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133-461: The giant cuttlefish ( Sepia apama ), also known as the Australian giant cuttlefish , is the world's largest cuttlefish species, growing to 50 cm (20 in) in mantle length and up to 100 cm (39 in) in total length (total length meaning the whole length of the body including outstretched tentacles). They can be over 10.5 kg (23 lb) in weight. Like all cuttlefish species,

266-670: A mutation , as in albinism ), not all pigment-containing cells are chromatophores. Haem , for example, is a biochrome responsible for the red appearance of blood. It is found primarily in red blood cells (erythrocytes), which are generated in bone marrow throughout the life of an organism, rather than being formed during embryological development. Therefore, erythrocytes are not classified as chromatophores. Chromatophores that contain large amounts of yellow pteridine pigments are named xanthophores; those with mainly red / orange carotenoids are termed erythrophores. However, vesicles containing pteridine and carotenoids are sometimes found in

399-494: A biological assay for rapidly identifying potential bioactive compounds using melanophores from the African clawed frog . Other scientists have developed techniques for using melanophores as biosensors , and for rapid disease detection (based on the discovery that pertussis toxin blocks pigment aggregation in fish melanophores). Potential military applications of chromatophore-mediated colour changes have been proposed, mainly as

532-440: A closed circulatory system. Like other marine mollusks, cuttlefish have ink stores that are used for chemical deterrence, phagomimicry , sensory distraction, and evasion when attacked. Its composition results in a dark colored ink, rich in ammonium salts and amino acids that may have a role in phagomimicry defenses. The ink can be ejected to create a " smoke screen " to hide the cuttlefish's escape, or it can be released as

665-587: A cyan biochrome of unknown chemical structure in cells named cyanophores. Although they appear unusual in their limited taxonomic range, there may be cyanophores (as well as further unusual chromatophore types) in other fish and amphibians. For example, brightly coloured chromatophores with undefined pigments are found in both poison dart frogs and glass frogs , and atypical dichromatic chromatophores, named erythro-iridophores have been described in Pseudochromis diadema . Many species are able to translocate

798-624: A deimatic display to warn off potential predators. Under some circumstances, cuttlefish can be trained to change color in response to stimuli, thereby indicating their color changing is not completely innate. Cuttlefish can also affect the light's polarization, which can be used to signal to other marine animals, many of which can also sense polarization, as well as being able to influence the color of light as it reflects off their skin. Although cuttlefish (and most other cephalopods) lack color vision, high-resolution polarisation vision may provide an alternative mode of receiving contrast information that

931-501: A leucistic disorder. Chromatophores are sometimes used in applied research. For example, zebrafish larvae are used to study how chromatophores organise and communicate to accurately generate the regular horizontal striped pattern as seen in adult fish. This is seen as a useful model system for understanding patterning in the evolutionary developmental biology field. Chromatophore biology has also been used to model human condition or disease, including melanoma and albinism. Recently,

1064-802: A pseudomorph of similar size to the cuttlefish, acting as a decoy while the cuttlefish swims away. Human use of this substance is wide-ranged. A common use is in cooking with squid ink to darken and flavor rice and pasta. It adds a black tint and a sweet flavor to the food. In addition to food, cuttlefish ink can be used with plastics and staining of materials. The diverse composition of cuttlefish ink, and its deep complexity of colors, allows for dilution and modification of its color. Cuttlefish ink can be used to make noniridescent reds, blues, and greens, subsequently used for biomimetic colors and materials. A common gene between cuttlefish and almost all other cephalopods allows them to produce venom, excreting it through their beak to help kill their prey. Additionally,

1197-540: A squid . Very little time is spent foraging (3.7% during the day and 2.1% at night); most of their time is spent resting and hiding in crevices from predators. The exception to this behavioral routine is the mass spawning aggregation, where cuttlefish are far more active during the days or weeks that they spend there. The Australian giant cuttlefish is eaten by Indo-Pacific bottlenose dolphins , which have been observed (in South Australia's Spencer Gulf) to have developed

1330-408: A basket-like melanophore layer with processes covering the iridophores. Both types of melanophore are important in physiological colour change. Flat dermal melanophores often overlay other chromatophores, so when the pigment is dispersed throughout the cell the skin appears dark. When the pigment is aggregated toward the centre of the cell, the pigments in other chromatophores are exposed to light and

1463-492: A bulk commodities port, should it be developed at Port Bonython , adjacent to Point Lowly. A new wharf for the loading of iron ore , and possibly copper concentrates, has been proposed but not constructed. A community action group called the Cuttlefish Coast Coalition and Alternative Port Working Party were formed in opposition to new desalination and port developments near the cuttlefish breeding habitat. In 2021,

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1596-487: A cause, but was otherwise inconclusive, and that further areas of Spencer Gulf would be closed in 2014. The population continued its decline, reaching the lowest numbers on record in 2013. In 2014, the cuttlefish population showed first signs of potential recovery, after 15 years of an overall trend of decline. Numbers increased again in 2015 confirming this trend. As of 2021, the population has recovered to an estimated population exceeding 240,000 animals. The fishing ban for

1729-429: A change in environment. This type of camouflage, known as background adaptation , most commonly appears as a slight darkening or lightening of skin tone to approximately mimic the hue of the immediate environment. It has been demonstrated that the background adaptation process is vision-dependent (it appears the animal needs to be able to see the environment to adapt to it), and that melanin translocation in melanophores

1862-433: A cuttlefish can be independent of the other side of the body; males can display courtship signals to females on one side while simultaneously showing female-like displays with the other side to stop rival males interfering with their courtship. The deimatic display (a rapid change to black and white with dark 'eyespots' and contour, and spreading of the body and fins) is used to startle small fish that are unlikely to prey on

1995-606: A cuttlefish is an unusual shade of green-blue, because it uses the copper-containing protein haemocyanin to carry oxygen instead of the red, iron-containing protein haemoglobin found in vertebrates' blood. The blood is pumped by three separate hearts: two branchial hearts pump blood to the cuttlefish's pair of gills (one heart for each), and the third pumps blood around the rest of the body. Cuttlefish blood must flow more rapidly than that of most other animals because haemocyanin carries substantially less oxygen than haemoglobin. Unlike most other mollusks, cephalopods like cuttlefish have

2128-550: A depth of 100 m (330 ft). In 2009 the species was listed at Near Threatened on the IUCN Red List of Threatened Species due to an observed declining trend at that time. Giant cuttlefish live for one to two years. Breeding takes place with the onset of the southern winter. Males abandon their normal cryptic colouring and set out to dazzle the females by adopting rapidly changing bright colours and striking patterns. Females are polyandrous , and collaborative research indicates

