Scallop () is a
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...
that encompasses various species of
marine
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
* Marine habitats
* Marine life
* Marine pollution
Military
* ...
bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
mollusks
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
in the
taxonomic
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families within the superfamily
Pectinoidea
The Pectinoidea are a superfamily of marine bivalve molluscs, including the scallops and spiny oysters.Gofas, S. (2012). Pectinoidea. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=15 ...
, which also includes the
thorny oyster
''Spondylus'' is a genus of bivalve molluscs, the only genus in the family Spondylidae.MolluscaBase (2019). MolluscaBase. Spondylus Linnaeus, 1758. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=t ...
s.
Scallops are a
cosmopolitan
Cosmopolitan may refer to:
Food and drink
* Cosmopolitan (cocktail), also known as a "Cosmo"
History
* Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953
Hotels and resorts
* Cosmopoli ...
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
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
byssal thread
A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilid ...
. The majority of species, however, live recumbent on sandy substrates, and when they sense the presence of a predator such as a
starfish
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. 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
Eyes are Organ (anatomy), organs of the visual system. They provide living organisms with Visual perception, vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of ...
s situated around the edge of their
mantles.
Many species of scallops are highly prized as a food source, and some are farmed as
aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
. The word "scallop" is also applied to the meat of these bivalves, the
adductor muscle A adductor muscle is any muscle that causes adduction. It may refer to:
Humans
* Adductor muscles of the hip, the most common reference in humans, but may also refer to
** Adductor brevis muscle, a muscle in the thigh situated immediately behind ...
, that is sold as
seafood
Seafood is any form of sea life regarded as food by humans, prominently including fish and shellfish. Shellfish include various species of molluscs (e.g. bivalve molluscs such as clams, oysters and mussels, and cephalopods such as octopus an ...
. The brightly coloured, symmetric, fan-shaped shells of scallops with their radiating and often fluted
ornamentation
An ornament is something used for decoration.
Ornament may also refer to:
Decoration
*Ornament (art), any purely decorative element in architecture and the decorative arts
*Biological ornament, a characteristic of animals that appear to serve on ...
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
beachcombers
''The Beachcombers'' is a Canadian comedy-drama television series that ran on CBC Television from October 1, 1972, to December 12, 1990. With over 350 episodes, it is one of the longest-running dramatic series ever made for English-language Canad ...
and vacationers. The shells also have a significant place in popular culture.
Biology
Distribution and habitat
Scallops inhabit all the oceans of the world, with the largest number of species living in the
Indo-Pacific
The Indo-Pacific is a vast biogeographic region of Earth.
In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...
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
Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the orde ...
,
kelp
Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms.
Kelp grows in "underwat ...
, sand, or mud. Most scallops begin their lives as
byssally attached juveniles, an ability that some retain throughout their lives while others grow into free-living adults.
Anatomy and physiology
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.
Orientation
![Scallop Diagram2](https://upload.wikimedia.org/wikipedia/commons/4/42/Scallop_Diagram2.svg)
The shell of a scallop consists of two sides or
valves
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings ...
, a left valve and a right one, divided by a
plane of symmetry
In mathematics, reflection symmetry, line symmetry, mirror symmetry, or mirror-image symmetry is symmetry with respect to a reflection. That is, a figure which does not change upon undergoing a reflection has reflectional symmetry.
In 2D ther ...
. 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. 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.
Valves
![Buried inequivalved scallop](https://upload.wikimedia.org/wikipedia/commons/b/ba/Buried_inequivalved_scallop.svg)
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. 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
The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for eating, preening, manipulating objects, killing prey, fighting, probing for food ...
" surrounded by a generally raised area called the "
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
entoliids and the Aviculopectinidae, did not possess it.
Muscular system
![Opened scallop shell](https://upload.wikimedia.org/wikipedia/commons/a/a8/Opened_scallop_shell.jpg)
Like the true oysters (family
Ostreidae
The Ostreidae, the true oysters, include most species of molluscs commonly consumed as oysters. Pearl oysters are not true oysters, and belong to the order Pteriida.
Like scallops, true oysters have a central adductor muscle, which means the sh ...
), 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 A adductor muscle is any muscle that causes adduction. It may refer to:
Humans
* Adductor muscles of the hip, the most common reference in humans, but may also refer to
** Adductor brevis muscle, a muscle in the thigh situated immediately behind ...
of scallops is larger and more developed than those of
oyster
Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not al ...
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
archetypal
The concept of an archetype (; ) appears in areas relating to behavior, historical psychology, and literary analysis.
An archetype can be any of the following:
# a statement, pattern of behavior, prototype, "first" form, or a main model that ...
form of a
seashell
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal or organism that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washe ...
.
Digestive system
Scallops are
filter feeder
Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
s, and eat
plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...
. Unlike many other bivalves, they lack
siphons
A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...
. Water moves over a filtering structure, where food particles become trapped in mucus. Next, the
cilia
The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...
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 mollusks, enters and leaves the animal's heart) and exits via the anus.
Nervous system
![Scallop Neurological Diagram](https://upload.wikimedia.org/wikipedia/commons/e/e9/Scallop_Neurological_Diagram.svg)
Like all bivalves, scallops lack actual brains. Instead, their nervous system is controlled by three paired
ganglia
A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympatheti ...
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. 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
The statocyst is a balance sensory receptor present in some aquatic invertebrates, including bivalves, cnidarians, ctenophorans, echinoderms, cephalopods, and crustaceans. A similar structure is also found in ''Xenoturbella''. The statocyst cons ...
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.
Reproduction
The scallop family is unusual in that some members of the family are
dioecious
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...
(males and females are separate), while others are simultaneous hermaphrodites (both sexes in the same individual), and a few are
protoandrous hermaphrodites
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...
