Scallop Pearls or Lion's Paw Pearls, are extremely rare non-nacreous pearls, produced by a bivalve mollusk, commonly known as the Scallop, Lion's Paw or in Spanish "Mano de Leon" (hand of the lion), belonging to the class Pelecypoda and family Pectinidae.
The family name Pectinidae has been derived from the ancient Latin name, Pecten, meaning "comb," given for scallops by Pliny the Elder, the Roman author, naturalist and philosopher, because of their round and ridged outline with radiating ribs that resembled a type of comb used during the Roman empire. The name "scallop" is derived from the Old French "escalope," which means shell. Two of the pearl producing Scallop species are mainly found on the Pacific coast off Baja California or in the Atlantic coast off northeast America, from Newfoundland to North Carolina, and these pearls are sometimes referred to by their ocean of origin, as Pacific scallop pearls and Atlantic scallop pearls respectively.
The world's most prolific pearl producers, the oysters and mussels that produce saltwater pearls and freshwater pearls respectively, also belong to the bivalve mollusks (class : Bivalvia), and these pearls are known as nacreous pearls, as the biogenic material of which they are composed, is known as "nacre," consisting of layers of microscopic platelets of aragonite and/or calcite (calcium carbonate), bound together by a fine network of a complex scleroprotein, called conchiolin, which imparts spectacular optical effects on the pearls, such as luster, orient or iridescence and overtone colors.
Saltwater clams and scallops, that also belong to the Bivalvia, rarely produce pearls, but these pearls are non-nacreous, as the pearl forming substance is mainly composed of calcite that do not form microscopic platelets, but long microcrystalline needles, that do not scatter light, and hence do not impart the characteristic luster, orient and overtones of nacreous pearls. Among the saltwater clams that produce non-nacreous pearls are the Quahog clam, Mercenaria mercenaria, found along the Atlantic coastline of north America, that produces the rare Quahog pearl, and the giant clam, Tridacna gigas, found on the coral reefs, off the coast of the Island of Palawan, in the Philippines, and on the Great Barrier Reef, off the coast of Queensland in northeast Australia, that produces extremely rare and sometimes massive calcareous concretions, such as the "Pearl of Allah" and the "Palawan Princess," reputed to be among the world's largest pearls. Among the Scallops, there are four species that are known to produce pearls. These species are the Atlantic Lion's Paw (Nodipecten nodosus), the Pacific Lion's Paw (Nodipecten subnodosus), the Atlantic Sea Scallop (Placopecten magellanicus), and the Atlantic bay scallop (Argopecten irradians).
In the Gastropod mollusks (class : Gastropoda), pearls produced by sea-snails, such as Melo melo sea-snail (bailer volute) that produces the extremely rare melo-melo pearl, Strombus gigas sea snail (queen conch) that produces the rare conch pearls, and Pleuroploca gigantea (horse conch) that also produces rare horse-conch pearls, are all non-nacreous pearls. Usually pearls produced by sea-snails are non-nacreous, but here too there can be exceptions, such as the Abalone sea-snail that produces nacreous pearls, whose color, brilliance and luster is unsurpassed by all other natural pearls.
Thus from the above information we can arrive at the following general conclusions :-
1) That nacreous pearls are generally produced by bivalve mollusks, such as the seawater oysters and freshwater mussels, except abalone pearls that are produced by the univalve mollusk (gastropod mollusk), the abalone sea-snail.
2) That non-nacreous pearls are generally produced by univalve mollusks (gastropod mollusks), such as melo-melo pearls, and conch pearls, except quahog pearls, giant clam pearls and scallop pearls that are produced by bivalve mollusks.
3) The occurrence of all natural pearls are generally rare, but the occurrence of nacreous pearls is relatively greater than the occurrence of non-nacreous pearls. The occurrence of most non-nacreous pearls is extremely rare, such as the melo-melo pearl, the quahog pearls and the scallop pearls.