2261-822: A desalination plant at Point Lowly. The major sponsor of Come Out Festival in 2009 was the BHP Billiton Youth Fund, the same company which proposed to construct the desalination plant. The overarching theme of the festival that year was 'Colliding Worlds'. BHP Billiton has not sponsored the Come Out Festival since the 2009 event. During the Adelaide Fringe Festival in March 2012, the RiAus presented Sepia , an original work by Welsh playwright, Emily Steel. Set in Whyalla,

2394-798: A female cuttlefish. Changing their body color, and even pretending to be holding an egg sack , disguised males are able to swim past the larger guard male and mate with the female. Cephalopods are able to communicate visually using a diverse range of signals. To produce these signals, cephalopods can vary four types of communication element: chromatic (skin coloration), skin texture (e.g. rough or smooth), posture, and locomotion. Changes in body appearance such as these are sometimes called polyphenism . The common cuttlefish can display 34 chromatic, six textural, eight postural and six locomotor elements, whereas flamboyant cuttlefish use between 42 and 75 chromatic, 14 postural, and seven textural and locomotor elements. The Caribbean reef squid ( Sepioteuthis sepioidea )

2527-432: A fraction of a second. Located in three layers under the skin, leucophores make up the bottom layer, with chromatophores the outermost. By selective blocking, the three layers work together to produce polarised patterns. Unlike those in most animals, cuttlefish iridophores are physiologically active; they can change their reflectivity, and the degree of polarisation can also be controlled. Cuttlefish are colourblind ; however,

2660-613: A greater number of polarized light displays than males and also alter their behavior when responding to polarized patterns. The use of polarized reflective patterns has led some to suggest that cephalopods may communicate intraspecifically in a mode that is "hidden" or "private" because many of their predators are insensitive to polarized light. Leucophores, usually located deeper in the skin than iridophores, are also structural reflectors using crystalline purines , often guanine, to reflect light. Unlike iridophores, however, leucophores have more organized crystals that reduce diffraction. Given

2793-582: A lack of food leads to catabolism . Stomach-content analysis indicates fasting during the breeding season, and as S. apama can catabolise no more than 50% of its body weight, it slowly loses physical condition as the season progresses and eventually dies. Throughout their range, these cephalopods breed in pairs or small groups, laying eggs in suitable caves or rock crevices. Loose spawning aggregations can form, but rarely exceed 10 animals in any one location, with one known exception: hundreds of thousands aggregate along rockey reefs between Whyalla and Point Lowly in

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2926-437: A large competitor arrives to threaten the male cuttlefish. In these instances, the male first attempts to intimidate the other male. If the competitor does not flee, the male eventually attacks it to force it away. The cuttlefish that can paralyze the other first, by forcing it near its mouth, wins the fight and the female. Since typically four or five (and sometimes as many as 10) males are available for every female, this behavior

3059-489: A manner that clouds, varying in tint between a hyacinth red and a chestnut-brown, were continually passing over the body. Any part, being subjected to a slight shock of galvanism, became almost black: a similar effect, but in a less degree, was produced by scratching the skin with a needle. These clouds, or blushes as they may be called, are said to be produced by the alternate expansion and contraction of minute vesicles containing variously coloured fluids. The term chromatophore

3192-426: A new port development was approved for the site of the former Playford power stations , which were decommissioned and demolished in the mid 2010s. Increasing shipping traffic in the upper Spencer Gulf has the potential to impact cuttlefish behavior due to cephalopod sensitivity to high intensity, low frequency sound. The upper Spencer Gulf cuttlefish aggregation is celebrated each year by Cuttlefest, an event hosted by

3325-487: A new survey in 2008 found the biomass had decreased a further 17%. In 2011, an estimated 33% of the 2010 population had returned to breed, fewer than 80,000 cuttlefish. Beginning in May, the cuttlefish leave deep water and migrate along coastal reefs to reach their spawning grounds. Local fishermen claimed that a small "finger of land" near Point Lowly extends outside the exclusion zone and that commercial fishers have been targeting

3458-476: A novel deep (wine) red-colour pigment was identified in the melanophores of phyllomedusine frogs . Some species of anole lizards, such as the Anolis grahami , use melanocytes in response to certain signals and hormonal changes, and is capable of becoming colors ranging from bright blue, brown, and black. This was subsequently identified as pterorhodin , a pteridine dimer that accumulates around eumelanin core, and it

3591-419: A number of cell types generated in the neural crest , a paired strip of cells arising at the margins of the neural tube . These cells have the ability to migrate long distances, allowing chromatophores to populate many organs of the body, including the skin, eye, ear, and brain. Fish melanophores and iridophores have been found to contain the smooth muscle regulatory proteins [calponin] and caldesmon . Leaving

3724-583: A number of industrial pollution sources, and prospective sites for further development. As of 2021, operations that publicly report their pollution discharges to the sea in a controlled and measured manner include the Whyalla Steelworks , the Port Pirie lead smelter owned and operated by Nyrstar . The pollutants of primary concern to cuttlefish recruitment are changes of salinity (due to discharges from desalination plants) and nutrient enrichment, discharged by

3857-536: A pattern called the intense zebra pattern, considered to be an honest signal . If a male is intending to attack, it adopts a "dark face" change, otherwise, it remains pale. In at least one species, female cuttlefish react to their own reflection in a mirror and to other females by displaying a body pattern called "splotch". However, they do not use this display in response to males, inanimate objects, or prey. This indicates they are able to discriminate same-sex conspecifics , even when human observers are unable to discern

3990-480: A seawater desalination plant at Point Lowly to supply fresh water to the Olympic Dam mine. The plant, located within 200 m (660 ft) of the breeding grounds, would release around 120 ML (32,000,000 US gal) of brine (46–60 ppt ) into the area each day. As cuttlefish embryos underdevelop and die off as salinity levels rise (optimal range 28–38 ppt, 100% mortality at 50 ppt), public opposition to

4123-419: A series of catalysed chemical reactions. It is a complex chemical containing units of dihydroxyindole and dihydroxyindole-2- carboxylic acid with some pyrrole rings. The key enzyme in melanin synthesis is tyrosinase . When this protein is defective, no melanin can be generated resulting in certain types of albinism. In some amphibian species there are other pigments packaged alongside eumelanin. For example,

Giant cuttlefish - Misplaced Pages Continue

4256-530: A shell with a phragmocone divided into chambers separated by septa. The pores provide it with buoyancy , which the cuttlefish regulates by changing the gas-to-liquid ratio in the chambered cuttlebone via the ventral siphuncle . Each species ' cuttlebone has a distinct shape, size, and pattern of ridges or texture. The cuttlebone is unique to cuttlefish, and is one of the features that distinguish them from their squid relatives. Cuttlefish, like other cephalopods, have sophisticated eyes. The organogenesis and