(males when young then switching to female). Red
roe
Roe ( ) or hard roe is the fully ripe internal egg masses in the ovaries, or the released external egg masses, of fish and certain marine animals such as shrimp, scallop, sea urchins and squid. As a seafood, roe is used both as a cooking, coo ...
is that of a female, and white, is that of a male. Spermatozoa and ova are 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
annuli, the concentric rings of their shells.
Eyes
Scallops have a large number (up to 200) of small (about 1 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
Guanine () ( symbol G or Gua) is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine (uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside is called ...
crystals to focus and retro-reflect light instead of a lens as found in many other eye types. Additionally, their eyes possess a double-layered retina, the outer retina responding most strongly to light and the inner to abrupt darkness. 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. 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.
Adductor muscles
Scallops possess fast (
striated) and slow (
smooth
Smooth may refer to:
Mathematics
* Smooth function, a function that is infinitely differentiable; used in calculus and topology
* Smooth manifold, a differentiable manifold for which all the transition maps are smooth functions
* Smooth algebraic ...
)
adductor muscles
The adductor muscles of the hip are a group of muscles mostly used for bringing the thighs together (called adduction).
Structure
The adductor group is made up of:
*Adductor brevis
*Adductor longus
*Adductor magnus
* Adductor minimus This is o ...
, 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.
[ ]
Material was copied from this source, which is available under
Creative Commons Attribution 4.0 International License
Locomotion
![scallop jump](https://upload.wikimedia.org/wikipedia/commons/4/40/Scallop_jump.svg)
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
A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilid ...
, which attaches them to some form of substrate such as
eelgrass Eelgrass is a common name for several plants and may refer to:
* ''Zostera'', marine eelgrass
* ''Vallisneria
''Vallisneria'' (named in honor of Antonio Vallisneri) is a genus of freshwater aquatic plant, commonly called eelgrass, tape grass o ...
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 distorta
The chlamys (Ancient Greek: χλαμύς : chlamýs, genitive: χλαμύδος : chlamydos) was a type of an ancient Greek cloak. '' and ''
Hinnites multirigosus'').
However, the majority of scallops are free-living and can swim with brief bursts of speed to escape predators (mostly
starfish
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. 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). 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). Other scallops can extend their foot from between their valves, and by contracting the muscles in their foot, they can burrow into sand.
Mobility and behavior
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.
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. Scallops are highly sensitive to shadows, vibrations, water movement, and chemical stimuli. 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. Physiological fitness and exercise of scallops decrease with age due to the decline of cellular and especially mitochondrial function,
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.
Environmental factors, such as changes in oxidative stress parameters, can inhibit the growth and development of scallops.
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.
Pearls
![Scallop pearl2](https://upload.wikimedia.org/wikipedia/commons/f/f1/Scallop_pearl2.jpg)
Scallops do occasionally produce
pearl
A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle) of a living shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carb ...
s, though scallop pearls do not have the buildup of translucent layers or "nacre" which give desirability to the pearls of the
feather oyster
Pteriidae, also called the feather oysters, is a family of medium-sized to large saltwater clams. They are pearl oysters, marine bivalve molluscs in the order Pteriida.
Some of the species in this family are important economically as the sou ...
s, and usually lack both
lustre
Lustre or Luster may refer to:
Places
* Luster, Norway, a municipality in Vestlandet, Norway
** Luster (village), a village in the municipality of Luster
* Lustre, Montana, an unincorporated community in the United States
Entertainment
* '' ...
and
iridescence
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfl ...
. They can be dull, small, and of varying colour, but exceptions occur that are appreciated for their aesthetic qualities.
Mutualism
Some scallops, including ''Chlamys hastata'', frequently carry
epibiont
An epibiont (from the Ancient Greek meaning "living on top of") is an organism that lives on the surface of another living organism, called the basibiont ("living underneath"). The interaction between the two organisms is called epibiosis. An epi ...
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,
camouflages ''Chlamys hastata'' from predators,
or forms a physical barrier around byssal openings to prevent sea stars from inserting their digestive membranes.
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.
In fact, 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.
Lifecycle and growth
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
The Mid-Atlantic Bight is a coastal region running from Massachusetts to North Carolina. It contains the New York Bight. It is separated from the South Atlantic Bight by Cape Hatteras to the south and the Gulf of Maine to the north by Cape Cod
...
.
The females of scallops are highly fecund, capable of producing hundreds of millions of eggs per year.
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.
The lifespans of some scallops have been known to extend over 20 years.
Taxonomy and phylogeny
Etymology
The family name Pectinidae, which is based on the name of the type genus, ''
Pecten'', comes from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''
pecten'' meaning
comb
A comb is a tool consisting of a shaft that holds a row of teeth for pulling through the hair to clean, untangle, or style it. Combs have been used since prehistoric times, having been discovered in very refined forms from settlements dating ba ...
, in reference to a comb-like structure of the shell which is situated next to the byssal notch.
Phylogeny
![Chlamys Pliocene Cyprus](https://upload.wikimedia.org/wikipedia/commons/8/80/Chlamys_Pliocene_Cyprus.jpg)
The fossil history of scallops is rich in species and specimens. The earliest known records of true scallops (those with a ctenolium) can be found from the
Triassic period
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
, over 200 million years ago.
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. 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
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising ...
, but the group almost disappeared completely by the end of the
Cretaceous period
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of t ...
. The survivors
speciate
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...
d rapidly during the
Tertiary period
Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago.
The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...
. Nearly 7,000 species and subspecies names have been introduced for both fossil and recent Pectinidae.
The
cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
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.
Taxonomic structure
Scallops are the family Pectinidae, marine bivalve molluscs within the superfamily
Pectinoidea
The Pectinoidea are a superfamily of marine bivalve molluscs, including the scallops and spiny oysters.Gofas, S. (2012). Pectinoidea. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=15 ...
. 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
Propeamussiidae, sometimes referred to as glass scallops mud scallops or mud pectens, are a taxonomic family of saltwater clams, marine bivalve molluscs in the order Pectinida. As members of the superfamily Pectinoidea, they are closely relat ...
