Dipturus laevis

(MITCHILL, 1818)


Barndoor skate
Classification: Elasmobranchii Rajiformes Rajidae

Reference of the original description
MITCHILL, S.L. (1818)
Memoir on Ichthyology. The fishes of New York, described and arranged (supplement). American Monthly Magazine and Critical Review, 2: 241–248, 321–328

Image of the original description
No image in first description.

Synonyms / new combinations and misspellings
Raia laevis, Raja laevis

Types
Dipturus laevis



Description :


Citation: Dipturus laevis (MITCHILL, 1818): In: Database of modern sharks, rays and chimaeras, www.shark-references.com, World Wide Web electronic publication, Version 05/2019

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Common names
fra \(T\) Grande raie, eng Barn-door skate, eng Barn-door winter skate, eng Barndoor skate

Short Description
Disk broad, with sharply angled corners and a pointed snout; front edges concave. No middorsal spines on disk. Tail with 3 rows of spine (1 middorsal row and 1 row on each side). Dorsal fins close together [17658]. Upper surface brownish, with many scattered small dark spots. Mucous pores on nuchal region. Lower surface white, blotched irregularly with gray [199].

Distribution
Western Atlantic: Grand Bank and southern Gulf of St. Lawrence in Canada to North Carolina, USA. Threatened with extinction by intensive trawling [20203]. Source: www.gbif.org

Human uses
fisheries: of no interest; gamefish: yes

Biology
Oviparous, paired eggs are laid. Embryos feed solely on yolk [733]. Distinct pairing with embrace. Young may tend to follow large objects, such as their mother [17086]. Occurs from water"quot;s edge to 430 m depth; absent from shoal waters in south during warm months. Lives on all kinds of bottom [4625]. It tolerates a wide temperature range (1.2-20°C). Voracious predator(Ref. 5951); feeds on bivalve mollusks, squids, rock crabs, lobsters, shrimps, worms and fishes [4625]. Food also includes fishes like spiny dogfish, alewife, Atlantic herring, butterfish, sand lance, cunner, hakes and flatfishes. Parasites of the species include 1 turbellarian, 3 trematodes, 4 cestodes, 2 nematodes and 4 copepods, found on gills, skin and digestive tract; infestation is relatively severe (Ref. 5951).
Diet (Georges Bank, Atlantic, data: 273 individuals, 20 to 133.5 cm TL): [23013]A total of 31 prey species were identified. The Barndoor Skate feeds primarily upon sand shrimp Crangon septemspinosa, the rock crab Cancer irroratus, the Acadian hermit crab Pagurus acadianus, and teleost fish. Length-specific analysis revealed four significant feeding groups (ANOVA: P < 0.01). Skate < 35 cm TL were specialized feeders foraging solely on caridean shrimp, and as size increased (35–75 cm TL), they began to feed upon rock crab and then the Acadian hermit crab. At lengths ranging from 85 to 105 cm TL, no caridean shrimp were found in the skate’s diet and the prevalence of crustaceans decreased. Large skate (>105 cm TL) began to prey heavily upon teleost fish, yet also continued to consume larger crustaceans. Significant sex-specific differences in food habits were also observed in the biggest skate (>105 cm TL): males fed primarily on teleost fish (»80%); however, females maintained a diet of approximately equal amounts of fish and crustaceans.

Size / Weight / Age
152 cm TL (male/unsexed; (Ref. 5951)); max. published weight: 18.0 kg [17658]

Habitat
demersal; oceanodromous [17660]; marine; depth range 0 - 750 m (Ref. 55276), usually 0 - 150 m (Ref. 55276)

Remarks
shark-references Species-ID=2007;

Parasites (arranged by Jürgen Pollerspöck)
Monogenea
  • Rajonchocotyle laevis PRICE, 1942 [17205]

Cestoda
Trematoda
  • Hemiurus levinseni ODHNER, 1905 [12575]
  • Steganoderma formosum STAFFORD, 1904 [12575]
  • Stichocotyle nephropis CUNNINGHAM, 1887 [25979]

Nematoda
  • Anisakis sp. [12575]
  • Pseudanisakis rotundata (RUDOLPHI, 1819) [12575]

Isopoda
  • Natatolana borealis (LILLJEBORG, 1851) [23898]