4389-543: A similar effect by cell signalling . Such signals can be hormones or neurotransmitters and may be initiated by changes in mood, temperature, stress or visible changes in the local environment. Chromatophores are studied by scientists to understand human disease and as a tool in drug discovery . Aristotle mentioned the ability of the octopus to change colour for both camouflage and signalling in his Historia animalium (ca 4th century BC): The octopus ... seeks its prey by so changing its colour as to render it like

4522-675: A source of white light, they produce a white shine, in red they produce red, and in blue they produce blue. Leucophores assist in camouflage by providing light areas during background matching (e.g. by resembling light-colored objects in the environment) and disruptive coloration (by making the body appear to be composed of high-contrasting patches). The reflectance spectra of cuttlefish patterns and several natural substrates ( stipple , mottle , disruptive ) can be measured using an optic spectrometer . Cuttlefish sometimes use their color patterns to signal future intent to other cuttlefish. For example, during agonistic encounters, male cuttlefish adopt

4655-629: A spectacular array of skin colours by making good use of the divisional effect. The control and mechanics of rapid pigment translocation has been well studied in a number of different species, in particular amphibians and teleost fish. It has been demonstrated that the process can be under hormonal or neuronal control or both and for many species of bony fishes it is known that chromatophores can respond directly to environmental stimuli like visible light, UV-radiation, temperature, pH, chemicals, etc. Neurochemicals that are known to translocate pigment include noradrenaline , through its receptor on

4788-660: A technique for removing the ink and cuttlebone from a cuttlefish before eating it. They are also eaten by Long-nosed fur seals . Yellowtail kingfish are also known to eat cephalopods. This has raised concerns about Yellowtail kingfish escapees from commercial fish farms impacting other species in Spencer Gulf including eating emergent Giant Australian cuttlefish or their eggs. Unpublished scientific data indicated that there are several genetically-distinct populations of giant cuttlefish living in Australian waters. Discovered by divers in

4921-409: A threatened species under Australian law was made during the government's consideration of BHP Billiton's Olympic Dam mine expansion project. The application was made following an observed and unexplained population decline and public concerns about future risks posed by industrial pollution. On 2 February 2011, the Australian government's Threatened Species Scientific Committee ruled that the species

5054-428: A type of active camouflage , which could as in cuttlefish make objects nearly invisible. Coleoid cephalopods (including octopuses, squids and cuttlefish ) have complex multicellular organs that they use to change colour rapidly, producing a wide variety of bright colours and patterns. Each chromatophore unit is composed of a single chromatophore cell and numerous muscle, nerve, glial , and sheath cells. Inside

5187-425: Is a neritic demersal species. They are carnivorous , opportunistic and voracious predators who feed predominantly on crustaceans and fish. Using neurally controlled cells known as chromatophore organs (red to yellow), iridophores ( iridescent : spans the entire visible spectrum from blue to near- IR ) and leucophores (white), the cuttlefish can put on spectacular displays, changing colour and patterns in

5320-433: Is about 1–2 years. Studies are said to indicate cuttlefish to be among the most intelligent invertebrates . Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates. The Greco-Roman world valued the cuttlefish as a source of the unique brown pigment the creature releases from its siphon when it is alarmed. The word for the cuttlefish in both Greek and Latin , sepia , now refers to

5453-446: Is also present in a variety of tree frog species from Australia and Papua New Guinea . While it is likely that other lesser-studied species have complex melanophore pigments, it is nevertheless true that the majority of melanophores studied to date do contain eumelanin exclusively. Humans have only one class of pigment cell, the mammalian equivalent of melanophores, to generate skin, hair, and eye colour. For this reason, and because

Giant cuttlefish - Misplaced Pages Continue

5586-470: Is grouped with 13 other species, such as the broadclub cuttlefish , the reaper cuttlefish , and the flamboyant cuttlefish . Genetic studies have shown that little if any interbreeding occurs between giant cuttlefish populations. While some genetic divergence is seen, the various populations are not considered taxonomically distinct and are commonly referred to by their location, e.g. Sepia apama upper Spencer Gulf population. The upper Spencer Gulf population

5719-436: Is inevitable. Cuttlefish are indeterminate growers , so smaller cuttlefish always have a chance of finding a mate the next year when they are bigger. Additionally, cuttlefish unable to win in a direct confrontation with a guard male have been observed employing several other tactics to acquire a mate. The most successful of these methods is camouflage; smaller cuttlefish use their camouflage abilities to disguise themselves as

5852-455: Is just as defined. The cuttlefish's wide pupil may accentuate chromatic aberration, allowing it to perceive color by focusing specific wavelengths onto the retina. The three broad categories of color patterns are uniform, mottle, and disruptive. Cuttlefish can display as many as 12 to 14 patterns, 13 of which have been categorized as seven "acute" (relatively brief) and six "chronic" (long-lasting) patterns. although other researchers suggest

5985-440: Is no strong evidence to suggest that fishing is impacting on the giant cuttlefish, therefore, further closures would be ineffective." On 28 March 2013, the state government introduced a temporary ban on fishing for cuttlefish in the northern Spencer Gulf for the 2013 breeding season. Fisheries Minister Gago announced that research into the reasons behind the 90% decline in the cuttlefish population had ruled out commercial fishing as

6118-425: Is not always obvious, but, in general, iridophores are considered to generate iridescent or metallic colours , whereas leucophores produce reflective white hues. Melanophores contain eumelanin , a type of melanin , that appears black or dark- brown because of its light absorbing qualities. It is packaged in vesicles called melanosomes and distributed throughout the cell. Eumelanin is generated from tyrosine in

6251-434: Is one to one, Spencer Gulf males outnumber females by up to 11 to one in the spawning aggregation. If this is due to fewer females taking part or to males breeding for a longer period of time than females is not known. With densities of one cuttlefish per square metre (0.093 cuttlefish per square foot), covering about 61 hectares (150 acres), the sheer numbers of giant cuttlefish make this breeding aggregation unique in

6384-676: Is served as deep-fried strips or in a variant of feijoada , with white beans. Black pasta is often made using cuttlefish ink. Chromatophore Chromatophores are largely responsible for generating skin and eye colour in ectothermic animals and are generated in the neural crest during embryonic development . Mature chromatophores are grouped into subclasses based on their colour under white light: xanthophores (yellow), erythrophores (red), iridophores ( reflective / iridescent ), leucophores (white), melanophores (black/brown), and cyanophores (blue). While most chromatophores contain pigments that absorb specific wavelengths of light,

