Brazilian guitarfish

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Brazilian guitarfish
Rhinobatos horkelii 2.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Batoidea
Order: Rhinopristiformes
Family: Rhinobatidae
Genus: Pseudobatos
Species:
P. horkelii
Binomial name
Pseudobatos horkelii
Synonyms [2]
  • Rhinobatos horkeli Müller & Henle, 1841
  • Rhinobatus horkelii Müller & Henle, 1841

The Brazilian guitarfish (Pseudobatos horkelii) is a species of fish in the family Rhinobatidae. It is endemic to Brazil, where its natural habitat is coastal waters on the continental shelf. This fish is viviparous and has a long gestation period, concluding with the birth of live pups in February. At this time the fish are subject to intense fishing activity but catches have been dwindling in recent years as a result of overfishing. Because so few breeding-size fish remain, the International Union for Conservation of Nature has assessed the fish's conservation status as being "critically endangered".

Contents

Taxonomy

The Brazilian guitarfish was first described as Rhinobatos horkelii by Müller & Henle in 1841. They named the new species in honour of the German botanist, Dr. Johann Horkel, Professor of Plant Physiology at the University of Berlin, who had sent them a specimen of the fish preserved in alcohol. [3]

Description

At Peruibe Aquarium, Sao Paulo, Brazil Brazilian Guitarfish.jpg
At Peruibe Aquarium, Sao Paulo, Brazil

This species can grow to a length of 138 cm (54 in), but a more usual adult size is about 60 cm (24 in). The dorsal surface is a uniform olive-grey or brown. There is a dark patch on the snout and the nostrils are long. The crown is transversely flattened or slightly convex. [4]

Ecology

1865 watercolor of a Brazilian guitarfish by Jacques Burkhardt. Arraia viola (Rio de Janeiro, Brazil, 20 July 1865).jpg
1865 watercolor of a Brazilian guitarfish by Jacques Burkhardt.

The Brazilian guitarfish is a low-fecundity viviparous fish. Mating takes place on the inner continental shelf in March and soon afterwards the adults disperse to outer areas of the shelf. The eggs are contained within a casing and remain dormant inside the female until she return to the warm, shallow waters of the inner continental shelf in November. [1] The young develop inside the female, at first obtaining nourishment from their yolk sacs, and later from maternal uterine secretions; [4] they grow from a length of about 1 cm (0.4 in) in December to about 29 cm (11 in) in February when they are born. The females mature at about 4 years of age and litter sizes range from 4 to 12, with larger fish having larger litters. The inner shelf provides important nursery areas for the young fish. Here both females and juveniles are particularly susceptible to being caught by pair-trawling and beach seine netting. Most of the catch is pregnant females. Later in the year, the adults disperse more widely over the inner shelf and are caught by otter-trawling. [5]

Status

The major threat faced by P. horkelii is overfishing. The fish is caught by trawling, beach seine and gillnet and has traditionally been the main batoid fish caught along the coast of southern Brazil. The main ports at which it is landed are Rio Grande and Itajaí. In 1975, 842 tonnes were landed at Rio Grande and by 1984, that had risen to 1804 tonnes. Since then the catch has dwindled to 157 tonnes in 2002 and has continued to decline since. In southern Brazil waters, the fish seems to have declined by more than 80% since 1986. Based on this evidence, the International Union for Conservation of Nature is concerned that the Brazilian guitarfish may become extinct within about ten years due to overfishing, and has therefore assessed its conservation status as being "critically endangered". [1]

Related Research Articles

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The guitarfish, also referred to as shovelnose rays, are a family, Rhinobatidae, of rays. The guitarfish are known for an elongated body with a flattened head and trunk and small, ray-like wings. The combined range of the various species is tropical, subtropical, and warm temperate waters worldwide.

<span class="mw-page-title-main">Shovelnose guitarfish</span> Species of cartilaginous fish

The shovelnose guitarfish, Pseudobatos productus, is a ray in the family Rhinobatidae. It becomes mature at an estimated seven to eight years old. Males are between 90–100 cm (35–39 in) long, while females are around 99 cm (39 in) at that age. The ray can live up to 11 years, and full-grown sizes are around 120 cm (47 in) for males, and females reach 137 cm (54 in). They range from central California south to the Gulf of California. Morphological and genetic variations occur in the mitochondrial DNA in those found in the Gulf of California, evidencing their isolation from the rest. Because of this, the conservation of this species must be carefully managed to preserve the biological diversity. The shovelnose is considered to be a primitively developed ray, with many features of both sharks and rays.

<span class="mw-page-title-main">Black dogfish</span> Species of shark

The black dogfish is a species of dogfish shark in the family Etmopteridae. It is common over the outer continental shelf and continental slope at depths of 180–2,250 m (590–7,380 ft). Females generally inhabit deeper water than males, and depending on the region, smaller sharks may occur at different depths than larger ones. This species is distributed widely in the Atlantic Ocean, from Greenland and Iceland to Virginia and West Africa in the north, and off southwestern Africa and Argentina in the south. The largest member of its family, the black dogfish, typically measures 60–75 cm (24–30 in) long. It has a stocky, dark brown body that is darker below than above, and bears scattered, minute bioluminescent organs. Its two dorsal fins are preceded by stout spines, and the anal fin is absent.

