View source for Giant cuttlefish

{{Short description|Species of cephalopod}}
{{Use Australian English|date=August 2024}}
{{Use dmy dates|date=August 2024}}
{{Speciesbox
| image = Sepia apama 2.jpg
| image_caption = Giant cuttlefish from [[Whyalla]], [[South Australia]]
| status = NT
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Barratt, I. |author2=Allcock, L. |date=2012 |title=''Sepia apama'' |volume=2012 |page=e.T162627A931625 |doi=10.2305/IUCN.UK.2012-1.RLTS.T162627A931625.en |access-date=19 November 2021}}</ref>
| genus = Sepia
| parent = Sepia (Sepia)
| species = apama
| authority = [[John Edward Gray|Gray]], 1849<ref name= WoRMS>{{cite web |url= http://www.marinespecies.org/aphia.php?p=taxdetails&id=342111 |title= ''Sepia apama'' Gray, 1849 |access-date=18 February 2018 |publisher= Flanders Marine Institute |author= Finn, Julian |year= 2016 |work= World Register of Marine Species}}</ref>
| synonyms =
*''Sepia palmata''<br /><small>Owen, 1881</small>
*''Amplisepia verreauni''<br /><small>[[Tom Iredale|Iredale]], 1926</small>
*''Amplisepia parysatis''<br /><small>[[Tom Iredale|Iredale]], 1954</small>
*''Ascarosepion apama''<br /><small>[[Nik Lupše|Lupše]], [[Kubodera]] 2023</small>
| range_map = Sepia apama distribution.png
| range_map_caption = Distribution of ''Sepia apama''
}}

The '''giant cuttlefish''' ('''''Sepia apama'''''), also known as the  '''Australian giant cuttlefish''',<ref>{{cite web|title=Giant Cuttlefish - Sepia apama |url= http://australianmuseum.net.au/Giant-Cuttlefish-Sepia-apama-Gray-1849 |website=Australian Museum|access-date=27 August 2014}}</ref> is the world's largest [[cuttlefish]] species, growing to {{cvt|50|cm|in}} in [[mantle (mollusc)|mantle]] length and up to {{cvt|100|cm|in}} in total length (total length meaning the whole length of the body including outstretched tentacles). They can be over {{convert|10.5|kg|abbr=on}} in weight.<ref>Reid, A., P. Jereb, & C.F.E. Roper 2005. Family Sepiidae. ''In:'' P. Jereb & C.F.E. Roper, eds. ''Cephalopods of the world. An annotated and illustrated catalogue of species known to date. Volume 1. Chambered nautiluses and sepioids (Nautilidae, Sepiidae, Sepiolidae, Sepiadariidae, Idiosepiidae and Spirulidae)''. FAO Species Catalogue for Fishery Purposes. No. 4, Vol. 1. Rome, FAO. pp. 57–152.</ref><ref>{{Cite news|url=http://www.watoday.com.au/wa-news/wa-fisherman-bags-whopper-cuttlefish-20170509-gw0vfu.html|title=WA fisherman bags whopper cuttlefish|last=Poulsen|first=Adam|date=10 May 2017|work=[[WAtoday]]|access-date=10 May 2017|language=en-US}}</ref> Like all cuttlefish species, the giant cuttlefish has 8 arms and 2 feeding tentacles, as well as blue blood and 3 hearts.<ref>{{cite web|url=https://www.whyalla.com/cuttlefish |title=Giant Cuttlefish }}</ref> Using cells known as [[chromatophore]]s, 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 a depth of {{cvt|100|m}}.<ref>Norman, M.D. 2000. ''Cephalopods: A World Guide''. ConchBooks.</ref> 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.<ref>{{Cite web|last1=Barratt (SRLI)|first1=Iain|last2=Allcock (SRLI)|first2=Louise|date=11 March 2009|title=IUCN Red List of Threatened Species: Sepia apama|url=https://www.iucnredlist.org/en|access-date=29 May 2021|website=IUCN Red List of Threatened Species}}</ref>

