Strombus Gigas
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''Aliger gigas,'' originally known as ''Strombus gigas'' or more recently as ''Lobatus gigas'', commonly known as the queen conch, is a
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of large
sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...
, a marine
gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
mollusc 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
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 ...
of true conches, the
Strombidae Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails in the superfamily Stromboidea, and the Epifamily Neostromboidae. The term true conchs, being a common name, does not have an exact me ...
. This species is one of the largest molluscs native to the Caribbean Sea, and
tropical northwestern Atlantic The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
, from
Bermuda ) , anthem = "God Save the King" , song_type = National song , song = " Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , e ...
to
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
, reaching up to in shell length. ''A. gigas'' is closely related to the goliath conch, '' Lobatus goliath'', a species
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to Brazil, as well as the rooster conch, '' Aliger gallus''. The queen conch is
herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
. It feeds by browsing for plant and algal material growing in the
seagrass 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 ...
beds, and scavenging for decaying plant matter. These large sea snails typically reside in seagrass beds, which are sandy plains covered in swaying sea grass and associated with coral reefs, although the exact habitat of this species varies according to developmental age. The adult animal has a very large, solid and heavy
shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...
, with knob-like spines on the shoulder, a flared, thick outer lip, and a characteristic pink or orange
aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...
(opening). The outside of the queen conch is sandy colored, helping them blend in with their surroundings. The flared lip is absent in juveniles; it develops once the snail reaches reproductive age. The thicker the shell's flared lip is, the older the conch is. The external
anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...
of the soft parts of ''A. gigas'' is similar to that of other snails in the family Strombidae; it has a long snout, two
eyestalk In anatomy, an eyestalk (sometimes spelled eye stalk and also known as an ommatophore) is a protrusion that extends an eye away from the body, giving the eye a better field of view. It is a common feature in nature and frequently appears in fic ...
s with well-developed eyes, additional sensory
tentacles In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...
, a strong foot and a
corneous Corneous is a biological and medical term meaning horny, in other words made out of a substance similar to that of horns and hooves in some mammals. The word is generally used to describe natural or pathological anatomical structures made out ...
,
sickle A sickle, bagging hook, reaping-hook or grasshook is a single-handed agricultural tool designed with variously curved blades and typically used for harvesting, or reaping, grain crops or cutting succulent forage chiefly for feeding livestock, ei ...
-shaped operculum. The shell and soft parts of living ''A. gigas'' serve as a home to several different kinds of
commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...
animals, including slipper snails,
porcelain crab Porcelain crabs are decapod crustaceans in the widespread family Porcellanidae, which superficially resemble true crabs. They have flattened bodies as an adaptation for living in rock crevices. They are delicate, readily losing limbs when attack ...
s and a specialized species of
cardinalfish Cardinalfishes are a family, Apogonidae, of ray-finned fishes found in the Atlantic, Indian, and Pacific Oceans; they are chiefly marine, but some species are found in brackish water and a few (notably '' Glossamia'') are found in fresh water. A ...
known as the conchfish '' Astrapogon stellatus''. Its
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s include
coccidia Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an a ...
ns. The queen conch's natural predators include several species of large
predatory Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
sea snails,
octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttle ...
,
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 ...
,
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s and
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s (
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
,
sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhead, ...
s,
nurse shark The nurse shark (''Ginglymostoma cirratum'') is an elasmobranch fish in the family Ginglymostomatidae. The conservation status of the nurse shark is globally assessed as Vulnerable in the IUCN List of Threatened Species. They are considered t ...
s). It is an especially important food source for large predators like sea turtles and nurse sharks. Human capture and consumption dates back into prehistory. Its shell is sold as a
souvenir A souvenir (), memento, keepsake, or token of remembrance is an object a person acquires for the memories the owner associates with it. A souvenir can be any object that can be collected or purchased and transported home by the traveler as a m ...
and used as a decorative object. Historically, Native Americans and indigenous Caribbean peoples used parts of the shell to create various tools. International trade in the Caribbean queen conch is regulated under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (
CITES CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
) agreement, in which it is listed as ''Strombus gigas''. This species is not endangered in the Caribbean as a whole, but is commercially threatened in numerous areas, largely due to extreme
overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...
.


