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{{Short description|Family of shellfish, many edible}}
{{About||verb senses|Scalloping (disambiguation){{!}}Scalloping|potato scallops|Potato cake|scalloped potatoes|Gratin#Potatoes gratiné|the cut of meat|Escalope|the scallop shell moth|Rheumaptera undulata|the sculpture by Maggi Hambling|Scallop (sculpture)}}
{{distinguish|Scallion}}
{{Cleanup|reason=Article has prose that repeats itself|date=July 2025}}
{{Use dmy dates|date=July 2024}}
{{Automatic taxobox
| name = Scallop
| fossil_range = {{fossil range|247|0|[[Middle Triassic]]-present}}
| image = Argopecten irradians.jpg
| image_caption = ''[[Argopecten irradians]]'', the Atlantic bay scallop
| taxon = Pectinidae
| authority = [[Charles Wilkes|Wilkes]], 1810
| subdivision_ranks = Genera
| subdivision = See text
| synonyms = Pectenidae
| synonyms_ref = {{citation needed|date=July 2024}}
}}

'''Scallop''' ({{IPAc-en|ˈ|s|k|ɒ|l|ə|p|,_|ˈ|s|k|æ|l|-}}){{efn|Also occasionally written '''scollop''' and once spelled '''scalap''', '''-opp''', '''scalop''', '''skalop''', '''scalepp''', '''-oppe''', '''scalloppe''', '''skallap''', '''-op''', '''scallope''', '''scallap''', '''s(c)kollop''', and '''scollup''', '''-op''' as well as '''escallop''', '''escalop''', and '''escollop''', though ''scallop'' appears to have become the dominant way of spelling the word in English.<ref>Whitney, D. W. (1890) [https://books.google.com/books?id=HVMwGk1g3awC "Scallop"]. ''[[Century Dictionary|The Century Dictionary: An Encyclopedic Lexicon of the English Language]]'' p.5371, [[The Century Company]].</ref><ref>"Scallop" (2009). ''[[The Oxford English Dictionary]]'' (2nd ed.), [[Oxford University Press]].</ref>}} is a [[common name]] that encompasses various species of [[marine invertebrates|marine]] [[Bivalvia|bivalve]] [[mollusc]]s in the [[taxonomy (biology)|taxonomic]] [[family (biology)|family]] '''Pectinidae''', the scallops. However, this common name is also sometimes applied to species in other closely related families within the superfamily [[Pectinoidea]], which also includes the [[Spondylus|thorny oysters]].

Scallops are a [[cosmopolitan distribution|cosmopolitan]] family of bivalves found in all of the world's oceans, although never in fresh water. They are one of the very few groups of bivalves to be primarily "free-living", with many species capable of rapidly swimming short distances and even migrating some distance across the ocean floor. A small minority of scallop species live cemented to rocky [[substrate (biology)|substrates]] as adults, while others attach themselves to stationary or rooted objects such as seagrass at some point in their lives by means of a filament they secrete called a [[byssus|byssal thread]].

The majority of species, however, live recumbent on sandy substrates, and when they sense the presence of a predator such as a [[starfish]], they may attempt to escape by swimming swiftly but erratically through the water using jet propulsion created by repeatedly clapping their shells together. Scallops have a well-developed nervous system, and unlike most other bivalves all scallops have a ring of numerous [[simple eye]]s situated around the edge of their [[mantle (mollusc)|mantles]].

Many species of scallops are highly prized as a food source, and some are farmed as [[scallop aquaculture|aquaculture]]. The word "scallop" is also applied to the meat of these bivalves, the [[adductor muscles (bivalve)|adductor muscle]], that is sold as [[seafood]]. The brightly coloured, symmetrical, fan-shaped shells of scallops with their radiating and often fluted [[sculpture (mollusc)|ornamentation]] are valued by shell collectors, and have been used since ancient times as motifs in art, architecture, and design.

Owing to their widespread distribution, scallop shells are a common sight on beaches and are often brightly coloured, making them a popular object to collect among [[beachcombing|beachcombers]] and vacationers.{{sfn|Robinson|Robinson|2000|page=[https://books.google.com/books?id=kNYJdHyNRgsC&pg=PA65 65]}} The shells also have a significant place in popular culture.

== Etymology ==
The family name Pectinidae, which is based on the name of the type genus, ''[[Pecten (bivalve)|Pecten]]'', comes from the [[Latin (language)|Latin]] ''[[wikt:pecten|pecten]]'' meaning [[comb]], in reference to a comb-like structure of the shell which is situated next to the byssal notch.{{sfn|Rice|2012|page=[https://books.google.com/books?id=4CD72deHDwQC&pg=PA47 47]}}

== Description ==
Very little variation occurs in the internal arrangement of organs and systems within the scallop family, and what follows can be taken to apply to the anatomy of any given scallop species.{{sfn|Shumway|Parsons|2011|page=[https://books.google.com/books?id=rSu_GLwLQmEC&pg=PA124 124]}}{{Additional citation needed|date=July 2025|reason=Statement needs to be supported by a claim from a more recent source, such as a textbook or monograph}}

=== Orientation ===
[[File:Scallop Diagram2.svg|400px|thumb|Anatomical diagram of an [[Atlantic bay scallop]] with the left (i.e., upper) valve removed; anterior is to the left, posterior to the right]]
The shell of a scallop consists of two sides or [[Valve (mollusc)|valves]], a left valve and a right one, divided by a [[plane of symmetry]].{{sfn|Milsom|Rigby|2009|page=[https://books.google.com/books?id=e8Xr6pXKdcEC&pg=PA62 62]}} Most species of scallops rest on their right valve, and consequently, this valve is often deeper and more rounded than the left (i.e., upper) valve, which in many species is actually concave. With the hinge of the two valves oriented towards the top, one side corresponds to the animal's morphological ''anterior'' or front, the other is the ''posterior'' or rear, the hinge is the ''dorsal'' or back/top region, and the bottom corresponds to the ''ventral'' or (as it were) underside/belly.{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}} However, as many scallop shells are more or less bilaterally symmetrical ("equivalved"), as well as symmetrical front/back ("equilateral"), determining which way a given animal is "facing" requires detailed information about its valves.{{citation needed|date=January 2017}}

=== Valves ===
[[File:Buried inequivalved scallop.svg|thumb|left|Diagram of a scallop with two differently sized valves shown positioned in ocean floor sediment: the right valve (shown at the bottom) much deeper than the left, allowing the scallop to appear less visible to predators]]
The model scallop shell consists of two similarly shaped valves with a straight hinge line along the top, devoid of teeth, and producing a pair of flat wings or "ears" (sometimes called "auricles", though this is also the term for two chambers in its heart) on either side of its midpoint, a feature which is unique to and apparent in all adult scallops.{{sfn|Shumway|Parsons|2011|page=[https://books.google.com/books?id=rSu_GLwLQmEC&pg=PA59 59]}} These ears may be of similar size and shape, or the anterior ear may be somewhat larger (the posterior ear is never larger than the anterior one, an important feature for distinguishing which valve is which). As is the case in almost all bivalves, a series of lines and/or growth rings originates at the center of the hinge, at a spot called the "[[beak (bivalve)|beak]]" surrounded by a generally raised area called the "[[umbo (bivalve)|umbo]]". These growth rings increase in size downwards until they reach the curved ventral edge of the shell. The shells of most scallops are streamlined to facilitate ease of movement during swimming at some point in their lifecycles, while also providing protection from predators. Scallops with ridged valves have the advantage of the architectural strength provided by these ridges called "ribs", although the ribs are somewhat costly in weight and mass. A unique feature of the scallop family is the presence, at some point during the animal's lifecycle, of a distinctive and taxonomically important shell feature, a comb-like structure called a [[ctenolium]] located on the anterior edge of the ''right'' valve next to the valve's byssal notch. Though many scallops lose this feature as they become free-swimming adults, all scallops have a ctenolium at some point during their lives, and no other bivalve has an analogous shell feature. The ctenolium is found in modern scallops only; both putative ancestors of modern scallops, the [[entoliidae|entoliids]] and the Aviculopectinidae, did not possess it.<ref name="Hautmann">{{cite journal|doi=10.1007/s12542-009-0041-5| journal= Paläontologische Zeitschrift| title=The first scallop| volume=84| issue=2| pages=317–322| last=Hautmann| date=2010| first=Michael| bibcode= 2010PalZ...84..317H| s2cid= 84457522|url=https://www.zora.uzh.ch/id/eprint/21138/10/ZORA_NL_21138.pdf}}</ref>

=== Muscular system ===
[[File:Opened scallop shell.jpg|thumb|left|A live opened scallop showing the internal anatomy: The pale orange circular part is the adductor muscle; the darker orange curved part is the "coral", a culinary term for the ovary or [[roe]].]]
Like the true oysters (family [[Ostreidae]]), scallops have a single central adductor muscle, thus, the inside of their shells has a characteristic central scar, marking the point of attachment for this muscle. The [[Adductor muscle (Bivalvia)|adductor muscle]] of scallops is larger and more developed than those of [[oyster]]s, because scallops are active swimmers; some species of scallops are known to move ''en masse'' from one area to another. In scallops, the shell shape tends to be highly regular, and is commonly used as an [[archetype|archetypal]] form of a [[seashell]].{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}}

====Adductor muscles====
[[File:Fast and slow adductor muscles of the Yesso scallop, Patinopecten yessoensis.webp|thumb|upright=1.4|right|Adductor muscles of a scallop. a:&nbsp;photo in a live scallop. b:&nbsp;after removal of organs and tissues.]]

