The curled octopus (Eledone cirrhosa), also known as the horned octopus,[4]lesser octopus or northern octopus,[5] is a species of cephalopod found in the northeast Atlantic, ranging from Norway to the Mediterranean, including the British Isles. The total length of an adult is around 50 cm, but their arms are often tightly curled. It immobilises and eats large crustaceans by drilling a hole through their shell. It is mainly by-catch in commercial fisheries of the north eastern Atlantic and Mediterranean, where the common octopus is the preferred species.
It has a broad, ovoid-shaped mantle and can reach a total length (including arms) of up to 50 cm (20 in). The head is narrower than the rest of the body with a filament over each eye. The octopus's colour is yellowish or reddish-orange to reddish-brown dorsally with diffuse rust-brown patches, and white on the underside. The skin is covered with very fine, closely set granulations, interspersed with larger warts. The relatively short arms have a single series of suckers on them and at rest are held with the tips lightly curled, hence the species's common name.[6] This species maximum weight is 1 kilogram (2.2 lb) in the more southerly parts of its distribution and 2 kilograms (4.4 lb) in the northern part.[7]
Oral and ventral view
Habitat and distribution
The curled octopus is mainly found at depths between 0 and 150 m (0 and 492 ft) and may occur down to 800 m (2,600 ft). It lives in the northeast Atlantic Ocean, including the English Channel, the North Sea, and the Mediterranean Sea. In recent years the North Sea populations have increased, probably due to overfishing of large predatory fish such as Atlantic cod. This has had an effect on crab and lobster fisheries as the curled octopus readily enters pots to take the bait or the catch. In seas of Scotland, E. cirrhosa is infrequently caught when trawling over rocky substrates and are more frequently captured when fishing over sandy or muddy substrates.[8] A survey using different methods found that Eledone cirrhosa was common and widespread throughout the Scottish inshore waters covered by fishing activity, from the shoreline down to 140m, on substrates ranging through rocky, stoney, sandy and muddy. Specimens were caught throughout the year but is most common in inshore waters during the summer months and moves further offshore to the trawling grounds in October–December.[9]
Diet
The curled octopus feeds on crabs and other large crustaceans, as well as fish.[5]Serological analysis of the crop of specimens sampled in the Moray Firth and Sound of Jura revealed the main prey to be Liocarcinus spp, Nephrops norvegicus, Cancer pagurus , Crangon crangon and Carcinus maenas, although a large proportion of the samples analysed did not react in the tests suggesting they had consumed alternative prey.[10] It is cited as a significant predator of such commercially important species as Homarus gammarus (European lobster), Nephrops norvegicus (Norway lobster), and Cancer pagurus (edible crab) from traps.[9] When preying on crabs, it immobilises the crab by injecting toxins into the body of the crab through a hole created in its shell using the octopus's radula.[11] The octopus then injects saliva into the crab and the digestive enzymes contained in that saliva break down the crab's internal attachments to its shell, allowing the octopus to easily remove the carapace.[5]
Biology
The growth rate of the curled octopus is quite rapid and its life span is generally short at 1–5 years, although there may be some variation between warmer and colder areas. The curled octopus matures at around 1 year (on reaching a total length of 12–40 cm or 4.7–15.7 in for females, slightly smaller for males) and with 1,000–5,000 eggs laid on average. The females normally attain sexual maturity when they reach a body size of between 400–1000 g but some females weighing up to 1000–1200 g show no evidence of enlargement of the ovaries.[12] The males reach just over 600g and typically have well-developed reproductive organs from around 200g.[13] It breeds at a lower rate than the partially sympatricOctopus vulgaris (common octopus). Populations are apparently at their lowest density in the autumn, probably due to post-spawning die off as reproduction involves females laying eggs, guarding them and dying once the eggs hatch. Curled octopuses are solitary animals, generally inhabiting depths of less than 100 m (330 ft), and more common in shallow water, but they have been found down to 800 m (2,600 ft).[14]
Breeding activity of the curled octopus peaks between July and September and there are many juveniles present in October. In 2017 Storm Brian was followed by reports of many curled octopus on beaches and rock pools around the island of Anglesey and the Llyn Peninsula in north Wales. These were mostly juveniles which with their weaker suction than the adults were more affected by waves created by the storm, swept away from their hiding places among the rocks and stranded.[15]
Analysis carried out on the stomach contents of stranded Risso's dolphins demonstrates that the most important species fed on in Scottish waters is the curled octopus.[8]
Fisheries
The curled octopus is taken as bycatch in trawl fisheries for other species. It is also captured in earthenware pots in the Mediterranean, although the fishery for curled octopuses is less important than that of the common octopus. International Council for the Exploration of the Sea (ICES) catch data for both the curled octopus and common octopus, from all ICES regions (NE Atlantic) in 2006, indicated around 8,999 tonnes, but more recent estimates indicate a substantial increase to around 19,000 tonnes in 2008 (ICES WGCEPH, 2010). Nearly all landings of both species within these regions are taken by Portugal and Spain, with Spain taking the vast majority, although most of these will be of the common octopus.[16] Neither species is subject to either stock assessment or quota controls in Europe and in the case of the curled octopus there is no minimum size for landing.[17] In the Adriatic this species is caught and sold alongside Eledone moschata but is the less numerous of the two.[4] It is not regarded as a commercially viable species in Scotland and any caught are normally discarded.[8]
References
Wikimedia Commons has media related to Eledone cirrhosa.