Taxonomy and etymology


History

The queen conch was originally described from a shell in 1758 by Swedish naturalist and
taxonomist In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given ...
Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...
, who originated the system of
binomial nomenclature In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
. Linnaeus named the species ''Strombus gigas'', which remained the accepted name for over 200 years. Linnaeus did not mention a specific locality for this species, giving only "America" as the type locality. The specific name is the
ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
word ' (), which means "giant", referring to the large size of this snail compared with almost all other gastropod molluscs. ''Strombus lucifer'', which was considered to be a synonym much later, was also described by Linnaeus in ''Systema Naturae''. In the first half of the 20th century, the
type material In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes t ...
for the species was thought to have been lost; in other words, the shell on which Linnaeus based his original description and which would very likely have been in his own collection, was apparently missing, which created a problem for taxonomists. To remedy this, in 1941 a
neotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...
of this species was designated by the American
malacologist Malacology is the branch of invertebrate zoology that deals with the study of the Mollusca (mollusks or molluscs), the second-largest phylum of animals in terms of described species after the arthropods. Mollusks include snails and slugs, clams, ...
s
William J. Clench William James Clench (24 October 1897 – 22 February 1984) was an American malacologist, professor at Harvard University and curator of the mollusk collection in the malacology department of the Museum of Comparative Zoology at Harvard. Early l ...
and
R. Tucker Abbott Robert Tucker Abbott (September 28, 1919 – November 3, 1995) was an American conchologist (seashells) and malacologist (molluscs). He was the author of more than 30 books on malacology, which have been translated into many languages. Abbot ...
. In this case, the neotype was not an actual shell or whole
specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository ...
, but a figure from a 1684 book ', published 23 years before Linnaeus was born by the Italian
Jesuit , image = Ihs-logo.svg , image_size = 175px , caption = ChristogramOfficial seal of the Jesuits , abbreviation = SJ , nickname = Jesuits , formation = , founders ...
scholar Filippo Buonanni (1638–1723). This was the first book that was solely about
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 ...
s. In 1953 the Swedish malacologist
Nils Hjalmar Odhner Nils Hjalmar Odhner (6 December 1884 – 12 June 1973) was a Swedish zoologist who studied mollusks, a malacologist. He was professor of invertebrate zoology at the Swedish Museum of Natural History, Stockholm, and a member of the Royal Swedish Aca ...
searched the Linnaean Collection at
Uppsala University Uppsala University ( sv, Uppsala universitet) is a public university, public research university in Uppsala, Sweden. Founded in 1477, it is the List of universities in Sweden, oldest university in Sweden and the Nordic countries still in opera ...
and discovered the missing type shell, thereby invalidating Clench and Abbott's neotype designation.
Strombidae Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails in the superfamily Stromboidea, and the Epifamily Neostromboidae. The term true conchs, being a common name, does not have an exact me ...
's taxonomy was extensively revised in the 2000s and a few subgenera, including '' Eustrombus'', were elevated to
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
level by some authors. Petuch and Petuch and Roberts recombined this species as ''Eustrombus gigas'', and Landau and collaborators (2008) recombined it as ''Lobatus gigas''. In 2020, it was recombined as ''Aliger gigas'' by Maxwell and colleagues, which is the current valid name according to the
World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ...
.


Phylogeny

The
phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
relationships among the Strombidae were mainly studied by Simone (2005) and Latiolais (2006), using two distinct methods. Simone proposed a
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 ...
(a tree of descent) based on an extensive
morpho The morpho butterflies comprise many species of Neotropical butterfly under the genus ''Morpho''. This genus includes more than 29 accepted species and 147 accepted subspecies, found mostly in South America, Mexico, and Central America. ''Morph ...
-
anatomical Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...
analysis of representatives of
Aporrhaidae Aporrhaidae is a family of sea snails commonly called the "pelican's foot snails." The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classif ...
, Strombidae,
Xenophoridae Xenophoridae, commonly called carrier shells, is a family of medium-sized to large sea snails, marine gastropod mollusks in the clade Littorinimorpha. According to the taxonomy of the Gastropoda by Bouchet & Rocroi (2005) the family Xenophor ...
and Struthiolariidae, which included ''A. gigas'' (there referred to as ''Eustrombus gigas''). With the exception of ''
Lambis ''Lambis'' is a genus of large sea snails sometimes known as spider conchs, marine gastropod mollusks in the family Strombidae, the true conch family.Bouchet, P.; Rosenberg, G. (2011)Lambis Röding, 1798 Accessed through: World Register of Ma ...
'' and '' Terebellum'', the remaining taxa were previously allocated in the genus ''Strombus'', including ''A. gigas''. However, according to Simone, only '' Strombus gracilior'', '' Strombus alatus'' and '' Strombus pugilis'', the
type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
, remained within ''Strombus'', as they constituted a distinct group based on at least five
synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...
(traits that are shared by two or more
taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...
and their
most recent common ancestor In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...
). The remaining taxa were previously considered subgenera and were elevated to genus level by Simone. Genus ''Eustrombus'' (now considered a synonym of '' Lobatus''), in this case, included ''Eustrombus gigas'' (now considered a synonym of ''Aliger gigas'') and ''Eustrombus goliath'' (= '' Lobatus goliath''), which were thus considered closely related. In a different approach, Latiolais and colleagues (2006) proposed another cladogram that attempts to show the phylogenetic relationships of 34 species within the family Strombidae. The authors analysed 31 ''Strombus '' species, including ''Aliger gigas'' (there referred to as ''Strombus gigas''), and three species in the allied genus ''Lambis''. The cladogram was based on DNA sequences of both nuclear
histone H3 Histone H3 is one of the five main histones involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N-terminal tail, H3 is involved with the structure of the nucleosomes of the 'beads on a stri ...
and mitochondrial cytochrome-c oxidase I (COI) protein-coding
gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
regions. In this proposed phylogeny, ''Strombus gigas'' and ''Strombus gallus'' (= '' Lobatus gallus'') are closely related and appear to share a
common ancestor Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. All living beings are in fact descendants of a unique ancestor commonly referred to as the last universal comm ...
.