4) Nacreous pearls both saltwater and freshwater have been successfully cultured, beginning with the Akoya pearl cultured by Mikimoto in Japan 1916. Non-nacreous pearls have not been successfully cultured up to now. Thus most of the non-nacreous pearls that appear in the pearl markets from time to time are all, without any doubt, natural pearls. However, recently a successful breakthrough has been achieved in the culturing of conch pearls from the Atlantic and Caribbean queen conch sea-snail, by research scientists at the Florida Atlantic University's Harbor Branch Oceanographic Institute. The research scientists Dr. HÃ©ctor Acosta-SalmÃ³n and Dr. Megan Davis who are the co-inventors of the novel and proprietary seeding techniques to produce beaded and non-beaded cultured pearls from the queen conch, have successfully produced more than 200 high-quality cultured conch pearls applying this technique. The pearls have been handed over to the GIA for extensive testing at its state-of-the-art laboratories, and initial tests have revealed that several of the pearls tested were indeed top-quality gems.
Non-nacreous pearls are generally much rarer than nacreous pearls. the following is an attempt to quantify their rarity based on available information.
For conch pearls, produced by the Atlantic and Caribbean queen-conch, Strombus gigas, the frequency of occurrence is about 1 in 10,000 sea-snails, out of which only about 1 in 100 is gem-quality. Thus gem quality conch pearls are indeed very rare, with a probability of occurrence of 1/10,000 x 1/100 = 1/1,000,000 i.e. 1 in 1 million.
For Quahog pearls, produced by the Quahog clams, the frequency of occurrence of a purple pearl was given as 1 in 100,000, out of which only 1 in 20 was said to be of gem-quality. This gives a probability of occurrence of 1/100,000 x 1/20 = 1/2,000,000 i.e. 1 in 2 million. This is an extremely rare occurrence, and purple quahog pearls are considered to be the rarest of all natural pearls.
Melo-melo pearls like Quahog pearls are also one of the rarest natural pearls in the world, but unfortunately statistics of their occurrence are not available. Hence the computation of their probability of occurrence is difficult. However, the experience of sea-snail fisherman, divers, people involved in the cleaning and processing of its meat for consumption, has shown that during their lifetime they had seen just one or two pearls, or sometimes never seen any pearls at all. Melo-melo pearls were so so rare, that they were not known at all in the west, until as recently as the 1990s. Even the "Book of the Pearl" by George F. Kunz, the most comprehensive compendium on pearls of the world, published in 1908, had no reference to the rare melo-melo pearls of Southeast Asia.
Giant clam pearls became internationally renowned after the discovery of the 6.1 kg "Pearl of Allah" the largest pearl ever discovered from a mollusk, and the largest non-nacreous pearl ever discovered, in 1934, from the coral reefs off the Island of Palawan, in the Philippines. Since then the discovery of not more than 10 such massive calcareous concretions from the giant clam, Tridacna gigas has been reported, during a period of 76 years. This gives a clear indication of their extreme rarity. Such massive non-nacreous pearls, usually referred to as calcareous concretions, have a great collector's value due to their extreme rarity. The most recent of such finds was the 2.27 kg "Palawan Princess" the second largest non-nacreous pearl, ever discovered, that came up for sale, at a Bonham's auction, held on December 6, 2009.
Wild scallops are mainly harvested by scallop fisherman for their meat, and any pearls collected are by products of this scallop fishing industry. The wild scallops harvested are cleaned on board the fishing vessels, and the viscera and shells thrown overboard. The shucking of scallops is done manually, and the process is very fast, that any pearls on the shell or within the mantle, may not be seen before the shells and viscera are thrown overboard. It is only the adductor muscle of the scallop that is used as meat, and the other parts of the mollusk are discarded. It has been estimated that only around 1 in 10,000 scallops produce pearls. Out of this around 1 in 5 pearls are gem-quality. Thus the probability of occurrence of gem-quality scallop pearls is 1/10,000 x 1/5 = 1/50,000 i.e. 1 in 50,000. This is quite high when compared to the occurrence of conch pearls and quahog pearls, which is 1 in 1 million and 1 in 2 million respectively. Thus, contrary to the common belief, gem-quality scallop pearls are not so scarce as queen conch pearls and quahog pearls. This is due to the occurrence of a higher percentage of gem-quality pearls in a given quantity of pearls harvested.
