Undulate ray

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Undulate ray
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Batoidea
Order: Rajiformes
Family: Rajidae
Genus: Raja
Species:
R. undulata
Binomial name
Raja undulata

The undulate ray (Raja undulata) is a species of

Mediterranean and East Atlantic from southern Ireland and England to the Gulf of Guinea.[1] It is found in areas with mud or sand, and may occur as deep as 200 m (660 ft), though it prefers shallower depths.[1] It is considered endangered due to overfishing.[1]

Description

The undulate ray features a disc-shaped body, triangular in the front and near-circular in the rear, and

gill slits. Tail is as long as body, and has two well separated dorsal fins near its end, usually with two spines between them. The colouring of the dorsal surface varies from light brown to citrine or grey, with darker waved bands and numerous small white patches. Snout and margins are frequently clearer with dark spots.[3] The underside is creamy-white with a greyish margin. It typically weighs about 10 lb (4.5 kg), but can reach to as much as 22.13 lb (10.04 kg) and 100 cm (39 in) in length.[4]

Distribution and habitat

This species has a patchy and discontinuous distribution in northeastern Atlantic. It is found from southern

continental slope, even if it's sometimes possible to find it in shallower water.[7]

Biology

Young Raja undulata at the Aquarium of Genoa

There are few data about biology of this species. Using vertebrae as growth markers,

maximum lifespan was supposed to be 21–23 years.[8]
It's an
mermaid's purse" (as are the eggcases of other rays, skates and sharks). They usually are 72– 90 mm long and 42– 52 mm wide. These "purses" often wash up on beaches after rough weather, although usually they wash up empty, the young ray having already hatched out.[10]

Diet

The ray eats small

molluscs and other macrobenthos.[2]

Human interactions

Like other benthonic species of similar size this ray is caught incidentally or intentionally by commercial fisheries using

gillnets, and line gears.[5] It is a common host in public aquariums
as fares relatively well.

Protection

Because of its late sexual maturity and low rate of population growth, undulate ray is extremely vulnerable to exploitation by fisheries.[11] In the north Atlantic, populations have declined severely from the Irish area, and there are no longer records of catches of this species in the English Channel. Since 2009 it has been illegal to keep Undulate Rays fished in EU waters due to concerns over the decreasing size of stocks. They must be returned unharmed if possible.[12]

Reproduction

During a study it was found that the gonadosomatic index for the females was higher in the winter, which means that this specie reproduces during this season. Females also matured at significantly larger sized and older ages than males.[13]

References

  1. ^
    doi:10.2305/IUCN.UK.2009-2.RLTS.T161425A5420694.en. Retrieved 20 November 2021.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  2. ^ a b Hurst, Richard. "Undulate ray Raja undulata" (PDF). Shark Trust. Retrieved 4 January 2015.
  3. ^ "Undulate ray (Raja undulata)". Marine Species Identification Portal. KeyToNature Project Consortium. Retrieved 4 January 2015.
  4. ^ "Undulate Ray (RAJA UNDULATA)". the European Federation Of Sea Anglers. Retrieved 4 January 2015.
  5. ^ a b "Raja undulata Undulate Ray". Encyclopedia of Life. Retrieved 4 January 2015.
  6. ^ Guide of Mediterranean Skates and Rays (Raja undulata). Oct. 2022. Mendez L., Bacquet A. and F. Briand.http://www.ciesm.org/Guide/skatesandrays/raja-undulata
  7. PMID 22497373
    .
  8. ^ Coelho R, et al. (September 2002). Fisheries Biology of the Undulate Ray, Raja undulata , in the Algarve ( Southern Portugal) (PDF). Northwest Atlantic Fisheries Organization Scientific council meeting. Retrieved 4 January 2015.
  9. ^ Pollerspöck, Jürgen. "Raja undulata LACEPÈDE, 1802". www.shark-references.com. Retrieved 4 January 2015.
  10. ^ "Skate and Ray Eggcase Identification Guide" (PDF). Marine Conservation Society. Retrieved 4 January 2015.
  11. doi:10.1016/j.fishres.2006.05.017
    .
  12. ^ Rossell, Robert. "Raja undulata – undulate ray". National Museums Northern Ireland. Retrieved 4 January 2015.
  13. ^ Universidade do Algarve, Faculdade de Ciências do Mar e Ambiente/Centro de Ciências do Mar, Campus de Gambelas, 8000 Faro, Portugal

External links

Wikimedia Commons has media related to Raja undulata.
Wikispecies has information related to Raja undulata.
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