Common names

Common names include "queen conch" and "pink conch" in English, ' and ' in
Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
, ', ', ' and ' in
Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
, ', ' in the
Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...
and Grenada, and ' in
Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...
.


Anatomy


Shell

The mature
shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...
grows to in length in three to five years while the maximum reported size is . However, even though they only grow to be this maximum length, the thickness of the shell is constantly increasing. The shell is very solid and heavy, with 9 to 11
whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...
and a widely flaring and thickened outer lip. The thickness is highly important because the thicker the shell, the better protected it is. Additionally, instead of increasing in size once it reaches its maximum, the outside shell thickens as time goes on- an important indicator of how old the queen conch is. Although this notch is not as well developed as elsewhere in the family, the shell feature is nonetheless visible in an adult dextral (normal right-handed) specimen, as a secondary anterior indentation in the lip, to the right of the siphonal canal (viewed ventrally). The animal's left eyestalk protrudes through this notch. The
spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...
is a protruding part of the shell that includes all of the whorls except the largest and final whorl (known as the body whorl). It is usually more elongated than in other strombid snails, such as the closely related and larger goliath conch, ''Lobatus goliath'' that is endemic to Brazil. In ''A. gigas'', the glossy finish or glaze around the
aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...
of the adult shell is primarily in pale shades of pink. It may show a cream, peach or yellow colouration, but it can also sometimes be tinged with a deep
magenta Magenta () is a color that is variously defined as pinkish- purplish-red, reddish-purplish-pink or mauvish-crimson. On color wheels of the RGB (additive) and CMY (subtractive) color models, it is located exactly midway between red and blue. I ...
, shading almost to red. The periostracum, a layer of protein (
conchiolin Conchiolins (sometimes referred to as conchins) are complex proteins which are secreted by a mollusc's outer epithelium (the mantle). These proteins are part of a matrix of organic macromolecules, mainly proteins and polysaccharides, that ass ...
) that is the outermost part of the shell surface, is thin and a pale brown or tan colour. The overall shell morphology of ''A. gigas'' is not solely determined by the animal's genes; environmental conditions such as location, diet, temperature and depth, and biological interactions such as predation, can greatly affect it.Tewfik, A. (1991)."An assessment of the biological characteristics, abundance, and potential yield of the queen conch (''Strombus gigas'' L.) fishery on the Pedro Bank off Jamaica". ''Thesis submitted in partial fulfilment of the requirements for the Degree of Masters of Science (Biology)''. Acadia University, Canada. Juvenile conches develop heavier shells when exposed to predators. Conches also develop wider and thicker shells with fewer but longer spines in deeper water. The shells of juvenile queen conches are strikingly different in appearance from those of the adults. Noticeable is the complete absence of a flared outer lip; juvenile shells have a simple sharp
lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...
, which gives the shell a conical or
biconic Many shapes have metaphorical names, i.e., their names are metaphors: these shapes are named after a most common object that has it. For example, "U-shape" is a shape that resembles the letter U, a bell-shaped curve has the shape of the vertical ...
outline. In
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
, juvenile queen conches are known as "rollers", because wave action very easily rolls their shells, whereas it is nearly impossible to roll an adult specimen, due to its shell's weight and asymmetric profile. Subadult shells have a thin flared lip that continues to increase in thickness until death. Conch shells are about 95% calcium carbonate and 5% organic matter.


Historic illustrations

' (published in 1742 by the Italian
physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...
and malacologist
Niccolò Gualtieri Niccolò Gualtieri (9 July 1688 – 15 February 1744) was an Italian doctor and malacologist. He established a private natural history collection, and catalogued its contents, the best known being of the molluscs. Gualtieri was born in Florenc ...
) contains three illustrations of adult shells from different perspectives. The knobbed spire and the flaring outer lip, with its somewhat wing-like contour expanding out from the last whorl, is a striking feature of these images. The shells are shown as if balancing on the edge of the lip and/or the apex; this was presumably done for artistic reasons as these shells cannot balance like this. One of the most prized shell publications of the 19th century, a series of books titled ' (published by the French naturalist
Jean-Charles Chenu Jean-Charles Chenu (30 August 1808 – 12 November 1879) was a French physician, naturalist and author. Bibliography Natural history *''Illustrations conchyliologiques ou description et figures de toutes les coquilles connues vivantes et fossiles ...
from 1842 to 1853), contains illustrations of both adult and juvenile ''A. gigas'' shells and one uncoloured drawing depicting some of the animal's soft parts. Almost forty years later, a colored illustration from the ''Manual of Conchology'' (published in 1885 by the American malacologist
George Washington Tryon George Washington Tryon Jr. (20 May 1838 – 5 February 1888) was an American malacologist who worked at the Academy of Natural Sciences in Philadelphia. Biography George Washington Tryon was the son of Edward K. Tryon and Adeline Savidt ...
) shows a dorsal view of a small juvenile shell with its typical brown and white patterning.