<span class="mw-page-title-main">Urolophidae</span> Family of cartilaginous fishes

The Urolophidae are a family of rays in the order Myliobatiformes, commonly known as stingarees or round stingrays. This family formerly included the genera Urobatis and Urotrygon of the Americas, which are presently recognized as forming their own family Urotrygonidae. Stingarees are found in the Indo-Pacific region, with the greatest diversity off Australia. They are sluggish, bottom-dwelling fish that have been recorded from shallow waters close to shore to deep waters over the upper continental slope. Measuring between 15 and 80 cm long, these rays have oval to diamond-shaped pectoral fin discs and relatively short tails that terminate in leaf-shaped caudal fins, and may also have small dorsal fins and lateral skin folds. Most are smooth-skinned, and some have ornate dorsal color patterns.

<span class="mw-page-title-main">Daggernose shark</span> Species of shark

The daggernose shark is a little-known species of requiem shark, in the family Carcharhinidae, and the only extant member of its genus. It inhabits shallow tropical waters off northeastern South America, from Trinidad to northern Brazil, favoring muddy habitats such as mangroves, estuaries, and river mouths, though it is intolerant of fresh water. A relatively small shark typically reaching 1.5 m (4.9 ft) in length, the daggernose shark is unmistakable for its elongated, flattened, and pointed snout, tiny eyes, and large paddle-shaped pectoral fins.

<span class="mw-page-title-main">Spot-tail shark</span> Species of shark

The spot-tail shark, or sorrah shark, is a species of requiem shark, in the family Carcharhinidae, found in the tropical Indo-West Pacific Ocean between latitudes 31°N and 31°S from the surface to a depth around 72 m (236 ft). This shark grows to about 1.6 m. It is fished commercially over much of its range and the IUCN considers it to be near threatened.

<span class="mw-page-title-main">Barbeled houndshark</span> Species of shark

The barbeled houndshark is a species of ground shark and the only member of the family Leptochariidae. This demersal species is found in the coastal waters of the eastern Atlantic Ocean from Mauritania to Angola, at depths of 10–75 m (33–246 ft). It favors muddy habitats, particularly around river mouths. The barbeled houndshark is characterized by a very slender body, nasal barbels, long furrows at the corners of the mouth, and sexually dimorphic teeth. Its maximum known length is 82 cm (32 in).

<span class="mw-page-title-main">Spotless smooth-hound</span> Species of shark

The spotless smooth-hound is a species of houndshark, in the family Triakidae, found on the continental shelves of the northwest Pacific, between latitudes 40° N and 11° N, from the surface to a depth of 300 m. It can grow to a length of up to 1 m.

<span class="mw-page-title-main">African sawtail catshark</span> Species of shark

The African sawtail catshark is a species of catshark, part of the family Scyliorhinidae. Demersal in nature, it is found at depths of 160–720 m (520–2,360 ft) off the western African coast from Morocco to South Africa. This slender species has a rather long, pointed snout, a series of dark saddles along the back and tail, and a prominent crest of enlarged dermal denticles along the upper edge of the caudal fin. Its maximum known length is 46 cm (18 in).

<i>Rhina ancylostoma</i> Species of cartilaginous fish

Rhina ancylostoma, also known as the bowmouth guitarfish, shark ray or mud skate, is a species of ray and a member of the family Rhinidae. Its evolutionary affinities are not fully resolved, though it may be related to true guitarfishes and skates. This rare species occurs widely in the tropical coastal waters of the western Indo-Pacific, at depths of up to 90 m (300 ft). Highly distinctive in appearance, Rhina ancylostoma has a wide and thick body with a rounded snout and large shark-like dorsal and tail fins. Its mouth forms a W-shaped undulating line, and there are multiple thorny ridges over its head and back. It has a dorsal color pattern of many white spots over a bluish gray to brown background, with a pair of prominent black markings over the pectoral fins. This large species can reach a length of 2.7 m (8.9 ft) and weight of 135 kg (298 lb).

<span class="mw-page-title-main">Pale-edged stingray</span> Species of cartilaginous fish

The pale-edged stingray or sharpnose stingray is a species of stingray in the family Dasyatidae, found in the Indian and Pacific Oceans from India to the western Malay Archipelago and southern Japan. This bottom-dwelling ray is most commonly found over sandy areas shallower than 100 m (330 ft), as well as in estuaries. Measuring up to 29 cm (11 in) across, the pale-edged stingray has a diamond-shaped pectoral fin disc, a long projecting snout, small eyes, and a whip-like tail with both dorsal and ventral fin folds. It is chocolate brown above and white below.