According to Craig Fancy of Fancy Jewelers, based in Annapolis Royal, Nova Scotia, Canada, who had been designing and manufacturing jewelry using scallop pearls, since around 1989, a 35-mm film canister holds about 200 pieces of scallop pearls of about 3-5 mm in diameter. Of these, he says there may be about 10 pearls, that have a near-perfect symmetry, such as spherical and near-spherical, and having the best color. i.e. about 1 in 20 belong to this category. Of the remaining he says, there will be about 30 pearls that have good color and some symmetry, such as buttons, drops and ovals. which can be ground or polished to make setting easier. The rest are too small, misshapen, or an undesirable brown color. Thus, out of the 200 scallop pearls, 40 pearls are of gem-quality, suitable for setting in jewelry. The frequency of occurrence of gem-quality scallop pearls in harvested scallop pearls, is therefore 40 in 200, which works out to 1 in 5. This is the frequency that has been used in the above calculation. Due to the low frequency of occurrence of scallop pearls in the wild, around 1 in 10,000, it is said that a typical scallop fisherman might discover only a handful of these rare beauties throughout his entire career.
Characteristics of scallop pearls depend on the species of scallop from which the pearls were harvested, which necessarily means the source or the geographic range where the species is found predominantly. Thus, we have two main types of scallop pearls :- the Pacific scallop pearls and the Atlantic scallop pearls.
Pacific scallop pearls originate from the scallop species found in the Pacific, known as Nodipecten subnodosus (Pacific Lion's Paw), mainly in the coastal waters off Central America, such as the waters off the coast of Baja California. It is also found in the inland Sea of Cortez in Mexico.
These scallop pearls vary in size, from the size of seed pearls to a maximum of around 40 carats. In terms of dimensions, this may mean from less than 2 mm to over 10 mm in size. Rarely pearls are multiple, with several pearls combined together.
The finding of Craig Fancy for Atlantic scallop pearls, that out of around 200 pearls, 40 are gem-quality, with the desired shape, symmetry and color, also holds good for Pacific scallop pearls. Thus only one out of five harvested scallop pearls have some form of symmetry in their shape. The rest are either too small, or irregular, baroque pearls or have an undesirable brown color. One out of five or 20% of harvested scallop pearls having desirable shapes, is quite high, which led to some accounts of scallop pearls characterizing them as natural pearls that are mostly symmetrical in shape, which is strictly speaking not true. The symmetrical shapes that one comes across in these pearls are round, near-round, button, drops and ovals.
Pacific scallop pearls have a wide range of colors, that vary from the lighter tones, such as white, cream, yellow, pink and mauve (pale purple) to the darker tones such as orange, brown, deep-purple, plum (reddish-purple), maroon (dark brownish-red) and brownish-purple. Most scallop pearls have a mosaic or mottling of light and dark colors, which is believed to be an optical phenomenon. The lighter color is invariably white, cream or yellow and the darker colors, brown, brownish-purple, plum and maroon. Scallop pearls with a single color are very rare.
Being non-nacreous, scallop pearls lack the brilliance (luster) and orient of nacreous pearls. But, as if to compensate for this the calcite microcrystalline bundles of fibers, arranged parallely as seen in SEM images, impart a unique 3-dimensional effect or sheen on the pearl, when viewed in light, also known as a flash effect, similar to the flame structure of conch and melo-melo pearls. According to the CIBJO's description of scallop pearls, the surface appearance of scallop pearls is comprised of a patchwork of cells, with each cell being formed from three sub-cells. The orientation of these sub-cells and the low magnification fibrous appearance of structures within them, give the scallop pearl a peculiar surface sheen.
Atlantic scallop pearls can originate from three different species of scallops found in the northeastern North American region, the natural geographic range of these scallops. These species are the North Atlantic deep-sea scallop, Placopecten magellanicus; the Atlantic bay scallop, Argopecten irradians, and the Atlantic Lion's Paw, Nodipecten nodosus. The scallops occur along the continental shelf of North America from Newfoundland and Labrador to Cape Hatteras in North Carolina. North of Cape Cod in the State of Massachusetts, scattered concentrations of scallops occur in shallow water, just below the low tide mark. Further south concentrations are restricted to deeper and cooler off shore waters. This is because Sea Scallops cannot tolerate water temperatures above 20 to 22Â°C. Dense and extensive scallop beds that can support commercial fishing exist from Port au Bay, Newfoundland to the Virginia Capes, at depths of between 40 to 100 meters. The species found at these depths is Placopecten magellanicus, the North Atlantic deep-sea scallop. Digby in Nova Scotia, "the Scallop Capital of the World" is the center of a commercially important deep sea scallop fishery as well as inshore fishery, harvesting the smaller bay scallop (Argopecten irradians) in the Bay of Fundy off Digby.