, 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 million years ago;
in terms of diversity, it has been a thriving family to the present day.
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.
Raines and Poppe 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
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
. Although species are generally well-circumscribed, their attribution to
subfamilies
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
and genera is sometimes equivocal, and information about
phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
and relationships of the species are minimal, not the least because most work has been based only on adult
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
*Morphology (archaeology), study of the shapes or forms of artifacts
*Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
.
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.
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.
The framework of its phylogeny shows that repeated life habit states derive from evolutionary convergence and parallelism. 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. 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.
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.
There have been a number of efforts to address phylogenetic studies. Only three have assessed more than ten species
and only one has included multiple outgroups.
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.
In molecular phylogenies of the Bivalvia, both the Spondylidae and the Propeamussiidae have been resolved as sister to the Pectinidae.
List of subfamilies and genera
![Semipallium fulvicostatum 001](https://upload.wikimedia.org/wikipedia/commons/7/7f/Semipallium_fulvicostatum_001.jpg)
The following are recognised in the family Pectinidae:
*Subfamily
Camptonectinae Habe, 1977
** ''
Camptonectes''
Agassiz, 1864
** ''
Ciclopecten''
Seguenza, 1877
** ''
Delectopecten''
Stewart, 1920
** ''
Hyalopecten
''Hyalopecten'' is a genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and b ...
''
A. E. Verrill, 1897
** ''
Pseudohinnites''
Dijkstra, 1989
** ''
Sinepecten ''
Schein, 2006
*Subfamily
Palliolinae Korbkov in Eberzin, 1960
**Tribe
Adamussiini Habe, 1977
*** ''
Adamussium
''Adamussium'' is a genus of scallops belonging to the family Pectenidae from the Southern Ocean around Antarctica. There are three known species but only one is extant, the Antarctic scallop (''A. colbecki''). Of the two extinct species ''A. jo ...
''
Thiele, 1934
*** ''
Antarctipecten''
Beu & Taviani, 2013 †
*** ''
Duplipecten''
Marwick, 1928 †
*** ''
Lentipecten''
Marwick, 1928 †
*** ''
Leoclunipecten''
Beu & Taviani, 2013 †
*** ''
Ruthipecten''
Beu & Taviani, 2013 †
**Tribe
Eburneopectinini T. R. Waller, 2006 †
*** ''
Eburneopecten''
Conrad, 1865 †
**Tribe
Mesopeplini T. R. Waller, 2006
*** ''
Kaparachlamys''
Boreham, 1965 †
*** ''
Mesopeplum
''Mesopeplum'' is a genus of scallops, marine bivalve molluscs in the family Pectinidae.
Species in the genus ''Mesopeplum''
* ''Mesopeplum caroli''
* ''Mesopeplum convexum'' ( Quoy and Gaimard, 1835)
* ''Mesopeplum fenestratum''
* ''Mes ...
''
Iredale, 1929
*** ''
Phialopecten''
Marwick, 1928 †
*** ''
Sectipecten''
Marwick, 1928 †
*** ''
Towaipecten''
Beu, 1995 †
**Tribe
Palliolini Waller, 1993
*** ''
Karnekampia''
H. P. Wagner, 1988
*** ''
Lissochlamys
''Lissochlamys'' is a genus of scallops, marine (ocean), marine bivalve molluscs in the family Pectinidae, the scallops. Species within this genus have a West African and Northern Mediterranean distribution.
The fossil record of this species dat ...
''
Sacco, 1897
*** ''
Palliolum
''Palliolum'' is a genus of scallops, marine bivalve molluscs in the family Pectinidae, the scallops.
This genus is known in the fossil record from the Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 m ...
''
Monterosato, 1884
*** ''
Placopecten
''Placopecten'' is a genus of scallops, marine (ocean), marine bivalve molluscs in the family Pectinidae, the scallops.Abbott, R.T. & Morris, P.A. ''A Field Guide to Shells: Atlantic and Gulf Coasts and the West Indies.'' New York: Houghton Miffl ...
''
Verrill, 1897
*** ''
Pseudamussium''
Mörch, 1853
**Tribe
Serripectinini T. R. Waller, 2006 †
*** ''
Janupecten''
Marwick, 1928 †
*** ''
Serripecten''
Marwick, 1928 †
*Subfamily
Pectininae
**Tribe
Aequipectinini F. Nordsieck, 1969
*** ''
Aequipecten
''Aequipecten'' is a genus of scallops, marine bivalve mollusks in the family Pectinidae.Abbott, R.T. & Morris, P.A. ''A Field Guide to Shells: Atlantic and Gulf Coasts and the West Indies.'' New York: Houghton Mifflin, 1995. 30-31.
Fossil re ...
''
P. Fischer, 1886
*** ''
Argopecten
''Argopecten'' is a genus of saltwater clams, or scallops, marine bivalve mollusks in the family Pectinidae.
Species
Species within the genus ''Argopecten'' include:
* '' Argopecten gibbus'' (Linnaeus, 1767) — Atlantic calico scallop
* ...
''
Monterosato, 1889
*** ''
Cryptopecten
''Cryptopecten'' is a genus of molluscs in the family Pectinidae.Abbott, R.T. & Morris, P.A. ''A Field Guide to Shells: Atlantic and Gulf Coasts and the West Indies.'' New York: Houghton Mifflin, 1995. 31.
Selected species
* ''Cryptopecten phry ...
''
Dall, Bartsch & Rehder, 1938
*** ''
Flexopecten
''Flexopecten'' is a genus of saltwater scallops, marine bivalve mollusks in the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. ...
''
Sacco, 1897
*** ''
Haumea
Haumea (minor-planet designation 136108 Haumea) is a dwarf planet located trans-Neptunian object, beyond Neptune's orbit. It was discovered in 2004 by a team headed by Michael E. Brown, Mike Brown of Caltech at the Palomar Observatory in the United ...