Scallops possess fast ([[striated muscle tissue|striated]]) and slow ([[Smooth muscle|smooth]]) [[Adductor muscles (bivalve)|adductor muscles]], which have different structures and contractile properties. These muscles lie closely apposed to one another but are divided by a connective tissue sheet. The striated adductor muscle contracts very quickly for swimming, whereas the smooth catch adductor muscle lacks striations, and contracts for long periods, keeping shells closed with little expenditure of energy.<ref name=Sun2018>{{cite journal |doi = 10.1186/s12864-018-4770-2|title = Differences between fast and slow muscles in scallops revealed through proteomics and transcriptomics|year = 2018|last1 = Sun|first1 = Xiujun|last2 = Liu|first2 = Zhihong|last3 = Wu|first3 = Biao|last4 = Zhou|first4 = Liqing|last5 = Wang|first5 = Qi|last6 = Wu|first6 = Wei|last7 = Yang|first7 = Aiguo|journal = BMC Genomics|volume = 19|issue = 1|page = 377|pmid = 29783952|pmc = 5963113 | doi-access=free }} [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>

=== Digestive system ===
Scallops are [[filter feeder]]s, and eat [[plankton]]. Unlike many other bivalves, they lack [[siphon (mollusc)|siphons]]. Water moves over a filtering structure, where food particles become trapped in mucus. Next, the [[cilia]] on the structure move the food toward the mouth. Then, the food is digested in the digestive gland, an organ sometimes misleadingly referred to as the "liver, " which envelops part of the oesophagus, intestine, and entire stomach. Waste is passed on through the intestine (the terminus of which, like that of many molluscs, enters and leaves the animal's heart) and exits via the anus.{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}}{{rp|p.20}}

=== Nervous system ===
[[File:Scallop Neurological Diagram.svg|thumb|upright=1.8|Neural map of a [[giant scallop]]]]

Like all bivalves, scallops lack actual brains. Instead, their nervous system is controlled by three paired [[ganglion|ganglia]] located at various points throughout their anatomy, the cerebral or cerebropleural ganglia, the pedal ganglia, and the visceral or parietovisceral ganglia. All are yellowish. The visceral ganglia are by far the largest and most extensive of the three, and occur as an almost-fused mass near the center of the animal – proportionally, these are the largest and most intricate sets of ganglia of any modern bivalve. From this radiate all of the nerves which connect the visceral ganglia to the circumpallial nerve ring which loops around the mantle and connects to all of the scallop's tentacles and eyes. This nerve ring is so well developed that, in some species, it may be legitimately considered an additional ganglion.{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}}{{rp|p.46}} The visceral ganglia are also the origin of the branchial nerves which control the scallop's gills. The cerebral ganglia are the next-largest set of ganglia and lie distinct from each other a significant distance dorsal to the visceral ganglia. They are attached to the visceral ganglia by long cerebral-visceral connectives, and to each other via a cerebral commissure that extends in an arch dorsally around the esophagus. The cerebral ganglia control the scallop's mouth via the palp nerves and connect to [[statocyst]]s which help the animal sense its position in the surrounding environment. They are connected to the pedal ganglia by short cerebral-pedal connectives. The pedal ganglia, though not fused, are situated very close to each other near the midline. From the pedal ganglia, the scallop puts out pedal nerves which control the movement of, and sensation in, its small muscular foot.{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}}{{rp|pp. 43–47}}

=== Vision ===
{{multiple image
 | align     = right
 | direction = horizontal
 | footer    = Closeups of the [[Iridescence|iridescent]] blue eyes of the bay scallop, ''[[Argopecten irradians]]''<ref>{{cite journal |doi = 10.1098/rsif.2019.0383|title = Core–shell nanospheres behind the blue eyes of the bay scallop Argopecten irradians|year = 2019|last1 = Harris|first1 = Olivia K.|last2 = Kingston|first2 = Alexandra C. N.|last3 = Wolfe|first3 = Caitlin S.|last4 = Ghoshroy|first4 = Soumitra|last5 = Johnsen|first5 = Sönke|last6 = Speiser|first6 = Daniel I.|journal = Journal of the Royal Society Interface|volume = 16|issue = 159|pmid = 31640501|pmc = 6833330}}</ref>
 | width1    = 310
 | image1    = Scallop eyes2.jpg
 | width2    = 170
 | image2    = Argopecten irradians eye.jpg
}}

Scallops have a large number (up to 200) of small (about 1&nbsp;mm) eyes arranged along the edge of their mantles. These eyes represent a particular innovation among molluscs, relying on a concave, parabolic mirror of [[guanine]] crystals to focus and retro-reflect light instead of a lens as found in many other eye types.<ref>{{cite journal |last1=Speiser |first1=Daniel I. |last2=Johnsen |first2=Sönke |title=Comparative Morphology of the Concave Mirror Eyes of Scallops (Pectinoidea) |journal=American Malacological Bulletin |date=29 December 2008 |volume=26 |issue=1–2 |pages=27–33 |doi=10.4003/006.026.0204 |bibcode=2008AMalB..26...27S |s2cid=11584708 }}</ref> Additionally, their eyes possess a double-layered retina, the outer retina responding most strongly to light and the inner to abrupt darkness.<ref>{{cite journal |last1=Speiser |first1=Daniel I. |last2=Loew |first2=Ellis R. |last3=Johnsen |first3=Sönke |title=Spectral sensitivity of the concave mirror eyes of scallops: potential influences of habitat, self-screening and longitudinal chromatic aberration |journal=Journal of Experimental Biology |date=1 February 2011 |volume=214 |issue=3 |pages=422–431 |doi=10.1242/jeb.048108 |pmid=21228201 |doi-access=free |bibcode=2011JExpB.214..422S }}</ref> While these eyes are unable to resolve shapes with high fidelity, the combined sensitivity of both retinas to light entering the eye and light retro-reflected from the mirror grants scallops exceptional contrast definition, as well as the ability to detect changing patterns of light and motion.<ref>{{cite web|url=http://www.asknature.org/strategy/1e779a45a88aef5c45448073f1e77216|title=Eyes detect changing movement patterns: queen scallop|website=asknature.org}}</ref><ref>{{cite journal |last1=Land |first1=M F |last2=Fernald |first2=R D |title=The Evolution of Eyes |journal=Annual Review of Neuroscience |date=March 1992 |volume=15 |issue=1 |pages=1–29 |doi=10.1146/annurev.ne.15.030192.000245 |pmid=1575438 }}</ref> Scallops primarily rely on their eyes as an 'early-warning' threat detection system, scanning around them for movement and shadows which could potentially indicate predators. Additionally, some scallops alter their swimming or feeding behaviour based on the turbidity or clarity of the water, by detecting the movement of particulate matter in the water column.<ref>{{cite journal |last1=Speiser |first1=Daniel I. |last2=Johnsen |first2=Sönke |title=Scallops visually respond to the size and speed of virtual particles |journal=Journal of Experimental Biology |date=1 July 2008 |volume=211 |issue=13 |pages=2066–2070 |doi=10.1242/jeb.017038 |pmid=18552295 |doi-access=free |bibcode=2008JExpB.211.2066S |url=http://journals.biologists.com/jeb/article-pdf/211/13/2066/1399166/2066.pdf }}</ref>

== Distribution and habitat ==
Scallops inhabit all the oceans of the world, with the largest number of species living in the [[Indo-Pacific]] region. Most species live in relatively shallow waters from the low tide line to 100 m, while others prefer much deeper water. Although some species only live in very narrow environments, most are opportunistic and can live under a wide variety of conditions. Scallops can be found living within, upon, or under either rocks, coral, rubble, [[sea grass]], [[kelp]], sand, or mud. Most scallops begin their lives as [[byssus|byssally]] attached juveniles, an ability that some retain throughout their lives while others grow into free-living adults.{{sfn|Shumway|Parsons|2011|page=[https://books.google.com/books?id=rSu_GLwLQmEC&pg=PA207 207]}}

==Biology==
=== Locomotion ===
[[File:scallop swim.svg|thumb|upright=1.4|right|Overhead view of a scallop engaged in a zig-zag swimming motion]] 
[[File:scallop jump.svg|thumb|right|upright=1.4|Overhead view of a scallop engaged in a unidirectional jumping motion]]

Scallops are mostly free-living and active, unlike the vast majority of bivalves, which are mostly slow-moving and infaunal. All scallops are thought to start out with a [[byssus]], which attaches them to some form of substrate such as [[Zostera|eelgrass]] when they are very young. Most species lose the byssus as they grow larger. A very few species go on to cement themselves to a hard substrate (e.g. ''[[Chlamys (bivalve)|Chlamys distorta]]'' and ''[[Hinnites|Hinnites multirigosus]]'').{{sfn|Shumway|Parsons|2011|pages=[https://books.google.com/books?id=rSu_GLwLQmEC&pg=PA689 689–690]}}

However, the majority of scallops are free-living and can swim with brief bursts of speed to escape predators (mostly [[starfish]]) by rapidly opening and closing their valves. Indeed, everything about their characteristic shell shape – its symmetry, narrowness, smooth and/ or grooved surface, small flexible hinge, powerful adductor muscle, and continuous and uniformly curved edge – facilitates such activity. They often do this in spurts of several seconds before closing the shell entirely and sinking back to the bottom of their environment. Scallops are able to move through the water column either forward/ventrally (termed swimming) by sucking water in through the space between their valves, an area called the gape, and ejecting it through small holes near the hinge line called exhalant apertures, or backward/dorsally (termed jumping) by ejecting the water out the same way it came in (i.e. ventrally). A jumping scallop usually lands on the sea floor between each contraction of its valves, whereas a swimming scallop stays in the water column for most or all of its contractions and travels a much greater distance (though seldom at a height of more than 1 m off the sea bed and seldom for a distance of greater than 5 m).{{sfn|Shumway|Parsons|2011|pages=[https://books.google.com/books?id=rSu_GLwLQmEC&pg=PA689 689–690]}} Both jumping and swimming movements are very energy-intensive, and most scallops cannot perform more than four or five in a row before becoming completely exhausted and requiring several hours of rest. Should a swimming scallop land on its left side, it is capable of flipping itself over to its right side via a similar shell-clapping movement called the righting reflex. So-called singing scallops are rumored to make an audible, soft popping sound as they flap their shells underwater (though whether or not this happens is open to some debate).{{sfn|Dore|2013|page=[https://books.google.com/books?id=5lLUBwAAQBAJ&pg=PA152 152]}} Other scallops can extend their foot from between their valves, and by contracting the muscles in their foot, they can burrow into sand.{{sfn|Gosling|2015|page=[https://books.google.com/books?id=QIO4CAAAQBAJ&pg=PA29 29]}}

==== Mobility and behavior ====
[[File:Purcell’s swimming scallop with reciprocal motion.png|thumb|upright=1.4|A scallop swims by slowly opening its two halves, then quickly closing them. This is a successful swimming method because the [[inertial force]] of the surrounding water dominates over the [[Viscosity|viscous force]]. As demonstrated by the [[scallop theorem]], in a low [[Reynolds number]] environment, a scallop would only oscillate in place.<ref name="Purcell1977">{{Citation|title=Life at low reynolds number|journal=American Journal of Physics|volume=45|issue=1|pages=3–11|language=en|doi=10.1119/1.10903|year=1977|last1=Purcell|first1=E. M.|bibcode=1977AmJPh..45....3P|hdl=2433/226838|hdl-access=free}}</ref>]]
{{see also|Scallop theorem}}

Most species of the scallop family are free-living, active swimmers, propelling themselves through the water through the adductor muscles to open and close their shells. Swimming occurs through the clapping of valves for water intake. Closing the valves propels water with a strong force near the hinge via the velum, a curtain-like fold of the mantle that directs water expulsion around the hinge. Scallops swim in the direction of the valve opening unless the velum directs an abrupt change in course direction.<ref>{{cite journal |last=Cheng |first=J.-Y. |author2=Davison, I. G. |author3=Demont, M. E. |title=Dynamics and energetics of scallop locomotion |journal=Journal of Experimental Biology |year=1996 |volume=199 |issue=9 |pages=1931–1946 |doi=10.1242/jeb.199.9.1931 |pmid=9319845 |bibcode=1996JExpB.199.1931C |url=https://journals.biologists.com/jeb/article-pdf/199/9/1931/2546518/jexbio_199_9_1931.pdf}}</ref><ref>{{cite journal |last=Joll |first=L. M. |title=Swimming behavior of the saucer scallop ''Amusium balloti'' (Mollusca: Pectinidae) |year=1989 |journal=[[Marine Biology (journal)|Marine Biology]] |volume=102 |issue=3 |pages=299–305 |doi=10.1007/BF00428481 |bibcode=1989MarBi.102..299J |s2cid=84250961 }}</ref>