==Lifecycle and reproduction==
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 [[Polyandry in animals|polyandrous]], and collaborative research indicates the tendency for females to reproduce using male genetic material deposited in [[Gametangium|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 [[Semelparity and iteroparity#Semelparity|semelparous]], and death follows shortly after a single mating cycle and laying of eggs that will spawn the next generation.<ref name="TSSC"/> ''S. apama'' has poor [[Anaerobic respiration|anaerobic]] capability compared to most aquatic invertebrates and 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,<ref name="BHP"/> with one known exception: hundreds of thousands aggregate along rockey reefs between Whyalla and Point Lowly in the Upper [[Spencer Gulf]].<ref>{{Cite web|date=12 July 2021|title=Students' 'CuttleCam' streams congregation of giant cuttlefish|url=https://www.abc.net.au/news/2021-07-12/cuttlecam-goes-live-off-the-coast-of-whyalla/100286032|access-date=12 July 2021|website=[[ABC News (Australia)|ABC News]]|language=en-AU}}</ref> 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.<ref>{{Cite news|last=Steer|first=M.A.|date=1 March 2015|title=Surveying, Searching and Promoting Giant Australian Cuttlefish Spawning Activity in Northern Spencer Gulf|work=Final Report to the Fisheries Research & Development Corporation, South Australia|url=https://pir.sa.gov.au/__data/assets/pdf_file/0004/252751/Giant_Australian_Cuttlefish_FRDC_Report_-_FINAL.pdf|access-date=12 July 2021}}</ref>

==Physiology and biochemistry==
The [[World Register of Marine Species]] lists the giant cuttlefish under the [[genus]] '''''Ascarosepion'''''; within this genus it is grouped with 13 other species, such as the [[broadclub cuttlefish]], the [[reaper cuttlefish]], and the [[flamboyant cuttlefish]].<ref>{{cite web |title=WoRMS taxon details |url=https://marinespecies.org/aphia.php/aphia.php?p=taxdetails&id=876727 |website=WoRMS |access-date=19 October 2023}}</ref><ref>{{cite web |title=WoRMS taxon details |url=https://marinespecies.org/aphia.php/aphia.php?p=taxdetails&id=1666995 |website=WoRMS |access-date=19 October 2023}}</ref>[[File:Sepia apama.jpg|thumb|left|Individual from [[Fairy Bower Beach|Fairy Bower]], [[Manly, New South Wales]]]]

