column. Drifting at the mercy of the currents they often accumulate in large numbers in sheltered bays and estuaries. (The formation of these ‘blooms’ is a complex process that depends on ocean currents, nutrients, temperature and ambient oxygen concentrations.)

Snorkelling along and finding oneself in a bloom (or in a “smack” which is the term for a group of jellies) is a memorable, exhilarating and gentle experience.

The Blue Blubber jelly is the most commonly seen jelly in Victoria and I’ve encountered good numbers in both Geelong and St Leonards.

An elementary nervous system, a “nerve net”, allows sea jellies to smell, detect light, and respond to other stimuli. The simple digestive cavity of a sea jelly acts as both its stomach and intestine. The nutrients are absorbed using the gastrodermal lining of the gastrovascular cavity. Like all members of the phylum Cnidaria (which anemones and corals belong to), the body parts of a sea jelly radiate from a central axis, and it is this radial symmetry that allows jellies to detect and respond to food or danger from any direction. Pretty cool. They do not need a respiratory system since their skin is thin enough that the body is oxygenated by diffusion.

To identify as a Blue Blubber, they will have a noticeable cross (the gastrovascular cavity) visible through the surface of the bell. The bell is rounded, up to 35 cm across, they have eight textured arms (the texture like cauliflower), and each arm has three ‘wings’. They have stinging cells along the arms which help catch prey (being carnivores). Their body, is fleshy, sturdy and fairly opaque. There colour can vary slightly from a creamy white to a bluey-white as produced by the jellies own pigment. (Some sea jellies have symbiotic relationships with algal plant cells that are kept inside their bodies, which create the colour hues. For those jellies, the algae photosynthesise, converting sunlight into energy that can be used by the sea jelly.)

They are either male or female (dioecious). In most jelly species, spawning is controlled by light, so the entire population spawns at about the same time of day, often at either dusk or dawn. To reproduce, both genders release either sperm or eggs into the surrounding water, where the unprotected eggs are fertilized and mature into new organisms.

The lifespan of sea jellies typically ranges from only a few hours up to 6 x months, with most of the large coastal jelly’s, like this one, living for about 2 to 6 months.

There is an interesting theory associated with the noticeable increase in the numbers of jellies in general around the world. Increased nutrients in the water, ascribed to agricultural run off, climate change, pollution, habitat destruction, trash, chemical waste, and overfishing are suggested for seeing increased numbers of jellies. This is due to; ecosystems in which there are high levels of nutrients, provide nourishment for the small organisms, on which jellyfish feed. In waters where there is eutrophication, low oxygen levels often result, favouring jellies as they thrive in less oxygen-rich water than fish can tolerate.

Plastic bags immediately look like sea jellies when in the sea (and in any water). Sea turtles are their natural predator, and whilst the leatherback sea turtle relies on jellies as their main meal, many marine animals including penguins, birds, and crabs, include jellies in their diets.

Large adult sea jellies are often accompanied by small fish which hide amongst their tentacles for protection which is super cool to see.

The Blue Blubber sea jelly lives in Vic (notably in areas such as Port Philip Bay) NSW and QLD. I photographed and videod these examples at St Leonard’s.

The mini photos are parts of various sea jellies as they appear when washed ashore.

Happy sea jelly day to you ?

-Rebecca Hosking

Welcome to Marine Mondays. ?? Following on in the steps of Fossil Friday and Wildlife Wednesday is Marine Monday, where I’ll share marine related finds from along our beautiful coastline. Hidden mainly from view, below the surface of the sea, in the rock pools, under the waves, there is much “going on” underneath.

Today’s post features the Maori Octopus (Octopus maorum) of the Cephalopod class.

(I had promised myself to make posts shorter although this one is longer again. The next one will be far shorter so is more reader-friendly.)

This group of marine molluscs includes squid, octopus, cuttlefish and nautilus. Cephalopod translates to “head feet” and is a reference to the way the cephalopod’s head connects to its many arms.

The basic cephalopod body plan includes two eyes, a mantle, a funnel (also called a siphon), and eight arms. They have bilateral body symmetry, a prominent head, and their foot has been modified into arms or tentacles.

Cephalopods are found in all of the world’s oceans. They are found at all depths, from hydrothermal vents to the sea surface. All Cephalopods are carnivores.

Coloration of this species can vary and they will be either orange-brown or dark purple-grey. The Maori Octopus is a carnivore and is nocturnal (is active at night). It is the largest octopus in our area and whilst they only live a short life (around 2-3 years) they can reportedly weigh up to 12 kg when fully grown. The octopus has numerous small iridescent white spots on the web, arms and dorsal arm crown but there are no spots present on the mantle.