6517-441: Is the major factor in colour change. Some animals, such as chameleons and anoles , have a highly developed background adaptation response capable of generating a number of different colours very rapidly. They have adapted the capability to change colour in response to temperature, mood, stress levels, and social cues, rather than to simply mimic their environment. During vertebrate embryonic development , chromatophores are one of

6650-441: Is thought to communicate to potential prey – "stop and watch me" – which some have interpreted as a type of "hypnosis". Cuttlefish are able to rapidly change the color of their skin to match their surroundings and create chromatically complex patterns, despite their inability to perceive color, through some mechanism which is not completely understood. They have been seen to have the ability to assess their surroundings and match

6783-418: Is thought to have up to 35 distinct signalling states. Cuttlefish are sometimes referred to as the " chameleons of the sea" because of their ability to rapidly alter their skin color – this can occur within one second. Cuttlefish change color and pattern (including the polarization of the reflected light waves), and the shape of the skin to communicate to other cuttlefish, to camouflage themselves, and as

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6916-426: Is unique in that a permanent salinity gradient in the Spencer Gulf may physiologically exclude other populations from the zone occupied by the upper Spencer Gulf population. The upper Spencer Gulf population may in fact be a separate species, as it does show some hallmarks, such as genetic separation, differences in morphology , and different patterns of sexual dimorphism from adjacent populations. The giant cuttlefish

7049-824: The Qing Dynasty manual of Chinese gastronomy , the Suiyuan shidan , the roe of the cuttlefish, is considered a difficult-to-prepare, but sought-after delicacy. Cuttlefish thick soup is a signature dish in Taiwan . Cuttlefish are quite popular in Europe. For example, in northeast Italy, they are used in risotto al nero di seppia (risotto with cuttlefish ink), also found in Croatia and Montenegro as crni rižot (black risotto), and in various recipes (either grilled or stewed) often served together with polenta . Catalan cuisine , especially that of

7182-462: The diffraction of light within the stacked plates. Orientation of the chemochromes determines the nature of the color observed. By using biochromes as colored filters, iridophores create an optical effect known as Tyndall or Rayleigh scattering , producing bright blue or blue-green colors. Iridophores vary in size, but are generally smaller than 1 mm. Squid at least are able to change their iridescence. This takes several seconds or minutes, and

7315-603: The melanocyte , has been identified in these animals. It was only in the 1960s that chromatophores were well enough understood to enable them to be classified based on their appearance. This classification system persists to this day, even though the biochemistry of the pigments may be more useful to a scientific understanding of how the cells function. Colour-producing molecules fall into two distinct classes: biochromes and structural colours or "schemochromes". The biochromes include true pigments, such as carotenoids and pteridines . These pigments selectively absorb parts of

7448-676: The optic cup , which, in turn, forms the retina . When and how multipotent chromatophore precursor cells (called chromatoblasts ) develop into their daughter subtypes is an area of ongoing research. It is known in zebrafish embryos, for example, that by 3 days after fertilization each of the cell classes found in the adult fish—melanophores, xanthophores and iridophores—are already present. Studies using mutant fish have demonstrated that transcription factors such as kit , sox10 , and mitf are important in controlling chromatophore differentiation. If these proteins are defective, chromatophores may be regionally or entirely absent, resulting in

7581-633: The visible light spectrum that makes up white light while permitting other wavelengths to reach the eye of the observer. Structural colours are produced by various combinations of diffraction, reflection or scattering of light from structures with a scale around a quarter of the wavelength of light. Many such structures interfere with some wavelengths (colours) of light and transmit others, simply because of their scale, so they often produce iridescence by creating different colours when seen from different directions. Whereas all chromatophores contain pigments or reflecting structures (except when there has been

7714-565: The City of Whyalla. In May 2009, D'Faces of Youth Arts and Snuff Puppets produced a live theatre performance for Come Out Festival . It featured several large cuttlefish puppets and appeared in Adelaide 's Victoria Square , at the Adelaide Airport and at a Whyalla performance. Some controversy surrounded the performances after a participant in the project was openly critical of the plan to build

7847-487: The European common squid ( Alloteuthis subulata ) has yellow and red, and the common octopus has yellow, orange, red, brown, and black. In cuttlefish, activation of a chromatophore can expand its surface area by 500%. Up to 200 chromatophores per mm of skin may occur. In Loligo plei , an expanded chromatophore may be up to 1.5 mm in diameter, but when retracted, it can measure as little as 0.1 mm. Retracting

7980-584: The Northern Water Supply Project, led by SA Water , which intends to build a similar-sized desalination plant to that originally proposed by the company. Prospective sites are all located within the upper Spencer Gulf, renewing the threat posed to the aggregation. An environmental impact statement is anticipated mid-2024. Due to its proximity to the ore deposits of the Middleback Ranges , several mining companies have indicated they might use

8113-484: The Upper Spencer Gulf . While surveys suggest that juveniles leave these spawning grounds after hatching, nothing is known of their subsequent movement or lifestyle strategies as a juvenile. Adults return to the aggregation site the following winter, or delay their return by an additional year. The World Register of Marine Species lists the giant cuttlefish under the genus Ascarosepion ; within this genus it

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8246-452: The area, intercepting the squid before they can reach the spawning grounds. Being semelparous breeders, ecologist Bronwyn Gillanders believed the cuttlefish were in danger, stating that determining whether this is a natural phenomenon or something else is difficult, and that the cause requires more research. In 2012, the number of cuttlefish that returned to the spawning ground again dropped again. A cross-government Cuttlefish Working Group

8379-417: The atmosphere, is cited as a potential threat. Some studies suggest that ocean acidification does not impair normal embryonic development, survival rates or body size. Unlike other cephalopods, cuttlefish possess a unique internal structure called the cuttlebone , a highly modified internal shell, which is porous and is made of aragonite . Except for spirula , they are the only coleoid cephalopods with

8512-408: The best den during mating season. During this challenge, no direct contact is usually made. The animals threaten each other until one of them backs down and swims away. Eventually, the larger male cuttlefish mate with the females by grabbing them with their tentacles, turning the female so that the two animals are face-to-face, then using a specialized tentacle to insert sperm sacs into an opening near

8645-411: The brain in a pattern isomorphic to that of the chromatophores they each control. This means the pattern of colour change functionally matches the pattern of neuronal activation . This may explain why, as the neurons are activated in iterative signal cascade, one may observe waves of colour changing. Like chameleons, cephalopods use physiological colour change for social interaction . They are also among