The Atlantic scallop pearls are a by product of a thriving scallop fishery taking place at several places along the geographic range of the deep sea scallop, including the important fishery out of Digby, Nova Scotia. Pearls produced by the deep-sea scallop Placopecten magellanicus are usually irregular (baroque) and small, with a size of around 1-2 mm (seed pearls). However, older animals produce larger pearls, with an average size of 3-5 mm and sometimes can reach a size of 5-6 mm. Pearls lager than this are very rare, but Craig Fancy had owned some exceptional specimens, such as two button-shaped scallop pearls with dimensions of 10 x 9 mm and 12.2 x 8.5 mm; a large baroque pearl, with dimensions of 20 x 9 x 8 mm; and four large round pearls with dimensions of 8-11 mm.
Most of the Atlantic scallop pearls are small and baroque in shape, less than 2 mm in size and falling under seed pearls. Craig Fancy, the pioneer jeweler from Nova Scotia, who first began setting Atlantic scallop pearls on pieces of jewelry, in the 1990s, estimated that out of around 200 scallop pearls only around 40 were of gem-quality, with the desired symmetrical shape, and color. This works out to 1 in 5 or 20% of harvested pearls. The symmetrical shapes that were found were round, near-round, button, drop and oval.
Gem-quality Atlantic scallop pearls were white, off-white, or pale-tan in color. Non gem-quality scallop pearls were small, misshapen (baroque) and have an undesirable brown color.
The pearls are non-nacreous and do not have the luster and orient of nacreous pearls. However, the pearls have a silvery sheen, that complement the white and pale-tan colors of the pearls, an optical effect caused by the parallel calcite fibers on the surface, a 3-D effect, also known as a flash effect. This is similar to the chatoyancy caused in gemstones such as beryls, sapphires, quartz etc that produces a catseye effect or star effect, an optical effect caused by rutile fibers.
The existence of scallop pearls had been known by scallop fisherman of the Atlantic coast of northeast America for a long time, who had found them casually while shucking harvested scallops for their meat, on board their fishing vessels. However, as pointed out earlier the shucking process is so quick, lasting just a few seconds, in order to preserve the volume and quality of the meat, that any pearls on the shell or within the mantle cavity, may not be discovered, before the shells and viscera are thrown overboard. Perhaps, one reason for the lack of concern, for the possible existence of a pearl inside a scallop, was because the scallop pearl was largely unknown to the outside world, and had no market value at all.
This was in complete contrast to conch pearls, also a by product of the queen conch fishery in the Caribbean, that became very popular in the late-Victorian and Edwardian periods, but whose popularity died down soon after the end of world war I, when the successful culturing of Akoya pearls by the Japanese, flooded the pearl markets of the world, with a range of cultured pearls, in a variety of colors, shapes and sizes, and at affordable prices. The success of the Japanese, dealt a death blow, to the natural pearl fishing industry across the world. Unlike conch pearls, scallop pearls had never been known to the world before, and when the scallop fishing industry developed, even though their existence came to light, it did not create any impact as the natural pearl industry was virtually dead, in a world dominated by Mikimoto's cultured pearls. The cultured pearl industry had dominated the pearl markets for over eight decades. However, beginning in the 1990s, there had been a resurgence in the demand for natural pearls in the Middle East , Europe and America, which was clearly reflected in enhanced prices realized for pieces of jewelry incorporating old natural Oriental, Venezuelan, and black Tahitian pearls, at auctions conducted by renowned auction houses, such as Christie's and Sotheby's. See table below. The increase in demand for old natural pearls was followed by an increase in demand for other contemporary natural pearls, such as conch pearls, abalone pearls, freshwater natural pearls from America, quahog pearls, melo-melo pearls and finally the scallop pearls.
