Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Australian Giant Cuttlefish - Sepia apama
Australian Giant Cuttlefish - Sepia apama

[Image: 2455528734_d265cd961b.jpg]

Scientific classification 
Kingdom: Animalia 
Phylum: Mollusca 
Class: Cephalopoda 
Order: Sepiida 
Family: Sepiidae 
Genus: Sepia 
Subgenus: Sepia 
Species: Sepia apama

The Australian giant cuttlefish is the largest of the world’s 100 or so species of cuttlefish.

Life span
2-3 years

The giant cuttlefish can grow to lengths of 1.5m (5 feet) and weigh nearly 15kg (33 pounds).

Physical Description
Giant cuttlefish have sucker-lined appendages growing from the head, eight long and prehensile arms, and two retractile tentacles. Cuttlefish have a highly developed central nervous system and highly developed complex eyes, which focus by changing the shape of the eyeball. Light entering the eye is controlled by the shape of the lid. They may be colour-blind, but they distinguish a vast number of tones. They have thick, internal calcified shells beneath an elongated muscular mantle. This mantle is expanded and contracted to expel water from the mantle cavity through the funnel. The mouth consists of a parrot-like beak, jaws, and a rasping tongue.

[Image: Sepia_apama.jpg]

They inhabit coastal waters from western Australia to Tasmania to as far north as Coffs Harbour.

The main diet of cuttlefish consists of small fish and crustaceans (such as prawns and crabs and small reef fish). Cuttlefish shoot out two tentacles, which are usually tucked away in pouches under their eyes. Prey is pulled into the powerful suckered arms and then eaten by crushing the animal with their beak.

Giant cuttlefish can crawl, swim or employ jet propulsion in bursts of surprising speed. They are usually solitary, attracted to bright colours, and curious about divers. Cuttlefish have a remarkable facility for changing colour to show aggression, fear or sexual excitement. Under their skin they possess a dense layer of elastic pigment sacs called chromatophores, which are used to change their colour. As camouflage, colour changes are used to match surroundings with extraordinary accuracy. Like all members of the squid family they use jets of ink to confuse attackers. These colourful cephalopods aggregate in their millions along the south Australian coast every autumn. Giant cuttlefish need a hard substrate on which to lay their eggs, so they gather on rocky reefs to breed. The result is one of Australia’s great underwater spectacles. The cuttlefish hover like alien spacecraft, constantly bickering as they bump into one another in the dense gathering. Males duel using an intricate combination of colour and body language, pulsing vivid stripes of blues, purples and greens over their mantles. Groups of up to seven huge males battle with each other using intense blasts of colour until one emerges as the winner. He then turns his attentions to the smaller females, mesmerizing them with another kaleidoscopic display.

[Image: se12a.jpg]

Fertilization is internal. Mating takes place when the male places his spermatophore in a pouch under the female's mouth. The capsules burst, releasing sperm into the female's mantle, thus fertilizing the eggs. After mating a female will lay about 200 golfball-size eggs among crevices in the reef, which hatch into miniature adults several months later. These tiny creatures go on to live and develop for two or three years, longer than any other species of cuttlefish, which is perhaps why giant cuttlefish grow to such an immense size.

Conservation status
Until recently the cuttlefish harvest at the spawning grounds near Whyalla, South Australia, was limited. New markets in Asia caused a dramatic increase in commercial fishing beginning in 1996. Public concern resulted in closing the spawning grounds to commercial fishing during 1999 and 2000 in order to conduct research that will aid understanding and protection of the animal. Giant cuttlefish are not listed by the IUCN Red List of Threatened Species.

[Image: Giant-Cuttlefish_big.jpg]

[Image: wildcat10-CougarHuntingDeer.jpg]
Stealth Camouflage At Night

ScienceDaily (Mar. 16, 2007) — Giant Australian cuttlefish employ night camouflage to adapt quickly to a variety of microhabitats on temperate rock reefs. New research sheds light on the animal's remarkable visual system and nighttime predator/prey interactions.

Cuttlefish are well-known masters of disguise who use highly developed camouflage tactics to blend in almost instantaneously with their surroundings. These relatives of octopuses and squid are part of a class of animals called cephalopods and are found in marine habitats worldwide. Cephalopods use camouflage to change their appearance with a speed and diversity unparalleled in the animal kingdom, however there is no documentation to date that they use their diverse camouflage repertoire at night. 

