Arctica islandica
{{Short description|Species of bivalve}}
{{Italic title}}
{{Speciesbox
| name = Ocean quahog
| taxon = Arctica islandica
| image = Arctica islandica valves.jpg
| image_caption = A shell of Arctica islandica with the valves separated
| authority = Linnaeus, 1767
| display_parents = 3
}}
File:Arctica islandica Islandmuschel.jpg of A. islandia from Wales]]
The ocean quahog (Arctica islandica) is a species of edible clam, a marine bivalve mollusk in the family Arcticidae. This species is native to the North Atlantic Ocean, and it is harvested commercially as a food source. This species is also known by a number of different common names, including Icelandic cyprine,Sabatini, M. & Pizzola, P.F., 2007. Arctica islandica. Icelandic cyprine. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 14 September 2007]. Available from:
| last = Hackney
| first = Cameron R.
| author2 = Thomas E. Rippen
| editor = Roy E. Martin |editor2=Emily Paine Carter Jr. |editor3=George J. Flick |editor4=Lynn M. Davis
| title = Marine and Freshwater Products Handbook
| year = 2000
| publisher = CRC Press
| isbn = 1-56676-889-6
| pages = 323–324
| chapter = The Molluscan Shellfish Industry
}}
The typical A. islandica resembles the quahog, but the shell of the ocean quahog is rounder, the periostracum is usually black, and on the interior of the shell, the pallial line has no indentation, or sinus. Unlike the quahog, which lives intertidally and can be collected by clam digging, this species lives subtidally, and can only be collected by dredging. They grow to sizes exceeding 50 mm or two inches shell height.{{cite journal|url=http://www.vliz.be/imisdocs/publications/56725.pdf |title=The distribution and population structure of the bivalve Arctica islandica L. in the North Sea: what possible factors are involved? |author1=R. Witbaard |author2=M.J.N. Bergman |journal=Journal of Sea Research |volume=50 |issue=1 |year=2003 |pages=11–25 |doi=10.1016/s1385-1101(03)00039-x |url-status=dead |archive-url=https://web.archive.org/web/20110928101137/http://www.vliz.be/imisdocs/publications/56725.pdf |archive-date=2011-09-28 |bibcode=2003JSR....50...11W }} An individual specimen was reported to have lived 507 years, making it the longest-lived non-clonal metazoan whose age was accurately known.
Right and left valve of the same specimen:
File:Arctica islandica 01.jpg|Right valve
File:Arctica islandica 02.jpg|Left valve
Life cycle and longevity
A. islandica shows slower growth rate than other species of clams, it takes an average rate of 4 days for birth (embryo to larvae stage). Furthermore, it takes an average of 5.8 years for A. islandica to reach maturity; at this point the somatic costs start going down. Dynamic Energy Models (DEM) predict that A. islandica's extreme longevity arises from lowered somatic maintenance costs and a low aging acceleration.{{Cite journal|title=Energetics of the extremely long-living bivalve Arctica islandica based on a Dynamic Energy Budget model|pages=173–182|journal=Journal of Sea Research | volume=143 | doi=10.1016/j.seares.2018.09.016|date=January 2019|bibcode=2019JSR...143..173B|last1=Ballesta-Artero | first1=Irene|last2=Augustine|first2=Starrlight | last3=Witbaard|first3=Rob | last4=Carroll|first4=Michael L.|last5=Mette|first5=Madelyn J.|last6=Wanamaker Alan|first6=D.|last7=Van Der Meer|first7=Jaap|s2cid=92037627 |url=http://www.vliz.be/imisdocs/publications/61/321561.pdf}} For individuals in populations in cold areas the growth rate is probably further slowed because growth occurs only in summer.{{cite journal |last1=Ballesta-Artero |first1=Irene |last2=Witbaard |first2=Rob |last3=Carroll |first3=Michael L. |last4=van der Meer |first4=Jaap |title=Environmental factors regulating gaping activity of the bivalve Arctica islandica in Northern Norway |journal=Marine Biology |date=2017 |volume=164 |issue=5 |page=116 |doi=10.1007/s00227-017-3144-7|pmid=28546647 |pmc=5409809 |doi-access=free }} This slow life style results in exceptional longevity, e.g., with a reported age, for Ming the clam, of 507 years. It is the longest lived non-colonial metazoan species with an authenticated lifespan.{{cite journal|author1=Butler, P.|author2 = Wanamaker, A. Jr.|author3 = Scourse, J.|author4 = Richardson, C.