Table of some famous natural pearls/pearl jewelry sold at public auctions conducted by international auction houses, giving the date of auction and the prices realized, during the period 1970 to 2009. The table shows a resurgence in demand after around 1986.
|S/N||Name of pearl/pearl jewelry||Probable period of origin||
|date of auction||Price realized|
|1||La Peregrina||1513||203.84 grains||1969||USD 37,000|
|2||Mancini pearls||1500-1600||400 grains||Oct.1979||USD 253,000|
|3||Mona Bismarck 2-strand pearl necklace||1920-1930||Double-strand of 70 pearls||May 1986||USD 410,000|
|4||Duchess of Windsor pearl necklace||1910-1936||Single-strand of 28 natural pearls. Total weight 1266.33 grains||April 1987
|5||Empress Eugenie tiara||1853||212 pearls, 2,520 grains||Nov 1992||USD 650,000|
|6||Nina Dyer black pearl necklace||1950s||151 natural black pearls||Nov 1997||USD 913,320|
|7||Barbara Hutton pearls||1600-1666||44 natural pearls, total weight of 1,816.68 grains||May 1992
|8||Unidentified natural pearl necklace by Cartier||Historical provenance not revealed||Double-strand necklace with 88 natural pearls||Nov 2004||USD 3,100,000|
|9||La Regente||1811||302.68 grains||Nov 2005||USD 2,483,968|
|10||Gulf pearl parure designed by Harry Winston||1932-1978||Nov 2006||USD 4,100,000|
|11||Baroda pearl necklace||1856-1870||Double-strand with 68 natural pearls from the original 7-strand necklace||April 2007||USD 7,096,000|
|12||Umm Kulthum pearl necklace||1880||nine-stranded necklace with 1,888 pearls||April 2008||USD 1,390,000|
|13||Pearl necklace from an unidentified notable collection||Historical provenance not revealed||Single-strand necklace with 41 natural pearls||Nov 2008||USD 1,321,110|
|14||Unidentified pearl and diamond festoon necklace||Historical provenance not revealed||Nine-strand pearl and diamond festoon necklace. Length 645mm to 1060mm||Nov 2008||USD 946,610|
|15||Pearl Carpet of Baroda||1860||1.5-2.0 million natural seed pearls||March 2009||USD 5,500,000|
In fact it was only after the Tucson show of year 2000, that Pacific scallop pearls received international attention, after their exhibition and sale at the show, by Wes Rankin, the natural pearl dealer, of Pacific Coast Pearls, Petaluma, California. The scallop pearls that were offered at the Tuscon show, were the Pacific scallop pearls, that occurred in a wide range of colors, with their characteristic mosaic or mottling of light and dark colors. Since then Wes Rankin had sold an average of 100 Pacific scallop pearls every year, which he purchased from divers. Presently, the demand for Pacific scallop pearls has exceeded all expectations, and the annual supply of these pearls is hardly enough to meet the rapidly increasing demand. The present price range for these pearls is between $100 to $2,000 per carat depending on the quality of the pearl. One of the most beautiful scallop pearls, which Wes Rankin had ever seen, an 18-carat oval pearl, with a nutmeg-orange color, was sold by him to an Asian collector, at a price of $36,000 in the year 2004, a record price for a scallop pearl, that gives a price per carat value of $2,000.
The recent upsurge in the popularity of Atlantic scallop pearls, is also attributed to one single jeweler, Craig Fancy of Fancy Jewelers, based in Annapolis Royal, Nova Scotia, Canada, who had been turning out pieces of jewelry using Atlantic scallop pearls, since around 1989. During that year a scallop fisherman brought some scallop pearls, asking him to set them in a pendant for his wife, which he did. During the next 6 to 8 years more requests came in, and he set scallop pearls of different sizes and shapes in custom-made designs, to suit the taste of his customers. He then began designing pieces of jewelry, that were not only attractive but affordable, in the local as well as the tourist markets. He developed several designs for pendants, earrings and rings in 14K gold, that suit the delicate nature of the pearls very well. These pieces of jewelry are sold at his family jewelry stores in Annapolis Royal and Digby. The supply of Atlantic scallop pearls is still small and unreliable, and the chances of the Digby scallop pearls turning into a major new industry in Canada are still remote.