Soft parts

Many details about the anatomy of ''Aliger gigas'' were not well known until Colin Little's 1965 general study.abstract
In 2005, R. L. Simone gave a detailed anatomical description. ''A. gigas'' has a long extensible snout with two eyestalks (also known as ommatophores) that originate from its base. The tip of each eyestalk contains a large, well-developed lensed eye, with a black
pupil The pupil is a black hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black ...
and a yellow
iris Iris most often refers to: *Iris (anatomy), part of the eye *Iris (mythology), a Greek goddess * ''Iris'' (plant), a genus of flowering plants * Iris (color), an ambiguous color term Iris or IRIS may also refer to: Arts and media Fictional ent ...
and a small, slightly posterior sensory tentacle. Amputated eyes completely regenerate. Inside the mouth of the animal is a radula (a tough ribbon covered in rows of microscopic teeth) of the taenioglossan type. Both the snout and the eyestalks show dark spotting in the exposed areas. The mantle is darkly coloured in the anterior region, fading to light gray at the posterior end, while the mantle collar is commonly orange. The
siphon 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 ...
is also orange or yellow. When the soft parts of the animal are removed from the shell, several organs are distinguishable externally, including the kidney, the nephiridial gland, the
pericardium The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made of ...
, the genital glands, stomach, style sac and the digestive gland. In adult males, the penis is also visible.


Foot/locomotion

The species has a large and powerful foot with brown spots and markings towards the edge, but is white nearer to the visceral hump that stays inside the shell and accommodates internal organs. The base of the anterior end of the foot has a distinct groove, which contains the opening of the pedal gland. Attached to the posterior end of the foot for about one third of its length is the dark brown,
corneous Corneous is a biological and medical term meaning horny, in other words made out of a substance similar to that of horns and hooves in some mammals. The word is generally used to describe natural or pathological anatomical structures made out ...
,
sickle A sickle, bagging hook, reaping-hook or grasshook is a single-handed agricultural tool designed with variously curved blades and typically used for harvesting, or reaping, grain crops or cutting succulent forage chiefly for feeding livestock, ei ...
-shaped operculum, which is reinforced by a distinct central rib. The base of the posterior two-thirds of the animal's foot is rounded; only the anterior third touches the ground during locomotion. The
columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...
, the central pillar within the shell, serves as the attachment point for the white columellar muscle. Contraction of this strong muscle allows the animal's soft parts to shelter in the shell in response to undesirable stimuli. ''Aliger gigas'' has an unusual means of
locomotion Locomotion means the act or ability of something to transport or move itself from place to place. Locomotion may refer to: Motion * Motion (physics) * Robot locomotion, of man-made devices By environment * Aquatic locomotion * Flight * Locomo ...
, first described in 1922 by
George Howard Parker George Howard Parker (December 23, 1864 – March 26, 1955) was an American zoology, zoologist. He was a professor at Harvard University, Harvard, and investigated the anatomy and physiology of sense organs and animal reactions. Biography George ...
(1864–1955). The animal first fixes the posterior end of the foot by thrusting the point of the sickle-shaped operculum into the substrate, then it extends the foot in a forward direction, lifting and throwing the shell forward in a so-called leaping motion. This way of moving is considered to resemble that of
pole vaulting Pole vaulting, also known as pole jumping, is a track and field event in which an athlete uses a long and flexible pole, usually made from fiberglass or carbon fiber, as an aid to jump over a bar. Pole jumping competitions were known to the M ...
, making ''A. gigas'' a good climber even of vertical concrete surfaces. This leaping locomotion may help prevent predators from following the snail's chemical traces, which would otherwise leave a continuous trail on the substrate.abstract