8778-446: The cell, cyclic adenosine monophosphate (cAMP) has been shown to be an important second messenger of pigment translocation. Through a mechanism not yet fully understood, cAMP influences other proteins such as protein kinase A to drive molecular motors carrying pigment containing vesicles along both microtubules and microfilaments . Most fish, reptiles and amphibians undergo a limited physiological colour change in response to

8911-447: The cell. However, a similar effect is achieved.The energy cost of the complete activation of the chromatophore system is very high equally being nearly as much as all the energy used by an octopus at rest. Octopuses and most cuttlefish can operate chromatophores in complex, undulating chromatic displays, resulting in a variety of rapidly changing colour schemata. The nerves that operate the chromatophores are thought to be positioned in

9044-417: The chromatophore cell, pigment granules are enclosed in an elastic sac, called the cytoelastic sacculus. To change colour the animal distorts the sacculus form or size by muscular contraction, changing its translucency , reflectivity, or opacity . This differs from the mechanism used in fish, amphibians, and reptiles in that the shape of the sacculus is changed, rather than translocating pigment vesicles within

9177-474: The chromatophore. These are under neural control and when they expand, they reveal the hue of the pigment contained in the sac. Cuttlefish have three types of chromatophore: yellow/orange (the uppermost layer), red, and brown/black (the deepest layer). The cuttlefish can control the contraction and relaxation of the muscles around individual chromatophores, thereby opening or closing the elastic sacs and allowing different levels of pigment to be exposed. Furthermore,

9310-461: The chromatophores contain luminescent protein nanostructures in which tethered pigment granules modify light through absorbance, reflection, and fluorescence between 650 and 720 nm. For cephalopods in general, the hues of the pigment granules are relatively constant within a species, but can vary slightly between species. For example, the common cuttlefish and the opalescent inshore squid ( Doryteuthis opalescens ) have yellow, red, and brown,

9443-414: The chromatophores reveals the iridophores and leucophores beneath them, thereby allowing cuttlefish to use another modality of visual signalling brought about by structural coloration . Iridophores are structures that produce iridescent colors with a metallic sheen. They reflect light using plates of crystalline chemochromes made from guanine . When illuminated, they reflect iridescent colors because of

9576-464: The coastal regions, uses cuttlefish and squid ink in a variety of tapas and dishes such as arròs negre . Breaded and deep-fried cuttlefish is a popular dish in Andalusia . In Portugal , cuttlefish is present in many popular dishes. Chocos com tinta (cuttlefish in black ink), for example, is grilled cuttlefish in a sauce of its own ink. Cuttlefish is also popular in the region of Setúbal , where it

9709-746: The coasts of East and South Asia, Western Europe, and the Mediterranean, as well as all coasts of Africa and Australia, but are totally absent from the Americas. By the time the family evolved, ostensibly in the Old World, the North Atlantic possibly had become too cold and deep for these warm-water species to cross. The common cuttlefish ( Sepia officinalis ), is found in the Mediterranean, North and Baltic seas, although populations may occur as far south as South Africa. They are found in sublittoral depths, between

9842-530: The color of leucophores and iridophores is produced by their respective scattering and optical interference properties. Some species can rapidly change colour through mechanisms that translocate pigment and reorient reflective plates within chromatophores. This process, often used as a type of camouflage , is called physiological colour change or metachrosis . Cephalopods, such as the octopus , have complex chromatophore organs controlled by muscles to achieve this, whereas vertebrates such as chameleons generate

9975-403: The color, contrast and texture of the substrate even in nearly total darkness. The color variations in the mimicked substrate and animal skin are similar. Depending on the species, the skin of cuttlefish responds to substrate changes in distinctive ways. By changing naturalistic backgrounds, the camouflage responses of different species can be measured. Sepia officinalis changes color to match

10108-591: The colour of the stones adjacent to it; it does so also when alarmed. Giosuè Sangiovanni was the first to describe invertebrate pigment-bearing cells as cromoforo in an Italian science journal in 1819. Charles Darwin described the colour-changing abilities of the cuttlefish in The Voyage of the Beagle (1860): These animals also escape detection by a very extraordinary, chameleon-like power of changing their colour. They appear to vary their tints according to

10241-499: The constructive interference of light. Fish iridophores are typically stacked guanine plates separated by layers of cytoplasm to form microscopic, one-dimensional, Bragg mirrors . Both the orientation and the optical thickness of the chemochrome determines the nature of the colour observed. By using biochromes as coloured filters, iridophores create an optical effect known as Tyndall or Rayleigh scattering , producing bright- blue or - green colours. A related type of chromatophore,

10374-465: The cuttlefish becomes texturally as well as chromatically similar to objects in its environment such as kelp or rocks. While the preferred diet of cuttlefish is crabs and fish, they feed on small shrimp shortly after hatching. Cuttlefish are caught for food in the Mediterranean, East Asia, the English Channel, and elsewhere. In East Asia, dried, shredded cuttlefish is a popular snack food. In

10507-670: The cuttlefish breeding grounds, first discovered in 2008. In 2014, the Adelaide Fringe Festival launched Stobie the Disco Cuttlefish , a 13-metre-long (43 ft) electrified cuttlefish puppet, equipped with strobing, coloured lighting and a sound system. Stobie the Disco Cuttlefish first appeared during the Adelaide Fringe Opening Parade, then performed with a troupe of dancers each Saturday night during

10640-411: The cuttlefish, but use the flamboyant display towards larger, more dangerous fish, and give no display at all to chemosensory predators such as crabs and dogfish. One dynamic pattern shown by cuttlefish is dark mottled waves apparently repeatedly moving down the body of the animals. This has been called the passing cloud pattern. In the common cuttlefish, this is primarily observed during hunting, and

10773-599: The development of a retro computer game called Cuttle Scuttle . Cuttlefish Cuttlefish , or cuttles , are marine molluscs of the suborder Sepiina . They belong to the class Cephalopoda which also includes squid , octopuses , and nautiluses . Cuttlefish have a unique internal shell , the cuttlebone , which is used for control of buoyancy . Cuttlefish have large, W-shaped pupils , eight arms , and two tentacles furnished with denticulated suckers, with which they secure their prey. They generally range in size from 15 to 25 cm (6 to 10 in), with

10906-403: The egg. In consequence, they may prefer to hunt the prey they saw before hatching. Cuttlefish have eight arms and two additional elongated tentacles that are used to grasp prey. The elongated tentacles and mantle cavity serve as defense mechanisms; when approached by a predator, the cuttlefish can suck water into its mantle cavity and spread its arms in order to appear larger than normal. Though