Other species of scallops can be found on the ocean floor attached to objects by byssal threads. Byssal threads are strong, silky fibers extending from the muscular foot, used to attach to a firm support, such as a rock. Some can also be found on the ocean floor, moving with an extendable foot between their valves or burrowing themselves in the sand by extending and retracting their feet.{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}} Scallops are highly sensitive to shadows, vibrations, water movement, and chemical stimuli.<ref>{{cite journal |last=Land|first=M.F. |title=Activity in the optic nerve of Pecten maximus in response to changes in light intensity, and to pattern and movements in optical environment |journal=Journal of Experimental Biology|year=1966 |volume=45 |issue=1 |pages=83–99 |doi=10.1242/jeb.45.1.83 |pmid=5969013 |url=http://jeb.biologists.org/content/45/1/83.full.pdf|doi-access=free }}</ref> All possess a series of 100 blue eyes, embedded on the edge of the mantle of their upper and lower valves that can distinguish between light and darkness. They serve as a vital defense mechanism for avoiding predators. Though rather weak, their series of eyes can detect surrounding movement and alert precaution in the presence of predators, most commonly sea stars, crabs, and snails.{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}} Physiological fitness and exercise of scallops decrease with age due to the decline of cellular and especially mitochondrial function,<ref name="Philipp 2008 2492–2501">{{cite journal|last=Philipp|first=E.E.R.|author2=Schmidt, M. |author3=Gsottbauer, C. |author4=Sänger, A. M. |author5=Abele, D. |title=Size- and age-dependent changes in adductor muscle swimming physiology of the scallop Aequipecten opercularis|journal=Journal of Experimental Biology|year=2008|volume=211|issue=15|pages=2492–2501|doi=10.1242/jeb.015966 |pmid=18626084|doi-access=free|bibcode=2008JExpB.211.2492P |url=http://journals.biologists.com/jeb/article-pdf/211/15/2492/1400098/2492.pdf}}</ref> thus increasing the risk of capture and lowering rates of survival. Older individuals show lower mitochondrial volume density and aerobic capacity, as well as decreased anaerobic capacity construed from the amount of glycogen stored in muscle tissue.<ref name="Philipp 2008 2492–2501" /> Environmental factors, such as changes in oxidative stress parameters, can inhibit the growth and development of scallops.<ref>{{cite journal|last=Guerra|first=C.|author2=Zenteno-Savín, T. |author3=Maeda-Martínez, A. N. |author4=Abele, D. |author5=Philipp, E. E. R. |title=The effect of predator exposure and reproduction on oxidative stress parameters in the Catarina scallop Argopecten ventricosus|journal=Comparative Biochemistry and Physiology A|year=2013|volume=165|issue=1|pages=89–96|doi=10.1016/j.cbpa.2013.02.006|pmid=23416890}}</ref>

Seasonal changes in temperature and food availability have been shown to affect muscle metabolic capabilities. The properties of mitochondria from the phasic adductor muscle of ''Euvola ziczac'' varied significantly during their annual reproductive cycle. Summer scallops in May have lower maximal oxidative capacities and substrate oxidation than any other time in the year. This phenomenon is due to lower protein levels in adductor muscles.<ref>{{cite journal|last=Boadas|first=M.A.|author2=Nusetti, O. |author3=Mundarain, F. |title=Seasonal variation in the properties of muscle mitochondria from the tropical scallop Euvola (Pecten) ziczac|journal=Marine Biology|year=1997|volume=128|issue=2|pages=247–255|doi=10.1007/s002270050089|bibcode=1997MarBi.128..247B |s2cid=84538863}}</ref>

Scallops are known to be infected by [[virus]]es, [[bacteria]], [[microalga]]e of the [[heterokont]]s and [[dinoflagellate]]s.<ref name="ShumwayParsons2016" /> {{ rp | page = 71 }}

=== Mutualism ===
Some scallops, including ''Chlamys hastata'', frequently carry [[epibiont]]s such as sponges and barnacles on their shells. The relationship of the sponge to the scallop is characterized as a form of mutualism, because the sponge provides protection by interfering with adhesion of predatory sea-star tube feet,<ref name="Bloom">{{cite journal|last=Bloom|first=S.|title=The motile escape response of a sessile prey: a sponge-scallop mutualism|journal=Journal of Experimental Biology and Ecology |year=1975|volume=17 |issue=3|pages=311–321|url=https://www.researchgate.net/publication/248246332|doi=10.1016/0022-0981(75)90006-4|bibcode=1975JEMBE..17..311B }}</ref><ref name="Pitcher 1987 233–249">{{cite journal|last=Pitcher|first=C.R.|author2=Butler, A.J.|title=Predation by asteroids, escape response, and morphometrics of scallops with epizoic sponges|journal=[[Journal of Experimental Marine Biology and Ecology]] |year=1987|volume=112|issue=3|pages=233–249|doi=10.1016/0022-0981(87)90071-2|bibcode=1987JEMBE.112..233P }}</ref><ref name="Forester 1979 1–10">{{cite journal|last=Forester|first=A.J.|title=The association between the sponge ''Halichondria panicea'' (Pallas) and scallop ''Chlamys varia'' (L.): a commensal protective mutualism|journal=Journal of Experimental Marine Biology and Ecology|year=1979|volume=36|issue=1|pages=1–10|doi=10.1016/0022-0981(79)90096-0|bibcode=1979JEMBE..36....1F }}</ref> camouflages ''Chlamys hastata'' from predators,<ref name="Pitcher 1987 233–249" /> or forms a physical barrier around byssal openings to prevent sea stars from inserting their digestive membranes.<ref name="Forester 1979 1–10" /> Sponge encrustation protects ''C. hastata'' from barnacle larvae settlement, serving as a protection from epibionts that increase susceptibility to predators. Thus, barnacle larvae settlement occurs more frequently on sponge-free shells than on sponge-encrusted shells.<ref name="Bloom"/>

Barnacle encrustation negatively influences swimming in ''C. hastata''. Those swimming with barnacle encrustation require more energy and show a detectable difference in anaerobic energy expenditure than those without encrustation. In the absence of barnacle encrustation, individual scallops swim significantly longer, travel further, and attain greater elevation.<ref>{{cite journal|last=Donovan|first=D.|author2=Bingham, B. |author3=Farren, H. |author4=Gallardo, R. |author5=Vigilant, V. |title=Effects of sponge encrustation on the swimming behaviour energetics and morphometry of the scallop ''Chlamys hastata''|journal=[[Journal of the Marine Biological Association of the United Kingdom]]|year=2002|volume=82|issue=3|pages=469–476|url=http://www.biol.wwu.edu/donovan/papers/scallop_barnacle.pdf|doi=10.1017/s0025315402005738|bibcode=2002JMBUK..82..469D |s2cid=56338849}}</ref>

=== Lifecycle and growth ===
[[File:Life cycle of the scallop Mizuhopecten yessoensis.png|thumb|upright=1.8| {{center|[[Biological life cycle|Life cycle]] of the giant [[Yesso scallop]] found north of Japan{{hsp}}<ref>{{cite journal | last1=Dvoretsky | first1=Alexander G. | last2=Dvoretsky | first2=Vladimir G. | title=Biological Aspects, Fisheries, and Aquaculture of Yesso Scallops in Russian Waters of the Sea of Japan | journal=Diversity | publisher=MDPI AG | volume=14 | issue=5 | date=19 May 2022 | issn=1424-2818 | doi=10.3390/d14050399 | page=399| doi-access=free | bibcode=2022Diver..14..399D }} [[File:CC-BY icon.svg|50px]] Modified material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>}}]]

The scallop family is unusual in that some members of the family are [[dioecious]] (males and females are separate), while others are [[simultaneous hermaphrodite]]s (both sexes in the same individual), and a few are [[protoandrous hermaphrodites]] (males when young then switching to female). Female scallops have red [[roe]] and male scallops have white roe, corresponding to ova and spermatozoa respectively, which are [[Spawning|released freely into the water]] during mating season and fertilized ova sink to the bottom. After several weeks, the immature scallops hatch and the larvae, miniature transparent versions of the adults called "spat", drift in the plankton until settling to the bottom again (an event called spatfall) to grow, usually attaching by means of byssal threads. Some scallops, such as the Atlantic bay scallop ''Argopecten irradians'', are short-lived, while others can live 20 years or more. Age can often be inferred from [[annulus (zoology)|annuli]], the concentric rings of their shells.{{sfn|Drew|1906|pages=[https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5 5–6]}}

Many scallops are hermaphrodites (having female and male organs simultaneously), altering their sex throughout their lives, while others exist as dioecious species, having a definite sex. In this case, males are distinguished by roe-containing white testes and females with roe-containing orange ovaries. At the age of two, they usually become sexually active, but do not contribute significantly to egg production until four. The reproduction process occurs externally through spawning, in which eggs and sperm are released into the water. Spawning typically occurs in late summer and early autumn; spring spawning may also take place in the [[Mid-Atlantic Bight]].<ref name="Hart 2004">{{cite journal|last=Hart|first=D.R.|author2=Chute, A.S.|title=Essential Fish Habitat Source Document: Sea Scallop, Placopecten magellanicus, Life History and Habitat Characteristics|journal=NOAA Tech Memo NMFS NE-189|year=2004|url=http://www.nefsc.noaa.gov/nefsc/publications/tm/tm189/tm189.pdf}}</ref> The females of scallops are highly fecund, capable of producing hundreds of millions of eggs per year.<ref name="Hart 2004" />

Once an egg is fertilized, it is then planktonic, a collection of microorganisms that drift abundantly in fresh or salt water. Larvae stay in the water column for four to seven weeks before dissipating to the ocean floor, where they attach themselves to objects through byssus threads. Byssus is eventually lost with adulthood, transitioning almost all scallop species into free swimmers. Rapid growth occurs within the first several years, with an increase of 50–80 % in shell height and quadrupled size in meat weight, and reaches a commercial size at about four to five years of age.<ref name="Hart 2004" /> The lifespans of some scallops have been known to extend over 20 years.<ref>{{cite web|title=Scallop Aquaculture |url=http://www.marine.usf.edu/pjocean/packets/sp98/scallop_1.pdf |publisher=College of Marine Science, [[University of South Florida]]}}</ref>