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.<ref name="TSSC">[http://www.environment.gov.au/biodiversity/threatened/species/pubs/69365-listing-advice.pdf Amendment to the list of Threatened Population under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).] Threatened Species Scientific Committee.</ref> The upper Spencer Gulf population 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.<ref name="TSSC"/> 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 (biology)|morphology]], and different patterns of sexual dimorphism from adjacent populations.<ref name="BHP">[http://www.bhpbilliton.com/home/aboutus/regulatory/Documents/odxEisAppendixO5AustralianGiantCuttlefish.pdf Natural History of the Giant Australian Cuttlefish] [[BHP|BHP Billiton]]</ref><ref name="scuttle">Clare Peddie, Heather Kennett ''The cuttle scuttle'' [[The Advertiser (Adelaide)|The Advertiser]] 29 September 2012 Pg 67</ref>
[[File:Sepia apama creating coincident disruptive pattern.jpg|thumb|Eating an [[Achoerodus viridis|eastern blue groper]] while making a [[coincident disruptive pattern]].]]
The giant cuttlefish is a [[neritic]] [[Demersal fish|demersal]] species. They are [[carnivorous]], opportunistic and voracious [[predators]] who feed predominantly on [[crustacean]]s and fish.<ref name="BHP" /> Using [[Nervous system|neurally controlled]] cells known as [[chromatophore]] organs (red to yellow), [[iridophores]] ([[iridescent]]: spans the entire visible spectrum from blue to near-[[Infrared|IR]]) and [[Chromatophore|leucophores]] (white), the cuttlefish can put on spectacular displays, changing colour and patterns in 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, the photoreceptors of cuttlefish eyes are arranged in a way which gives them the ability to see the linear [[Polarization (waves)|polarisation of light]]. While the [[mantis shrimp]] is the only known creature to have true polarisation vision, [[cephalopod]]s may also.<ref>{{cite journal|first1=Lydia M.|last1=Mäthger |first2=Nadav|last2=Shashar |first3=Roger T.|last3=Hanlon |url=http://www.mbl.edu/mrc/hanlon/pdfs/mathger_polariz09.pdf |title=Do cephalopods communicate using polarized light reflections from their skin?|journal=[[Journal of Experimental Biology]]|volume=212 |pages=2133–2140 |publisher=The Company of Biologists |doi=10.1242/jeb.020800 |date=21 April 2009 |issue=14 |pmid=19561202 |s2cid=10216731 |access-date=4 November 2011 |url-status=dead |archive-url=https://web.archive.org/web/20100528000228/http://www.mbl.edu/mrc/hanlon/pdfs/mathger_polariz09.pdf |archive-date=28 May 2010 |quote=Silvery fish reflect polarised light; they reflect the same amount of light in the same direction as the light they are viewed against, making them almost invisible in water. If the polarisation is reduced, the fish become easily visible. Cuttlefish ignore fish with reduced polarisation and preferentially attack fish emitting polarised light.}}</ref> 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.<ref name="Mathger">{{cite web | last = Mäthger | date = 21 April 2009 | title = Do cephalopods communicate using polarized light reflections from their skin? | work = Journal of Experimental Biology 212, 2133-2140 | url = http://www.mbl.edu/mrc/hanlon/pdfs/mathger_polariz09.pdf | access-date = 4 November 2011 | display-authors = etal | url-status = dead | archive-url = https://web.archive.org/web/20100528000228/http://www.mbl.edu/mrc/hanlon/pdfs/mathger_polariz09.pdf | archive-date = 28 May 2010 }}</ref> By raising elaborate [[Papule|papillae]] on their skin, ''S.&nbsp;apama'' squid can change the shape and the texture of their skin to imitate rock, sand, or seaweed.<ref>Alison King [http://www.thecephalopodpage.org/chroma2.php The Colourful World of Cephalopods - Cephalopod body patterning II]. The Cephalopod Page.</ref>
A [[bioenergetics]] study found that the giant cuttlefish is primarily diurnal and has a small home range ({{cvt|90|-|550|m|disp=or}}) 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 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.<ref>Hanlon, R.T. 2008. [http://www.eol.org/taxa/16486539?category_id=194 Australian Giant Cuttlefish - Physiology and Biochemistry] {{webarchive|url=https://web.archive.org/web/20080624014943/http://www.eol.org/taxa/16486539?category_id=194 |date=24 June 2008 }}. [[Encyclopedia of Life]].</ref><ref>{{cite journal | last1 = Aitken | first1 = J.P. | last2 = O'Dor | first2 = R.K. | last3 = Jackson | first3 = G.D. | year = 2005 | title = The secret life of the giant Australian cuttlefish ''Sepia apama'' (Cephalopoda): Behaviour and energetics in nature revealed through radio acoustic positioning and telemetry (RAPT) | journal = [[Journal of Experimental Marine Biology & Ecology]] | volume = 320 | issue = 1 | pages = 77–91 | doi=10.1016/j.jembe.2004.12.040| bibcode = 2005JEMBE.320...77A }}</ref>

==Predators==
The Australian giant cuttlefish is eaten by [[Indo-Pacific bottlenose dolphin]]s, which have been observed (in South Australia's Spencer Gulf) to have developed a technique for removing the ink and cuttlebone from a cuttlefish before eating it.<ref>[https://www.independent.co.uk/environment/nature/catch-cuttlefish-drain-off-the-ink-then-fillet-serves-five-dolphins-1521693.html Catch cuttlefish, drain off the ink, then fillet. Serves five (dolphins): Scientists stunned by mammals' elaborate culinary preparations]</ref> They are also eaten by [[Arctocephalus forsteri|Long-nosed fur seals]]. [[Yellowtail amberjack|Yellowtail kingfish]] are also known to eat cephalopods.<ref>{{Cite book|last1=de Jong|first1=M|url=https://www.pir.sa.gov.au/__data/assets/pdf_file/0015/231522/No_130_Environmental_risk_assessment_of_marine_finifish_aquaculture_in_south_australia.pdf|title=Environmental risk assessment of marine finfish aquaculture in South Australia|last2=Tanner|first2=Jason|publisher=SARDI|year=2004|location=South Australia|pages=70}}</ref> This has raised concerns about Yellowtail kingfish escapees from commercial fish farms impacting other species in Spencer Gulf<ref>{{Cite journal|last1=Gillanders|first1=Bronwyn M.|last2=Joyce|first2=Tanya C.|date=2005|title=Distinguishing aquaculture and wild yellowtail kingfish via natural elemental signatures in otoliths|url=http://www.publish.csiro.au/?paper=MF04133|journal=Marine and Freshwater Research|language=en|volume=56|issue=5|pages=693|doi=10.1071/MF04133|issn=1323-1650}}</ref> including eating emergent Giant Australian cuttlefish or their eggs.<ref>{{Cite web|last=Mayfield|first=Louis|date=18 March 2020|title=Cuttlefish concerns over Clean Seas|url=https://www.whyallanewsonline.com.au/story/6685426/cuttlefish-concerns-over-clean-seas/|access-date=29 May 2021|website=[[Whyalla News]]|language=en-AU}}</ref>