Life cycle

''Aliger gigas'' is
gonochoristic In biology, gonochorism is a sexual system where there are only two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism c ...
, which means each individual snail is either distinctly male or distinctly female. Females are usually larger than males in natural populations, with both sexes existing in similar proportion. After
internal fertilization Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. For inter ...
, the females lay eggs in gelatinous strings, which can be as long as . These are layered on patches of bare sand or seagrass. The sticky surface of these long egg strings allows them to coil and agglutinate, mixing with the surrounding sand to form compact egg masses, the shape of which is defined by the anterior portion of the outer lip of the female's shell while they are layered. Each one of the egg masses may have been fertilized by multiple males. The number of eggs per egg mass varies greatly depending on environmental conditions such as food availability and temperature. Commonly, females produce 8–9 egg masses per season, each containing 180,000–460,000 eggs, but numbers can be as high as 750,000 eggs. ''A. gigas'' females may spawn multiple times during the reproductive season, which lasts from March to October, with activity peaks occurring from July to September. Queen conch
embryos An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sper ...
hatch 3–5 days after spawning. At the moment of hatching, the
protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...
(
embryonic Embryonic may refer to: *Of or relating to an embryo * ''Embryonic'' (album), a 2009 studio album by the Flaming Lips *''Embryonics ''Embryonics'' is a double-CD compilation of tracks by the Australian progressive metal band, Alchemist. It w ...
shell) is translucent and has a creamy, off-white background color with small, pustulate markings. This coloration is different from other Caribbean ''Lobatus'', such as ''
Lobatus raninus ''Lobatus raninus'', common name the hawk-wing conch, is a species of medium to large sea snail, a marine gastropod mollusk in the family Strombidae, the true conchs.Bouchet, P. (2010). Lobatus raninus (Gmelin, 1791). Accessed through: World ...
'' and '' Lobatus costatus'', which have unpigmented embryonic shells. Afterwards, the emerging two-lobed
veliger A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells. Description The veliger is the characteristic larva of the gastropod, bivalve and scaphopod ...
(a larval form common to various marine and fresh-water gastropod and
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) spend several days developing in the
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 ...
, feeding primarily on
phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...
.
Metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...
occurs some 16–40 days from the hatching, when the fully grown protoconch is about 1.2 mm high. After the metamorphosis, ''A. gigas'' individuals spend the rest of their lives in the
benthic zone The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning " ...
(on or in the sediment surface), usually remaining buried during their first year of life. The queen conch reaches sexual maturity at approximately 3 to 4 years of age, reaching a shell length of nearly 180 mm and weighing up to 5 pounds. Individuals may usually live up to 7 years, though in deeper waters their lifespan may reach 20–30 years and maximum lifetime estimates reach 40 years.NOA
"Queen Conch (''Strombus gigas'')"
Retrieved 4 July 2009.
It is believed that the
mortality rate Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of de ...
tends to be lower in matured conchs due to their thickened shell, but it could be substantially higher for juveniles. Estimates have demonstrated that its mortality rate decreases as its size increases and can also vary due to habitat, season and other factors.


Ecology


Distribution

''Aliger gigas'' is native to the tropical Western Atlantic coasts of North and Central America in the greater Caribbean tropical zone. Although the species undoubtedly occurs in other places, this species has been recorded within the
scientific literature : ''For a broader class of literature, see Academic publishing.'' Scientific literature comprises scholarly publications that report original empirical and theoretical work in the natural and social sciences. Within an academic field, scie ...
as occurring, in:
Aruba Aruba ( , , ), officially the Country of Aruba ( nl, Land Aruba; pap, Pais Aruba) is a constituent country of the Kingdom of the Netherlands physically located in the mid-south of the Caribbean Sea, about north of the Venezuela peninsula of ...
, (
Netherlands Antilles nl, In vrijheid verenigd"Unified by freedom" , national_anthem = , common_languages = Dutch English Papiamento , demonym = Netherlands Antillean , capital = Willemstad , year_start = 1954 , year_end = 2010 , date_start = 15 December , ...
);
Barbados Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of the Americas, and the most easterly of the Caribbean Islands. It occupies an area of and has a population of about 287,000 (2019 estimate). ...
;
the Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...
;
Belize Belize (; bzj, Bileez) is a Caribbean and Central American country on the northeastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a wate ...
;
Bermuda ) , anthem = "God Save the King" , song_type = National song , song = " Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , e ...
; North and northeastern regions of Brazil (though this is contested); Old Providence Island in
Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
;
Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
; the Dominican Republic;
Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...
; Swan Islands in
Honduras Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...
;
Jamaica Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of His ...
;
Martinique Martinique ( , ; gcf, label=Martinican Creole, Matinik or ; Kalinago: or ) is an island and an overseas department/region and single territorial collectivity of France. An integral part of the French Republic, Martinique is located in th ...
; Alacran Reef,
Campeche Campeche (; yua, Kaampech ), officially the Free and Sovereign State of Campeche ( es, Estado Libre y Soberano de Campeche), is one of the 31 states which make up the 32 Federal Entities of Mexico. Located in southeast Mexico, it is bordered by ...
,
Cayos Arcas The Cayos Arcas is a chain of three tiny sand cays and an accompanying reef system in the Gulf of Mexico, from the mainland. It is located approximately from the mainland, west of Campeche. Their aggregate land area is . They belong to the muni ...
and
Quintana Roo Quintana Roo ( , ), officially the Free and Sovereign State of Quintana Roo ( es, Estado Libre y Soberano de Quintana Roo), is one of the 31 states which, with Mexico City, constitute the 32 federal entities of Mexico. It is divided into 11 mu ...
, in Mexico; Puerto Rico;
Saint Barthélemy Saint Barthélemy (french: Saint-Barthélemy, ), officially the Collectivité territoriale de Saint-Barthélemy, is an overseas collectivity of France in the Caribbean. It is often abbreviated to St. Barth in French, and St. Barts in English ...
;
Mustique Mustique is a small private island in the nation of Saint Vincent and the Grenadines, which is part of the Grenadines, a chain of islands in the West Indies. The island is located within Grenadines Parish, and the closest island is the uninhab ...
and
Grenada Grenada ( ; Grenadian Creole French: ) is an island country in the West Indies in the Caribbean Sea at the southern end of the Grenadines island chain. Grenada consists of the island of Grenada itself, two smaller islands, Carriacou and Pe ...
in the Grenadines;
Pinar del Río Pinar del Río is the capital city of Pinar del Río Province, Cuba. With a population of 139,336 (2004) in a municipality of 190,332, it is the List of cities in Cuba, 10th-largest city in Cuba. Inhabitants of the area are called ''Pinareños'' ...
, North Havana Province, North Matanzas, Villa Clara,
Cienfuegos Cienfuegos (), capital of Cienfuegos Province, is a city on the southern coast of Cuba. It is located about from Havana and has a population of 150,000. Since the late 1960s, Cienfuegos has become one of Cuba's main industrial centers, especial ...
,
Holguín Holguín () is a municipality and city in Cuba, and the capital of Province of Holguín. After Havana, Santiago de Cuba, and Camagüey, it is the fourth largest city in Cuba. History Before Columbus, the Taino people settled in huts made fro ...
,
Santiago de Cuba Santiago de Cuba is the second-largest city in Cuba and the capital city of Santiago de Cuba Province. It lies in the southeastern area of the island, some southeast of the Cuban capital of Havana. The municipality extends over , and contains t ...
and Guantánamo, in the
Turks and Caicos The Turks and Caicos Islands (abbreviated TCI; and ) are a British Overseas Territory consisting of the larger Caicos Islands and smaller Turks Islands, two groups of tropical islands in the Lucayan Archipelago of the Atlantic Ocean and n ...
Islands and
Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...
; South Carolina,
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
, with the Florida Keys and Flower Garden Banks National Marine Sanctuary, in the United States; Carabobo, Falcon, Gulf of Venezuela, Los Roques archipelago, Los Testigos Islands and Sucre (state), Sucre in Venezuela; all islands of the United States Virgin Islands.