== Phylogeny ==
[[File:Chlamys Pliocene Cyprus.jpg|thumb|Fossil scallop ''Chlamys'' with encrusters; Nicosia Formation ([[Pliocene]]) of [[Cyprus]]]]

The fossil record of scallops is rich in both species and specimens. The earliest known records of true scallops (those with a ''ctenolium'') can be found from the [[Triassic period]], over 200 million years ago.<ref name="Hautmann" /> The earliest species were divided into two groups, one with a nearly smooth exterior: ''[[Pleuronectis]]'' von Schlotheim, 1820, while the other had radial ribs or riblets and auricles: ''[[Praechlamys]]'' Allasinaz, 1972.<ref>{{cite journal | last1 = Waller | first1 = T. R. | year = 1993 | title = The evolution of Chlamys (Mollusca: Bivalvia: Pectinidae) in the tropical western Atlantic and eastern Pacific | journal = American Malacological Bulletin | volume = 10 | issue = 2| pages = 195–249 |url=http://biostor.org/reference/143241 }}</ref> Fossil records also indicate that the abundance of species within the Pectinidae has varied greatly over time; Pectinidae was the most diverse bivalve family in the [[Mesozoic era]], but the group almost disappeared completely by the end of the [[Cretaceous period]]. The survivors [[speciate]]d rapidly during the [[Tertiary period]]. Nearly 7,000 species and subspecies names have been introduced for both fossil and recent Pectinidae.{{sfn|Harper|Taylor|Crame|Geological Society of London|2000|page=[https://books.google.com/books?id=QpkfKzsOOfUC&pg=PA254 254]}}

The [[cladogram]] is based on molecular phylogeny using mitochondrial (12S, 16S) and nuclear (18S, 28S, and H3) gene markers by Yaron Malkowsky and Annette Klussmann-Kolb in 2012.<ref>{{cite journal |last1=Malkowsky |first1=Yaron |last2=Klussmann-Kolb |first2=Annette |title=Phylogeny and spatio-temporal distribution of European Pectinidae (Mollusca: Bivalvia) |journal=Systematics and Biodiversity |date=May 2012 |volume=10 |issue=2 |pages=233–242 |doi=10.1080/14772000.2012.676572 |bibcode=2012SyBio..10..233M |s2cid=84085349 |url=https://www.researchgate.net/publication/254315377}}</ref>
{{clade
|label1=[[Pteriomorphia]]
|1={{clade
   |1={{clade
      |label1=(c. 247 mya) '''[[Pectinidae]]'''
      |1={{clade
         |1={{clade
            |1={{clade
               |1={{clade
                  |1=[[Palliolinae]] (in part) [[File:Pectinidae - Palliolum excisum.JPG|70px]]
                  |2=[[Palliolinae]] (in part) and [[Camptonectinae]]
                  }}
               |2=[[Chlamydinae]] [[File:Chlamys islandica.jpg|60px]]
               }}
            |2=(70 mya) ''[[Pecten (bivalve)|Pecten]]'' [[File:Pecten ochlockoneensis SR 02-227 A 02.jpg|60px]]
            }}
         |2={{clade
            |1=''[[Flexopecten]]'' [[File:Pectinidae - Flexopecten hyalinus.jpg|60px]]
            |2=(247 mya) ''[[Aequipecten]]'' [[File:Aequipecten opercularis gelb.jpg|60px]]
            }}
         }}
      |2=[[Limidae]] (file shells) [[File:Limidae - Lima lima.jpg|60px]]
      }}
   |2=other [[Pteriomorphia]] ([[oyster]]s, [[mussel]]s) [[File:Crassostrea gigas p1040848.jpg|70px]]
   }}
}}

=== Taxonomic structure ===
[[File:Semipallium fulvicostatum 001.jpg|thumb|''[[Bractechlamys vexillum]]'']]
[[File:Naturalis Biodiversity Center - RMNH.MOL.321025 - Pecten tigris Lamarck, 1819 - Pectinidae - Mollusc shell.jpeg|thumb|''[[Pecten tigris]] Lamarck, 1819'', museum specimens]]
Scallops are the family Pectinidae, marine bivalve molluscs within the superfamily [[Pectinoidea]]. Other families within this same superfamily share a somewhat similar overall shell shape, and some species within some of the related families are also commonly referred to as "scallops" (for example, [[Propeamussiidae]], the glass scallops).

The family Pectinidae is the most diversified of the pectinoideans in present-day oceans. It is one of the largest marine bivalve families and contains over 300 extant species in 60 genera. Its origin dates back to the Middle Triassic Period, approximately 240&nbsp;million years ago;<ref name="Hautmann" /> in terms of diversity, it has been a thriving family to the present day.<ref>{{cite book |last=Waller |first=Thomas R. |title=New phylogenies of the Pectinidae (Mollusca: Bivalvia): Reconciling morphological and molecular approaches |year=2006 |publisher=[[Elsevier]] |location=Amsterdam |work=Scallops: biology, ecology and aquaculture II |editor-first=Sandra E. |editor-last=Shumway |pages=1–44}}</ref>

Evolution from its origin has resulted in a successful and diverse group: pectinids are present in the world's seas, found in environments ranging from the intertidal zone to the hadal depths. The Pectinidae play an extremely important role in many benthic communities and exhibit a wide range of shell shapes, sizes, sculptures, and cultures.<ref>{{Cite book |last=Brand|first=A.R.|title=Scallop ecology: distributions and behavior|chapter=Chapter 12 Scallop ecology: Distributions and behaviour |journal=[[Scallops: Biology, Ecology and Aquaculture]] |year=2006|volume=35 |pages=651–744 |doi=10.1016/S0167-9309(06)80039-6|series=Developments in Aquaculture and Fisheries Science|isbn=9780444504821}}</ref>

Raines and Poppe{{efn|Raines, B. K. & Poppe, G. T. (2006): ''The Family Pectinidae''.{{sfn|Raines|Poppe|Groh|2006}}}} listed nearly 900 species names of scallops, but most of these are considered either questionable or invalid. Raines and Poppe mentioned over 50 genera, around 250 species, and [[subspecies]]. Although species are generally well-circumscribed, their attribution to [[Subfamily|subfamilies]] and genera is sometimes equivocal, and information about [[phylogeny]] and relationships of the species are minimal, not the least because most work has been based only on adult [[morphology (biology)|morphology]].<ref>Barucca, M., Olmo, E., Schiaparelli, S. & Canapa, A. (2004): Molecular phylogeny of the family Pectinidae (Mollusca: Bivalvia)</ref>

This family's earliest and most comprehensive taxonomic treatments were based on macroscopic morphological characters of the adult shells and represent broadly divergent classification schemes.<ref>{{cite book|last=Waller|first=Thomas R.|title=The functional significance of some shell micro-structures in the Pectinacea|year=1972|publisher=[[International Geological Congress]] |work=Paleontology|pages=48–56}}</ref><ref name="ShumwayParsons2016">{{cite book|editor1-first=Sandra E.|editor1-last=Shumway|editor2-first=G. Jay|editor2-last=Parsons|title=Scallops: Biology, Ecology, Aquaculture, and Fisheries|url=https://books.google.com/books?id=vhGdBAAAQBAJ&pg=PA27|date=7 June 2016|publisher=Elsevier Science|isbn=978-0-444-62719-3|page=5}}</ref> Some level of taxonomic stability was achieved when Waller's studies in 1986, 1991, and 1993 concluded evolutionary relationships between pectinid taxa based on hypothesized morphological synapomorphies, which previous classification systems of Pectinidae failed to do. He created three Pectinidae subfamilies: Camptonectinidae, Chlamydinae and Pectininae.<ref>{{cite journal|last=Waller|first=Thomas R.|title=A new genus and species of scallop (Bivalvia: Pectinidae) from off Somalia, and the definition of a new tribe Decatopectinin i|journal=[[The Nautilus (journal)|Nautilus]] |year=1986|volume=100 |issue=2|pages=39–46|url=http://biostor.org/reference/101267|doi=10.5962/bhl.part.26491|doi-access=free|bibcode=1986Nauti.100...39. }}</ref>{{sfn|Waller|1991|pages=1–73}}<ref>{{cite journal|last=Waller|first=Thomas R. |title=The evolution of "Chlamys" (Mollusca: Bivalvia: Pectinidae) in the tropical western Atlantic and eastern Pacific|journal=American Malacological Bulletin|year=1993|volume=10|issue=2 |pages=195–249}}</ref>

The framework of its phylogeny shows that repeated life habit states derive from evolutionary convergence and parallelism.<ref>{{cite journal|last=Alejandrino|first=A.|author2=Puslednik, L. |author3=Serb, J. M. |title=Convergent and parallel evolution in life habit of the scallops|journal=BMC Evolutionary Biology|year=2011|volume=11|issue=1|page=164|pmc=3129317|doi=10.1186/1471-2148-11-164|pmid=21672233 |doi-access=free }}</ref><ref>{{cite journal|last=Waller|first=Thomas R.|title=The evolutionary and biogeographic origins of the endemic Pectinidae (Mollusca: Bivalvia) of the Galápagos Islands|journal=[[Journal of Paleontology]]|year=2007|volume=81|issue=5|pages=929–950|doi=10.1666/pleo05-145.1|bibcode=2007JPal...81..929W |s2cid=86121432}}</ref> Studies have determined the family Pectinidae is monophyletic, developing from a single common ancestor. The direct ancestors of Pectinidae were scallop-like bivalves of the family Entoliidae.<ref>{{cite journal|last=Dijkstra|first=H.H.|author2=Maestrati, P.|title=Pectinoidea (Mollusca, Bivalvia, Propeamussiidae, Cyclochlamydidae n. fam., Entoliidae and Pectinidae) from the Vanuatu Archipelago|journal=[[Zoosystematics and Evolution|Zoosystema]]|year=2012|volume=34|issue=2|pages=389–408|url=http://dare.uva.nl/cgi/arno/show.cgi?fid=454509|doi=10.5252/z2012n2a12|s2cid=85935928}}</ref> Entoliids had auricles and a byssal notch only at youth, but they did not have a ctenolium, a comb-like arrangement along the margins of the byssal notch in Pectinidae. The ctenolium is the defining feature of the modern family Pectinidae and is a characteristic that has evolved within the lineage.<ref>{{cite journal|last=Waller|first=Thomas R.|title=The ctenolium of scallop shells: functional morphology and evolution of a key family-level character in the Pectinacea (Mollusca: Bivalvia)|journal=Malacologia|year=1984|volume=25|issue=1|pages=203–219|url=http://pterioidea.myspecies.info/content/ctenolium-scallop-shells-functional-morphology-and-evolution-key-family-level-character-pect}}</ref>