In a paper published in the April 2007 issue of The American Naturalist, MBL (Marine Biological Laboratory) Senior Scientist Roger Hanlon and his colleagues report, for the first time, that giant Australian cuttlefish employ night camouflage to adapt quickly to a variety of microhabitats on temperate rock reefs. The research sheds light on the animal's remarkable visual system and nighttime predator/prey interactions. 

While it's known that some marine fish and invertebrates use night camouflage as an anti-predator tactic, most camouflage studies are based on observations taken during daytime or dusk because videotaping behavioral data at night can be technically difficult. According to Hanlon, many animals perform some type of nocturnal color change, but the biological explanations behind the phenomenon have received scant attention in the science world. "The scarcity of studies on visual predator/prey interactions at night constitutes a major gap in sensory and behavioral ecology," he says.

Using a Remotely Operated Vehicle (ROV) equipped with a video camera, Hanlon and his team observed the giant Australian cuttlefish, Sepia apama, on their southern Australian spawning grounds over the course of a week. They observed that only 3% of cuttlefish were camouflaged during the day, during peak spawning periods. However, at dusk, the animals settled to the bottom and 86% of them quickly adapted their body patterns to blend in with habitats from sea grass to rocky reefs. 

"The fact that we observed multiple camouflage pattern types, each effective in different microhabitats, provides two important insights into visual predator/prey interactions at night," says Hanlon. "First, it provides the first behavioral evidence that cuttlefish have fine-tuned night vision. We know that in daytime they use visual information of their immediate surrounds to choose their camouflage pattern, and these new data demonstrate that they can fine-tune their camouflage patterns in concert with different visuals surrounds of each microhabitat at night. Curiously, the visual mechanism for night vision is largely unknown for cephalopods. Second, such fine-tuned camouflaged patterning implies strongly that fish predator vision at night is keen as well."

Visual predation at night is an unstudied phenomenon in the marine world, notes Hanlon. "From the perspective of a behavioral ecologist, we are ignorant of perhaps half of what goes on each daily cycle. There is a large ocean frontier out there yet to be studied."

[Image: 070309141100_1_540x360.jpg]
Photo showing the cuttlefish using night camouflage in seaweed. 

Story Source: Marine Biological Laboratory. "Stealth Camouflage At Night." ScienceDaily. (accessed October 21, 2015).
[Image: wildcat10-CougarHuntingDeer.jpg]
Cuttlefish Change Color, Shape-Shift to Elude Predators

Dave Hansford in Wellington, New Zealand 
for National Geographic News 
August 06, 2008

Cuttlefish have been captured on film exhibiting sophisticated camouflage strategies at night, according to scientists who are using new high-resolution cameras to bring these dramatic changes into focus. 

They are also using underwater spectrometers to measure color wavelength to determine how other marine creatures perceive these shifts. 

The findings are helping to crack the code of cephalopods, including cuttlefish, which also employ shape-shifting strategies to conceal themselves as coral or algae. 

Each summer, giant cuttlefish—molluscan relatives of octopuses and squid—gather along spawning grounds off the south Australian coast. 

For the last nine breeding seasons, Roger Hanlon, senior scientist at the Marine Biological Laboratory at Woods Hole, Massachusetts, and a National Geographic Society grantee, has closely studied their camouflage strategies. (National Geographic News is owned by the National Geographic Society.) 

His work takes place at a cuttlefish spawning site—a five-mile (eight-kilometer) stretch of shallow, flat reef—in Spencer Gulf, Australia. 

This summer Hanlon went back to Australia with collaborators from the University of Sydney and the University of Queensland and used an autonomous underwater vehicle, or AUV, with a pair of high-resolution cameras and a powerful strobe to take detailed pictures of the concealed cuttlefish at night. 

The cameras were synchronized and aimed at the same spot so they captured three-dimensional images. 

Researchers want to know if the cuttlefish have taken their extraordinary talent for camouflage to the next step by employing color wavelengths invisible to their predators. 

One of Hanlon's co-researchers, Professor Justin Marshall of the University of Queensland, used a sophisticated underwater spectrometer. "It tells you every wavelength present, and how much there is of it," Hanlon said. 