Kingdom : Animalia
Phylum : Mollusca
Class : Bivalvia
Order ; Ostreoida
Family : Pectenidae
Genus : Placopecten
species : magellanicus
Common name : Atlantic sea scallop
The largest wild scallop fishery in the world is based on the scallop species Atlantic sea scallop, Placopecten magellanicus, found off northeastern United States and eastern Canada. The U.S. fishery, the largest wild scallop fishery in the world, based on the Atlantic sea scallop had an output of 53.5 million pounds of sea scallop meat in 2008, worth $370 million. The industry was mainly centered around Massachusetts and New Jersey. Japan has a scallop fishery based on both wild and cultured scallops, and China, a fishery based only on cultured Atlantic bay scallop, Argopecten irradians. In Europe, Russia was the main leader in the industry. The entire worldwide scallop fishery is worth billions of dollars. The scallop fishery seem to be based around scallop species adapted to cooler temperate waters. However, scallops are a cosmopolitan family, with around 350 species, found around the world, in all of the world's oceans.
1) As a source of food :- Scallop meat is valued as a food in many Western as well as Eastern countries (China and Japan). In some countries such as the United States and Canada, only the well developed adductor muscle is used as meat, while in other countries apart from the adductor muscle, other parts of the scallop are also used. Scallop fishery is an industry found in many countries across the world with an annual value running into billions of dollars. Fortunately, the industry has been well managed in many countries, with a minimum of impact on wild populations.
2) As a source of non-nacreous pearls :- An important by product of the worldwide scallop fishery is the extremely rare scallop pearl, a non-nacreous pearl, with a unique 3-dimensional effect that produces a metallic sheen. Since the resurgence in demand for natural pearls, beginning from the 1990s, scallop pearls have come to the forefront as the latest natural pearl, commanding premium prices.
3) Scallop shells valued as a collector's item :- The decorative, brightly- colored fan-shaped shells of some scallops are highly valued by shell collectors.
4) Decorative and ornamental value :- Brightly-colored scallop shells has a decorative and ornamental value, used in household decoration or turned into pieces of jewelry.
5) As a decorative motif :- The regular and pleasing geometric shape of the scallop shell, has inspired artists as a decorative motif, and has been used as a motif on the edge of draperies, clothing and also in jewelry.
5) Symbolic value - Brightly-colored and decorative scallop shells, had a symbolic value since very ancient times. Greek temples and Roman vases, were adorned with scallop shell motifs. The Triton Fountain in Rome of mediaeval origin, made of marble and designed by Bernini in 1642, depicts Triton, the son of sea god Poseidon, perched on a large, open, scallop shell, supported by two dolphins.
In the middle ages Scallop shells were worn as a badge by pilgrims to the shrine of St. James the Apostle in Campostello, Spain. The Apostle St. James association with the scallop can be traced to the legend that he once rescued a knight covered in scallops, or that when 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 French name for a dish containing scallops, "Coquille St. Jacques" meaning "shell of St. James," appears to be associated with this legend.
The scallop was considered a symbol of fertility by ancient Romans, who associated it with Venus, the Roman goddess of love and fertility. Paintings of the goddess was always associated with a scallop shell.
The scallop shell symbol entered the coat-of-arms of many families, as a badge of those who had been on pilgrimage to Compostela, and later a symbol of pilgrimage in general. Sir Winston Churchill's family coat-of-arms included a scallop.
The Atlantic bay scallop was adopted as New York State's official "State Shell" in 1988.
The scallop shell is also the inspiration for not only the symbol, but also the name, of one of the most successful energy and petrochemical companies in the world, based in Netherlands, The Royal Dutch Shell Plc. which has become an international household word.
Scallop "eyes" along the edges of the mantle
Scallops like true oysters are marine bivalve mollusks, with a soft body, protected by two hard shells or valves. The shape of the shells are highly regular and ridged, the lower valve usually larger than the upper, with flared ears at the hinge. Ridges radiate out from the hinge along each valve in the shape of a fan. The edges of the shells are sharp and undulating, because of the ridges. The valves are opened and closed by a single large adductor muscle, which is more developed than that of oysters, because scallops are active swimmers. In fact scallops are the only migratory bivalves that can move from one place to another. Along the edges of the mantle are several eyes, with a lens and retina, that are more complex compared to other bivalves, yet primitive, as they cannot see shapes, but can detect light and motion.