==Upper Spencer Gulf population==
{{multiple image
 | align   = right
 | footer  = Dorsal (left) and ventral views of ''S. apama'': lithographic proofs from ''Prodromus of the Zoology of Victoria'' by [[John James Wild]]
 | image1  = Sepia apama by John James Wild.jpg
 | width1  = 224
 | image2  = Sepia apama 2 by John James Wild.jpg
 | width2  = 219
}}
Unpublished scientific data indicated that there are several genetically-distinct populations of giant cuttlefish living in Australian waters. Discovered by divers in 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 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 {{convert|1|/m2|/sqft|disp=preunit|cuttlefish&nbsp;|abbr=off|spell=in}}, covering about {{convert|61|ha}}, the sheer numbers of giant cuttlefish make this breeding aggregation unique in 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.<ref name="BHP" /> Professor [[Roger Hanlon]] of the [[Woods Hole Oceanographic Institution]] has called the breeding aggregation "the premier marine attraction on the planet."<ref name="scuttle" />

The upper Spencer Gulf population displays two alternative lifecycles in both sexes (growth pattern [[Polymorphism (biology)|polymorphism]]). The first involves rapid growth with maturity reached in seven to eight months with small adults returning to spawn in the first year. The second involves slow growth with maturity reached in two years, with large adults returning to spawn in the second year.<ref name="TSSC" /> 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"<ref>Life. Extraordinary Animals, Extreme Behaviour by BBC Books, Martha Holmes & Michael Gunton, 2009 {{ISBN|978-1-84607-642-8}}, pg 28.</ref> mimic female colouring and form to gain access to 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 {{convert|2|to|5|m|ftin|abbr=on}}.<ref name="BHP" />

=== Conservation ===
[[File:Giant cuttlefish (Sepia apama).webm|thumb|Giant cuttlefish (Sepia apama), short video taken off Point Lowly, SA]]

An unsuccessful application to list this population of giant cuttlefish as a threatened species under Australian law was made during the government's consideration of [[BHP|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 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.<ref name="EPBC">[http://www.environment.gov.au/biodiversity/threatened/species/pubs/69365-listing-advice.pdf Conservation Assessment]. Advice to the Minister for Sustainability, Environment, Water, Population and Communities from the Threatened Species Scientific Committee (the Committee) on Amendment to the list of Threatened Population under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) 2 February 2011.</ref> 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.

=== Commercial fishing ===

Prior to the mid-1990s, the upper Spencer Gulf population was fished for [[Lutjanidae|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 the estimated biomass) before dropping to 3.7 tonnes in 1999. The catch data for 2000 to 2005 were initially withheld citing commercial confidentiality.<ref name="hall" />

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, the fishery caught less than 3 tonnes per annum.<ref>{{Cite book|last1=Fowler|first1=A. J.|url=http://pir.sa.gov.au/__data/assets/pdf_file/0006/236904/SA-Marine-Scalefish-Fishery-Status-Report.pdf|title=The South Australian Marine Scalefish Fishery Status Report - Analysis of Fishery Statistics for 2013/14|last2=McGarvey|first2=R.|last3=Steer|first3=M. A.|last4=Feenstra|first4=J. E.|publisher=[[South Australian Research and Development Institute]]|year=2014|location=Adelaide, South Australia|pages=42}}</ref>