Octopuses are considered to be the most intelligent of all invertebrates . They have a highly complex nervous system, only part of which is located in its brain. Apparently about two-thirds of octopus’ brain cells are in each of octopus’ arms. Laboratory experiments with mazes and problem-solving have shown that they do have both short-term and long-term memory. The octopus also uses tools in it’s habitat and their arms show a wide range of complicated reflex actions. Some of my favourite stories involve anecdotes of the intelligence and problem solving skills of octopus.

Not only being intelligent and active hunters, their biology is also interesting.

Cephalopods are the only mollusks with a closed circulatory system. They have three hearts: two gill hearts that transport blood through the capillaries of the gills (to pack the blood with oxygen before transferring it to the large one) and a third larger single heart that pumps the oxygenated blood through the rest of the body. Cephalopods use the pigment hemocyanin, a copper-containing protein, rather than hemoglobin to transport oxygen. This means their blood is colourless when deoxygenated and turns blue when exposed to air.

They have suckers on their arms that are also extremely sensitive; they can pick up subtle chemical signals and move individually, even folding in half in a pinching gesture.

Octopuses are the “masters of disguise”. As well as having the ability to hide in very small spaces, as the only hard part of their body is their beak (much like a parrots beak), they can change their colour by the chromatophores in their skin, papillae, in just three-tenths of a second.

An example of the chromatophores in use is captured in the photos above (taken from a distance). It’s arms were active whilst it’s arms sought out crabs in the distance.

They also can raise their skin, up to 3cm in adults, to create a texture to match it’s surroundings (to mimic speficic objects, for e.g., to match a rock with bumps on it) so as to disappear into the underwater scenery) taking this level of camouflaging to the next level. Other defence and survival mechanisms include jet propulsion (from it’s mantle) for fast movements/escapes over short distances and activating it’s ink sac to create a “smoke screen” to distract it’s predator and allow it to escape.

Octopuses have excellent eyesight and a very well developed sense of touch. Octopuses move about slowly by crawling, walking on their arms, or by swimming.

All Cephalopods have a two-part beak and most have a radula, They feed by capturing prey with their arms, drawing it in to their mouth where they have a strong beak (much like a parrots) that breaks through the carapaces of crabs, and they take bites of their prey that includes, small fish, molluscs and crustaceans. To prevent their prey from escaping, they have modified salivary glands that produce a venom (a saliva with bacteria) although all octopuses produce venom only the small blue-ringed octopuses are deadly to humans. It is thought that perhaps these “juices” that are ejected from their salivary glands onto their captured prey also assists with separating the flesh of their prey from the bone or shell.

The Maori Octopus lives in the benthic zone (ocean floor), in soft-sediment and rubble habitats, with depths of 0-549m and will sometimes forage in nearby hard-reef habitats. I have spotted them myself in the intertidal zone in Aireys Inlet and Lorne. Whilst it is said that live in temporary shelters there are a few locations that are known as regular habitats. The one featured in this post was at Aireys Inlet, in the Eagle Rock Marine Sanctuary, and was sheltered under a semi cave, and was taking advantage of the overcast day to venture out to look for food during the late afternoon. I have also been gently tapped on the foot by a gentle inquisitive octopus arm whilst standing in a deep rock pool area for a lengthy time on a dark and overcast day.

They live solitarily in a den for up to 3 months at a time. They gather prey remains to form a midden (piles of shells, bones and rocks) which is used to conceal the entrance to their den.

The adult male and adult female octopus mate with the male octopus then becoming senescent and dieting shortly after. The female usually stops eating for 2 weeks during the laying eggs period and continue to look after the eggs until they hatched (a month). She may lay approximate 7000 eggs. Their eggs are usually clusters of 3-12 eggs and cemented directly to a rocky surface. The mother uses her arms to “sweep” across the eggs to keep them well oxygenated, clean and safe from predators. “During brooding period female will stop feeding so that it produce less wastes and ensure the water quality is good for the eggs. When the eggs are about to hatch the mother will frequently squirt water on the eggs using siphon until the eggs hatched.” After the eggs hatch, the female will swim away and dies shortly after, as she has been greatly weakened from her dedication in safe guarding her eggs. Newly hatched octopuses live amongst the plankton and eat copepods and larval crabs and starfish.

The main predators of adult octopuses are seals, eels, dolphins, sharks, sea lions, wobbegongs, school and gummy sharks, mulloway, queen snapper and dolphins, and perhaps penguins, as well as humans.

Cephalopods have existed since Carboniferous period, which is roughly 296 million years ago.

Happy octopus day to you.

– Rebecca Hosking