He hopes the device will help reveal just how closely the cuttlefish's camouflage coloration matches their surroundings. 

Then, the pair will take that data this fall and superimpose them over what they know of fish color vision. This will allow them to determine how well the color of the cuttlefish matches the color vision spectrum of their predators, Hanlon explained. 

Cloak of Many Colors 

All day, male cuttlefish duel for mating rights, flashing contrasting patterns to deter rivals and impress females. 

Come dusk, the cuttlefish turn from colorful billboards into masters of disguise, retiring to the seafloor, where they use their extraordinary color manipulation to hide from predators such as dolphins. 

Plenty of sea creatures employ camouflage at night, says Hanlon, but cuttlefish have made it an art form. 

"Each animal adopts a tailor-made camouflage pattern for the particular microhabitat that it settles in. An animal that settles in sand will appear one way, and ten feet (three meters) away, where it's all algae, another will be camouflaged differently," he added. 

What really thrilled Hanlon was the discovery in 2003 that the cuttlefish are performing sophisticated camouflage in a pitch-black ocean. This was the first time cuttlefish were seen matching their various surroundings at night. 

It seems the cuttlefish can assess the color, contrast, even the texture, of their surroundings and emulate it—in seconds and in total darkness. 

Cuttlefish in HD 

Cuttlefish skin has been likened to a color television—it has a way of combining basic colors to form more complex hues and dynamic patterns. "It really is electric skin," Hanlon said, because it's all controlled by neurons in the brain that transmit impulses and information to the rest of the body. 

"A cuttlefish has maybe ten million little color cells in its skin, and each one of them is controlled by a neuron. If you turn some on, but leave others switched off, you can create patterns," Hanlon explained. 

Cuttlefish use pigmented organs, elastic sacs called chromatophores, to display red, yellow, brown, and black directly. 

Bands of muscle radiate from each chromatophore, like the spokes of a wheel, so the creature can change the hue or opacity at will simply by contracting or relaxing those muscles to expose or conceal different color layers. 

With up to 200 chromatophores per .001 square inch (square millimeter), cuttlefish skin is like high-definition TV. 

Ironically enough, cuttlefish are colorblind. So how do they match their camouflage and their environment so accurately? 

Leave that, Hanlon said, partly to a separate layer of cells called leucophores, which reflect white light. 

"When you think about what white is, it's all colors at once. So in very shallow water, [leucophores] will look white, but as you go deeper, [the ocean] gets a little more green and blue, so those cells will reflect green and blue," he said. 

"They can do some matching in a passive way; it doesn't require the eye to assess anything. It's a cool trick." 


Mark Norman, senior curator of mollusks at Museum Victoria in Melbourne, said the cuttlefish have a still more ingenious camouflage trick up their sleeve—or at least under their skin. 

"They can also change the sculpture of their skin with bands of circular muscle," Norman explained. "As they contract, the near liquid in the center gets forced up as little nodes, or spikes, or flat blades that stick up." 

By employing such "skin sculpture," he said, cuttlefish could take on the appearance of kelp or rock. 

"By adding that structural component, [the cuttlefish] gets rid of outline and profile, and predators that are looking for shapes will be confused," Norman added. 

He said those predators have provided the evolutionary selection pressure for the cuttlefish's camouflage strategies over millions of years, "because they are such a good, soft, rump steak-kind of meal." 

While other mollusks, such as clams and nautiluses, have developed hard shells for protection, cuttlefish have instead relied on invisibility, a talent that may have applications for human technology. 

Norman said the military has shown interest in cuttlefish camouflage with a view to one day incorporating similar mechanisms in soldiers' uniforms. 

[Image: 080608-cuttlefish-camouflage-missions_big.jpg]
A giant cuttlefish (Sepia apama), photographed off the south Australian coast, retires to the ocean floor at night, employing complex camouflage strategies to blend in with the sand and hide from predators. Researchers are now studying how other marine creatures perceive the cuttlefish's colors. 
[Image: wildcat10-CougarHuntingDeer.jpg]
Vobby Wrote:

A really good video, showing this animal's incredible abilities.