<i>Rhinobatos</i> Genus of cartilaginous fishes

Rhinobatos is a genus of fish in the Rhinobatidae family. Although previously used to encompass all guitarfishes, it was found to be polyphyletic, and recent authorities have transferred many species included in the genus to Acroteriobatus, Glaucostegus, and Pseudobatos.

<span class="mw-page-title-main">Eastern shovelnose ray</span> Species of cartilaginous fish

The eastern shovelnose ray is a species of guitarfish in the family Rhinobatidae of order Rhinopristiformes. The species is endemic to the east coast of Australia and inhabits subtropical and temperate waters from southern Queensland to southern New South Wales.

<span class="mw-page-title-main">Common guitarfish</span> Species of cartilaginous fish

The common guitarfish is a species of cartilaginous fish in the family Rhinobatidae. It is native to the eastern Atlantic Ocean and the Mediterranean Sea. It is a bottom-dwelling fish feeding on crustaceans, other invertebrates and fish. The females give birth to live young. Its lifestyle makes it vulnerable to trawling and other fishing methods, populations seem to be declining and it has disappeared from parts of its range.

<span class="mw-page-title-main">Peppered maskray</span> Species of cartilaginous fish

The peppered maskray or speckled maskray, is a species of stingray in the family Dasyatidae, found in shallow waters off northeastern Australia. This small, thin-bodied ray attains a maximum width of 32 cm (13 in). It has a diamond-shaped pectoral fin disc with a row of tiny thorns along the midline, and a relatively short, whip-like tail with both upper and lower fin folds. Its upper surface has a speckled color pattern consisting of black spots and brownish reticulations on a light yellow to brown background.

<span class="mw-page-title-main">Tasmanian numbfish</span> Species of cartilaginous fish

The Tasmanian numbfish is a species of electric ray in the family Narcinidae. Endemic to southeastern Australia, this common ray inhabits shallow continental shelf waters in the southern portion of its range and deeper continental slope waters in the northern portion of its range. It prefers sand and mud habitats. This species can be identified by its spade-shaped pectoral fin disc with concave anterior margins, long tail with well-developed skin folds along either side, and plain dark brown dorsal colouration. Its maximum known length is 47 cm (19 in).

<i>Brevitrygon walga</i> Species of cartilaginous fish

Brevitrygon walga, the dwarf whipray or mangrove whipray, is a small stingray, a cartilaginous fish in the family Dasyatidae. It is a demersal fish and is found over the continental and insular shelf of the west central Pacific Ocean where it is heavily fished. The IUCN has assessed it as being "near-threatened".

<span class="mw-page-title-main">Blackchin guitarfish</span> Species of cartilaginous fish

The blackchin guitarfish is a species of cartilaginous fish in the family Rhinobatidae. It is native to the eastern Atlantic Ocean and the Mediterranean Sea. It is a bottom-dwelling fish feeding on crustaceans, other invertebrates and fish. The females give birth to live young. Its lifestyle makes it vulnerable to trawling and other fishing methods, populations seem to be declining and it is subject to intensive fishing pressure, with its fins being sold into the Asian market. The International Union for Conservation of Nature has assessed its conservation status as being "critically endangered".

<i>Acroteriobatus</i> Genus of cartilaginous fishes

Acroteriobatus is a genus of fish in the Rhinobatidae family. Although its constituent species were previously assigned to Rhinobatos, recent authors treat it as distinct.

<i>Pseudobatos</i> Genus of cartilaginous fishes

Pseudobatos is a genus of fish in the Rhinobatidae family. Although its constituent species were previously assigned to Rhinobatos, recent authors treat it as distinct.

References

  1. 1 2 3 Pollom, R.; Barreto, R.; Charvet, P.; Chiaramonte, G.E.; Cuevas, J.M.; Herman, K.; Martins, M.F.; Montealegre-Quijano, S.; Motta, F.; Paesch, L. & Rincon, G. (2020). "Pseudobatos horkelii". IUCN Red List of Threatened Species . 2020: e.T41064A2951089. doi: 10.2305/IUCN.UK.2020-3.RLTS.T41064A2951089.en . Retrieved 30 April 2023.
  2. 1 2 Bailly, Nicolas (2015). "Rhinobatos horkelii Müller & Henle, 1841". WoRMS. World Register of Marine Species . Retrieved 15 January 2016.
  3. Watkins, Michael; Beolens, Bo (2015). Sharks: An Eponym Dictionary. Pelagic Publishing Ltd. p. 69. ISBN   978-1-78427-037-7.
  4. 1 2 "Rhinobatos horkelii Müller & Henle, 1841: Brazilian guitarfish". FishBase. Retrieved 15 January 2016.
  5. Seeliger, Ulrich; Odebrecht, Clarisse; Castello, Jorge P. (2012). Subtropical Convergence Environments: The Coast and Sea in the Southwestern Atlantic. Springer Science & Business Media. pp. 174, 192. ISBN   978-3-642-60467-6.