{{Bar graph
| title = South Australian cuttlefish fishery – Targeted commercial catch
| bar_width = 40
| width_units = em
| label_type = Financial Year
| label1 = 1992–93
| label2 = 1993–94
| label3 = 1994–95
| label4 = 1995–96
| label5 = 1996–97
| label6 = 1997–98
| label7 = 1998–99
| label8 = 1999–00
| label9 = 2000–01
| label10 = 2001–02
| label11 = 2002–03
| label12 = 2003–04
| label13 = 2004–05
| label14 = 2005–06
| label15 = 2006–07
| label16 = 2007–08
| label17 = 2008–09
| label18 = 2009–10
| label19 = 2010–11
| label20 = 2011–12
| label21 = 2012–13
| label22 = 2013–14
| data_type = Tonnes caught
| data_max = 270
| data1 = 3
| data2 = 7
| data3 = 35
| data4 = 71
| data5 = 263
| data6 = 170
| data7 = 15
| data8 = 16
| data9 = 19
| data10 = 27
| data11 = 11
| data12 = 6
| data13 = 9
| data14 = 8
| data15 = 11
| data16 = 6
| data17 = 4
| data18 = 10
| data19 = 5
| data20 = 3
| data21 = 4
| data22 = 2
}}

=== Population decline ===
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.<ref name="hall">MA Steer and KC Hall [http://www.pir.sa.gov.au/__data/assets/pdf_file/0005/46508/rd05_0012_1_cutfish.pdf Estimated Abundance and Biomass of the Unique Spawning Aggregation of the Giant Australian Cuttlefish (Sepia apama) in Northern Spencer Gulf, South Australia.]{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }} [[Primary Industries and Regions SA]] October 2005</ref> The closure was subsequently expanded to the entire spawning grounds, and anecdotal observations suggested increased numbers in 2006 and 2007; however, a new survey in 2008 found the biomass had decreased a further 17%.<ref name="TSSC" /><ref name="BHP" />

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 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.<ref>''Mystery of the Missing Cuttlefish.'' [[The Advertiser (Adelaide)|The Advertiser]], 24 July 2011. p. 7.</ref>

In 2012, the number of cuttlefish that returned to the spawning ground again dropped again. A cross-government Cuttlefish Working Group was established and recommended investigating broader ecological factors.{{Citation needed|date=March 2016}} 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."<ref>''Drastic loss in giant colony.'' [[The Advertiser (Adelaide)|The Advertiser]], 25 September 2012. p. 24.</ref>

The [[Conservation Council of South Australia]], which believes 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 is no strong evidence to suggest that fishing is impacting on the giant cuttlefish, therefore, further closures would be ineffective."<ref name="scuttle" />

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 a cause, but was otherwise inconclusive, and that further areas of Spencer Gulf would be closed in 2014.<ref name="PIRSA1">{{cite web|title=Cuttlefish update|url=http://www.pir.sa.gov.au/__data/assets/pdf_file/0019/185014/Cuttlefish_Update_-_24_April_2013.pdf|work=Primary Industries and Regions SA|access-date=25 June 2013}}</ref><ref name="Advert27">{{cite news|title=Giant cuttlefish decline prompts catch ban parts of South Australia's Spencer Gulf|url=http://www.adelaidenow.com.au/news/south-australia/giant-cuttlefish-decline-prompts-catch-ban-parts-of-south-australias-spencer-gulf/story-e6frea83-1226607925984|access-date=25 June 2013|newspaper=[[The Advertiser (Adelaide)|The Advertiser]]|date=27 March 2013}}</ref> 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.{{Citation needed|date=March 2016}} Numbers increased again in 2015<ref name=":0">{{Cite news|last=Broadstock|first=Amelia|date=15 March 2016|title=Wildlife photographer captures amazing photo of breeding SA giant cuttlefish|newspaper=The Advertiser|url=http://www.adelaidenow.com.au/technology/science/wildlife-photographer-captures-amazing-photo-of-breeding-sa-giant-cuttlefish/news-story/b2fca8044bd455c47e21e036a44f9a74|access-date=16 March 2016}}</ref> confirming this trend. As of 2021, the population has recovered to an estimated population exceeding 240,000 animals.<ref>{{Cite web|last=Department of Primary Industries and Regions|first=South Australia|date=6 August 2020|title=Giant Australian Cuttlefish|url=https://www.pir.sa.gov.au/fishing/recreational_fishing/cuttlefish|access-date=27 May 2021|website=www.pir.sa.gov.au|language=en-au}}</ref>