Ceph Wrote:
Quote:Infrared invisibility stickers inspired by cephalopods

 Bioelectronics and 2015 Journal of Materials Chemistry C Hot Papers

The skin morphology of cephalopods endows them with remarkable dynamic camouflage capabilities. Cephalopod skin has therefore served as an inspiration for the design of camouflage devices that function in the visible region of the electromagnetic spectrum. In contrast, despite the importance of infrared signaling and detection for numerous industrial and military applications, there have been fewer attempts to translate the principles underlying cephalopod adaptive coloration to infrared camouflage systems. Herein, we draw inspiration from the structures and proteins found in cephalopod skin to fabricate biomimetic camouflage coatings on transparent and flexible adhesive substrates. The substrates can be deployed on arbitrary surfaces, and we can reversibly modulate their reflectance from the visible to the near infrared regions of the electromagnetic spectrum with a mechanical stimulus. These stickers make it possible to disguise common objects with varied roughnesses and geometries from infrared visualization. Our findings represent a key step towards the development of wearable biomimetic color- and shape-shifting technologies for stealth applications.

Ceph Wrote:Chemists Dissect Cephalopod Camouflage
Volume 93 Issue 34 | p. 32
Issue Date: August 31, 2015
ACS Meeting News: Methods tease apart pigment granules that help squid and related critters change color
By Celia Henry Arnaud

Cephalopods are masters of disguise. These animals, which include octopi, squid, and cuttlefish, rapidly change their skin color to blend in with their environment.
Researchers would like to mimic these color-changing capabilities in new types of materials for displays and textiles. But before they can do that, they need a better understanding of what’s happening in the cephalopods. There’s some understanding of the physical mechanism but almost no understanding of the chemical underpinnings.
Cephalopods rapidly change their colors in part by expanding or collapsing skin organs called chromatophores, which are filled with a network of pigment-loaded granules. Leila F. Deravi, an assistant professor of chemistry and materials science at the University of New Hampshire, and coworkers are developing methods to identify the components of these pigment granules. They reported some of their preliminary work earlier this month at the American Chemical Society national meeting in Boston in sessions sponsored by the Divisions of Analytical Chemistry, Chemical Education, and Physical Chemistry.
Deravi’s team is working with multiple species of cephalopod. “The cuttlefish is one of the highest-definition cephalopods,” Deravi said. “It’s got more chromatophores per unit area on its skin, enabling its rapid and adaptive camouflage.” But those small chromatophores are difficult to separate from other organs in the skin that absorb and reflect light.
Instead, Deravi’s group is focusing on the squid Loligo pealeii. “It’s got the largest chromatophores and is one of the easiest cephalopods to isolate off the coast of New England—as opposed to cuttlefish, which are native to the Mediterranean and Southeast Asia,” Deravi said.
The isolated pigment granules have interesting photonic properties, including a unique fluorescence profile, Deravi told C&EN. The shift in wavelength between where they absorb, in the blue-green spectral region around 410 nm, and where they emit, in the far red region around 630 nm, is quite large, she said.
Despite the interesting optical properties, the actual composition of the granules is not well characterized. In fact, many people assumed that the pigment was melanin and therefore unremarkable.

[Image: 1440615345175.jpg]
Scanning electron micrographs show cuttlefish pigment granules before (from left) and after being denatured in 0.2 M NaOH.
Credit: J. R. Soc. Interface