In a 2008 paper, Puslednik et al. identified considerable convergence of shell morphology in a subset species of gliding Pectinidae, which suggests iterative morphological evolution may be more prevalent in the family than previously believed.<ref>{{cite journal|last=Puslednik|first=L.|author2=Serb, J.M.|title=Molecular phylogenetics of the Pectinidae (Mollusca: Bivalvia) and the effect of outgroup selection and increased taxon sampling on tree topology|journal=[[Molecular Phylogenetics and Evolution]]|year=2008|volume=48|issue=3|pages=1178–1188|doi=10.1016/j.ympev.2008.05.006|pmid=18579415}}</ref>

There have been a number of efforts to address phylogenetic studies. Only three have assessed more than ten species<ref>{{cite journal|last=Barucca|first=M.|author2=Olmo, E. |author3=Schiaparelli, S. |author4=Capana, A. |title=Molecular phylogeny of the family Pectinidae (Mollusca: Bivalvia) based on mitochondrial 16S and 12S rRNA genes|journal=Molecular Phylogenetics and Evolution|year=2004|volume=31|issue=1|pages=89–95|doi=10.1016/j.ympev.2003.07.003 |pmid=15019610|bibcode=2004MolPE..31...89B }}</ref><ref name="Matsumoto 477–488">{{cite journal|last=Matsumoto|first=M.|author2=Hayami, I.|title=Phylogenetic analysis of the family Pectinidae (Bivalvia) based on mitochondrial cytochrome C oxidase subunit|journal=[[Journal of Molluscan Studies]]|volume=66|issue=4|pages=477–488|doi=10.1093/mollus/66.4.477|year=2000|doi-access=free}}</ref><ref>{{cite journal|last=Saavedra|first=C.|author2=Peña, J.B|title=Phylogenetics of American scallops (Bivalvia: Pectinidae) based on partial 16S and 12S ribosomal RNA gene sequences|journal=[[Marine Biology (journal)|Marine Biology]]|year=2006|volume=150|issue=1|pages=111–119|url=https://www.researchgate.net/publication/225820089|doi=10.1007/s00227-006-0335-z|bibcode=2006MarBi.150..111S |s2cid=84205954}}</ref> and only one has included multiple outgroups.<ref name="Matsumoto 477–488" /> Nearly all previous molecular analyses of the Pectinidae have only utilized mitochondrial data. Phylogenies based only on mitochondrial sequence data do not always provide an accurate estimation on the species tree. Complicated factors can arise due to the presence of genetic polymorphisms in ancestral species and resultant lineage sorting.<ref>{{cite journal|last=Pamilo|first=P.|author2=Nei, M.|title=Relationships between gene trees and species trees|journal=Molecular Biology and Evolution|year=1988|volume=5|issue=5|pages=568–583|pmid=3193878|doi=10.1093/oxfordjournals.molbev.a040517|doi-access=free}}</ref><ref>{{cite journal|last=Wu|first=C.I.|title=Inferences of species phylogeny in relation to segregation of ancient polymorphisms|journal=Genetics|year=1991|volume=127|issue=2|pages=429–435|doi=10.1093/genetics/127.2.429|pmc=1204370|pmid=2004713}}</ref>

In molecular phylogenies of the Bivalvia, both the Spondylidae and the Propeamussiidae have been resolved as sister to the Pectinidae.<ref name="Matsumoto 477–488" /><ref>Waller, Thomas R., 1998. Origin of the Molluscan Class Bivalvia and a Phylogeny of Major Groups. Pp. 1–45. In: P.A. Johnston & J.W. Haggart (eds), ''Bivalves: An Eon of Evolution''. Calgary: [[University of Calgary Press]] xiv + 461 pp.</ref>

=== List of subfamilies and genera ===
The following are recognised in the family Pectinidae:
{{div col|colwidth=24em}} 
*Subfamily [[Camptonectinae]] <small>Habe, 1977</small>{{sfn|Habe|1977}}
** ''[[Camptonectes]]'' <small>Agassiz, 1864</small>
** ''[[Ciclopecten]]'' <small>[[Giuseppe Seguenza|Seguenza]], 1877</small>
** ''[[Delectopecten]]'' <small>Stewart, 1920</small>
** ''[[Hyalopecten]]'' <small>A. E. Verrill, 1897</small>
** ''[[Pseudohinnites]]'' <small>Dijkstra, 1989</small>
** ''[[Sinepecten ]]'' <small>Schein, 2006</small>
*Subfamily [[Palliolinae]] <small>Korbkov in Eberzin, 1960</small>
**Tribe [[Adamussiini]] <small>Habe, 1977</small>
*** ''[[Adamussium]]'' <small>Thiele, 1934</small> 
*** ''[[Antarctipecten]]'' <small>Beu & Taviani, 2013</small> †
*** ''[[Duplipecten]]'' <small>Marwick, 1928</small> †
*** ''[[Lentipecten]]'' <small>Marwick, 1928</small> †
*** ''[[Leoclunipecten]]'' <small>Beu & Taviani, 2013</small> †
*** ''[[Ruthipecten]]'' <small>Beu & Taviani, 2013</small> †
**Tribe [[Eburneopectinini]] <small>T. R. Waller, 2006</small> †
*** ''[[Eburneopecten]]'' <small>Conrad, 1865</small> †
**Tribe [[Mesopeplini]] <small>T. R. Waller, 2006</small>
*** ''[[Kaparachlamys]]'' <small>Boreham, 1965</small> †
*** ''[[Mesopeplum]]'' <small>Iredale, 1929</small>
*** ''[[Phialopecten]]'' <small>Marwick, 1928</small> †
*** ''[[Sectipecten]]'' <small>Marwick, 1928</small> †
*** ''[[Towaipecten]]'' <small>Beu, 1995</small> †
**Tribe [[Palliolini]] <small>Waller, 1993</small>
*** ''[[Karnekampia]]'' <small>H. P. Wagner, 1988</small>
*** ''[[Lissochlamys]]'' <small>Sacco, 1897</small>
*** ''[[Palliolum]]'' <small>[[Tommaso Allery de Maria Monterosato|Monterosato]], 1884</small>
*** ''[[Placopecten]]'' <small>[[Addison Emery Verrill|Verrill]], 1897</small>
*** ''[[Pseudamussium]]'' <small>Mörch, 1853</small>
**Tribe [[Serripectinini]] <small>T. R. Waller, 2006</small> †
*** ''[[Janupecten]]'' <small>Marwick, 1928</small> †
*** ''[[Serripecten]]'' <small>Marwick, 1928</small> †
*Subfamily [[Pectininae]]
**Tribe [[Aequipectinini]] <small>F. Nordsieck, 1969</small>
*** ''[[Aequipecten]]'' <small>P. Fischer, 1886</small> 
*** ''[[Argopecten]]'' <small>Monterosato, 1889</small> 
*** ''[[Cryptopecten]]'' <small>Dall, Bartsch & Rehder, 1938</small> 
*** ''[[Flexopecten]]'' <small>Sacco, 1897</small> 
*** ''[[Haumea (bivalve)|Haumea]]'' <small>Dall, Bartsch & Rehder, 1938</small> 
*** ''[[Leptopecten]]'' <small>Verrill, 1897</small> 
*** ''[[Volachlamys]]'' <small>Iredale, 1939</small> 
**Tribe [[Amusiini]] <small>Ridewood, 1903</small>
***''[[Amusium]]'' <small>Röding, 1798</small>
***''[[Dentamussium]]'' <small>Dijkstra, 1990</small>
***''[[Euvola]]'' <small>Dall, 1898</small>
***''[[Leopecten]]'' <small>Masuda, 1971</small>
***''[[Ylistrum]]'' <small>Mynhardt & Alejandrino, 2014</small>
**Tribe [[Austrochlamydini]] <small>Jonkers, 2003</small>
***''[[Austrochlamys]]'' <small>Jonkers, 2003</small>
**Tribe [[Decatopectinini]] Waller, 1986
***''[[Anguipecten]]'' <small>[[W. H. Dall|Dall]], Bartsch & Rehder, 1938</small>
***''[[Antillipecten]]'' <small>T. R. Waller, 2011</small>
***''[[Bractechlamys]]'' <small>[[Tom Iredale|Iredale]], 1939</small>
***''[[Decatopecten]]'' <small>Rüppell in G. B. Sowerby II, 1839</small>
***''[[Excellichlamys]]'' <small>[[Tom Iredale|Iredale]], 1939</small>
***''[[Glorichlamys]]'' <small>Dijkstra, 1991</small>
***''[[Gloripallium]]'' <small>[[Tom Iredale|Iredale]], 1939</small>
***''[[Juxtamusium]]'' <small>[[Tom Iredale|Iredale]], 1939</small>
***''[[Lyropecten]]'' <small>Conrad, 1862</small>
***''[[Mirapecten]]'' <small>[[W. H. Dall|Dall]], Bartsch & Rehder, 1938</small>
***''[[Nodipecten]]'' <small>Dall, 1898</small>
**Tribe [[Pectinini]] <small>Wilkes, 1810</small>
*** ''[[Annachlamys]]'' <small>Iredale, 1939</small>
*** †''[[Fascipecten]]'' <small> Freneix, Karache & Salvat 1971</small> 
*** †''[[Gigantopecten]]'' <small>Rovereto, 1899</small>
*** ''[[Minnivola]]'' <small>[[Tom Iredale|Iredale]], 1939</small>
*** †''[[Oopecten]]'' <small>Sacco, 1897</small>
*** †''[[Oppenheimopecten]]'' <small>Teppner, 1922</small>
*** ''[[Pecten (bivalve)|Pecten]]'' <small>[[Otto Friedrich Müller|Müller]], 1776</small> 
*** ''[[Serratovola]]'' <small>Habe, 1951</small>
*Subfamily  [[Pedinae]] <small>Bronn, 1862</small>  
**Tribe [[Chlamydini]] <small>von Teppner, 1922</small>
*** ''[[Austrohinnites]]'' <small>Beu & Darragh, 2001</small> †
*** ''[[Azumapecten]]'' <small>Habe, 1977</small>
*** ''[[Chesapecten]]'' <small>Ward & Blackwelder, 1975</small> †
*** ''[[Chlamys (bivalve)|Chlamys]]'' <small>[[Peter Friedrich Röding|Röding]], 1798</small>
*** ''[[Chokekenia]]'' <small>Santelli & del Río, 2018</small> †
*** ''[[Ckaraosippur]]'' <small>Santelli & del Río, 2019</small> †
*** ''[[Complicachlamys]]'' <small>Iredale, 1939</small> 
*** ''[[Coralichlamys]]'' <small>[[Tom Iredale|Iredale]], 1939</small>
*** ''[[Dietotenhosen]]'' <small>Santelli & del Río, 2019</small> †
*** ''[[Equichlamys]]'' <small>[[Tom Iredale|Iredale]], 1929</small>
*** ''[[Hemipecten]]'' <small>A. Adams & Reeve, 1849</small>
*** ''[[Hinnites]]'' <small>Deference, 1821</small>
*** ''[[Laevichlamys]]'' <small>Waller, 1993</small>
*** ''[[Manupecten]]'' <small>[[Tommaso Allery de Maria Monterosato|Monterosato]], 1872</small>
*** ''[[Moirechlamys]]'' <small>Santelli & del Río, 2018</small> †
*** ''[[Notochlamys]]'' <small>Cotton, 1930</small>
*** ''[[Pascahinnites]]'' <small>Dijkstra & Raines, 1999</small>
*** ''[[Pixiechlamys]]'' <small>Santelli & del Río, 2018</small> †
*** ''[[Praechlamys]]'' <small>Allasinaz, 1972</small> †
*** ''[[Scaeochlamys]]'' <small>[[Tom Iredale|Iredale]], 1929</small>
*** ''[[Semipallium]]'' <small>Jousseaume in Lamy, 1928</small>
*** ''[[Swiftopecten]]'' <small>Hertlein, 1936</small>
*** ''[[Talochlamys]]'' <small>Iredale, 1929</small>
*** ''[[Veprichlamys]]'' <small>Iredale, 1929</small>
*** ''[[Yabepecten]]'' <small>Masuda, 1963</small> †
*** ''[[Zygochlamys]]'' <small>Ihering, 1907</small>
**Tribe [[Crassadomini]] <small>Waller, 1993</small>
*** ''[[Caribachlamys]]'' <small>Waller, 1993</small>
*** ''[[Crassadoma]]'' <small>Bernard, 1986</small>
**Tribe [[Fortipectinini]] <small>Masuda, 1963</small>
*** ''[[Fortipecten]]'' <small>Yabe & Hatai, 1940</small> †
*** ''[[Kotorapecten]]'' <small>Masuda, 1962</small> †
*** ''[[Masudapecten]]'' <small>Akiyama, 1962</small> †
*** ''[[Mizuhopecten]]'' <small>Masuda, 1963</small>
*** ''[[Nipponopecten]]'' <small>Masuda, 1962</small> †
*** ''[[Patinopecten]]'' <small>Dall, 1898</small>
**Tribe [[Mimachlamydini]] <small>Waller, 1993</small>
*** ''[[Mimachlamys]]'' <small>Iredale, 1929</small>
*** ''[[Spathochlamys]]'' <small>Waller, 1993</small>
**Tribe [[Pedini]] <small>Bronn, 1862</small>
*** ''[[Pedum (bivalve)|Pedum]]'' <small>Bruguière, 1792</small>
*Subfamily ''[[incertae sedis]]''
** ''[[Agerchlamys]]'' <small>Damborenea, 1993</small> †
** ''[[Athlopecten]]'' <small>Marwick, 1928</small> †
** ''[[Camptochlamys]]'' <small>Arkell, 1930</small> †
** ''[[Indopecten]]'' <small>Douglas, 1929</small> †
** ''[[Jorgechlamys]]'' <small>del Río, 2004</small> †
** ''[[Lamellipecten]]'' <small>Dijkstra & Maestrati, 2010</small>
** ''[[Lindapecten]]'' <small>Petuch, 1995</small>
** ''[[Mixtipecten]]'' <small>Marwick, 1928</small> †
** ''[[Pseudopecten]]'' <small>Bayle, 1878</small> †
{{div col end}}