''
Dall, Bartsch & Rehder, 1938
*** ''
Leptopecten
''Leptopecten'' is a genus of bivalves belonging to the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "sca ...
''
Verrill, 1897
*** ''
Volachlamys''
Iredale, 1939
**Tribe
Amusiini Ridewood, 1903
***''
Amusium
''Amusium'' is a genus of scallops, marine bivalve molluscs belonging to the family Pectinidae.
Extant species
* '' Amusium pleuronectes'' Linnaeus, 1758
Extinct species
Extinct species within this genus include:
* †''Amusium aguaclarens ...
''
Röding, 1798
***''
Dentamussium''
Dijkstra, 1990
***''
Euvola
''Euvola'' is a genus of marine bivalve mollusks in the family Pectinidae, the scallops.Abbott, R.T. & Morris, P.A. ''A Field Guide to Shells: Atlantic and Gulf Coasts and the West Indies.'' New York: Houghton Mifflin, 1995. 26-27. In shells of t ...
''
Dall, 1898
***''
Leopecten
''Leopecten'' is a genus of bivalves belonging to the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scall ...
''
Masuda, 1971
***''
Ylistrum
''Ylistrum'' is a genus of marine bivalve mollusks in the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "s ...
''
Mynhardt & Alejandrino, 2014
**Tribe
Austrochlamydini Jonkers, 2003
***''
Austrochlamys''
Jonkers, 2003
**Tribe
Decatopectinini Waller, 1986
***''
Anguipecten''
Dall, Bartsch & Rehder, 1938
***''
Antillipecten T. R. Waller, 2011''
T. R. Waller, 2011
***''
Bractechlamys
''Bractechlamys'' is a genus of molluscs in the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" i ...
''
Iredale, 1939
***''
Decatopecten''
Rüppell in G. B. Sowerby II, 1839
***''
Excellichlamys''
Iredale, 1939
***''
Glorichlamys''
Dijkstra, 1991
***''
Gloripallium
''Gloripallium'' is a genus of bivalves belonging to the family Pectinidae.
The species of this genus are found in Indian and Pacific Ocean.
Species:
*''Gloripallium maculosum''
*''Gloripallium pallium''
*''Gloripallium speciosum''
*''Glorip ...
''
Iredale, 1939
***''
Juxtamusium''
Iredale, 1939
***''
Lyropecten''
Conrad, 1862
***''
Mirapecten''
Dall, Bartsch & Rehder, 1938
***''
Nodipecten
''Nodipecten'' is a genus of large scallops, marine bivalve molluscs in the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. Howev ...
''
Dall, 1898
**Tribe
Pectinini Wilkes, 1810
*** ''
Annachlamys
''Annachlamys'' is a genus of scallops, marine bivalve molluscs in the family Pectinidae.
Species
The World Register of Marine Species lists the following species:
* ''Annachlamys flabellata'' (Lamarck, 1819)
* ''Annachlamys iredalei'' (Powell, ...
''
Iredale, 1939
*** †''
Fascipecten''
Freneix, Karache & Salvat 1971
*** †''
Gigantopecten
''Gigantopecten'' is a genus of fossil scallops, marine bivalve molluscs in the family Pectinidae, the scallops.
These facultatively mobile low-level epifaunal suspension feeders lived from the Oligocene to the Quaternary period (from 33. ...
''
Rovereto, 1899
*** ''
Minnivola''
Iredale, 1939
*** †''
Oopecten''
Sacco, 1897
*** †''
Oppenheimopecten''
Teppner, 1922
*** ''
Pecten''
Müller, 1776
*** ''
Serratovola''
Habe, 1951
*Subfamily
Pedinae Bronn, 1862
**Tribe
Chlamydini von Teppner, 1922
*** ''
Austrohinnites''
Beu & Darragh, 2001 †
*** ''
Azumapecten''
Habe, 1977
*** ''
Chesapecten
''Chesapecten'' is an extinct genus of scallop known from marine strata from the early Miocene to the early Pleistocene of the Eastern United States.
It flourished in the shallow seas along the Mid-Atlantic during this period. Other scallop ...
''
Ward & Blackwelder, 1975 †
*** ''
Chlamys
The chlamys (Ancient Greek: χλαμύς : chlamýs, genitive: χλαμύδος : chlamydos) was a type of an ancient Greek cloak. ''
Röding, 1798
*** ''
Chokekenia''
Santelli & del Río, 2018 †
*** ''
Ckaraosippur''
Santelli & del Río, 2019 †
*** ''
Complicachlamys''
Iredale, 1939
*** ''
Coralichlamys''
Iredale, 1939
*** ''
Dietotenhosen''
Santelli & del Río, 2019 †
*** ''
Equichlamys''
Iredale, 1929
*** ''
Hemipecten
''Hemipecten'' is a genus of scallops, marine bivalve molluscs in the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the ...
''
A. Adams & Reeve, 1849
*** ''
Hinnites
''Hinnites'' is a genus of rock scallops, marine bivalve mollusks in the family Pectinidae, the scallops.
These mollusks have been recorded as fossils from the Triassic to the Quaternary (from 235.0 to 0.126 Ma). Fossils have been found in the ...
''
Deference, 1821
*** ''
Laevichlamys''
Waller, 1993
*** ''
Manupecten''
Monterosato, 1872
*** ''
Moirechlamys''
Santelli & del Río, 2018 †
*** ''
Notochlamys''
Cotton, 1930
*** ''
Pascahinnites''
Dijkstra & Raines, 1999
*** ''
Pixiechlamys''
Santelli & del Río, 2018 †
*** ''
Praechlamys''
Allasinaz, 1972 †
*** ''
Scaeochlamys
''Scaeochlamys'' is a genus of bivalves belonging to subfamily Pedinae of the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. Howev ...