“In my lab, we’re trying to break down the individual nanoparticles to see what the hierarchical structure is,” Deravi said. “What inside the nanoparticles gives them these interesting photonic properties?”
To answer that question, Deravi’s group is developing new analytical methods to separate the components. During her time as a postdoc at Harvard University, she and her coworkers denatured isolated cuttlefish pigment granules in concentrated sodium hydroxide and did mass-spectrometry-based proteomic analysis to investigate whether proteins contribute to granular structure in the chromatophores. Through that work, they figured out that two types of proteins—reflectin, which has a high refractive index, and crystallin, which they hypothesize might help focus light into the chromatophores—are the main structural components in the chromatophore (J. R. Soc. Interface 2014, DOI: 10.1098/rsif.2013.0942).
Now, her group at UNH has turned its attention to the composition of the pigments embedded in squid pigment granules. To determine that, they are currently extracting the compounds with a milder solvent and analyzing the extract with thin-layer chromatography and mass spectrometry.
Even when they combine the material collected from 10 to 20 chromatophores, the researchers don’t have much to work with. “With TLC, we’re able to take that small amount of material and pull out as much information as we can,” Deravi said.
They isolated four pigment bands, which they then analyzed by mass spec. From the initial analysis, they think the pigments are ommochromes, but they haven’t yet determined the exact composition. Ommochromes are redox-active substituted phenoxazinones, which are derived from tryptophan. These pigments are found in insects and other arthropods. Deravi’s team doesn’t yet know how these pigments might help squid change colors.
Other researchers have focused on the size of the pigment nanoparticles and how that leads to interesting scattering properties. But Deravi thinks the chemical composition is just as important. After they determine the precise composition, she hopes to use that information to develop new materials.
Taking color-changing tips from these cephalopods is a good strategy, says Jason Heikenfeld, a professor of electrical engineering and materials science at the University of Cincinnati. “Mother Nature is still far more powerful than man-made technology when it comes to making surfaces that can change color and do so with very high energy efficiency,” he says. “If we had just looked at what Mother Nature was doing instead of trying to invent stuff, we would have had really cool technologies in optics much earlier.”
Chemical & Engineering News
ISSN 0009-2347
Copyright © 2015 American Chemical Society
[Image: wildcat10-CougarHuntingDeer.jpg]
Giant cuttlefish numbers bounce back in South Australian waters, numbers up 128 per cent this year

891 ABC Adelaide By Brett Williamson
Updated about 4 hours ago

[Image: 6873252-3x2-700x467.jpg]
PHOTO: The population of South Australia's giant cuttlefish has risen strongly after two near-perfect mating seasons. (Supplied: SARDI)

Breeding numbers of giant cuttlefish are bouncing back in South Australian waters, with a 128 per cent rise this season.

Fears had been held for the sepia apama species population, when in 2013 numbers dropped to 13,500.

But two consecutive years of growth has seen the population rise back to an estimated 130,771 this year.

Dr Michael Steer has researched giant cuttlefish for the South Australian Research and Development Institute (SARDI) for more than a decade.

YOUTUBE: SARDI giant cuttlefish footage

Following the lives and loves of nature's underwater 'rockstars'

"They are an incredibly important part of the ecosystem, because they occupy that middle food chain area," Dr Steer said.

"They provide a really good food resource for higher predators like your bigger fish, snapper, sharks, seabirds and mammals."

With a single breeding cycle and a lifespan of only 18 months, Dr Steer said the species was known to "live fast and die young".

The giant cuttlefish — which can weigh up to 10kg — are one of the most visually spectacular underwater animals because of its ability to produce an array of luminescent patterns and colours on their body.

Cuttlefish numbers were first recorded at Port Lowly, near Whyalla, in South Australia in 1998.

Concerns were raised at the time that commercial fisherman had begun targeting the unique site during the breeding season to catch the animals for bait and commercial purposes.

Port Lowly is one of the few sites known in Australia where the cuttlefish migrate on mass to breed.

"Given our understanding of the population and their biology, we realised that taking that kind of quantity out of a spawning population was quite risky," Dr Steer said.

Closure of fishing for the animals was soon enacted in the area, and numbers returned to more than 180,000 in 1999.

[Image: 6873262-3x2-700x467.jpg]
PHOTO: With a lifespan of just 18 months, giant cuttlefish are known to "live fast and die young". (Supplied: SARDI)

Colder winters behind 2013 decline

With irregular counts carried out since 1999, it came as quite a shock when external research revealed the population had dropped to the 13,500 in 2013.

Annual counts followed, with the numbers of cuttlefish boosted to 57,300 in 2014, and more than doubling to 130,771 in 2014.

Dr Steer said it was unfortunate to see the plummet in numbers in 2013, but the species were known to be exceptional at bouncing back if conditions were right.

In 2014 and 2015, the median water temperatures in the area were above average in the final weeks of the breeding cycle.

Colder than average winter water temperatures were experienced in 2011, 2012 and 2013.

When in warmer waters, hatchlings were able to grow faster and, when released, were less likely to be attacked by smaller predators.

"It really highlights the fact that the population is very responsive to the environment," Dr Steer said.

"The conditions for growth, reproduction and survival of the species were very good [in 2014 and 2015].