11039-869: The end of the Cretaceous period, represented by Ceratisepia from the Late Maastrichtian Maastricht Formation of the Netherlands. Although the Jurassic Trachyteuthis was historically considered possibly related to cuttlefish, later studies considered it to be more closely related to octopuses and vampire squids. The family Sepiidae, which contains all cuttlefish, inhabits tropical and temperate ocean waters. They are mostly shallow-water animals, although they are known to go to depths of about 600 m (2,000 ft). They have an unusual biogeographic pattern; they are present along

11172-527: The estimated biomass) before dropping to 3.7 tonnes in 1999. The catch data for 2000 to 2005 were initially withheld citing commercial confidentiality. Catch data for the South Australian cuttlefish fishery are reported in annual reports of the Marine Scalefish Fishery, published by SARDI. The pre-2014 data are graphed below. From its establishment in 1987 to the financial year ending June 1992,

11305-422: The female's mouth. As males can also use their funnels to flush others' sperm out of the female's pouch, the male then guards the female until she lays the eggs a few hours later. After laying her cluster of eggs, the female cuttlefish secretes ink on them making them look very similar to grapes. The egg case is produced through a complex capsule of the female accessory genital glands and the ink bag. On occasion,

11438-483: The females being protected by the dominant males, which are extremely territorial. Male genetic material is deposited in sperm receptacles directly. The females, which potentially lay hundreds of eggs, extract one egg at a time and fertilise it by passing it over the sperm receptacle before attaching it to the underside of a rock at depths of 2 to 5 m (6 ft 7 in to 16 ft 5 in). An unsuccessful application to list this population of giant cuttlefish as

11571-489: The festival. The soundtrack to the performance included samples from the Bee Gees hit " Stayin' Alive " and the entire theme song from the movie Fame . In 2016, underwater photographer Scott Portelli's image Cuttlefish aggregation won the national first prize (Australia) in the 2015 Sony World Photography Awards—the world's biggest photography competition. The mass aggregation of giant cuttlefish at Point Lowly has inspired

11704-595: The final structure of the cephalopod eye fundamentally differ from those of vertebrates , such as humans. Superficial similarities between cephalopod and vertebrate eyes are thought to be examples of convergent evolution . The cuttlefish pupil is a smoothly curving W-shape. Although cuttlefish cannot see color, they can perceive the polarization of light , which enhances their perception of contrast . They have two spots of concentrated sensor cells on their retinas (known as foveae ), one to look more forward, and one to look more backward. The eye changes focus by shifting

11837-447: The first two months. Before death, cuttlefish go through senescence when the cephalopod essentially deteriorates, or rots in place. Their eyesight begins to fail, which affects their ability to see, move, and hunt efficiently. Once this process begins, cuttlefish tend to not live long due to predation by other organisms. Cuttlefish start to actively mate at around five months of age. Male cuttlefish challenge one another for dominance and

11970-416: The first year. The second involves slow growth with maturity reached in two years, with large adults returning to spawn in the second year. The upper Spencer Gulf population displays reproductive behaviours unique to this population, possibly as a result of the high spawning densities. Large males defend females and egg-laying sites, while small males, "sneakers" mimic female colouring and form to gain access to

12103-501: The fishery caught less than 3 tonnes per annum. Surveys indicated that the cuttlefish biomass remained stable from 1998 to 2001 as commercial fishing pressure was reduced by regulation. A survey in 2005 revealed a 34% decrease in biomass since 2001 that was attributed to natural variability and illegal fishing during the peak spawning period. The closure was subsequently expanded to the entire spawning grounds, and anecdotal observations suggested increased numbers in 2006 and 2007; however,

12236-609: The gene responsible for the melanophore-specific golden zebrafish strain, Slc24a5 , was shown to have a human equivalent that strongly correlates with skin colour . Chromatophores are also used as a biomarker of blindness in cold-blooded species, as animals with certain visual defects fail to background adapt to light environments. Human homologues of receptors that mediate pigment translocation in melanophores are thought to be involved in processes such as appetite suppression and tanning , making them attractive targets for drugs . Therefore, pharmaceutical companies have developed

12369-575: The giant cuttlefish has 8 arms and 2 feeding tentacles, as well as blue blood and 3 hearts. Using cells known as chromatophores , the cuttlefish can put on spectacular displays, changing colour in an instant. The giant cuttlefish is native to temperate and subtropical waters of Australia , from Brisbane in Queensland to Shark Bay in Western Australia and Tasmania to the south. It occurs on rocky reefs, seagrass beds, and sand and mud seafloor to

12502-537: The large number and contrasting colour of the cells usually make them very easy to visualise, melanophores are by far the most widely studied chromatophore. However, there are differences between the biology of melanophores and that of melanocytes . In addition to eumelanin, melanocytes can generate a yellow/red pigment called phaeomelanin . Nearly all the vibrant blues in animals and plants are created by structural coloration rather than by pigments. However, some types of Synchiropus splendidus do possess vesicles of

12635-401: The largest species , the giant cuttlefish ( Sepia apama ), reaching 50 cm (20 in) in mantle length and over 10.5 kg (23 lb) in mass. Cuttlefish eat small molluscs, crabs, shrimp, fish, octopuses, worms, and other cuttlefish. Their predators include dolphins, larger fish (including sharks), seals, seabirds, and other cuttlefish. The typical life expectancy of a cuttlefish

12768-410: The late 1990s, the upper Spencer Gulf population is the best studied, largely because it is the world's only known mass cuttlefish spawning aggregation. It has also become a popular ecotourism attraction for divers and snorkelers. Hundreds of thousands of giant cuttlefish gather on subtidal reefs around Point Lowly near Whyalla between May and August. While outside of the breeding season, the sex ratio

12901-416: The leucophore, is found in some fish, in particular in the tapetum lucidum . Like iridophores, they utilize crystalline purines (often guanine) to reflect light. Unlike iridophores, leucophores have more organized crystals that reduce diffraction. Given a source of white light, they produce a white shine. As with xanthophores and erythrophores, in fish the distinction between iridophores and leucophores

13034-555: The low tide line and the edge of the continental shelf, to about 180 m (600 ft). The cuttlefish is listed under the Red List category of "least concern" by the IUCN Red List of Threatened Species. This means that while some over-exploitation of the marine animal has occurred in some regions due to large-scale commercial fishing, their wide geographic range prevents them from being too threatened. Ocean acidification, however, caused largely by higher levels of carbon dioxide emitted into

13167-477: The mantle cavity is used for jet propulsion, the main parts of the body that are used for basic mobility are the fins, which can maneuver the cuttlefish in all directions. The suckers of cuttlefish extend most of the length of their arms and along the distal portion of their tentacles. Like other cephalopods, cuttlefish have "taste-by-touch" sensitivity in their suckers, allowing them to discriminate among objects and water currents that they contact. The blood of