^Allcock, L.; Taite, M.; Headlam, J.; Allen, G. (2018). "Eledone cirrhosa". IUCN Red List of Threatened Species. 2018: e.T163307A995942. doi:10.2305/IUCN.UK.2018-2.RLTS.T163307A995942.en. Retrieved 20 November 2021.
^SCICOM STEERING GROUP ON ECOSYSTEM FUNCTIONS (SSGEF) (2013). "Report of the Working Group on Cephalopod Fisheries and Life History (WGCEPH)" (PDF). International Council for the Exploration of the Sea. Retrieved 20 April 2018.
^ abcMacLeod, C. D.; Santos, M. B.; Burns, F.; Brownlow, A.; Pierce, G. J. (March 2014). "MacLeod, C.D., Santos, M.B and Pierce, G.J. 2014. Can habitat modelling for the octopus Eledone cirrhosa help identify key areas for Risso's dolphin in Scottish waters? Scottish Natural Heritage Commissioned Report No. 530". Scottish Natural Heritage. doi:10.1007/s10750-013-1555-0. hdl:2164/5728. S2CID 1335648. Retrieved 24 December 2016. {{cite journal}}: Cite journal requires |journal= (help)
^ abP.R. Boyle (1986). "A Descriptive Ecology of Eledone Cirrhosa (Mollusca: Cephalopoda) in Scottish Waters (abstract)". Journal of the Marine Biological Association of the United Kingdom. 66 (4): 855–865. doi:10.1017/s0025315400048487. S2CID 86564565.
^P.R. Boyle; M. S. Grisley; G. Robertson (1986). "Crustacea in the Diet of Eledone Cirrhosa (Mollusca: Cephalopoda) determined by Serological Methods (abstract)". Journal of the Marine Biological Association of the United Kingdom. 66 (4): 867–879. doi:10.1017/s0025315400048499. S2CID 84526994.
^N.W. Runham; C.J. Bailey; M. Carr; C.A. Evans; S. Malham (1997). "Hole drilling in crab and gastropod shells by Eledone cirrhosa (Lamarck, 1798)" (PDF). Scientia Marina. 61 (Supplement2): 67–76.
^P.R. Boyle; Daniela Knobloch (1983). "The female reproductive cycle of the octopus, Eledone cirrhosa (abstract)". Journal of the Marine Biological Association of the United Kingdom. 63 (1): 71–83. doi:10.1017/s002531540004981x. S2CID 86778330.
^P.R. Boyle (1984). "Male reproductive maturity in the octopus, Eledone cirrhosa (Cephalopoda: Octopoda) (abstract)". Journal of the Marine Biological Association of the United Kingdom. 64 (3): 573–579. doi:10.1017/s0025315400030265. S2CID 85572659.
^"Eledone cirrhosa". www.european-marine-life.org. Bay-Nouailhat A. Retrieved 24 December 2016.
