Scallop

Scallop
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Ostreoida
Suborder:	Pectinina
Superfamily:	Pectinoidea
Family:	Pectinidae Rafinesque, 1815
Genera
See Pectinidae

A scallop (Template:PronEng or /ˈskæləp/) is a marine bivalve mollusc of the family Pectinidae. Scallops are a cosmopolitan family, found in all of the world's oceans. Many scallops are highly prized as a food source. The brightly-colored, fan-shaped shells of some scallops with their radiating fluted pattern are valued by shell collectors.

The name "scallop" is derived from the Old French escalope, which means "shell".

Anatomy

Like the true oysters (family Ostreidae), scallops have a central adductor muscle, and thus the inside of their shells has a characteristic central scar, marking the point of attachment for this muscle. The adductor muscle of scallops is larger and more developed than that of oysters, because they are active swimmers; scallops are in fact the only migratory bivalve. Their shell shape tends to be highly regular, recalling one archetypal form of a seashell, and because of this pleasing geometric shape, the scallop shell is a common decorative motif. They also possess eyes with a lens and retina, which are more complex compared to other bivalves. Their eyes can't see shapes, but can detect light and motion.

Food and digestion

Most scallops are filter feeders, and eat fish. Coincidentally, the plankton can include scallop larvae. Siphons bring water over a filtering structure, where food becomes trapped in mucus. Next, the cilia on the structure moves the food toward the mouth. Then, the food is digested in the stomach and digestive gland. Waste is passed on through the intestine and exits via the anus.

Life habits

Most scallops are free-living, but some species can attach to a substrate by a structure called a byssus, or even be cemented to their substrate as adults (e.g. Hinnites spp.). Other scallops can extend a "foot" from between their valves (shell). By then contracting the foot, they can burrow themselves deeper into sand. A free-living scallop can swim, by rapidly opening and closing its shell. This method of locomotion is also a defensive technique, protecting it from threatening predators. Some scallops can make an audible soft popping sound as they flap their shells underwater, leading one seafood vendor to dub them "singing scallops".

Reproductive cycle

The scallop family is unusual in that some members of the family are dioecious (males and females are separate), while other are simultaneous hermaphrodites (both sexes in the same individual) and a few are protoandrous hermaphrodites (males when young then switching to female). Red roe is that of a female, and white, 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 scallop hatches and the larvae drift in the plankton until settling to the bottom again 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 by annuli, the concentric rings of their shells.

Seafood industry

Gathering scallops

By far the largest wild scallop fishery is for the Atlantic sea scallop (Placopecten magellanicus) found off northeastern United States and eastern Canada. Most of the rest of the world's production of scallops are from Japan (wild, enhanced, and aquaculture), and China (mostly cultured Atlantic bay scallops).

Scallops are most commonly harvested using scallop dredges or bottom trawls. Recently scallops harvested by divers, hand-caught on the ocean floor, have entered the marketplace. In contrast to scallops captured by a dredge across the sea floor, diver scallops tend to be less gritty. They may also be more ecologically friendly, as the harvesting method does not cause damage to undersea flora or fauna. In addition, dredge harvesting methods often result in delays of up to two weeks before the scallops arrive at market, which can cause the flesh to break down, and results in a much shorter shelf life.

Aquaculture

In 2005, China accounted for 80 percent of the global scallop and pecten catch according to a FAO study. Within Europe, Russia remained the industry leader.

Sustainability

New Zealand

The Tasman Bay area has been closed to commercial scallop harvesting for the past two years due to a decline in the numbers. Industry funded research is currently being conducted into scallop harvesting patterns. Forest and Bird list scallops as "Worst Choice" in their Best Fish Guide for sustainable seafood species.

United States

On the east coast of the United States, over the last 100 years, the populations of bay scallops have greatly diminished. This decrease is due to several factors, but probably is mostly due to reduction in sea grasses (to which bay scallop spat attach) due to increased coastal development and concomitant nutrient runoff. Another possible factor is reduction of sharks from overfishing. A variety of sharks used to feed on rays, which are a main predator of bay scallops. With the shark population reduced, in some places almost eliminated, the rays have been free to dine on scallops to the point of greatly decreasing their numbers. By contrast, the Atlantic sea scallop (Placopecten magellanicus) is at historically high levels of abundance after recovery from overfishing.

As food

Scallops are a popular type of shellfish in both Eastern and Western cooking. They are characterized by having two types of meat in one shell: the adductor muscle, called "scallop" which is white and meaty, and the roe, called "coral", which is red or white and soft.

In Western cuisine, scallops are commonly sautéed in butter, or else breaded and deep fried. Scallops are commonly paired with light semi-dry white wines. In the U.S., when a scallop is prepared, usually only the adductor muscle is used; the other parts of the scallop surrounding the muscle are ordinarily discarded. Sometimes markets sell scallops already prepared in the shell with only the adductor muscle intact. Outside the U.S. the scallop is often sold whole.

Scallops that are without any additives are called "dry packed" while scallops that are treated with sodium tripolyphosphate (STP) are called "wet packed". STP causes the scallops to absorb moisture prior to the freezing process, thereby getting a better price per unit of weight. The freezing process takes about two days.