13300-521: The mechanism is not understood. However, iridescence can also be altered by expanding and retracting the chromatophores above the iridophores. Because chromatophores are under direct neural control from the brain, this effect can be immediate. Cephalopod iridophores polarize light. Cephalopods have a rhabdomeric visual system which means they are visually sensitive to polarized light. Cuttlefish use their polarization vision when hunting for silvery fish (their scales polarize light). Female cuttlefish exhibit

13433-617: The muscles of the flamboyant cuttlefish ( Metasepia pfefferi ) contain a highly toxic, unidentified compound as lethal as the venom of fellow cephalopod, the blue-ringed octopus . However, this toxin is found only in the muscle and is not injected in any form, classifying it as poisonous, not venomous. Sleep is a state of immobility characterized by being rapidly reversible, homeostatically controlled, and increasing an organism's arousal threshold. To date one cephalopod species, Octopus vulgaris , has been shown to satisfy these criteria. Another species, Sepia officinalis , satisfies two of

13566-450: The nature of the ground over which they pass: when in deep water, their general shade was brownish purple, but when placed on the land, or in shallow water, this dark tint changed into one of a yellowish green. The colour, examined more carefully, was a French grey, with numerous minute spots of bright yellow: the former of these varied in intensity; the latter entirely disappeared and appeared again by turns. These changes were effected in such

13699-417: The neural crest in waves, chromatophores take either a dorsolateral route through the dermis, entering the ectoderm through small holes in the basal lamina , or a ventromedial route between the somites and the neural tube. The exception to this is the melanophores of the retinal pigmented epithelium of the eye. These are not derived from the neural crest. Instead, an outpouching of the neural tube generates

13832-449: The patterns occur on a continuum. The color-changing ability of cuttlefish is due to multiple types of cells. These are arranged (from the skin's surface going deeper) as pigmented chromatophores above a layer of reflective iridophores and below them, leucophores . The chromatophores are sacs containing hundreds of thousands of pigment granules and a large membrane that is folded when retracted. Hundreds of muscles radiate from

13965-510: The photoreceptors of cuttlefish eyes are arranged in a way which gives them the ability to see the linear polarisation of light . While the mantis shrimp is the only known creature to have true polarisation vision, cephalopods may also. Because the optic lobes of cuttlefish are larger than any other region of the brain and their skin produces polarised reflective patterns, they may communicate through this visual system. By raising elaborate papillae on their skin, S. apama squid can change

14098-648: The pigment inside their chromatophores, resulting in an apparent change in body colour. This process, known as physiological colour change , is most widely studied in melanophores, since melanin is the darkest and most visible pigment. In most species with a relatively thin dermis , the dermal melanophores tend to be flat and cover a large surface area. However, in animals with thick dermal layers, such as adult reptiles, dermal melanophores often form three-dimensional units with other chromatophores. These dermal chromatophore units (DCU) consist of an uppermost xanthophore or erythrophore layer, then an iridophore layer, and finally

14231-493: The play told the story of the fictitious character Neil, the proprietor of a caravan park who was struggling to come to terms with the cuttlefish decline whilst trying to keep his family together. The play also featured at the Melbourne Fringe Festival . Presenting partner RiAus is sponsored by the oil and gas company Santos . Santos was responsible for hydrocarbon groundwater contamination at Port Bonython, adjacent to

14364-423: The population to be a separate species based on unpublished scientific data, warned that the Spencer Gulf cuttlefish faced possible extinction within two or three years if nothing was done to better protect them. The state government working group recommended an immediate ban on fishing for the cuttlefish; however, this was rejected by the state cabinet on 3 September with Fisheries Minister Gail Gago stating, "There

14497-484: The position of the entire lens with respect to the retina, instead of reshaping the lens as in mammals. Unlike the vertebrate eye, no blind spot exists, because the optic nerve is positioned behind the retina. They are capable of using stereopsis , enabling them to discern depth/distance because their brain calculates the input from both eyes. The cuttlefish's eyes are thought to be fully developed before birth, and they start observing their surroundings while still in

14630-484: The possible impact of the plant on the cuttlefish population and two major contamination events have happened at the associated port and refinery. Santos denies that groundwater contamination detected in the late 2000s spread off-site, but the SA EPA said hydrocarbons had migrated through the rock strata beyond the plant and the barrier trench built by Santos. Santos now provides funding for cuttlefish research. The other incident

14763-501: The proposed plant was considerable because of the possible environmental impacts. The plan was approved in 2011, but was not constructed and was later officially abandoned. Since that time, two new, smaller scale seawater desalination plants have been commissioned and discharge brine into the gulf: one at the Whyalla Steelworks and another at Sundrop Farms, south of Port Augusta . In 2022, BHP sought to increase its water supply via

14896-712: The reddish-brown color sepia in English. "Cuttle" in "cuttlefish", sometimes called "cuttles", is derived from the Old English name for the species, cudele . The word may be cognate with the Old Norse koddi (cushion) and the Middle Low German Kudel (rag). Over 120 species of cuttlefish are currently recognized, grouped into six families divided between two suborders. One superfamily and three families are extinct. The earliest fossils of cuttlefish are from

15029-448: The same cell, in which case the overall colour depends on the ratio of red and yellow pigments. Therefore, the distinction between these chromatophore types is not always clear. Most chromatophores can generate pteridines from guanosine triphosphate , but xanthophores appear to have supplemental biochemical pathways enabling them to accumulate yellow pigment. In contrast, carotenoids are metabolised and transported to erythrophores. This

15162-414: The sand and appear one way, with another animal a few feet away in a slightly different microhabitat , settled in algae for example, will be camouflaged quite differently. Cuttlefish are also able to change the texture of their skin. The skin contains bands of circular muscle which as they contract, push fluid up. These can be seen as little spikes, bumps, or flat blades. This can help with camouflage when

15295-481: The sex of a cuttlefish in the absence of sexual dimorphism . Female cuttlefish signal their receptivity to mating using a display called precopulatory grey. Male cuttlefish sometimes use deception toward guarding males to mate with females. Small males hide their sexually dimorphic fourth arms, change their skin pattern to the mottled appearance of females, and change the shape of their arms to mimic those of nonreceptive, egg-laying females. Displays on one side of

15428-458: The shape and the texture of their skin to imitate rock, sand, or seaweed. A bioenergetics study found that the giant cuttlefish is primarily diurnal and has a small home range (90–550 m or 300–1,800 ft) over short recording periods while travelling large distances to breed. They are able to channel most of their energy directly into growth because they spend 95% of the day resting, suggesting bioenergetics more like that of an octopus than