^(PDF). Archived from the original (PDF) on 2012-01-10. Retrieved 2012-01-24.{{cite web}}: CS1 maint: archived copy as title (link)
External links
Photos of Curled octopus on Sealife Collection
January 31, 2023
curled, octopus, curled, octopus, eledone, cirrhosa, also, known, horned, octopus, lesser, octopus, northern, octopus, species, cephalopod, found, northeast, atlantic, ranging, from, norway, mediterranean, including, british, isles, total, length, adult, aroun. The curled octopus Eledone cirrhosa also known as the horned octopus 4 lesser octopus or northern octopus 5 is a species of cephalopod found in the northeast Atlantic ranging from Norway to the Mediterranean including the British Isles The total length of an adult is around 50 cm but their arms are often tightly curled It immobilises and eats large crustaceans by drilling a hole through their shell It is mainly by catch in commercial fisheries of the north eastern Atlantic and Mediterranean where the common octopus is the preferred species Curled octopusConservation statusLeast Concern IUCN 3 1 1 Scientific classificationKingdom AnimaliaPhylum MolluscaClass CephalopodaOrder OctopodaFamily EledonidaeGenus EledoneSpecies E cirrhosaBinomial nameEledone cirrhosa Lamarck 1798 2 Synonyms 3 Eledona aldrovandi Delle Chiaje Eledona ambrosiaca Risso 1854 Eledone aldrovandi Montfort 1802 Hallia sepioidea Rochebrune 1884 Octopus cirrhosus Lamarck 1798 Ozoena aldrovandi Rafinesque 1814 Ozoena cirrhosa Lamarck 1798 Sepia octopodia Linnaeus 1758 Contents 1 Description 2 Habitat and distribution 3 Diet 4 Biology 5 Fisheries 6 References 7 External linksDescription Edit Dorsal view It has a broad ovoid shaped mantle and can reach a total length including arms of up to 50 cm 20 in The head is narrower than the rest of the body with a filament over each eye The octopus s colour is yellowish or reddish orange to reddish brown dorsally with diffuse rust brown patches and white on the underside The skin is covered with very fine closely set granulations interspersed with larger warts The relatively short arms have a single series of suckers on them and at rest are held with the tips lightly curled hence the species s common name 6 This species maximum weight is 1 kilogram 2 2 lb in the more southerly parts of its distribution and 2 kilograms 4 4 lb in the northern part 7 Oral and ventral viewHabitat and distribution EditThe curled octopus is mainly found at depths between 0 and 150 m 0 and 492 ft and may occur down to 800 m 2 600 ft It lives in the northeast Atlantic Ocean including the English Channel the North Sea and the Mediterranean Sea In recent years the North Sea populations have increased probably due to overfishing of large predatory fish such as Atlantic cod This has had an effect on crab and lobster fisheries as the curled octopus readily enters pots to take the bait or the catch In seas of Scotland E cirrhosa is infrequently caught when trawling over rocky substrates and are more frequently captured when fishing over sandy or muddy substrates 8 A survey using different methods found that Eledone cirrhosa was common and widespread throughout the Scottish inshore waters covered by fishing activity from the shoreline down to 140m on substrates ranging through rocky stoney sandy and muddy Specimens were caught throughout the year but is most common in inshore waters during the summer months and moves further offshore to the trawling grounds in October December 9 Diet EditThe curled octopus feeds on crabs and other large crustaceans as well as fish 5 Serological analysis of the crop of specimens sampled in the Moray Firth and Sound of Jura revealed the main prey to be Liocarcinus spp Nephrops norvegicus Cancer pagurus Crangon crangon and Carcinus maenas although a large proportion of the samples analysed did not react in the tests suggesting they had consumed alternative prey 10 It is cited as a significant predator of such commercially important species as Homarus gammarus European lobster Nephrops norvegicus Norway lobster and Cancer pagurus edible crab from traps 9 When preying on crabs it immobilises the crab by injecting toxins into the body of the crab through a hole created in its shell using the octopus s radula 11 The octopus then injects saliva into the crab and the digestive enzymes contained in that saliva break down the crab s internal attachments to its shell allowing the octopus to easily remove the carapace 5 Biology EditThe growth rate of the curled octopus is quite rapid and its life span is generally short at 1 5 years although there may be some variation between warmer and colder areas The curled octopus matures at around 1 year on reaching a total length of 12 40 cm or 4 7 15 7 in for females slightly smaller for males and with 1 000 5 000 eggs laid on average The females normally attain sexual maturity when they reach a body size of between 400 1000 g but some females weighing up to 1000 1200 g show no evidence of enlargement of the ovaries 12 The males reach just over 600g and typically have well developed reproductive organs from around 200g 13 It breeds at a lower rate than the partially sympatric Octopus vulgaris common octopus Populations are apparently at their lowest density