The redspotted catshark (''Schroederichthys chilensis''), also known as the Chilean catshark, is a species of catshark commonly found in the coastal waters of the southeastern Pacific, from central

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

to southern

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. They are typically found in the rocky sublittoral areas at the edge of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

, in waters down to 100 m in depth. They spend the spring, summer, and fall in rocky subtidal areas, but winter in deeper offshore waters due to the strong currents at that time of year.

Description

Redspotted catsharks range in length from 30 to 66 cm, although these sizes are taken from captured sharks, and it is believed that they may grow larger than this. Their bodies are elongate and sleek, typical of the catshark family. Their dorsal side is a dark reddish brown with dark saddle patterns on their side. Their ventral sides are a creamy white with reddish spots. Redspotted catsharks have two

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

s, with the first dorsal

axil A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

over the

pelvic The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

region. Their dorsal fins do not have spines, and their tails have no upward bend. Redspotted catsharks have

multicuspid The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

teeth. However, males typically have longer teeth with fewer cusps. This is believed to aid in

courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...

biting.

Behavior

Redspotted catsharks are

solitary Solitary is the state of being alone or in solitude. The term may refer to: * shortened form of solitary confinement * Solitary animal, an animal that does not live with others in its species * Solitary but social, a type of social organization in ...

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

creatures. They stay in caves and crevices during the day and emerge at night to feed. They are migratory. However, they live most of the year near the edge of the continental shelf. Communication specific to the redspotted catshark is unknown. However, as with most other sharks, including other members of the family Scyliorhinidae, it is believed that they have a well-developed sense of smell, and that they are

electroreceptive Electroreception and electrogenesis are the closely-related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes to stu ...

, which allows them to detect electricity emitted by other animals, and may also allow them to detect

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

s, which aids in

navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...

. Redspotted catsharks are host to

trypanosomes Trypanosomatida is a group of kinetoplastid excavates distinguished by having only a single flagellum. The name is derived from the Greek ''trypano'' (borer) and ''soma'' (body) because of the corkscrew-like motion of some trypanosomatid species. ...

, parasites that are passed into the catsharks' bloodstream through

leech Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...

es. There are no known predators to the catshark, although juveniles typically spend their early life in the deeper offshore waters. This is believed to be to avoid predators, although what those predators are is unknown. Breeding and oviposition seem to occur throughout the year in an annual cycle. The paucity of ovigerous females during fall probably indicates that eggs were laid during summer, when massive depositions of egg-cases occurred on fronds of the subtidal brown kelp 'Lessonia trabeculata'.

Feeding

Redspotted catsharks feed on organisms that dwell on the rocky bottom near the

. Their primary food sources are various species of

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s and the rhynchocinetid rock

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

''Rhynchocinetes typus''. Redspotted catsharks are an important

predator 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 ...

within their

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

. They have a large influence on commercially fished

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 ancient Greek, βένθος (bénthos), meaning "t ...

organisms that dwell in the rocky near-shore areas. The research of presence/absence effect of kelp ''Lessonia trabeculata'' on the isotopic niche of redspotted catshark present that males were characterized by higher trophic position and enriched carbon sources compared to females in locations where kelp was present. In contrast, males and females were characterized by similar isotopic niche in absence of kelp. These differences are most probably an effect of higher prey diversity associated with microhabitats generated by kelp forests that allow sexual segregation of isotopic niche. Therefore, extensive kelp harvest may cause significant effects in isotopic niche and nutritional status of adult redspotted catshark and may negatively affect its populations.

Reproduction

Redspotted catsharks are

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...

. Breeding occurs in individuals in an annual cycle. However, they mate seasonally, typically in spring and winter, though females have occasionally been shown to have egg capsules in the summer. They are

polygynandrous Polygynandry is a mating system in which both males and females have multiple mating partners during a breeding season. In sexually reproducing diploid animals, different mating strategies are employed by males and females, because the cost of ga ...

and while the male fertilizes the female's eggs he typically performs what is called a "courtship ritual" that consists of the male biting the female. Redspotted catsharks are born from encapsulated eggs that are

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

and released into the water. There are typically two eggs in each capsule, which can also be called a

mermaid's purse An egg case or egg capsule, often colloquially called a mermaid's purse, is the casing that surrounds the eggs of oviparous sharks, skates and chimaeras. Egg cases typically contain one embryo, except for big skate and mottled skate egg cases ...

Embryo 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 spe ...

s feed on the

yolk Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...

of the egg until they hatch. Once these eggs hatch, the sharks appear to be miniature versions of adults. However, the sharks grow rapidly. It is believed that juveniles swim into deeper waters in order to avoid predation in the sublittoral zone that they return to when they are adults. Therefore, there is a spatial segregation between adult and juvenile populations.

Conservation status and economic impact

Redspotted catsharks are not listed as endangered on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

, the U.S. Federal List, or 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 ...

list. They are not known to be a vulnerable or

threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensat ...

species. Redspotted catsharks have a negative economic impact on humans. They feed heavily on near shore benthic

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. This is a detriment to

commercial fisherman Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

because crustaceans in this area have a large economic importance. Catsharks are also a frequent

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

of nearshore

fishing trawlers A fishing trawler is a commercial fishing vessel designed to operate fishing trawls. Trawling is a method of fishing that involves actively dragging or pulling a trawl through the water behind one or more trawlers. Trawls are fishing nets tha ...

, which, while not economically significant, can cause damage to nets as well as time lost in removing the bycatch from the viable catch.

References

* * * 2004. "Clase Elasmobranchii" (On-line). Accessed 29 October 2004 at http://www.biouls.cl/biozoo/Vertebra/sispez2.htm. * Ackley, V. and W. Fink. 2004. "Schroederichthys chilensis" (On-line), Animal Diversity Web. Accessed 28 March 2006 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Schroederichthys_chilensis.html. * Aedo, G., H. Arancibia. 2001. Gastric evacuation of the redspotted catshark under laboratory conditions. Journal of Fish Biology, 58: 1454–1457. * Budker, P. 1971. The Life of Sharks. New York: Columbia University Press. * Carpenter, K., S. Luna. 2004. "Schroederichthys chilensis Redspotted Catshark" (On-line). Accessed 29 October 2004 at http://filaman.uni-kiel.de/summary/SpeciesSummary.cfm?id=839. * Farina, J., F. Ojeda. 1993. Abundance, activity, and trophic patterns of the redspotted catshark, Schroederichthys chilensis, on the Pacific temperate coast of Chile. Copeia, 2: 545–549. * Morillas, J., M. George-Nascimento, H. Valeria, R. Khan. 1987. Trypanosoma humboldti n. sp. from the Chilean Catshark, Schoroederichthys chilensis. Journal of Protozoology, 34/3: 342–344. * Nelson, J. 1984. ''

Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...

''. New York: John Wiley and Sons. * Ommanney, F. 1964. ''The Fishes''. New York: Time, Inc. * Smith, M., P. Heemstra. 1986. ''Smiths' Sea Fishes''. South Africa: L. L. B. Smith Institute of Ichthyology. * Smith, J. 1949. ''The Sea Fishes of Southern Africa''. South Africa: Central News Agency LTD. *

External links

Animal Diversity Web
{{DEFAULTSORT:catshark, redspotted redspotted catshark Fish of Peru Fish of Chile Western South American coastal fauna redspotted catshark