15561-434: The signal into the cell. Melanocortins result in the dispersion of pigment, while melatonin and MCH results in aggregation. Numerous melanocortin, MCH and melatonin receptors have been identified in fish and frogs, including a homologue of MC1R , a melanocortin receptor known to regulate skin and hair colour in humans. It has been demonstrated that MC1R is required in zebrafish for dispersion of melanin. Inside

15694-457: The skin takes on their hue. Likewise, after melanin aggregation in DCUs, the skin appears green through xanthophore (yellow) filtering of scattered light from the iridophore layer. On the dispersion of melanin, the light is no longer scattered and the skin appears dark. As the other biochromatic chromatophores are also capable of pigment translocation, animals with multiple chromatophore types can generate

15827-451: The steelworks, lead smelter, municipal wastewater treatment plants and farming of yellowtail kingfish. Northern Spencer Gulf is an oligotrophic inverse estuary with naturally low levels of nutrients cycling through it. A potential exists for anthropogenic nutrient pollution to cause eutrophication in the region with associated ecological impacts to the cuttlefish and wider ecology. A long-term industrial nutrient pollution source exists to

15960-409: The substrate by disruptive patterning (contrast to break up the outline), whereas S. pharaonis matches the substrate by blending in. Although camouflage is achieved in different ways, and in an absence of color vision, both species change their skin colors to match the substrate. Cuttlefish adapt their own camouflage pattern in ways that are specific for a particular habitat. An animal could settle in

16093-490: The surface on melanophores. The primary hormones involved in regulating translocation appear to be the melanocortins , melatonin , and melanin-concentrating hormone (MCH), that are produced mainly in the pituitary, pineal gland, and hypothalamus, respectively. These hormones may also be generated in a paracrine fashion by cells in the skin. At the surface of the melanophore, the hormones have been shown to activate specific G-protein-coupled receptors that, in turn, transduce

16226-495: The tendency for females to reproduce using male genetic material deposited in spermatangia more favorably than in sperm receptacles directly. Females then attach their eggs to the undersides of rocks in caves or crevices, where they hatch within three to five months. S. apama is semelparous , and death follows shortly after a single mating cycle and laying of eggs that will spawn the next generation. S. apama has poor anaerobic capability compared to most aquatic invertebrates and

16359-505: The three criteria but has not yet been tested on the third (arousal threshold). Recent research shows that the sleep-like state in a common species of cuttlefish, Sepia officinalis , shows predictable periods of rapid eye movement, arm twitching and rapid chromatophore changes. The lifespan of a cuttlefish is typically around one to two years, depending on the species. They hatch from eggs fully developed, around 6 mm ( 1 ⁄ 4  in) long, reaching 25 mm (1 in) around

16492-420: The water column and sediment. Concerns have been raised about an observed correlation between fish farming intensification, fish mortalities and the decline and eventual recovery of the giant Australian cuttlefish after fish farming ceased in upper Spencer Gulf. In 1984, before the spawning grounds were discovered, Santos built a hydrocarbon processing plant at adjoining Port Bonython . Some concern exists over

16625-428: The west of the cuttlefish breeding reef at the Whyalla Steelworks. There, ammonia , a byproduct of its coking process for steel-making, and is discharged into Spencer Gulf via reed-beds and settling ponds. North of the cuttlefish aggregation, sea cage farming of yellowtail kingfish occurred commercially from the late 1990s until 2011. Fish farming is another nutrient pollution source, as uneaten feed and fish waste enter

16758-504: The whole of northern Spencer Gulf was extended until 2020, prohibiting their capture in all Spencer Gulf waters north of Wallaroo and Arno Bay . In 2020 the closed area rolled back to the same limited spatial closure that was in place in 2012, encompassing the waters of False Bay, from Whyalla to Point Lowly and extending northwards towards the Point Lowly North marina. The mass aggregation sites of Upper Spencer Gulf are proximate to

16891-621: The world. As the cuttlefish are oblivious to divers while spawning, they are now a major regional tourist attraction for divers from around the world. Professor Roger Hanlon of the Woods Hole Oceanographic Institution has called the breeding aggregation "the premier marine attraction on the planet." The upper Spencer Gulf population displays two alternative lifecycles in both sexes (growth pattern polymorphism ). The first involves rapid growth with maturity reached in seven to eight months with small adults returning to spawn in

17024-528: Was adopted (following Sangiovanni's chromoforo ) as the name for pigment-bearing cells derived from the neural crest of cold-blooded vertebrates and cephalopods. The word itself comes from the Greek words chrōma ( χρῶμα ) meaning "colour," and phoros ( φόρος ) meaning "bearing". In contrast, the word chromatocyte ( kytos ( κύτος ) meaning "cell") was adopted for the cells responsible for colour found in birds and mammals. Only one such cell type,

17157-406: Was established and recommended investigating broader ecological factors. Tour guide Tony Bramley , who had been taking divers to view the spawning grounds since they were discovered, stated, "It's heartbreaking, when you look at what's left ... [once] there were so many animals you couldn't land on the bottom, you had to push them aside." The Conservation Council of South Australia , which believes

17290-500: Was first demonstrated by rearing normally green frogs on a diet of carotene -restricted crickets . The absence of carotene in the frogs' diet meant that the red/orange carotenoid colour 'filter' was not present in their erythrophores. This made the frogs appear blue instead of green. Iridophores, sometimes also called guanophores, are chromatophores that reflect light using plates of crystalline chemochromes made from guanine . When illuminated they generate iridescent colours because of

17423-462: Was fished for snapper bait, with annual catches of around 4 tonnes (4,000 cuttlefish). During the 1995 and 1996 spawning seasons, commercial fishing of the spawning grounds harvested around 200 tonnes annually. Overexploitation was recognised after 245 tonnes were harvested in 1997, leading to 50% of the grounds being closed to commercial fishing in 1998. Despite half of the grounds being closed, commercial fishers took 109 tonnes in 1998 (about half of

17556-457: Was not eligible for listing, as the affected population was not taxonomically distinct from the rest of the species for the purposes of the Act. Further scientific work has determined the cuttlefish of northern Spencer Gulf to be genetically distinct from other giant cuttlefish populations in Australian waters though the results remain unpublished. Prior to the mid-1990s, the upper Spencer Gulf population

17689-451: Was the 1992 Port Bonython oil spill , whereby 300 tonnes of bunker C crude oil spilled into the sea after a tugboat pierced its hull during berthing. The effects of these events on the local population of S. apama are unknown. The dispersal of brine from seawater desalination plant effluent streams has concerned scientists and the Whyalla community. During the mid-to-late 2000s, mining and energy company BHP Billiton developed plans to build

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