''
Iredale, 1929
*** ''
Semipallium
''Semipallium'' is a genus of bivalves belonging to subfamily Pedinae of the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. Howeve ...
''
Jousseaume in Lamy, 1928
*** ''
Swiftopecten''
Hertlein, 1936
*** ''
Talochlamys''
Iredale, 1929
*** ''
Veprichlamys
''Veprichlamys'' is a genus of scallops in the family Pectinidae. This genus contains 8 extant species and one Extinction, extinct species (''Veprichlamys leprosa, V. leprosa'' from the Miocene of Australia).
Species
* ''Veprichlamys africana ...
''
Iredale, 1929
*** ''
Yabepecten''
Masuda, 1963 †
*** ''
Zygochlamys''
Ihering, 1907
**Tribe
Crassadomini Waller, 1993
*** ''
Caribachlamys
''Caribachlamys'' is a genus of molluscs in the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" i ...
''
Waller, 1993
*** ''
Crassadoma
''Crassadoma'' is a genus of rock scallops, marine bivalve molluscs in the family Pectinidae. It is monotypic, the only species being ''Crassadoma gigantea'', the rock scallop, giant rock scallop or purple-hinge rock scallop. Although the small ...
''
Bernard, 1986
**Tribe
Fortipectinini Masuda, 1963
*** ''
Fortipecten''
Yabe & Hatai, 1940 †
*** ''
Kotorapecten''
Masuda, 1962 †
*** ''
Masudapecten''
Akiyama, 1962 †
*** ''
Mizuhopecten
''Mizuhopecten'' is a genus of bivalves belonging to the family Pectinidae.
The species of this genus are found in Far East Asia.
Species:
*'' Mizuhopecten kitamiensis''
*''Mizuhopecten yessoensis
''Mizuhopecten yessoensis'' (Yesso scallo ...
''
Masuda, 1963
*** ''
Nipponopecten''
Masuda, 1962 †
*** ''
Patinopecten
''Patinopecten'' is a genus of bivalves belonging to the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "sc ...
''
Dall, 1898
**Tribe
Mimachlamydini Waller, 1993
*** ''
Mimachlamys
''Mimachlamys'' is a genus of scallops, marine bivalve molluscs in the taxonomic family Pectinidae. There are at least 11 living species, including the glory scallop '' Mimachlamys gloriosa'', and the '' Mimachlamys asperrima''.
Shell descri ...
''
Iredale, 1929
*** ''
Spathochlamys
''Spathochlamys'' is a genus of scallops
Scallop () is a common name that encompasses various species of Marine (ocean), marine bivalve mollusc, mollusks in the Taxonomy (biology), taxonomic Family (biology), family Pectinidae, the scallops. ...
''
Waller, 1993
**Tribe
Pedini
''Pedum'' is a monotypic genus of bivalves belonging to the family Pectinidae
Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name ...
Bronn, 1862
*** ''
Pedum
Pedum ( grc, Πέδα) was an ancient town of Latium in central Italy, located between Tivoli, Lazio#Roman%20age, Tibur and Palestrina#Ancient%20Praeneste, Praeneste, near modern Gallicano nel Lazio. The town was a member of the Latin League.
H ...
''
Bruguière, 1792
*Subfamily ''
incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
''
** ''
Agerchlamys''
Damborenea, 1993 †
** ''
Athlopecten''
Marwick, 1928 †
** ''
Camptochlamys''
Arkell, 1930 †
** ''
Indopecten''
Douglas, 1929 †
** ''
Jorgechlamys''
del Río, 2004 †
** ''
Lamellipecten''
Dijkstra & Maestrati, 2010
** ''
Lindapecten''
Petuch, 1995
** ''
Mixtipecten''
Marwick, 1928 †
** ''
Pseudopecten''
Bayle, 1878 †
Seafood industry
Aquaculture
Wild fisheries
The largest wild scallop fishery is for the Atlantic sea scallop (''
Placopecten magellanicus
''Placopecten magellanicus'', previously listed as ''Pecten tenuicostatus'' and as ''Pecten grandis'' and once referred to as the "giant scallop", common names Atlantic deep-sea scallop, deep sea scallop, North Atlantic sea scallop, American se ...
'') found off the northeastern United States and eastern Canada. Scallops are harvested using
scallop dredge
A fishing dredge, also known as a scallop dredge or oyster dredge, is a kind of dredge which is towed along the bottom of the sea by a fishing boat in order to collect a targeted edible bottom-dwelling species. The gear is used to fish for scallo ...
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).
In the
D'Entrecasteaux Channel
The D'Entrecasteaux Channel is a body of water located between Bruny Island and the south-east of the mainland of Tasmania, Australia. The channel is the mouth for the estuaries of the Derwent and the Huon Rivers and empties into the Tasman S ...
in the south of Tasmania dredging was banned in 1969, and since then
divers
Diver or divers may refer to:
*Diving (sport), the sport of performing acrobatics while jumping or falling into water
*Practitioner of underwater diving, including:
**scuba diving,
**freediving,
**surface-supplied diving,
**saturation diving, a ...
have caught them in this area.
Attempts to use lighted pots to attract
lobster
Lobsters are a family (biology), family (Nephropidae, Synonym (taxonomy), synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs ...
and
crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...
led to the discovery that they were effective in attracting scallops.
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 seeding in the 1980s helped it recover, and catches in the 1990s were up to 684 tonnes.
The
Tasman Bay / Te Tai-o-Aorere
Tasman Bay (; officially Tasman Bay / Te Tai-o-Aorere), originally known in English as Blind Bay, is a large V-shaped bay at the north end of New Zealand's South Island. Located in the centre of the island's northern coast, it stretches along ...
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.
Forest and Bird
Forest & Bird ( mi, Te Reo o te Taiao), also known by its formal name as the Royal Forest and Bird Protection Society of New Zealand, is an environmental organisation specialising in the protection and conservation of New Zealand's indigenous f ...
list scallops as the "Worst Choice" in their Best Fish Guide for sustainable seafood species.