• Scallops on display in a seafood market
  Scallops on display in a seafood market
• 
  Large scallops with a shrimp, human hands and a Memory Stick as size comparison
• 
  Dried scallops (also known as conpoy)
• Scallop prepared at a restaurant
  Scallop prepared at a restaurant
• 
  A scallop being grilled next to sausages at a yatai in Japan
• 
  Fish soup with roasted scallop

In European cuisine, scallops are often prepared in the form of a quiche or cooked and then set into a savoury custard. In Japanese cuisine, scallops may be served in soup or prepared as sashimi or sushi. Dried scallop is known in Cantonese Chinese cuisine as conpoy (乾瑤柱, 乾貝, 干貝).

In a sushi bar, hotategai (帆立貝, 海扇) is the traditional scallop on rice, and while kaibashira (貝柱) may be called scallops, it is actually the adductor muscle of any kind of shellfish, e.g. mussels, oysters, or clams.

Scallops have lent their name to the culinary term scalloped, which originally referred to seafood creamed and served hot in the shell (Rombauer 1964). Today it means a creamed casserole dish such as scalloped potatoes, which contains no seafood at all.

Symbolism

Portrait by Carlo Crivelli, c. 1480

Shell of Saint James

The scallop shell is the traditional emblem of James, son of Zebedee and is popular with pilgrims on the Way of St James to the apostle's shrine at Santiago de Compostela in Spain. Medieval Christians making the pilgrimage to his shrine often wore a scallop shell symbol on their hat or clothes. The pilgrim also carried a scallop shell with him, and would present himself at churches, castles, abbeys etc., where he could expect to be given as much sustenance as he could pick up with one scoop. Probably he would be given oats, barley, and perhaps beer or wine. Thus even the poorest household could give charity without being overburdened. 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 alternate version of the legend holds that while St. James' remains were being transported to Spain from Jerusalem, the horse of a knight fell into the water, and emerged covered in the shells.

• The German word for scallop is Jakobsmuschel.
• The Swedish word for scallop literally translates to pilgrim mussel.
• In France the scallop is called a coquille St. Jacques, literally a St James shellfish (in Canadian French, pétoncle is more commonly used).
• The Dutch name is Jakobsschelp (James being English for Jacobus) or kammossel.
• In Danish, ibskal (literally: "Ib's shell") refers to scallops worn by pilgrims from Santiago de Compostella (Ib being the Danish name for St. James), although when used in cooking it is referred to as kammusling.
• In Italian, scallops may be known as pettine di mare (literally, "sea combs") or as the capasanta or cappasanta (pl. capesante or cappesante). It is generally the large Pecten jacobaeus scallop, however, that goes by these latter names (also called the conchiglia di San Giacomo or St. Jacob's/St. James' Shell).
• The word for scallop for both Portuguese and Spanish, from Galician, is vieira.
• The Polish word for scallop is przegrzebek (literally: "rummager").

Fertility symbol

Aphrodite in a sea shell, from Amisos, now in the Louvre

One legend of the Way of St. James holds that the route was seen as a sort of fertility pilgrimage, undertaken when a young couple desired to bear offspring. The scallop shell is believed to have originally been carried therefore by pagans as a symbol of fertility.

Many paintings of Venus, 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 The Birth of Venus (which has even been nicknamed "Venus on the half-shell").

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) on the "Coast of Death" (Costa de Morta) and the "Sea of Darkness" (ie, the Abyss of Death, the Mare Tenebrosum, Latin for the Atlantic Ocean, itself named after the Dying Civilization of Atlantis). The reference to St. James rescuing a "knight covered in scallops" is therefore a reference to St. James healing, or resurrecting, a dying (setting sun) knight. Similarly, the notion of the "Sea of Darkness" (Atlantic Ocean) disgorging St. James' body, so that his relics are (allegedly) buried at Santiago de Compostella on the coast, is itself a metaphor for "rising up out of Death", that is, resurrection.

Heraldry

A scallop shell as a heraldic device on 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's family coat of arms includes a scallop; another example is the 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, or for other reasons.

State shell of New York

The U.S. state of New York made the Atlantic bay scallop its state shell in 1988.

In design

In design, scalloped edges or ridges refers to a wavy pattern reminiscent of the edge of a scallop's shell.

References

• Barucca M, Olmo E, Schiaparelli S, Canapa A (2004) Molecular phylogeny of the family Pectinidae (Mollusca: Bivalvia)
• Rombauer, Irma S. and Marion Rombauer Becker (1931 [1964]) The Joy of Cooking, p 369. Indianapolis: Bobbs-Merrill. ISBN 0-452-25665-8.

External links

• Scallop Shells Information
• Alaska Department of Fish and Game - scallop page
• NOAA Fisheries: Northeast Fisheries Science Center - Research on Bay Scallop Aquaculture and Enhancement
• Delaware Sea Grant, University of Delaware - scallop page
• Classification of Pectinoidea (Propeamussiidae and Pectinidae) - includes partly different genera, with subfamilies and tribes.
• "Too Few Jaws: Shark declines let rays overgraze scallops", Science News, March 31, 2007