''Concholepas concholepas'', the Chilean abalone or Peruvian tolina, is a species of large edible

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

, a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

. Despite the superficial resemblance, ''C. concholepas'' is not a true

abalone Abalone ( or ; via Spanish , from Rumsen language, Rumsen ''aulón'') is a common name for any small to very large marine life, marine gastropod mollusc in the family (biology), family Haliotidae, which once contained six genera but now cont ...

(a species in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Haliotidae), but a member of the family Muricidae, also known as murex snails or rock snails. This species is native to the coasts of

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

and

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

, where it is called ''loco'' (a

Chilean Spanish Chilean Spanish ( or ) is any of several varieties of the Spanish language spoken in most of Chile. Chilean Spanish dialects have distinctive pronunciation, grammar, vocabulary, and slang usages that differ from those of Standard Spanish, with ...

loanword from Mapudungun), ''pata de burro'', ''tolina'', or ''chanque'' ( Peruvian Spanish). Due to

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 stocks, fish stock), resu ...

, the harvesting of this species in Chile has been limited by law since 1989.

Shell description

''Concholepas concholepas'' has a thick, slightly oval, and white-brown to purple-grey

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 Science Biology * Seashell, a hard outer layer of a marine ani ...

. Its very few whorls makes it resemble a Phrygian cap in shape. The outer surface of the shell shows strong lamellose ribs of which are both radial and circular-concentric. The shell is shaped almost like that of an

, with a very large aperture compared to other muricids. A ''loco'' cannot hide completely inside the shell if it is turned upside down, so has no need of its operculum; instead, it relies on its strong foot to remain in place. The shell is made of

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

with an inner layer of

aragonite Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation fr ...

. The shells of this species are used as ashtrays in Chile.

Ecology

Habitat and distribution

''Concholepas concholepas'' is a

benthic 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 the Ancient Greek word (), meaning "the depths". ...

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

that lives on rocks in temperate waters from sea level to depths of 40 m. Its diet consists of mytilids (such as '' Semimytilus algosus'' and '' Perumytilus purpuratus'') and barnacles (such as '' Chthamalus scabrosus''). Its geographic distribution ranges from Lobos de Afuera in

, to

Cape Horn Cape Horn (, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which is Águila Islet), Cape Horn marks the nor ...

, including the

Juan Fernández Islands The Juan Fernández Islands () are a sparsely inhabited series of islands in the South Pacific Ocean, reliant on tourism and fishing. Situated off the coast of Chile, they are composed of three main volcanic islands: Robinson Crusoe Island, R ...

.
Catastro genético de locos y erizos del litoral chileno. Ministerio de Agricultura, Gobierno de Chile

Lifecycle

''Concholepas concholepas'' is

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, which means the populations are divided between male and females, though with no external evidence of

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

. The

fertilisation Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or of ...

in this species occurs internally. In central Chile, females lay egg capsules on low intertidal and shallow subtidal rocky surfaces during southern autumn months. After around one month of development inside the capsules, small planktotrophic

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 taxono ...

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e (260 µm) are released. The larvae spend the following three months in the water column and once they become competent, they dwell at the sea surface until they settle on rocky intertidal and shallow subtidal habitats down to 30 m. The normal size at which the snail reaches

sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans, it is related to both puberty and adulthood. ''Puberty'' is the biological process of sexual maturation, while ''adulthood'', the condition of being socially recognized ...

is between 5.4 and 6.7 cm; it takes about four years to reach this size. Shells of the species are parasitized by the barnacle species '' Cryptophialus minutus''.

Human uses

''Concholepas concholepas'' is used in

Chilean cuisine Chilean cuisine stems mainly from the combination of traditional Spanish cuisine, Chilean Indigenous peoples in Chile, Mapuche culture and local ingredients, with later important influences from other European cuisines, particularly from Germa ...

and is commercially marketed worldwide as a delicacy — misleadingly under the name "Chilean

". (True abalone are

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

s, whereas ''Concholepas concholepas'' is a muricid, a

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they ar ...

). Its economic value and ecological importance as top predator have made it the most studied marine

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

species in Chile.

Commercial fishery

On the Chilean coast, ''C. concholepas'' is one of the most important edible mollusc species and is a major product of the aquacultural industry. In 1975, about 5,000 tons were extracted annually. In 1980, the extraction peaked, with a catch of 25,000 tons. Since 1989, extraction is illegal in Chile, but from 1992 onwards, some exceptions have been made for accredited commercial divers. The minimum size allowed for extraction is 10 cm. Currently, the only legal way for artisan fishermen or other people to catch locos is to have a Marine Area of Benthonic Resources Extraction permit. Even in these areas, though, extraction is prohibited from December to July from Valparaíso Region northward and from January or February to July south of it. Populations have shrunk and a recent study shows extraction is making an

artificial selection Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant ...

to eliminate faster-growing individuals. The same study also showed the populations in Chile are relatively homogeneous with low genetic variability. Due to overextraction, scientists have studied the possibility of commercial cultivation since 1986.

Cuisine

, the meat of the foot of these snails is cooked and eaten with

mayonnaise Mayonnaise (), colloquially referred to as "mayo" (), is a thick, creamy sauce with a rich and tangy taste that is commonly used on sandwiches, hamburgers, Salad#Bound salads, bound salads, and French fries. It also forms the base for various o ...

or as a '' chupe de locos'' soup in an

earthenware Earthenware is glazed or unglazed Vitrification#Ceramics, nonvitreous pottery that has normally been fired below . Basic earthenware, often called terracotta, absorbs liquids such as water. However, earthenware can be made impervious to liquids ...

bowl. The ''chupe de locos'' typically contains about six snails' feet, 100 grams of a fatty cheese, such as Chanco cheese, two eggs, four spoons of grated bread, salt, and paprika.

Possible medical use

The hemocyanin found in the blood of ''C. concholepas'' has immunotherapeutic effects against

bladder The bladder () is a hollow organ in humans and other vertebrates that stores urine from the kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. In humans, the bladder is a distens ...

and

prostate cancer Prostate cancer is the neoplasm, uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Abnormal growth of the prostate tissue is usually detected through Screening (medicine), screening tests, ...

. In 2006 research,

mice A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

were primed with ''C. concholepas'' before implantation of bladder

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

(MBT-2) cells. Mice treated with ''C. concholepas'' showed a significant antitumor effect. The effects included prolonged survival, decreased tumor growth and incidence and lack of toxic effects.

Other possible scientific uses

''Concholepas concholepas''

s are a potential proxy-bearer for

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

studies. There are many fossil shell accumulations in

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

coastal terraces. Climate indicators are, by far, less abundant for ancient cold seas; therefore, investigating the ability of ''C. concholepas'' will provide valuable signals for long-term evolution of the sea surface temperatures in cold seas, and might be important in reconstructing the El Niño Southern Oscillation (ENSO) history. Other information ''C. concholepas'' won the Mollusc of the year 2023 competition.

References

Sources

*
Fishing resources database
{{DEFAULTSORT:Concholepas Concholepas concholepas Molluscs of South America Molluscs of Chile Fauna of Peru Commercial molluscs Gastropods described in 1789