The fishing ban for the whole of northern Spencer Gulf was extended until 2020, prohibiting their capture in all Spencer Gulf waters north of [[Wallaroo]] and [[Arno Bay]].<ref>{{Cite web|url=http://pir.sa.gov.au/fishing/closures_and_aquatic_reserves/fishing_closures|title=Fishing closures|website=pir.sa.gov.au|publisher=Department of Primary Industries and Regions, South Australia|language=en-au|access-date=16 March 2016}}</ref> 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.

==== Population estimates ====
{{Bar graph
| title = Standardised annual population estimates (SARDI)
| bar_width = 40
| width_units = em
| label_type = Year
| label1 = 1999
| label2 = 2000
| label3 = 2001
| label4 = 2002
| label5 = 2003
| label6 = 2004
| label7 = 2005
| label8 = 2006
| label9 = 2007
| label10 = 2008
| label11 = 2009
| label12 = 2010
| label13 = 2011
| label14 = 2012
| label15 = 2013
| label16 = 2014
| data_type = Population estimate
| data_max = 200,000
| data1 = 168,497
| data2 = 167,584
| data3 = 172,544
| data4 =0
| data5 =0
| data6 =0
| data7 = 124,867
| data8 =0
| data9 =0
| data10 = 75,173
| data11 = 123,105
| data12 =104,805
| data13 =38,373
| data14 = 18,531
| data15 = 13,492
| data16 = 57,317
|label17=2015|data17=130,771
|label18=2016|data18=177,091
|label19=2017|data19=127,992
}}
* Figure '0' is used to represent years in which surveys did not occur, and no estimation was made.
* 1999–2017 data sourced from [[SARDI]]
* Approximate 2016 population estimate was published in the ''Whyalla News''<ref>{{Cite news|url=https://www.whyallanewsonline.com.au/story/4103612/cuttlefish-opportunity/|title=Cuttlefish opportunity|last=Mayfield|first=Louis|date=17 August 2016|work=Whyalla News|access-date=29 April 2018|language=en}}</ref> and approximate 2017 numbers were first published by PIRSA.<ref>{{Cite web|url=http://www.pir.sa.gov.au/research/services/reports_and_newsletters/sardi_newsletter/issue_3_december_2017/giant_cuttlefish_survey|title=Giant Cuttlefish survey|date=7 November 2017|website=www.pir.sa.gov.au|publisher=Department of Primary Industries and Regions, South Australia|language=en-au|access-date=29 April 2018}}</ref> A slightly larger estimate for the 2017 season was published in 2018 by the ABC (reflected in the graph).<ref>{{Cite news|url=http://www.abc.net.au/news/2018-07-11/giant-australian-cuttlefish-numbers-soar-whyalla/9979992|title=Giant Australian cuttlefish put on vibrant breeding display as numbers soar|date=11 July 2018|work=ABC News|access-date=13 September 2018|language=en-AU}}</ref>

===Effect of local industrialisation===
{{See also|Port Bonython}}
The mass aggregation sites of Upper Spencer Gulf are proximate to 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 the steelworks, lead smelter, municipal wastewater treatment plants and farming of yellowtail kingfish.

==== Nutrient enrichment ====
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 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 amberjack|yellowtail kingfish]] occurred commercially from the late 1990s until 2011. Fish farming is another nutrient pollution source, as uneaten feed and fish waste enter 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.