|author5 = Reynolds, D. | year = 2013 | title = Variability of marine climate on the North Icelandic Shelf in a 1357-year proxy archive based on growth increments in the bivalve Arctica islandica | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | volume = 373 | pages = 141–51 | doi = 10.1016/j.palaeo.2012.01.016 |bibcode = 2013PPP...373..141B}}{{cite journal | last1 = Butler | first1 = P.G. | year = 2012 | title = Clam shells, climate change and ageing: The mollusc that had 500 birthdays | url = http://pages.bangor.ac.uk/~ossa07/Articles/Catalyst_23_1_526.pdf | journal = Catalyst Secondary School Review | volume = 23 | issue = 1| pages = 6–8 }}{{cite journal | last1 = Bulter | first1 = P. | display-authors = etal | year = 2012 | title = Characterising the microstructure of Arctica islandica shells using NanoSIMS and EBSD | url = http://pages.bangor.ac.uk/~ossa07/Papers/Karney_etal_2012_GGG.pdf | journal = Geochemistry, Geophysics, Geosystems| volume = 13 | issue = 4| page = Q04002 | doi = 10.1029/2011GC003961 | bibcode = 2012GGG....13.4002K | doi-access = free }} It is unknown how long it could have lived had it not been collected alive by a 2006 expedition.
This characteristic has proven useful in the science of sclerochronology, the study of periodic physical and chemical features in the hard tissues of animals that grow by accretion, and is especially valuable for modeling of paleoclimates. In 1868 one specimen, collected alive near Iceland, was 374 years old. The study of its growth rate and the oxygen isotope data showed that it had a highly variable growth at the peak of the Little Ice Age around 1550–1620 and mild climate near its end around 1765–1780 and had recorded the volcanic eruption of Mount Tambora in 1815.{{cite journal | last1 = Schone | first1 = B.R. | display-authors = etal | year = 2005 | title = Climate records from a bivalved Methuselah (Arctica islandica, Mollusca; Iceland)| journal = Palaeogeography, Palaeoclimatology, Palaeoecology | volume = 228 | issue = 1–2| pages = 130–148 | doi = 10.1016/j.palaeo.2005.03.049 | bibcode = 2005PPP...228..130S }}
One study found that in animals aged 4–192 years, antioxidant enzymes declined rapidly in the first 25 years, which includes the growth and sexual maturity stages, but afterwards remained stable for over 150 years. Though more detailed studies are warranted, it appears this species is a case of negligible senescence.{{Cite web | url=http://genomics.senescence.info/species/entry.php?species=Arctica_islandica | title=Ocean quahog clam (Arctica islandica) longevity, ageing, and life history}} In contrast to the exceptionally long-lived populations in relatively deep, cold parts of its range, more southern populations that experience greater seasonal variations in salinity and temperature are typically far shorter-lived. For example, A. islandica from the German Bay of Kiel typically only reach an age of about 30 years and those from the German Bight about 150.Strahl, Julia (2011). Life strategies in the long-lived bivalve Arctica islandica on a latitudinal climate gradient – Environmental constraints and evolutionary adaptations. Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, University of Bremen.
Feeding ecology
Like other clam species, A. islandica is a filter feeder. Feeding activity appears regulated by light levels, which can be used as a proxy for food availability. This means that at the northern extreme of the distribution, feeding is concentrated during eight months of the year, while during the rest of the year the clams only feed for a few days a month.
See also
Notes
{{Reflist}}
External links
{{Commons category|Arctica islandica}}
- [http://www.nefsc.noaa.gov/nefsc/publications/tm/tm148/tm148.pdf Ocean quahog, A. islandia, Life history and habitat] from the NOAA.
- [https://web.archive.org/web/20071031151756/http://www.palaeontologie.uni-mainz.de/Forschung/Publikationen/pdf/Schoene%20et%20al%202005%20PPP%20228_130-_Climate%20records%20sclero%20Arctica%20islandica%20Iceland%20ox%20carb%20iso%20d18O%20d13C.pdf Climate records from a bivalved Methuselah]
{{Commercial molluscs}}
{{Edible molluscs}}
{{Taxonbar|from=Q856177}}
Category:Marine molluscs of Europe
Category:Marine molluscs of North America
Category:Molluscs of the Atlantic Ocean
Category:Negligibly senescent organisms