On the east coast of the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, 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
rays
Ray may refer to:
Fish
* Ray (fish), any cartilaginous fish of the superorder Batoidea
* Ray (fish fin anatomy), a bony or horny spine on a fin
Science and mathematics
* Ray (geometry), half of a line proceeding from an initial point
* Ray (gra ...
, which are the main predator of bay scallops. With the shark population reduced – this
apex predator
An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own.
Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...
in some places almost eliminated – the rays have been free to feed on scallops to greatly decrease their numbers. By contrast, the Atlantic sea scallop (''
Placopecten magellanicus
''Placopecten magellanicus'', previously listed as ''Pecten tenuicostatus'' and as ''Pecten grandis'' and once referred to as the "giant scallop", common names Atlantic deep-sea scallop, deep sea scallop, North Atlantic sea scallop, American se ...
'') is at historically high levels of abundance after recovery from overfishing.
As food
![Scallops with wine sauce](https://upload.wikimedia.org/wikipedia/commons/8/8b/Scallops_with_wine_sauce.jpg)
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.
Scallops without any additives are called "dry-packed", while scallops that are treated with
(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.
In
Galician cuisine
Galician cuisine refers to the typical dishes and ingredients found in the cuisine of the autonomous community of Galicia, Spain. These include shellfish, ''empanadas, polbo á feira'' (a dish made of octopus), cheese ''queixo de tetilla'', '' ri ...
, scallops are baked with breadcrumbs, ham, and onions. In
Japanese cuisine
Japanese cuisine encompasses the regional and traditional foods of Japan, which have developed through centuries of political, economic, and social changes. The traditional cuisine of Japan (Japanese: ) is based on rice with miso soup and other ...
, scallops may be served in soup or prepared as ''
sashimi
is a Japanese delicacy consisting of fresh raw fish or meat sliced into thin pieces and often eaten with soy sauce.
Origin
The word ''sashimi'' means "pierced body", i.e. "刺身" = ''sashimi'', where 刺 し = ''sashi'' (pierced, stuck) ...
'' or ''
sushi
is a Japanese cuisine, Japanese dish of prepared , usually with some sugar and salt, accompanied by a variety of , such as seafood, often raw, and vegetables. Styles of sushi and its presentation vary widely, but the one key ingredient is " ...
''. In a sushi bar, ''hotategai'' (帆立貝, 海扇) is the traditional scallop on rice and, while ''kaibashira'' (貝柱) may be calscallop is more loosely used to include other shellfish species with round-shaped flesh (the adductor muscle), such as ''
Atrina
''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae.
A typical species is '' A. fragilis'', found in British waters. '' A. rigida'' ( Lightfoot, 1786) is found on the southeast coast of North America and in ...
'' (帶子). Dried scallop is known in
Cantonese
Cantonese ( zh, t=廣東話, s=广东话, first=t, cy=Gwóngdūng wá) is a language within the Chinese (Sinitic) branch of the Sino-Tibetan languages originating from the city of Guangzhou (historically known as Canton) and its surrounding are ...
Chinese cuisine
Chinese cuisine encompasses the numerous cuisines originating from China, as well as overseas cuisines created by the Chinese diaspora. Because of the Chinese diaspora and historical power of the country, Chinese cuisine has influenced many ot ...
as ''
conpoy
Conpoy or dried scallop is a type of Cantonese dried seafood product that is made from the adductor muscle of scallops. The smell of conpoy is marine, pungent, and reminiscent of certain salt-cured meats. Its taste is rich in umami due to its ...
'' (乾瑤柱, 乾貝, 干貝).
Smoked scallop
Smoked scallops are scallops that have been smoked. A scallop is a common name applied to many species of marine bivalve mollusks in the family Pectinidae, the scallops. Scallops are a cosmopolitan family, found in all of the world's oceans.
...
s are sometimes served as
appetizer
An hors d'oeuvre ( ; french: hors-d'œuvre ), appetiser or starter is a small dish served before a meal in European cuisine. Some hors d'oeuvres are served cold, others hot. Hors d'oeuvres may be served at the dinner table as a part of the ...
s or used as an ingredient in the preparation of various dishes and appetizers.
Scallops have lent their name to the culinary term "scalloped", which originally referred to seafood creamed and served hot in the shell. Today, it means a creamed casserole dish such as
scalloped potatoes
Gratin () is a culinary technique in which an ingredient is topped with a browned crust, often using breadcrumbs, grated cheese, egg or butter.Courtine, Robert J. (ed.) (2003) ''The Concise Larousse Gastronomique'' London: Hamlyn The term may ...
, which contains no seafood at all.
File:Large scallops.jpg, Adductor muscle meat of the giant scallop (seven white circular items) with a large shrimp
File:Upclosedriedscallop.jpg, Dried scallops, also known as ''conpoy
Conpoy or dried scallop is a type of Cantonese dried seafood product that is made from the adductor muscle of scallops. The smell of conpoy is marine, pungent, and reminiscent of certain salt-cured meats. Its taste is rich in umami due to its ...
''
File:BCfood17.JPG, Taiwanese steamed scallops
File:Scallop-Sausages-DSC2415.jpg, A scallop being grilled next to sausages in Japan
File:Fried scallops on stick.jpg, Fried scallops on a stick served with rice
File:Scallops (45640549224).jpg, Pan seared scallops
Symbolism of the shell
Shell of Saint James
The scallop shell is the traditional emblem of
St James the Great
James the Great, also known as James, son of Zebedee, Saint James the Great, Saint James the Greater, Saint James the Elder, or Saint Jacob (Aramaic ܝܥܩܘܒ ܒܪ ܙܒܕܝ, Arabic يعقوب, Hebrew בן זבדי , '' Yaʿăqōḇ'', Latin '' ...
and is popular with pilgrims returning from the Way of St James (
Camino de Santiago
The Camino de Santiago ( la, Peregrinatio Compostellana, "Pilgrimage of Compostela"; gl, O Camiño de Santiago), known in English as the Way of St James, is a network of pilgrims' ways or pilgrimages leading to the shrine of the apostle Saint ...