== Relation to humans ==
=== Scalloped shape ===
[[File:Basket (England), 1813–40 (CH 18349945).jpg|thumb|Scalloped edges of a porcelain basket]]
The term "scalloped" is used to designate a decorative pattern, resembling the wavy scallop surface, that is used at the edges of furniture,  fabrics, and other items.<ref>{{cite book | title=Court of Customs and Patent Appeals Reports | publisher=The Court of Customs and Patent Appeals | issue=v. 18, pt. 1 | year=1930 |url=https://books.google.com/books?id=oi-17Q3ZQhsC&pg=PA52 | ref={{sfnref | The Court of Customs and Patent Appeals | 1930}} | access-date=11 November 2023}}</ref>

=== Fisheries ===
{{see also|Scallop aquaculture}}
[[File:Scallop Pearl Net.jpg|thumb|upright=0.7|Pearl nets used to grow spat to juveniles in [[scallop aquaculture]]]]
The largest wild scallop fishery is for the Atlantic sea scallop (''[[Placopecten magellanicus]]'') found off the northeastern United States and eastern Canada. Scallops are harvested using [[scallop dredge]]s or bottom trawls. Most of the rest of the world's production of scallops is from Japan (wild, enhanced, and aquaculture) and China (mostly cultured Atlantic bay scallops).{{sfn|Shumway|Parsons|2011|page=[https://books.google.com/books?id=vhGdBAAAQBAJ&pg=PA902 902]}}{{rp|p.661}}

In the [[D'Entrecasteaux Channel]] in the south of Tasmania dredging was banned in 1969, and since then [[scuba diving|divers]] have caught them in this area.<ref name=SPUMS1991>{{cite journal |author=Walker, Margaret |title=What price Tasmanian scallops? A report of morbidity and mortality associated with the scallop diving season in Tasmania 1990 |journal=South Pacific Underwater Medicine Society Journal |year=1991 |volume=21 |issue=1 |url=http://archive.rubicon-foundation.org/9414 |access-date=16 July 2013 |archive-date=20 October 2013 |archive-url=https://web.archive.org/web/20131020041442/http://archive.rubicon-foundation.org/xmlui/handle/123456789/9414 |url-status=usurped }}</ref> Attempts to use lighted pots to attract [[lobster]] and [[crab]] led to the discovery that they were effective in attracting scallops.<ref>{{cite web|url=https://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-61710988 |title=Orkney part of 'scallop discos' fishing trial |work=[[BBC News]] |publisher=[[BBC]] |date=6 June 2022 |accessdate=7 June 2022 }}</ref>

==== Sustainability ====
The scallop fishery in New Zealand declined from a catch of 1246 tonnes in 1975 to 41 tonnes in 1980, at which point the government ordered the fishery closed. [[Spat (molluscs)|Spat]] seeding in the 1980s helped it recover, and catches in the 1990s were up to 684 tonnes.<ref name=":0">{{Cite journal|last=Arnold|first=Naomi|date=July–August 2018|title=What we do in the shallows|url=https://www.nzgeo.com/stories/what-we-do-in-the-shallows/|journal=New Zealand Geographic|volume=152|pages=56–73}}</ref> The [[Tasman Bay]] area was closed to commercial scallop harvesting from 2009 to 2011 due to a decline in the numbers. The commercial catch was down to 22 tonnes in 2015, and the fishery was closed again. The main causes for the decline seem to be fishing, climate effects, disease, pollutants, and sediment runoff from farming and forestry.<ref name=":0" /> [[Royal Forest and Bird Protection Society of New Zealand|Forest and Bird]] list scallops as the "Worst Choice" in their Best Fish Guide for sustainable seafood species.<ref>{{cite web|url=http://www.forestandbird.org.nz/what-we-do/publications/-best-fish-guide-/scallops|title=Scallops|website=Forest and Bird}}</ref>{{better source needed|date=January 2017}}

On the east coast of the [[United States]], over the last 100 years, the populations of bay scallops have greatly diminished due to several factors but probably mostly due to a reduction in seagrasses (to which bay scallop spat attach) caused by increased coastal development and concomitant nutrient runoff. Another possible factor is the reduction of sharks from overfishing. A variety of sharks used to feed on [[Batoidea|rays]], which are the main predator of bay scallops. With the shark population reduced – this [[apex predator]] in some places almost eliminated – the rays have been free to feed on scallops to greatly decrease their numbers.{{sfn|Pinet|2011|page=[https://books.google.com/books?id=iaTYBAAAQBAJ&pg=PA333 333]}} By contrast, the Atlantic sea scallop (''[[Placopecten magellanicus]]'') is at historically high levels of abundance after recovery from overfishing.{{sfn|Granata|Flick|Martin|2012|page=[https://books.google.com/books?id=-gPaFouCFikC&pg=PT96 96]}}

=== As food ===
{{Commons category|Scallop dishes}}
[[File:Making Thomas Keller's Caramelized Scallops.jpg|thumb|Scallops browning in clarified butter in a very hot pan]]

Scallops are characterized by offering two flavors and textures in one shell: the meat, called "scallop", which is firm and white, and the roe, called "coral", which is soft and often brightly coloured reddish-orange. Sometimes, markets sell scallops already prepared in the shell, with only the meat remaining. Outside the U.S., the scallop is often sold whole. They are available both with and without coral in the UK and Australia.{{sfn|Shumway|Parsons|2011|page=[https://books.google.com/books?id=rSu_GLwLQmEC&pg=PA1355 1355]}}

Scallops without any additives are called "dry-packed", while scallops that are treated with [[sodium tripolyphosphate]] (STPP) are called "wet-packed". STPP causes the scallops to absorb moisture prior to the freezing process, thereby increasing their weight. The freezing process takes about two days.{{sfn|Rolnick|Peterson|2014|page=[https://books.google.com/books?id=6YGBAwAAQBAJ&pg=PA47 47]}}{{Better source needed|date=October 2020}}

In [[French cuisine]], scallops are often quickly cooked in a hot buttered pan, sometimes with [[calvados]] and served with creamed leeks, or prepared in a white wine sauce. In [[Galician cuisine]], scallops are baked with breadcrumbs, ham, and onions.{{citation needed|date=January 2017}} 

Scallops are sometimes breaded, deep-fried, and served with [[coleslaw]] and [[french fries]] in the northeastern [[United States]] (either on their own or as part of a [[seafood basket|fisherman's platter]]).<ref name="Cahners 1977">{{cite book | title=Volume Feeding Institutions | publisher=Cahners. | issue=v. 80 | year=1977 | url=https://books.google.com/books?id=LvbiAAAAMAAJ&q=%22Seafood+basket%22+scallop | page=123}}</ref> In [[New England cuisine|New England]], some seafood restaurants offer scallop rolls, consisting of breaded scallops on a grilled, split-top [[hot dog bun]].<ref>{{cite web|url=https://santemagazine.com/eating-the-neighborhood-july-2023/|title=My Fried Seafood Love Affair and Some Wines to Pair|first=Ric|last=Orlando|website=Sante Magazine|date=6 July 2023|access-date=23 August 2024}}</ref>

In [[Japanese cuisine]], scallops may be served in soup or prepared as ''[[sashimi]]'' or ''[[sushi]]''.{{citation needed|date=January 2017}} In a sushi bar, ''hotategai'' (帆立貝, 海扇) is the traditional scallop on rice and, while ''kaibashira'' (貝柱) is more loosely used to include other shellfish species with round-shaped flesh (the adductor muscle), such as ''[[Atrina pectinata]]'' (帶子). 