==== Hydrocarbon pollution ====
In 1984, before the spawning grounds were discovered, [[Santos Limited|Santos]] built a hydrocarbon processing plant at adjoining [[Port Bonython]]. Some concern exists over the possible impact of the plant on the cuttlefish population and two major contamination events have happened at the associated port and refinery.<ref>{{Cite web |url=http://www.amsa.gov.au/marine_environment_protection/major_oil_spills_in_australia/Era/index.asp |title=Major Oil Spills - Era |access-date=7 October 2012 |archive-url=https://web.archive.org/web/20120328063834/http://www.amsa.gov.au/Marine%5FEnvironment%5FProtection/Major_Oil_Spills_in_Australia/Era/index.asp |archive-date=28 March 2012 |url-status=dead }}</ref><ref>{{cite news| url = http://www.abc.net.au/news/2010-03-22/epa-fears-bigger-santos-oil-spill/374516| title = EPA fears bigger Santos oil spill - ABC News| website = [[Australian Broadcasting Corporation]]| date = 22 March 2010}} </ref> 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.<ref name="DP">[https://web.archive.org/web/20120325040509/http://www.nigelmarshphotography.com/articles/whyalladp.htm Cuttlefish chaos at Whyalla]. Archived from Dive Pacific Issue No. 116, Feb/Mar 2010.</ref> The other incident 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.

==== Seawater desalination ====
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 a seawater [[desalination]] plant at Point Lowly to supply fresh water to the Olympic Dam mine. The plant, located within {{convert|200|m|abbr=on}} of the breeding grounds, would release around {{convert|120|ML|gal|abbr=on}} of [[brine]] (46–60 [[Parts-per notation|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 the proposed plant was considerable because of the possible environmental impacts.<ref name="DP" /><ref>[http://www.ffc.org.au/Desalination.html Desalination and South Australia's Gulfs ecosystems] {{webarchive|url=https://web.archive.org/web/20110907083755/http://www.ffc.org.au/Desalination.html |date=7 September 2011 }}. Fishers For Conservation Inc.</ref><ref name="EPBC" /> 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 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.<ref>{{Cite web |title=Premier keen to get cracking on SA desalination plant |url=https://au.news.yahoo.com/premier-keen-cracking-sa-desalination-062021811.html |access-date=30 March 2023 |website=Yahoo News |language=en-AU}}</ref>

==== Port proposals ====
Due to its proximity to the ore deposits of the [[Middleback Range]]s, several mining companies have indicated they might use 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.<ref name="DP" /> In 2021, a new port development was approved for the site of the former [[Playford A Power Station|Playford power stations]],<ref>{{Cite web|date=19 January 2021|title=SA approves Port Playford bulk export development - Daily Cargo News|url=https://www.thedcn.com.au/news/logistics-and-supply-chain/sa-approves-port-playford-bulk-export-development/|access-date=29 May 2021|website=The DCN|language=en-AU}}</ref> 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.<ref>{{Cite journal|last1=Samson|first1=Julia E.|last2=Mooney|first2=T. Aran|last3=Gussekloo|first3=Sander W. S.|last4=Hanlon|first4=Roger T.|date=15 December 2014|title=Graded behavioral responses and habituation to sound in the common cuttlefish Sepia officinalis|journal=[[Journal of Experimental Biology]]|volume=217|issue=Pt 24|pages=4347–4355|doi=10.1242/jeb.113365|issn=1477-9145|pmid=25394634|s2cid=15772018|doi-access=free}}</ref>

== In popular culture ==
The upper Spencer Gulf cuttlefish aggregation is celebrated each year by Cuttlefest, an event hosted by the City of Whyalla.<ref>{{Cite web|title=Cuttlefest 2020|url=https://www.whyalla.com/cuttlefest|access-date=29 May 2021|website=Whyalla|language=English}}</ref>

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, Adelaide|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 a desalination plant at Point Lowly.<ref>McDonald, Patrick [http://www.adelaidenow.com.au/news/fun-with-a-serious-message/story-e6frea6u-1225713218808 "Fun with a serious message as Come Out'09 launched"] ''The Advertiser'', South Australia (17 May 2009). Retrieved 2014-01-22.</ref> 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'.<ref>[http://www.artssmart.sa.edu.au/files/links/ComeOutProgram 2009.pdf Come Out Festival 2009 Program]{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }} ''Come Out Festival'', South Australia (2009). Accessed 22 January 2014.</ref> BHP Billiton has not sponsored the Come Out Festival since the 2009 event.

