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 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 ...

to southern

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 ...

. They are typically found in the rocky

sublittoral The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely in ...

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 islan ...

, in waters down to 100 m in depth. They spend the spring, summer, and fall in rocky

subtidal The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminate ...

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 Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

side is a dark reddish brown with dark saddle patterns on their side. Their

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

sides are a creamy white with reddish spots. Redspotted catsharks have two

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

s, with the first dorsal

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

over the

pelvic The pelvis (: pelves or pelvises) is the lower part of an anatomical 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). ...

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 tooth ...

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 or committed romantic, ''de facto'' relationship. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marri ...

biting.

Behavior

Redspotted catsharks are

solitary Solitary is the state of being alone or in solitude. The term may refer to: * ''Solitary'' (album), 2008 album by Don Dokken * ''Solitary'' (2020 film), a British sci-fi thriller film * ''Solitary'' (upcoming film), an American drama film * "S ...

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

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 Scyliorhinidae is a Family (biology), family of sharks, one of a few families whose members share the common name catsharks, belonging to the Order (biology), order Carcharhiniformes, the ground sharks. Although they are generally known as cats ...

, it is believed that they have a well-developed sense of smell, and that they are electroreceptive, which allows them to detect electricity emitted by other animals, and may also allow them to detect

magnetic field A magnetic field (sometimes called B-field) is a physical 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 ...

s, which aids in

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

. Redspotted catsharks are host to

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

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...

that are passed into the catsharks'

bloodstream In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. It includes the cardiovascular system, or vascular system, that consists of the heart an ...

through

leech Leeches are segmented parasitism, parasitic or Predation, predatory worms that comprise the Class (biology), subclass Hirudinea within the phylum Annelida. They are closely related to the Oligochaeta, oligochaetes, which include the earthwor ...

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 (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s and the rhynchocinetid rock

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

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

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 ...

within their

ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

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

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 reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...

. Breeding occurs in individuals in an annual cycle. However, they mate

seasonally A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and polar ...

, 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 gam ...

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 zygote and initiate its development into a new individual organism or off ...

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 chondrichthyans. Living chondricthyans that produce egg cases include some sharks, skates and chimaeras. Egg cases t ...

Embryo An embryo ( ) is the initial stage of development for 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 sp ...

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 an inventory of the global conservation status and extinction risk of biological ...

, the U.S. Federal List, or the

CITES CITES (shorter acronym 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 inte ...

list. They are not known to be a vulnerable or

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

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

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s. This is a detriment to commercial fisherman 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 Trawling, 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 n ...

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

References

External links

Animal Diversity Web
{{Taxonbar, from=Q2716612 Schroederichthys Fish of Peru Fish of Chile Western South American coastal fauna Fish described in 1848