Atlantic Bay Scallop
Â© New York State Department of Environmental Conservation
Atlantic Scallop Pearl- Placopecten magellanicus
Placopecten magellanicus, the Atlantic sea scallop has a broad shell, which is almost circular and flattened at the hinge, and attaining a height of 15-20 cm. The shells are without ribs, having only radial striae. The right valve is smoother than the left. The ears are unequal and the valves have a slight convexity. The color of the shell is yellowish-grey to purplish-grey, or dirty-white. The inner surface of the shell is flaky-white.
Scallops like other bivalve mollusks are filter feeders, feeding on suspended food particles in the water, such as phytoplankton and other organic detritus, that are brought in by the incurrent siphon, filtered and trapped in mucus as the water passes over the gills. The action of the cilia on the gills, direct the food particles towards the mouth, which are then ingested.
Most scallops are free living, but some species attach themselves to the substrate after becoming adults, by byssal threads. Some species can burrow into the substrate by extending their foot. Free living young scallops are mobile, using jet propulsion to move, by opening and closing their shells quickly, and squirting water out by the ears of the shells in spurts. However, as the animals grow older and larger, they gradually lose this ability. The movement of scallops help them to escape from predators such as certain species of cod, wolffish, eel pout, flounder, crabs and lobsters.
Among the scallops some species are dioecious, male and female sexes being separate, while others are monoecious, both sexes being found in the same individual. Monoeciuos scallops, can be simultaneous hermaphrodites where male and female sex organs mature at the same time, or protoandrous hermaphrodites, being males when young and becoming females when old. Scallops attain reproductive maturity at the age of 2 years, but take part in active reproduction only around 4 years of age. When sex organs are mature, millions of spermatozoa and ova are released freely into the surrounding water where fertilization takes place. Fertilized ova sink to the bottom of the bed, where after several weeks they hatch to form larvae, which drift about in the water, and later settle at the bottom, attaching by byssal threads. Some scallops are short lived eg. Atlantic bay scallop, while others can live up to 20 years or more. Annuli on the shells can be used to estimate the age of scallops. They grow rapidly during the first half of their life span. It has been estimated that between the ages of 3 and 5 years, sea scallops grow up to 50 to 80% of their shell height (10-16 cm) and increase their meat weight four times. They can reach a maximum height of around 20 cm, but instances have been reported where the height of the shell reached 22-23 cm.
Specially rigged boats called "draggers" are used in harvesting scallops at depths of 40 to 100 meters. Drags equipped with large wire-mesh bags, are towed along the bottom of the ocean by these draggers. The drags are lifted on to the boats and the wire-mesh bags emptied. Empty shells and other debris are often found together with the scallops. Opening of scallops are done manually using a shucking knife, as successful mechanical shucking methods have not been developed up to now. The method is tedious, as every scallop has to be opened individually. The shucking knife is run around between the shells, cutting through the adductor muscle and flipping off the upper shell. The viscera is then lifted and pulled away, by running the knife under its edge, leaving the adductor muscle still attached to the lower shell. The adductor muscle known as the "meat" is then cut off and separated from the lower shell and placed in pails for processing. The scallop meat is treated with sodium tripolyphosphate (STP), before packing and freezing, a process known as wet-packing. STP causes scallop meat to absorb moisture before freezing, giving the fisherman a better price per unit of weight. When scallops are packed and frozen without adding any additives, the process is known as "dry packing."
You are welcome to discuss this post/related topics with Dr Shihaan and other experts from around the world in our FORUMS (forums.internetstones.com)
1) Scallop Pearls From Digby, Nova Scotia - Willow Wight. www.scalloppearl.ca
2) Gem Profile 23 : Scallop Pearl. www.airesjewelers.com
3) Scallop Pearls - www.pearl-guide.com
4) Scallop Pearls - www.allnaturalpearls.com
5) Scallop - From Wikipedia, the free encyclopedia
6) Atlantic Sea Scallop - FishWatch - U.S. Seafood Facts. National Marine Fisheries Service. www.nmfs.noaa.gov
Dr Shihaan Larif
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