in the autumn probably due to post spawning die off as reproduction involves females laying eggs guarding them and dying once the eggs hatch Curled octopuses are solitary animals generally inhabiting depths of less than 100 m 330 ft and more common in shallow water but they have been found down to 800 m 2 600 ft 14 Breeding activity of the curled octopus peaks between July and September and there are many juveniles present in October In 2017 Storm Brian was followed by reports of many curled octopus on beaches and rock pools around the island of Anglesey and the Llyn Peninsula in north Wales These were mostly juveniles which with their weaker suction than the adults were more affected by waves created by the storm swept away from their hiding places among the rocks and stranded 15 Analysis carried out on the stomach contents of stranded Risso s dolphins demonstrates that the most important species fed on in Scottish waters is the curled octopus 8 Fisheries EditThe curled octopus is taken as bycatch in trawl fisheries for other species It is also captured in earthenware pots in the Mediterranean although the fishery for curled octopuses is less important than that of the common octopus International Council for the Exploration of the Sea ICES catch data for both the curled octopus and common octopus from all ICES regions NE Atlantic in 2006 indicated around 8 999 tonnes but more recent estimates indicate a substantial increase to around 19 000 tonnes in 2008 ICES WGCEPH 2010 Nearly all landings of both species within these regions are taken by Portugal and Spain with Spain taking the vast majority although most of these will be of the common octopus 16 Neither species is subject to either stock assessment or quota controls in Europe and in the case of the curled octopus there is no minimum size for landing 17 In the Adriatic this species is caught and sold alongside Eledone moschata but is the less numerous of the two 4 It is not regarded as a commercially viable species in Scotland and any caught are normally discarded 8 References Edit Wikimedia Commons has media related to Eledone cirrhosa Allcock L Taite M Headlam J Allen G 2018 Eledone cirrhosa IUCN Red List of Threatened Species 2018 e T163307A995942 doi 10 2305 IUCN UK 2018 2 RLTS T163307A995942 en Retrieved 20 November 2021 Eledone cirrhosa Lamarck 1798 Integrated Taxonomic Information System S Gofas 2004 Eledone cirrhosa Lamarck 1798 World Register of Marine Species Retrieved 2 April 2017 a b Eledone cirrhosa Lamarck 1798 Adriamed FAO Retrieved 24 December 2016 a b c Curled octopus Eledone cirrhosa Wildscreen Arkive Wildscreen Archived from the original on 2016 12 24 Retrieved 24 December 2016 Wilson Emily 2008 Eledone cirrhosa Curled octopus Marine Life Information Network Biology and Sensitivity Key Information Sub programme Plymouth Marine Biological Association of the United Kingdom Retrieved 24 01 2012 SCICOM STEERING GROUP ON ECOSYSTEM FUNCTIONS SSGEF 2013 Report of the Working Group on Cephalopod Fisheries and Life History WGCEPH PDF International Council for the Exploration of the Sea Retrieved 20 April 2018 a b c MacLeod C D Santos M B Burns F Brownlow A Pierce G J March 2014 MacLeod C D Santos M B and Pierce G J 2014 Can habitat modelling for the octopus Eledone cirrhosa help identify key areas for Risso s dolphin in Scottish waters Scottish Natural Heritage Commissioned Report No 530 Scottish Natural Heritage doi 10 1007 s10750 013 1555 0 hdl 2164 5728 S2CID 1335648 Retrieved 24 December 2016 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help a b P R Boyle 1986 A Descriptive Ecology of Eledone Cirrhosa Mollusca Cephalopoda in Scottish Waters abstract Journal of the Marine Biological Association of the United Kingdom 66 4 855 865 doi 10 1017 s0025315400048487 S2CID 86564565 P R Boyle M S Grisley G Robertson 1986 Crustacea in the Diet of Eledone Cirrhosa Mollusca Cephalopoda determined by Serological Methods abstract Journal of the Marine Biological Association of the United Kingdom 66 4 867 879 doi 10 1017 s0025315400048499 S2CID 84526994 N W Runham C J Bailey M Carr C A Evans S Malham 1997 Hole drilling in crab and gastropod shells by Eledone cirrhosa Lamarck 1798 PDF Scientia Marina 61 Supplement2 67 76 P R Boyle Daniela Knobloch 1983 The female reproductive cycle of the octopus Eledone cirrhosa abstract Journal of the Marine Biological Association of the United Kingdom 63 1 71 83 doi 10 1017 s002531540004981x S2CID 86778330 P R Boyle 1984 Male reproductive maturity in the octopus Eledone cirrhosa Cephalopoda Octopoda abstract Journal of the Marine Biological Association of the United Kingdom 64 3 573 579 doi 10 1017 s0025315400030265 S2CID 85572659 Eledone cirrhosa www european marine life org Bay Nouailhat A Retrieved 24 December 2016 Frances Dipper 2017 Wildlife Reports Marine Life British Wildlife 29 2 135 137 Curled octopus at Fish online Archived copy PDF Archived from the original PDF on 2012 01 10 Retrieved 2012 01 24 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link External links EditPhotos of Curled octopus on Sealife Collection Retrieved from https en wikipedia org w index php title Curled octopus amp oldid 1136339549, wikipedia, wiki, book, books, library,