) and the apostle's shrine at
Santiago de Compostela
Santiago de Compostela is the capital of the autonomous community of Galicia, in northwestern Spain. The city has its origin in the shrine of Saint James the Great, now the Cathedral of Santiago de Compostela, as the destination of the Way of St ...
in
Galicia,
Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
.
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. An alternative version of the legend holds that while St. James' remains were being transported to Galicia (Spain) from
Jerusalem
Jerusalem (; he, יְרוּשָׁלַיִם ; ar, القُدس ) (combining the Biblical and common usage Arabic names); grc, Ἱερουσαλήμ/Ἰεροσόλυμα, Hierousalḗm/Hierosóluma; hy, Երուսաղեմ, Erusałēm. i ...
, the disciples witnessed a bridegroom on horseback fall into the water and emerge covered in the shells.
Indeed in French, the mollusc itself – as well as a popular preparation of it in cream sauce – is called . In German they are – literally "James's shellfish". Curiously the
Linnaean name ''
Pecten jacobeus
''Pecten jacobaeus'', the Mediterranean scallop, is a species of scallop, an edible saltwater scallop, a marine bivalve mollusc in the family Pectinidae, the scallops.
Description
''Pecten jacobaeus'' usually reaches a length of about , but ...
'' is given to the Mediterranean scallop, while the scallop endemic to Galicia is called ''Pecten maximus'' due to its bigger size.
The scallop shell is represented in the decoration of churches named after St. James, such as in
St James' Church, Sydney
St James' Church, commonly known as St James', King Street, is an Australian heritage-listed Anglican parish church located at 173 King Street, in the Sydney central business district in New South Wales. Consecrated in February 1824 and named ...
, where it appears in a number of places, including in the mosaics on the floor of the
chancel
In church architecture, the chancel is the space around the altar, including the choir and the sanctuary (sometimes called the presbytery), at the liturgical east end of a traditional Christian church building. It may terminate in an apse.
Ove ...
.
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.
Shell of Saint Augustine
Saint Augustine
Augustine of Hippo ( , ; la, Aurelius Augustinus Hipponensis; 13 November 354 – 28 August 430), also known as Saint Augustine, was a theologian and philosopher of Berber origin and the bishop of Hippo Regius in Numidia, Roman North Af ...
is said to have been walking along the seashore, meditating on the unfathomable mystery of the
Holy Trinity
The Christian doctrine of the Trinity (, from 'threefold') is the central dogma concerning the nature of God in most Christian churches, which defines one God existing in three coequal, coeternal, consubstantial divine persons: God the F ...
. A boy was using a shell to pour seawater into a little hole. When Augustine asked what he was doing, he replied, "I am emptying the sea into this hole." Thus did
Augustine
Augustine of Hippo ( , ; la, Aurelius Augustinus Hipponensis; 13 November 354 – 28 August 430), also known as Saint Augustine, was a theologian and philosopher of Berbers, Berber origin and the bishop of Hippo Regius in Numidia (Roman pr ...
understand that man would never penetrate to the depths of the mystery of God.
This symbolic meaning was taken up by
Joseph Ratzinger
Pope Benedict XVI ( la, Benedictus XVI; it, Benedetto XVI; german: link=no, Benedikt XVI.; born Joseph Aloisius Ratzinger, , on 16 April 1927) is a retired prelate of the Catholic church who served as the head of the Church and the sovereign ...
in his coat of arms as
Archbishop of Munich
The following people were bishops, prince-bishops or archbishops of Freising or Munich and Freising in Bavaria:
Bishops of Freising
* St. Corbinian (724–730); founded the Benedictine abbey in Freising, although the diocese was not organ ...
, and also retained by him when elected Pope
Benedict XVI
Pope Benedict XVI ( la, Benedictus XVI; it, Benedetto XVI; german: link=no, Benedikt XVI.; born Joseph Aloisius Ratzinger, , on 16 April 1927) is a retired prelate of the Catholic church who served as the head of the Church and the sovereign ...
. While a doctoral candidate in 1953, Ratzinger wrote his dissertation on ''The People of God and the House of God in Augustine's Teaching'', and the shell, therefore, has a personal connection with the thought of Saint Augustine.
Badge
![Wappen Bad Mingolfsheim](https://upload.wikimedia.org/wikipedia/commons/7/70/Wappen_Bad_Mingolfsheim.svg)
The scallop shell symbol found its way into
heraldry
Heraldry is a discipline relating to the design, display and study of armorial bearings (known as armory), as well as related disciplines, such as vexillology, together with the study of ceremony, rank and pedigree. Armory, the best-known branch ...
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 Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 Winston Churchill in the Second World War, dur ...
and
Diana, Princess of Wales
Diana, Princess of Wales (born Diana Frances Spencer; 1 July 1961 – 31 August 1997) was a member of the British royal family. She was the first wife of King Charles III (then Prince of Wales) and mother of Princes William and Harry. Her ac ...
' family, the
Spencer family
The Spencer family is an aristocratic family in the United Kingdom. From the 16th century, its members have held numerous titles including the dukedom of Marlborough, the earldoms of Sunderland and Spencer, and the Churchill barony. Two prom ...
coat of arms
A coat of arms is a heraldry, heraldic communication design, visual design on an escutcheon (heraldry), escutcheon (i.e., shield), surcoat, or tabard (the latter two being outer garments). The coat of arms on an escutcheon forms the central ele ...
includes a scallop, as well as both of Diana's sons
Prince William, Duke of Cambridge
William, Prince of Wales, (William Arthur Philip Louis; born 21 June 1982) is the heir apparent to the British throne. He is the elder son of King Charles III and his first wife Diana, Princess of Wales.