"At this stage it looks like water temperature is the clearest signal we have to date that is reconciling the population.".

Human interaction not a factor in fluctuating cuttlefish numbers

Dr Steer said although the breeding season of the cuttlefish had become a tourist attraction for the area, there was no evidence to suggest divers and snorkelers were discouraging the animals.

"Anyone who has been diving on that population would understand that once these animals are engaged in reproductive behaviour they are pretty focussed," Dr Steer said.

Dr Steer said the animals never lost their mojo.

"You can dive around them and get very close to them without disturbing them at all," he said.

Dr Steer said researchers monitored local tourism numbers with cuttlefish numbers and found no correlating patterns.
[Image: wildcat10-CougarHuntingDeer.jpg]
Righty Male Cuttlefish Are Better at Sex and Fighting

By Rafi Letzter, Staff Writer | March 13, 2019 03:47pm ET

[Image: aHR0cDovL3d3dy5saXZlc2NpZW5jZS5jb20vaW1h...lzaC5qcGc=]
Credit: Sarah Zylinski, Duke University

Righty cuttlefish males have more sex and win more fights. And this could help explain why lefty humans exist at all.
In a paper published March 13 in the journal Proceedings of the Royal Society B, scientists watched cuttlefish as they hooked up and threw down. Most male cuttlefish, it turns out, are "righties" in sexual situations — meaning that they examine females with their right eyes before mating, and approach females from their right side. But when it comes time to fight the competition, most cuttlefish are "lefties," approaching the fight left-side first.
These results came from a series of observations of cuttlefish mating and messing with each other in the wild, followed by laboratory experiments where the creatures were assigned enemies or lovers under the eye of a well-placed camera.
This finding, the researchers suggested, could explain why nine out of 10 people are right-handed, but lefties still exist.
This isn't just a human phenomenon: Across the animal kingdom, species tend to have a much-more-common favored side. The term for this is "lateralization." But if one side is more evolutionarily fit than another, why wouldn't it take over the whole species? And, conversely, if sidedness doesn't matter, why does the imbalance exist?
This cuttlefish study, the researchers suggested, demonstrates that there are circumstances in which a species benefits from sharing a dominant side. But individual members can gain some advantages of their own by doing the unusual, less common thing.
If most cuttlefish males are sexual righties, it's easy for cuttlefish females to coordinate with those males, because they know what to expect. The handful of lefties struggle because the females don't expect their style of approach.
But when it comes to fighting, the minority sidedness (again, righties) has an advantage, because that behavior is less predictable. (Human beings see a similar advantage in certain sports where lefties are overrepresented.)
So while most cuttlefish (or humans) play it safe by acting in a normal, predictable, sociable manner, a handful of outliers might seize some advantage by switching things up.

Journal Reference:
Alexandra K. Schnell, Christelle Jozet-Alves, Karina C. Hall, Léa Radday and Roger T. Hanlon Fighting and mating success in giant Australian cuttlefish is influenced by behavioural lateralization Published:13 March 2019

Behavioural lateralization is widespread. Yet, a fundamental question remains, how can lateralization be evolutionary stable when individuals lateralized in one direction often significantly outnumber individuals lateralized in the opposite direction? A recently developed game theory model predicts that fitness consequences which occur during intraspecific interactions may be driving population-level lateralization as an evolutionary stable strategy. This model predicts that: (i) minority-type individuals exist because they are more likely to adopt unpredictable fighting behaviours during competitive interactions (e.g. fighting); and (ii) majority-type individuals exist because there is a fitness advantage in having their biases synchronized with other conspecifics during interactions that require coordination (e.g. mating). We tested these predictions by investigating biases in giant Australian cuttlefish during fighting and mating interactions. During fighting, most male cuttlefish favoured the left eye and these males showed higher contest escalation; but minority-type individuals with a right-eye bias achieved higher fighting success. During mating interactions, most male cuttlefish favoured the left eye to inspect females. Furthermore, most male cuttlefish approached the female's right side during a mating attempt and these males achieved higher mating success. Our data support the hypothesis that population-level biases are an evolutionary consequence of the fitness advantages involved in intraspecific interactions.
[Image: wildcat10-CougarHuntingDeer.jpg]

Forum Jump:

Users browsing this thread: 1 Guest(s)