Habitat

''Aliger gigas'' lives at depths from 0.3–18 m to 25–35 m. Its depth range is limited by the distribution of
seagrass 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 ...
and algae cover. In heavily exploited areas, the queen conch is more abundant in the deepest range. The queen conch lives in seagrass meadows and on sandy substrate,Ulrich Wieneke (ed.
''Lobatus gigas''
In: Gastropoda Stromboidea. modified: 22 November 2008. Retrieved 23 June 2009.
usually in association with turtle grass (species of the genus ''Thalassia (plant), Thalassia'', specifically ''Thalassia testudinum''Davis, J.E. (2003)
"Population assessment of queen conch, ''Strombus gigas'', in the St. Eustatius Marine Park, Netherlands Antilles"
. St. Eustatius Marine Park.
and also ''Syringodium'' sp.) and manatee grass (''Cymodocea'' sp.). Juveniles inhabit shallow, inshore seagrass meadows, while adults favor deeper algal plains and seagrass meadows. The critical nursery habitats for juvenile individuals are defined by a series of characteristics, including tide, tidal circulation and macroalgae, macroalgal production, which together enable high rates of recruitment (biology), recruitment and survival. ''A. gigas'' is typically found in distinct aggregates that may contain several thousand individuals.McCarthy, K. (2007)
"A review of queen conch (''Strombus gigas'') life-history''
Sustainable Fisheries Division NOAA. ''SEDAR 14-DW-4''.


Diet

Strombid gastropods were widely accepted as carnivores by several authors in the 19th century, a concept that persisted until the first half of the 20th century. This erroneous idea originated in the writings of Jean-Baptiste Lamarck, who classified strombids with other supposedly carnivorous snails. This idea was subsequently repeated by other authors, but had not been supported by observation. Subsequent studies have refuted the concept, proving beyond doubt that strombid gastropods are
herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
animals. In common with other Strombidae, ''Aliger gigas'' is a specialized herbivore, that feeds on macroalgae (including red algae, such as species of ''Gracilaria'' and ''Hypnea''),George Washington Tryon, Tryon, G.W. (1885). ''Manual of Conchology, structural and systematic, with illustrations of the species
Volume 7
Terebridae, Cancellariidae, Strombidae, Cypraeidae, Ovulidae, Cassididae, Doliidae.'' p
107348
seagrass and unicellular algae, intermittently also feeding on algal detritus. The green macroalgae ''Batophora oerstedii'' is one of its preferred foods.