Dried scallop is known in [[Cantonese cuisine|Cantonese]] [[Chinese cuisine]] as ''[[conpoy]]'' (乾瑤柱, 乾貝, 干貝).{{citation needed|date=January 2017}} [[Smoked scallop]]s are sometimes served as [[appetizer]]s or used as an ingredient in the preparation of various dishes and appetizers.<ref>{{cite web|url=http://blogs.phoenixnewtimes.com/bella/2012/06/andytalk_appetizers-recipes-beyond_lox_-_smoked_s.php|title=AndyTalk: Beyond Lox – Smoked Seafood Hold the Bagels|first=Andy|last=Broder|website=[[Phoenix New Times]]|date=7 June 2012|access-date=31 January 2017|archive-date=9 June 2012|archive-url=https://web.archive.org/web/20120609002023/http://blogs.phoenixnewtimes.com/bella/2012/06/andytalk_appetizers-recipes-beyond_lox_-_smoked_s.php|url-status=dead}}</ref>

Scallops have lent their name to the culinary term "scalloped", which originally referred to seafood creamed and served hot in the shell.{{sfn|Rombauer|Becker|1964|page=369}} Today, it means a creamed casserole dish such as [[scalloped potatoes]], which contains no seafood at all.

<gallery mode="packed" heights="150px" style="float:left;">
File:Large scallops.jpg|Adductor muscle meat of [[Pecten maximus|giant scallop]]
File:Upclosedriedscallop.jpg|Dried scallops, also known as ''[[conpoy]]''
File:Fried scallops on stick.jpg|Fried scallops on a stick served with rice
File:Scallops (45640549224).jpg|Pan seared scallops
</gallery>
{{clear}}

=== Pearls ===
[[File:Scallop pearl2.jpg|thumb|A scallop pearl]]
Scallops do occasionally produce [[pearl]]s, though scallop pearls do not have the buildup of translucent layers or "nacre" which give desirability to the pearls of the [[feather oyster]]s, and usually lack both [[lustre (mineralogy)|lustre]] and [[iridescence]]. They can be dull, small, and of varying colour, but exceptions occur that are appreciated for their aesthetic qualities.{{sfn|Matlins|2001| page=56}}

=== Symbolism ===
The [[Shell plc|Shell]] company, one of the world's biggest companies, is represented by a scallop.

[[File:DEU Bad Mingolfsheim COA.svg|thumb|upright|A scallop shell in a German [[coat of arms]]]]
The scallop shell symbol found its way into [[heraldry]] as a badge of those who had been on the pilgrimage to Compostela, although later, it became a symbol of pilgrimage in general. [[Winston Churchill|Sir Winston Churchill]] and [[Diana, Princess of Wales|Lady Diana]]'s family, the [[Spencer family]] [[coat of arms]] includes a scallop, as well as both of Diana's sons [[William, Prince of Wales|Prince William]] and [[Prince Harry, Duke of Sussex|Prince Harry]]'s personal coats of arms; also Pope [[Benedict XVI]]'s personal coat of arms includes a scallop; another example is the surname [[Wilmot (surname)|Wilmot]] and also [[John Wesley]]'s (which as a result the scallop shell is used as an emblem of [[Methodism]]). However, charges in heraldry do not always have an unvarying symbolic meaning, and there are cases of arms in which no family member went on a pilgrimage, and the occurrence of the scallop is simply a pun on the name of the [[armiger]] (as in the case of [[Jacques Coeur]]), or for other reasons.{{sfn|Stix|Stix|Abbott|1968|page={{pages needed|date=January 2017}}}} In 1988, the State of [[New York (state)|New York]] in the US chose the [[Atlantic bay scallop|bay scallop]] (''Argopecten irradians'') as its [[List of U.S. state shells|state shell]].<ref>{{cite web |url=http://www.statesymbolsusa.org/New_York/shell_bayscallop.html |title=New York State Shell: Bay Scallop |website=State Symbols USA |access-date=24 May 2012}}</ref>

==== Shell of Saint James ====
<!-- [[Shell of Saint James]] redirects here-->
{{see also|Camino de Santiago#Scallop symbol}}
{{Multiple image
| total_width       = 400
| image1            = Carlo Crivelli 064.jpg
| image2            = Shield with symbol of St. James the Great, Church of the Good Shepherd (Rosemont, Pennsylvania).jpg
| footer            = Left: [[James, son of Zebedee|Saint James]] by [[Carlo Crivelli]], c. 1480
{{Space}}
Right: Shield with symbol of St. James the Great, [[Church of the Good Shepherd (Rosemont, Pennsylvania)]]
}}
The scallop shell is the traditional emblem of [[James, son of Zebedee|St James the Great]] and is popular with pilgrims travelling the Way of St James ([[Camino de Santiago]]).<ref name="StJ">{{cite book|last1=Thomas|first1=Hope B. Werness; line drawings by Joanne H. Benedict and Hope B. Werness; additional drawings by Tiffany Ramsay-Lozano and Scott |date=2003|title=The continuum encyclopedia of animal symbolism in art |location=New York |publisher=Continuum |isbn=9780826415257|page=359}}</ref> Medieval Christians would collect a scallop shell while at Compostela as evidence of having made the journey. The association of Saint James with the scallop can most likely be traced to the legend that the apostle once rescued a knight covered in scallops.<ref>{{cite book |last=Pullan |first=Wendy |date=2013 |chapter=Tracking the Habitual: Observations on the Pilgrim's Shell |title=Architecture and Pilgrimage, 1000–1500 |chapter-url=https://books.google.com/books?id=SSyFb0N_i8YC&pg=PA67 |publisher=Ashgate Publishing Company |page=67|isbn=9781472410832 }}</ref> An alternative version of the legend holds that while St. James' remains were being transported to Galicia (Spain) from [[Jerusalem]]. As the ship approached land, the wedding of the daughter of [[Queen Lupa]] was taking place on shore.<ref name="Bahrami">{{Cite book |last=Bahrami |first= Beebe  |url=https://books.google.com/books?id=f6F_cqGOAr4C&q=Queen+Lupa |title=The Spiritual Traveler: Spain : a Guide to Sacred Sites and Pilgrim Routes |date=2009 |publisher=Paulist Press |page=36| isbn=978-1-58768-047-2 }}</ref> The young groom was on horseback, and, upon seeing the ship's approach, his horse got spooked, and horse and rider plunged into the sea.{{sfn|Starkie|1965|pages=[https://books.google.com/books?id=9xJGrnvuNW4C&pg=PA70 70–71]}} Through miraculous intervention, the horse and rider emerged from the water alive, covered in seashells.{{sfn|Starkie|1965|p=71}}

Indeed, in French, the mollusc itself – as well as a popular preparation of it in cream sauce – is called {{Lang|fr|coquille St. Jacques}}. In German they are {{Lang|de|Jakobsmuscheln}} – literally "James's shellfish". Curiously the [[Linnaean taxonomy|Linnaean]] name ''[[Pecten jacobeus]]'' is given to the Mediterranean scallop, while the scallop endemic to Galicia is called ''Pecten maximus'' due to its bigger size.<ref name="Davies2013">{{cite book|editor1-last=Davies|editor1-first=Paul|editor2-last=Howard|editor2-first=Deborah|editor3-last=Pullan|editor3-first=Wendy|title=Architecture and pilgrimage, 1000–1500: southern Europe and beyond|date=2013|publisher=Ashgate Publishing|location=Aldershot, Hamps. |isbn=9781472410832 |pages=73–86}}</ref> The scallop shell is represented in the decoration of churches named after St. James, such as in [[St James' Church, Sydney]], where it appears in a number of places, including in the mosaics on the floor of the [[chancel]].{{sfn|St. James Church|1963|p=22}}

When referring to St James, a scallop shell valve is displayed with its convex outer surface showing. In contrast, when the shell refers to the goddess Venus (see below), it is displayed with its concave interior surface showing.<ref name="Davies2013"/>

==== Fertility symbol ====
[[File:Aphrodite Anadyomene Louvre CA2288.jpg|thumb|left|upright|[[Aphrodite Anadyomene]], from [[Amisos]], 1st century BC – 1st century AD]]

Throughout antiquity, scallops and other [[Bivalvia|hinged shells]] have symbolized the feminine principle.{{sfn|Salisbury|2001|page=11}} Outwardly, the shell can symbolize the protective and nurturing principle, and inwardly, the "life-force slumbering within the Earth",{{sfn|Fontana|1994|pages=88, 103}} [[Vagina and vulva in art|an emblem of the vulva]].<ref>{{cite journal | last1=Gutzwiller | first1=K | year=1992 | title=The Nautilus, the Halycon, and Selenaia: Callimachus's ''Epigram'' 5 Pf.= 14 G.-P | journal=[[Classical Antiquity (journal)|Classical Antiquity]] | volume=11 | issue=2| pages=194–209 |doi=10.2307/25010972 |jstor=25010972 }}</ref>{{sfn|Johnson|1994|page=230}}

Many paintings of [[Venus (mythology)|Venus]], the Roman goddess of love and fertility, included a scallop shell in the painting to identify her. This is evident in [[Sandro Botticelli|Botticelli's]] [[Classical antiquity|classically]] inspired 15th century painting ''[[The Birth of Venus (Botticelli)|The Birth of Venus]]''.<ref name="Botticelli">{{Cite web |url=http://www.artble.com/artists/sandro_botticelli/paintings/birth_of_venus |title=Birth of Venus |year=2017 |website=artble.com |access-date=25 February 2017}}</ref>

One legend of the [[Way of St. James]] holds that the route was seen as a fertility pilgrimage, undertaken when a young couple desired to bear offspring. The scallop shell is believed to have originally been carried by pagans as a symbol of fertility.<ref>{{cite journal | last1=Slavin | first1=S | year=2003 | title=Walking as Spiritual Practice: The Pilgrimage to Santiago de Compostela | journal=[[Body and Society]] | volume=9 | issue=1| page=18 | doi=10.1177/1357034X030093001 | s2cid=144403461 }}</ref>{{sfn|Gauding|2009|page=[https://books.google.com/books?id=SImTll3uupIC&dq=%22Way+of+St.+James%22+fertility+pilgrimage+scallop&pg=PA169 169]}}

====Other interpretations====
Alternatively, the scallop resembles the setting sun, which was the focus of the pre-Christian Celtic rituals of the area.{{citation needed|date=March 2018}} To wit, the pre-Christian roots of the ''Way of St. James'' was a Celtic death journey westwards towards the setting sun, terminating at the ''End of the World'' (''[[Finisterra]]'') on the "Coast of Death" ([[Costa da Morte]]) and the "Sea of Darkness" (i.e., the Abyss of Death, the ''Mare Tenebrosum'', Latin for the Atlantic Ocean, itself named after the ''Dying Civilization'' of Atlantis).<ref name=thomas_progess>{{cite web |last1=Thomas |first1=Isabella |url=http://www.europe.org.uk/index/-/id/289/|archive-url=https://web.archive.org/web/20080323234123/http://www.europe.org.uk/index/-/id/289/ |url-status=dead |archive-date=23 March 2008 |title=Pilgrim's Progress |website=Europe in the UK |publisher=[[European Commission]] |access-date=21 January 2017}}</ref>{{better source needed|date=April 2018|reason=This page just references 'legends' without further citation.}}