Born in London, William was educat ...
and
Prince Harry
Prince Harry, Duke of Sussex, (Henry Charles Albert David; born 15 September 1984) is a member of the British royal family. He is the younger son of Charles III and his first wife Diana, Princess of Wales. He is fifth in the line of succ ...
's personal coats of arms; also Pope
Benedict XVI
Pope Benedict XVI ( la, Benedictus XVI; it, Benedetto XVI; german: link=no, Benedikt XVI.; born Joseph Aloisius Ratzinger, , on 16 April 1927) is a retired prelate of the Catholic church who served as the head of the Church and the sovereign ...
's personal coat of arms includes a scallop; another example is the surname
Wilmot Wilmot may refer to:
Places Australia
*Division of Wilmot, an abolished Australian Electoral Division in Tasmania
*Wilmot, Tasmania, a locality in the North-West Region
Canada
*Wilmot, Nova Scotia, an unincorporated rural community and former to ...
and also
John Wesley
John Wesley (; 2 March 1791) was an English people, English cleric, Christian theology, theologian, and Evangelism, evangelist who was a leader of a Christian revival, revival movement within the Church of England known as Methodism. The soci ...
's (which as a result the scallop shell is used as an emblem of
Methodism
Methodism, also called the Methodist movement, is a group of historically related denominations of Protestant Christianity whose origins, doctrine and practice derive from the life and teachings of John Wesley. George Whitefield and John's br ...
). 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
In heraldry, an armiger is a person entitled to use a heraldic achievement (e.g., bear arms, an "armour-bearer") either by hereditary right, grant, matriculation, or assumption of arms. Such a person is said to be armigerous. A family or a cl ...
(as in the case of
Jacques Coeur
Ancient and noble French family names, Jacques, Jacq, or James are believed to originate from the Middle Ages in the historic northwest Brittany region in France, and have since spread around the world over the centuries. To date, there are over ...
), or for other reasons. In 1988, the State of
New York
New York most commonly refers to:
* New York City, the most populous city in the United States, located in the state of New York
* New York (state), a state in the northeastern United States
New York may also refer to:
Film and television
* '' ...
in the US chose the
bay scallop (''Argopecten irradians'') as its
state shell.
Fertility symbol
![Aphrodite Anadyomene Louvre CA2288](https://upload.wikimedia.org/wikipedia/commons/2/25/Aphrodite_Anadyomene_Louvre_CA2288.jpg)
Throughout antiquity, scallops and other
hinged shells have symbolized the feminine principle. Outwardly, the shell can symbolize the protective and nurturing principle, and inwardly, the "life-force slumbering within the Earth",
an emblem of the vulva.
Many paintings of
Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
, the Roman goddess of love and fertility, included a scallop shell in the painting to identify her. This is evident in
Botticelli's classically inspired 15th century painting ''
The Birth of Venus
''The Birth of Venus'' ( it, Nascita di Venere ) is a painting by the Italian artist Sandro Botticelli, probably executed in the mid 1480s. It depicts the goddess Venus arriving at the shore after her birth, when she had emerged from the sea ...
''.
One legend of the
Way of St. James
The Camino de Santiago ( la, Peregrinatio Compostellana, "Pilgrimage of Compostela"; gl, O Camiño de Santiago), known in English as the Way of St James, is a network of pilgrims' ways or pilgrimages leading to the shrine of the Twelve Apostle ...
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.
Other interpretations
Alternatively, the scallop resembles the setting sun, which was the focus of the pre-Christian Celtic rituals of the area. 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
Cape Finisterre (, also ; gl, Cabo Fisterra, italic=no ; es, Cabo Finisterre, italic=no ) is a rock-bound peninsula on the west coast of Galicia, Spain.
In Roman times it was believed to be an end of the known world. The name Finisterre, lik ...
'') on the "Coast of Death" (
Costa da Morte
Costa da Morte (; es, Costa de la Muerte; "Death Coast") is part of the Galician coast. The Costa da Morte extends from the villages of Muros and Malpica.
The Costa da Morte received its name because there have been so many shipwrecks along it ...
) 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).
Contemporary art
![The Scallop, Maggi Hambling, Aldeburgh](https://upload.wikimedia.org/wikipedia/commons/a/a7/The_Scallop%2C_Maggi_Hambling%2C_Aldeburgh.jpg)
The beach at
Aldeburgh
Aldeburgh ( ) is a coastal town in the English county, county of Suffolk, England. Located to the north of the River Alde. Its estimated population was 2,276 in 2019. It was home to the composer Benjamin Britten and remains the centre of the int ...
, Suffolk, England, features
Maggi Hambling
Margaret ("Maggi") J. Hambling (born 23 October 1945) is a British artist. Though principally a painter her best-known public works are the sculptures ''A Conversation with Oscar Wilde'' and '' A Sculpture for Mary Wollstonecraft'' in London, ...
's steel sculpture, ''The Scallop'', erected in 2003 as a memorial to the composer
Benjamin Britten
Edward Benjamin Britten, Baron Britten (22 November 1913 – 4 December 1976, aged 63) was an English composer, conductor, and pianist. He was a central figure of 20th-century British music, with a range of works including opera, other ...
, who had a long association with the town.
See also
*
Explanatory notes
Citations
General bibliography
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External links
Mollusca - Bivalvia - Pectinidaeat
Natural History Museum Rotterdam
The (; en, Natural History Museum Rotterdam) is a natural history museum located in Rotterdam, Netherlands.
The museum opened in 1927. It had 44,009 visitors in 2015.
History
In 1922, the Rotterdam section of the Koninklijke Nederlandse Natu ...
– photos of Pectinidae shells
{{Taxonbar, from=Q1311395
Bivalve families
Commercial molluscs
Extant Middle Triassic first appearances
Heraldic charges
Mollusc common names