Interactions

A few different animals establish
commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...
interactions with ''A. gigas'', which means that both organisms maintain a relationship that benefits (the commensal) species but not the other (in this case, the queen conch). Commensals of this species include certain mollusks, mainly Calyptraeidae, slipper shells (''Crepidula'' spp.) The
porcelain crab Porcelain crabs are decapod crustaceans in the widespread family Porcellanidae, which superficially resemble true crabs. They have flattened bodies as an adaptation for living in rock crevices. They are delicate, readily losing limbs when attack ...
''Porcellana sayana'' is also known to be a commensal and a small
cardinalfish Cardinalfishes are a family, Apogonidae, of ray-finned fishes found in the Atlantic, Indian, and Pacific Oceans; they are chiefly marine, but some species are found in brackish water and a few (notably '' Glossamia'') are found in fresh water. A ...
, known as the conch fish (''Astrapogon stellatus''), sometimes shelters in the conch's mantle for protection. ''A. gigas'' is very often parasite, parasitized by protists of the phylum Apicomplexa, which are common mollusk parasites. Those coccidium, coccidian parasites, which are spore-forming, single-celled microorganisms, initially establish themselves in large vacuole, vacuolated cell (biology), cells of the host (biology), host's digestive system of gastropods, digestive gland, where they reproduce freely. The infestation may proceed to the secretion, secretory cells of the same organ. The entire life cycle of the parasite typically occurs within a single host and tissue. ''Aliger gigas'' is a prey species for several carnivorous
gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
mollusks, including the apple murex ''Phyllonotus pomum'', the horse conch ''Triplofusus papillosus'', the lamp shell ''Turbinella angulata'', the moon snails ''Natica'' spp. and ''Polinices'' spp., the muricidae, muricid snail ''Phyllonotus margaritensis'', the trumpet triton ''Charonia variegata'' and the tulip snail ''Fasciolaria tulipa''. Crustaceans are also conch predators, such as the blue crab ''Callinectes sapidus'', the box crab ''Calappa gallus'', the giant hermit crab ''Petrochirus diogenes'', the spiny lobster ''Panulirus argus'' and others. Sea stars,
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s, Triplofusus papillosus, horse conch,
octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttle ...
, eagle ray,
nurse shark The nurse shark (''Ginglymostoma cirratum'') is an elasmobranch fish in the family Ginglymostomatidae. The conservation status of the nurse shark is globally assessed as Vulnerable in the IUCN List of Threatened Species. They are considered t ...
,
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
(such as the permit ''Trachinotus falcatus'' and the porcupine fish ''Diodon hystrix''), loggerhead sea turtles (''Caretta caretta'') and humans also eat the queen conch.


Uses

Conch meat has been consumed for centuries and has traditionally been an important part of the diet in many islands in the West Indies and Southern Florida. It is consumed raw, marinated, minced or chopped in a wide variety of dishes, such as salads, chowder, fritters, soups, stew, pâtés and other local recipes. In both English and Spanish-speaking regions, for example in the Dominican Republic, ''Aliger gigas'' meat is known as '. Although conch meat is used mainly for human consumption, it is also sometimes employed as fishing bait (usually the foot). ''A. gigas'' is among the most important fishery resources in the Caribbean: its harvest value was US$30 million in 1992, increasing to $60 million in 2003.CITES (2003)
''Review of Significant Trade in specimens of Appendix-II species. (Resolution Conf. 12.8 and Decision 12.75)''
. Nineteenth meeting of the Animals Committee, Geneva (Switzerland), 18–21.
The total annual harvest of meat of ''A. gigas'' ranged from 6,519,711 kg to 7,369,314 kg between 1993 and 1998, later production declined to 3,131,599 kg in 2001. Data about US imports shows a total of 1,832,000 kg in 1998, as compared to 387,000 kg in 2009, a nearly 80% reduction twelve years later. Queen conch shells were used by Native Americans in the United States, Native Americans and Caribbean Indians in a wide variety of ways. South Florida bands (such as the Tequesta), the Kalina people, Carib, the Arawaks, Arawak and Taíno people, Taíno used conch shells to fabricate tools (such as knife, knives, axe heads and chisels), jewelry, cookware and used them as blowing horns. In Mesoamerican history, Aztecs used the shell as part of jewelry mosaics such as the double-headed serpent. The Aztecs also believed that the sound of trumpets made from queen conch shells represented divine manifestations, and used them in religious ceremonies. In central Mexico, during rain ceremonies dedicated to Tlaloc, the Maya people, Maya used conch shells as hand protectors (in a manner similar to boxing gloves) during combat. Ancient middens of ''L. gigas'' shells bearing round holes are considered an evidence that pre-Columbian Lucayan people, Lucayan Indians in the Bahamas used the queen conch as a food source. Brought by explorers, queen conch shells quickly became a popular asset in early modern period, early modern Europe. In the late 17th century they were widely used as decoration over fireplace mantels and English gardens, among other places. In contemporary times, queen conch shells are mainly utilized in handicraft. Shells are made into Cameo (carving), cameos, bracelets and lamps, and traditionally as doorstops or Decorative arts, decorations by families of seafaring men. The shell continues to be popular as a decorative object, though its export is now regulated and restricted by the
CITES CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
agreement. In modern culture, queen conch shells are often represented in everyday objects such as coins and stamps. Very rarely (about 1 in 10,000 conchs), a conch pearl may be found within the mantle. Though these pearls occur in a range of colors corresponding to the colors of the interior of the shell, pink specimens are the most valuable. These pearls are considered semi-precious, and a popular tourist curio. The best specimens have been used to create necklaces and earrings. A conch pearl is a non-nacreous pearl (formerly referred to by some sources as a 'pearl#Pearls from other species, calcareous concretion'); it differs from most pearls that are sold as gemstones in that it is not iridescent. The specific weight of the conch pearl is 2.85, notably heavier than any other type. Due to the sensitive nature of the animal and the location of the pearl-forming portion of the snail within the spiral shell, commercial cultivation of pearls is considered virtually impossible. Research into the conch shell's unique architecture is currently under way at MIT.