===Contemporary art===
[[File:The Scallop, Maggi Hambling, Aldeburgh.jpg|thumb|Large sculpture by [[Maggi Hambling]] titled ''The Scallop'' erected in 2003 on the beach at [[Aldeburgh]], England]]
The beach at [[Aldeburgh]], Suffolk, England, features [[Maggi Hambling]]'s steel sculpture, ''The Scallop'', erected in 2003 as a memorial to the composer [[Benjamin Britten]], who had a long association with the town.{{sfn|Dunford|Lee|2012|page=[https://books.google.com/books?id=Ck0wTuoqTpkC&pg=PT486 486]}}

== See also ==
* {{Portal inline|Animals}}

== Explanatory notes ==
{{notelist}}

== Citations ==
{{Reflist}}

== General bibliography ==
{{refbegin|45em}}
* {{cite book|first1=Ian |last1=Dore|title=The New Fresh Seafood Buyer's Guide: A manual for distributors, restaurants and retailers|url=https://books.google.com/books?id=5lLUBwAAQBAJ&pg=PA152|date=29 June 2013|location=Boston, MA|publisher=[[Springer Science & Business Media]]|isbn=978-1-4757-5990-7|page=152 }}
* {{citation|last=Drew|first=Gilman Arthur|title=The Habits Anatomy, and Embryology of the Giant Scallop: (Pecten Tenuicostatus, Mighels)|url=https://books.google.com/books?id=yrwMAQAAIAAJ&pg=PA5|year=1906|location=Orono, Maine|pages=5–6 }}
* {{cite book|first1=Martin |last1=Dunford|first2=Phil |last2=Lee|title=The Rough Guide to Norfolk & Suffolk|url=https://books.google.com/books?id=Ck0wTuoqTpkC&pg=PT486|date=13 September 2012|publisher=Rough Guides|isbn=978-1-4053-9037-8|page=486 }}
* {{cite book |last1=Fontana |first1=David |year=1994 |title=The secret language of symbols: a visual key to symbols and their meanings |location=San Francisco |pages=88, 103 |publisher=[[Chronicle Books]] |isbn=978-0-8118-0462-2 }}
* {{cite book |last1=Gauding |first1=Madonna |year=2009 |page=[https://books.google.com/books?id=SImTll3uupIC&pg=PA169 169] |title=The Signs and Symbols Bible: The Definitive Guide to Mysterious Markings |publisher=[[Sterling Publishing Company]] |isbn=978-1-4027-7004-3 }}
* {{cite book|first1=Elizabeth |last1=Gosling|title=Marine Bivalve Molluscs|url=https://books.google.com/books?id=QIO4CAAAQBAJ&pg=PA29|date=27 April 2015|publisher=[[John Wiley & Sons]]|isbn=978-1-119-04522-9|page=29 }}
* {{cite book|first1=Linda Ankenman |last1=Granata| first2=George J. Jr. |last2=Flick|first3=Roy E. |last3=Martin|title=The Seafood Industry: Species, Products, Processing, and Safety|url=https://books.google.com/books?id=-gPaFouCFikC&pg=PT96|date=8 February 2012|publisher=John Wiley & Sons|isbn=978-1-118-22953-8|page=96 }}
* {{cite book|last=Habe|first=Tadashige |title= Systematics of mollusca in Japan: Bivalvia and Scaphopoda |publisher=Hokuryukan|year=1977 |chapter=Bivalvia and Scaphopoda }}
* {{cite book|first1=Elizabeth |last1=Harper|first2=John David |last2=Taylor|first3=J. Alistair |last3=Crame|author4=Geological Society of London |author4-link=Geological Society of London|title=The Evolutionary Biology of the Bivalvia|url=https://books.google.com/books?id=QpkfKzsOOfUC&pg=PA254|year=2000|publisher=Geological Society of London|isbn=978-1-86239-076-8 }}
* {{cite book |last1=Johnson |first1=Buffie |year=1994 |title=Lady of the beasts: the Goddess and her sacred animals |page=230 |location=Rochester, Vt |publisher=Inner Traditions/[[Bear & Company]] |isbn=978-0-89281-523-4 }}
* {{cite book|last= Matlins|first=Antoinette, L. |title=The Pearl Book: The Definitive Buying Guide: how to Select, Buy, Care for & Enjoy Pearls|publisher=Gemstone|date=2001| isbn=978-0-943763-35-4|page=56 |location=New York, NY }}
* {{cite book|first1=Clare |last1=Milsom|first2=Sue |last2=Rigby|author2-link=Sue Rigby|title=Fossils at a Glance|url=https://books.google.com/books?id=e8Xr6pXKdcEC&pg=PA62|date=1 April 2009 |location= Chichester|publisher=[[John Wiley & Sons]]|isbn=978-1-4443-1123-5|page=62 }}
* {{cite book|first1=Paul R. |last1=Pinet|title=Invitation to Oceanography|url=https://books.google.com/books?id=iaTYBAAAQBAJ&pg=PA333|date=28 December 2011|publisher=[[Jones & Bartlett Publishers]]|isbn=978-1-4496-0192-8|page=333 }}
* {{cite book|first1=Tony |last1=Rice|title=Can Squid Fly? Can squid fly?: answers to a host of fascinating questions about the sea and sea life |location=London |publisher=[[Adlard Coles Nautical|Thomas Reed publications]], [[Bloomsbury Publishing]] |date=3 December 2012 |isbn=978-1-4081-5130-3|page=[https://books.google.com/books?id=4CD72deHDwQC&pg=PA47 47] }}
* {{cite book|first1=Glenn |last1=Rolnick |first2=Chris |last2=Peterson |title=Carmine's celebrates: classic Italian recipes for everyday feasts |location=New York |publisher=[[St. Martin's Press]] |page=[https://books.google.com/books?id=6YGBAwAAQBAJ&pg=PA47 47] |date=4 November 2014 |isbn=978-1-4668-3723-2 }}
* {{cite book |last1=Raines |first1=Bret K. |first2=Guido T. |last2=Poppe |first3=Klaus |last3=Groh |year=2006 |title=A conchological iconography |location=Hackenheim Germany |publisher=ConchBooks |pages=402 |isbn=978-3-925919-78-7}}
* {{cite book|first1=Chuck |last1=Robinson|first2=Debbie |last2=Robinson|title=The Art of Shelling: A Complete Guide to Finding Shells and Other Beach Collectibles at Shelling Locations from Florida to Maine|url=https://books.google.com/books?id=kNYJdHyNRgsC&pg=PA65|year=2000|publisher=Old Squan Village Publishing|isbn=978-0-9647267-8-9|page=65 }}
* {{cite book|last1=Rombauer |first1=Irma S. |first2=Marion Rombauer |last2=Becker |orig-year=1931 |year=1964 |title=The Joy of Cooking |page=369 |location=Indianapolis, Indiana |publisher=[[Bobbs-Merrill]] |isbn=978-0-452-25665-1 }}
* {{cite book |last1=Salisbury |first1=Joyce E. |author-link= Joyce E. Salisbury |location=Santa Barbara, Calif |year=2001 |title=Encyclopedia of women in the ancient world |page=11 |publisher=[[ABC-CLIO]] |isbn=978-1-57607-092-5 }}
* {{cite book|editor1-first=Sandra E.|editor1-last=Shumway|editor2-first=G. Jay |editor2-last=Parsons|title=Scallops: Biology, Ecology and Aquaculture|url=https://books.google.com/books?id=rSu_GLwLQmEC&pg=PA689|date=22 September 2011 |edition=2nd |location=Amsterdam Boston|publisher=[[Elsevier]]|isbn=978-0-08-048077-0|pages=689–690 }}
* {{cite book | author1=St. James' Church (Sydney, N.S.W.) | title=A Short story of historic St. James', Sydney | publication-date=1963 | publisher=The Church | edition=2nd |url=https://trove.nla.gov.au/work/12401661 | access-date=25 September 2023 |ref={{sfnref|St. James Church|1963}} }}
* {{cite book |url=https://books.google.com/books?id=9xJGrnvuNW4C&pg=PA71 |last1=Starkie |first1=Walter |title=The Road to Santiago |page=71 |publisher=[[University of California Press]] |location=Berkeley, Los Angeles |year=1965 |orig-year=1959 |access-date=20 January 2017 }}
* {{cite book |first1=Hugh |last1=Stix |first2=Marguerite |last2=Stix |first3=Robert Tucker |last3=Abbott |title=The Shell: Five Hundred Million Years of Inspired Design |year=1968 |publisher=[[Harry N. Abrams, Inc.]] |location=New York NY |edition=First |isbn=978-0810904750 |url-access=registration |url=https://archive.org/details/shellfivehundred0000stix }}
* {{cite book |last=Waller |first=Thomas R. |date=1991 |chapter=Evolutionary relationships among commercial scallops (Mollusca: Bivalvia: Pectinidae) |pages= |editor=S. E. Shumway |title=Scallops: Biology, ecology and aquaculture |location=New York |publisher=Elsevier |isbn=}} 
* {{cite book|first1=Barbara |last1=Willard|first2=Mary B. |last2=Owens |title=Augustine Came to Kent |location=Warsaw, N.D.; San Francisco |publisher=Bethlehem Books, [[Ignatius Press]] |url=https://books.google.com/books?id=SZoIAQAAQBAJ&pg=PA68|date=1 September 1997|isbn=978-1-883937-21-8 }}
{{refend}}

==Further reading==
* [https://thesecretingredient.substack.com/p/when-did-your-favorite-foods-originate The Food Timeline (Illustrated Edition)]

== External links ==
{{Wiktionary}}
{{wikispecies|Pectinidae}}
{{cookbook}}
* [http://www.nmr-pics.nl/Pectinidae%20%28Europe%29/album/index.html Mollusca - Bivalvia - Pectinidae] {{Webarchive|url=https://web.archive.org/web/20220118103524/http://www.nmr-pics.nl/Pectinidae%20%28Europe%29/album/index.html |date=18 January 2022 }} at [[Natural History Museum Rotterdam]] – photos of Pectinidae shells

{{commercial molluscs}}
{{commercial fish topics}}
{{Edible molluscs}}
{{meat}}
{{seafood}}
{{Heraldic creatures}}
{{Taxonbar|from=Q1311395}}

[[Category:Pectinidae| ]]
[[Category:Bivalve families]]
[[Category:Commercial molluscs]]
[[Category:Extant Middle Triassic first appearances]]
[[Category:Heraldic charges]]
[[Category:Mollusc common names]]
[[Category:Symbols of New York (state)]]