[[File:Disco Cuttlefish at Adelaide Fringe Festival 2014.JPG|thumb|Stobie the Disco Cuttlefish at [[Adelaide Fringe Festival]] 2014|250x250px]]
During the [[Adelaide Fringe Festival]] in March 2012, the [[RiAus]] presented ''Sepia'', an original work by Welsh playwright, Emily Steel.<ref>Fuss, Eloise [http://www.abc.net.au/local/stories/2012/02/17/3433555.htm "Cuttlefish controversy takes centre stage"] ''[[ABC North & West SA]]'', South Australia (17 February 2012). Retrieved 2014-02-20.</ref> Set in Whyalla, 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]].<ref>[http://sepiatheplay.com/ Sepiatheplay.com] {{webarchive|url=https://web.archive.org/web/20130515065631/http://sepiatheplay.com/ |date=15 May 2013 }} Accessed 21 January 2014.</ref> Presenting partner RiAus is sponsored by the oil and gas company [[Santos Limited|Santos]]. Santos was responsible for hydrocarbon groundwater contamination at Port Bonython, adjacent to the cuttlefish breeding grounds, first discovered in 2008.

In 2014, the Adelaide Fringe Festival launched Stobie the [[Disco Cuttlefish]], a {{convert|13|m|ft|adj=mid|-long}} 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 the festival.<ref>Keen, Suzie [http://indaily.com.au/arts-and-culture/2013/11/29/record-line-up-for-2014-adelaide-fringe/ "Record line-up for 2014 Adelaide Fringe"] ''InDaily ''(29 November 2013)</ref> The soundtrack to the performance included samples from the [[Bee Gees]] hit "[[Stayin' Alive]]"<ref>[http://www.adelaidefringe.com.au/fringetix/free-events/cuttlefish Disco Cuttlefish] {{webarchive|url=https://web.archive.org/web/20140218002257/http://www.adelaidefringe.com.au/fringetix/free-events/cuttlefish |date=18 February 2014 }} - ''[[Adelaide Fringe Festival]]'' (2014). Accessed 20 February 2014.</ref> and the entire theme song from the movie [[Fame (1980 film)|''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.<ref name=":0" />

The mass aggregation of giant cuttlefish at Point Lowly has inspired the development of a retro computer game called ''Cuttle Scuttle''.<ref>{{IMDb title|qid=Q123616192|title=Cuttle Scuttle}}.</ref>

==See also==
* [[Cephalopod size]]

==References==
{{Reflist|30em}}
* {{cite journal | last1 = Kassahn | first1 = K.S. | last2 = Donnellan | first2 = S.C. | last3 = Fowler | first3 = A.J. | last4 = Hall | first4 = K.C. | last5 = Adams | first5 = M. | last6 = Shaw | first6 = P.W. | year = 2003 | title = Molecular and morphological analyses of the cuttlefish ''Sepia apama'' indicate a complex population structure | journal = Marine Biology | volume = 143 | issue = 5| pages = 947–962 | doi = 10.1007/s00227-003-1141-5 | bibcode = 2003MarBi.143..947K | s2cid = 85359163 }}

==External links==
{{Commons|Sepia apama}}
{{Wikispecies|Sepia (Sepia) apama}}
* {{Cite web |last=Graham |first=Debbie |title=10 cuttlefish facts you may not know |url=https://www.discoverwildlife.com/animal-facts/fish/cuttlefish-facts |access-date=25 April 2024 |website=www.discoverwildlife.com |language=en}}
* [https://earthobservatory.nasa.gov/images/148963/truly-giant-cuttlefish-in-false-bay Spencer Gulf in South Australia hosts the world’s largest cuttlefish mass spawning event] NASA [[Earth Observatory]], 16 October 202
* [https://web.archive.org/web/20051224170241/http://www.bbc.co.uk/nature/wildfacts/factfiles/3074.shtml BBC: Giant cuttlefish]
{{CephBase Species|11}}
* [https://www.youtube.com/watch?v=yjzYsXWFrD0 Video of ''Sepia apama''] at [[YouTube]]

{{Taxonbar|from=Q1632342}}

[[Category:Sepia]]
[[Category:Cephalopods of Australia]]
[[Category:Fauna of Western Australia]]
[[Category:Cephalopods described in 1849]]
[[Category:Taxa named by John Edward Gray]]
[[Category:Fauna of South Australia]]