Status


Threats

Queen conch populations have been rapidly declining throughout the years and have been mostly depleted in some areas in the Caribbean due to the fact that they are highly sought after for their meat and their value. Within the conch fisheries, one of the threats to sustainability stems from the fact that there is almost as much meat in large juveniles as there is in adults, but only sexual maturity, adult conchs can reproduce, and thus sustain a population. In many places where adult conchs have become rare due to overfishing, larger juveniles and subadults are taken before they ever mate. In the United States (
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
), it is currently illegal to gather or pick the queen conch either recreationally or commercially. In other parts of the world where it is legal, only adult conchs can be fished. The rule is to let each conch have ample time to reproduce before taken out of its habitat, potentially leading to a more stable population. However, this rule has not been followed by countless fishers. On a number of islands, subadults provide the majority of the harvest. The abundance of ''Aliger gigas'' is declining throughout its range as a result of
overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...
and poaching. Especially because of overfishing, many pockets of conch communities fall below the critical level needed for reproducing. A 2019 study predicted overfishing could lead to the extinction of queen conchs in as little as ten years. Additionally, if the conch fishery collapses, it could potentially leave over 9,000 Bahamian fishers out of work. Trade from many Caribbean countries, such as
the Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...
, Antigua and Barbuda,
Honduras Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...
, Haiti and the
Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...
, is known or thought to be unsustainable. As of 2001, queen conch populations in at least 15 Caribbean countries and states were overfished or overexploited. Illegal harvest, including fishing in foreign waters and subsequent illegal international trade, is a common problem in the region. The Caribbean "International Queen Conch Initiative" is an international attempt at managing this species. On 13 January 2019, the Bahamas' Department of Marine Resources announced it would be making official recommendations to better protect the conch, including ending exports and increasing regulatory staff. Presently, ocean acidification is another serious threat to the queen conch. Acidity levels are rising and adversely affecting shellfish larvae. Rising atmospheric CO2 levels result in rising levels of carbonic acid in seawater, which is particularly harmful to organisms with calcium carbonate shells and structures. Certain larval stages of shellfish are very sensitive to lower seawater pH.


Conservation

The queen conch fishery is usually managed under the regulations of individual nations. In the United States all taking of queen conch is prohibited in Florida and in adjacent Federal waters. No international regional fishery management organization exists for the whole Caribbean area, but in places such as Puerto Rico and the Virgin Islands, queen conch is regulated under the auspices of the Caribbean Fishery Management Council (CFMC). In 2014, the Parties to the Convention for the Protection and Development of the Marine Environment of the Wider Caribbean Region (Cartagena Convention) included queen conch in Annex III of its Protocol Concerning Specially Protected Areas and Wildlife (SPAW Protocol). Species included in the Annex III require special measures to be taken to ensure their protection and recovery, and their use is authorised and regulated accordingly. The species is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES) meaning international trade (import/export) in the species and its parts and derivatives is regulated by the CITES permitting system. The listing was proposed by the United States making queen conch the first large-scale fisheries product to be regulated by CITES (as ''Strombus gigas'').''Appendices I, II and III''
cites.org website. Retrieved 4 July 2009.
In 1995 CITES began reviewing the biological and trade status of the queen conch under its "Significant Trade Review" process. These reviews are undertaken to address concerns about trade levels in an Appendix II species. Based on the 2003 review, CITES recommended that all countries prohibit importation from Honduras, Haiti and the Dominican Republic, according to Standing Committee Recommendations. Queen conch meat continues to be available from other Caribbean countries, including Jamaica and Turks and Caicos, which operate well-managed queen conch fisheries. For conservation reasons, the Government of
Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
currently bans the commercialisation and consumption of the conch between the months of June and October. The Bahamas National Trust is building awareness by educating teachers and students through workshops and an awareness campaign which includes the catchy pop son
''Conch Gone''


References


Further reading

* Coomans H.E. (1965). "Shells and shell objects from an Indian site on Magueyes Island, Puerto Rico". ''Caribbean Journal of Science'' 5 (1–2): 15–23
PDF
* *


External links

* * ARKive
images and movies of the queen conch (''Strombus gigas'')



Microdocs

Bermuda Department of Conservation Services (includes Queen Conch Recovery Plan)
* {{Taxonbar , from=Q62603 Strombidae Molluscs of the Atlantic Ocean Fauna of the Caribbean Arthropods of the Dominican Republic Gastropods described in 1758 Taxa named by Carl Linnaeus