Brevitrygon walga

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Dwarf whipray
Himantura walga.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Superorder: Batoidea
Order: Myliobatiformes
Family: Dasyatidae
Genus: Brevitrygon
Species:
B. walga
Binomial name
Brevitrygon walga
(Müller & Henle, 1841) [2]
Synonyms [2]
  • Himantura walga(Müller & Henle, 1841)
  • Himantura heterurus (Bleeker, 1852)
  • Himantura nuda (Günther, 1870)
  • Himantura uylenburgi (Giltay, 1933)
  • Trygon walga Müller & Henle, 1841

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".

Contents

Description

The dwarf whipray has a maximum length of 45 cm (18 in). [2] The disc width is commonly about 24 cm (9 in). [1] In outline it is oval with a bluntly-pointed snout. The whip-like tail is longer than the body and lacks the skin fold found in some related species. Females have a shorter tail than males, with a bulbous tip, and both sexes have four to six erectile, venomous spines at the base of the tail. The dwarf whipray is a uniform pinkish or beige colour and has been mistaken for a horseshoe crab in turbid water. [3]

Distribution and habitat

The dwarf whipray is found in the western central Pacific Ocean. Its range extends from Thailand, Cambodia and Vietnam to Singapore, Malaysia, the Philippines and Indonesia. It has been recorded from India, but may have been confused there with the scaly whipray (Brevitrygon imbricata). It occurs close to the sandy seabed on the inner continental shelf at depths usually less than 50 m (164 ft). [1]

Biology

The dwarf whipray reaches maturity at a length of about 17 cm (7 in). Mating occurs when the male grasps the female with their ventral surfaces in contact. This fish is viviparous, giving birth to one or two young at a time. The gestation period is not known, but before birth, the pups are fed on secretions from the uterine wall, a process known as histotrophy. [1]

Use

The dwarf whipray is caught, largely as bycatch, over most of its wide range. Trawling for batoids is common in many places and trammel netting, in which the fish get entangled in the fine-meshed central net of a three-part net, is used over much of its range. The fish is used for human consumption, but is not specifically targeted, probably because of its small size. [1]

Status

The International Union for Conservation of Nature has assessed the conservation status of the dwarf whipray as being "near-threatened". The organisation considers the fish is experiencing intense fishing pressure over much of its range and is being over-exploited. Its abundance appears to be falling and the size of the fish caught also seems to be declining. [1]

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

The leopard whipray is a little-known species of stingray in the family Dasyatidae, found in the Indian and Pacific Oceans from the Andaman Sea to the Coral Triangle. It is found close to shore at depths shallower than 70 m (230 ft), over soft substrates. Attaining a width of 1.8 m (5.9 ft), this species has a diamond-shaped pectoral fin disc with a pointed snout and an extremely long, whip-like tail without fin folds. Adult rays have a leopard-like dorsal pattern of dark brown rings on a yellowish brown background, as well as a row of enlarged, heart-shaped dermal denticles along the midline of the disc. Newborns and small juveniles have large, solid dark spots and few denticles. The leopard whipray is caught by fisheries in many parts of its range, primarily for meat.

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

The honeycomb whipray is a species of stingray in the family Dasyatidae, found widely in the shallow coastal waters of the Indo-Pacific from India to the Malay Archipelago. This large species grows to 1.3 m (4.3 ft) across and has a diamond-shaped disc with rounded corners and a projecting, pointed snout. Its tail is long and whip-like, without fin folds. Adults have a striking dorsal color pattern consisting of large, dark brown rings and reticulations delineated by thin yellow lines, while juveniles have a pattern of large dark spots. This ray can also be distinguished from its similar relatives by an enlarged, pearl-like dermal denticle at the center of the back, which is followed by a few thorns. The International Union for Conservation of Nature (IUCN) has assessed the honeycomb whipray as endangered, as it faces heavy fishing pressure and habitat degradation across much of its range.

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

The whitenose whipray or Bleeker's whipray is a species of stingray in the family Dasyatidae native to the eastern Indian Ocean and the western central Pacific Ocean, where it is found in shallow water including estuaries.

References

  1. 1 2 3 4 5 6 Simpfendorfer, C.; Moore, A.; Elhassan, I.; Owfi, F.; Akhilesh, K.V. (2017). "Brevitrygon walga". IUCN Red List of Threatened Species . 2017: e.T104176764A111015783. doi: 10.2305/IUCN.UK.2017-2.RLTS.T104176764A111015783.en . Retrieved 11 November 2021.
  2. 1 2 3 "Himantura walga (Müller & Henle, 1841)". FishBase. Retrieved 2015-05-18.
  3. "Mangrove whipray: Himantura walga". Wild Singapore. Retrieved 2015-05-18.