Dipturus laevis (lat.) - a species of cartilaginous fish of the rhombic family of rays of the order of stingrays. They live in temperate waters of the central-western and north-western parts of the Atlantic Ocean between 51 ° С. w. and 33 ° c. W and between 84 ° C. D. and 42 ° C. They are found at a depth of up to 750 m. Their large, flattened pectoral fins form a rhombic disk with an elongated and pointed snout. The maximum recorded length is 152 cm. Eggs are laid. They are not the target fishing target [1] [2] [3] .
| Dipturus laevis |
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| No rank : | Bilateral symmetrical |
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Dipturus laevis ( Mitchill , 1818) |
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- Raja laevis Mitchill, 1818
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Endangered speciesIUCN 3.1 Endangered : 39771 |
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The species was first scientifically described in 1818 as Raja laevis [4] . Species epithet comes from the word Greek. λείος - “smooth”.
These demersal ramps inhabit the eastern coast of Canada and the United States. They are found along the continental shelf and in the upper part of the continental slope from the surf zone to 750 m, mainly not deeper than 150 m [3] , at temperatures from 0.4 to 20 ºC [2] .
The wide and flat pectoral fins of these rays form a rhombic disk with a rounded snout and rounded edges. On the ventral side of the disc are 5 gill slits, nostrils and mouth. On the long tail there are lateral folds. These skates have 2 reduced dorsal fins and a reduced caudal fin [1] . The middle row of spikes on the disk is missing. The front edge of the disc is concave. 3 rows of spines lie along the tail (one in the middle and two on the sides). Dorsal fins are located close to each other [5] . The dorsal surface of the disc is brownish in color with numerous dark spots, the ventral surface is white, covered with gray marks of irregular shape. Mucous pores are located on the occipital region [6] .
The maximum recorded length is 152 cm, and the mass is 18 kg [3] .
Like other rhombic, these stingrays lay eggs enclosed in a rigid horn capsule with protrusions at the ends. Embryos feed exclusively on yolk [3] . Males and females become sexually mature when they reach a length of 112 cm and 115 cm at the age of 10-14 years. Females lay up to 47 eggs per year. The diet consists of bivalves , squid , crab , lobster , shrimp , worms and fish [2] . On these slopes, cestodes Acanthobothrium coronatum , Grillotia erinaceus , Phyllobothrium dagnallium , trematodes Hemiurus levinseni , Pseudanisakis rotundata [7] and isopods Natatolana borealis [8] parasitize on these slopes.
These stingrays are caught as by-catch.
These skates are not subject to target fishing, but are caught in by- catch . In the waters of the United States for the period from 1960 to 1990, the number of this species in catches at a depth of up to 400 m decreased by 96–99%. The International Union for Conservation of Nature has assigned the species a Vulnerable status.
- ↑ 1 2 Froese, Rainer, and Daniel Pauly, eds. Family Rajidae - Skates (Neopr.) . FishBase
- ↑ 1 2 3 Dipturus laevis . The IUCN Red List of Threatened Species .
- ↑ 1 2 3 4 Dipturus laevis (English) in the FishBase database.
- ↑ Mitchill SL Memoir on Ichthyology. The fishes of New York, described and arranged (supplement) // American Monthly Magazine and Critical Review. - 1818. - No. 2 . - P. 241-248, 321-328.
- ↑ Robins, CR and GC Ray. A field guide to Atlantic coast fishes of North America. - Boston, USA: Houghton Mifflin Company, 1986. - P. 354.
- ↑ Bigelow, HB and Schroeder WC Sawfishes, guitarfishes, skates and rays = In Tee-Van J. et al. (eds.) Fishes of the western North Atlantic. Part two .. - New Haven, Sears Found. Mar. Res., Yale Univ., 1953. - P. 1-514.
- ↑ Betty J. Myers. Parasites from Elasmobranch Hosts from the Magdalen Islands Region of the Gulf of St. Lawrence // Canadian Journal of Zoology. - 1959-06-01. - T. 37 , no. 3 . - P. 245-246. - ISSN 0008-4301 . - DOI : 10.1139 / z59-029 .
- ↑ Plínio Soares Moreira, Victor Sadowsky. An annotated bibliography of parasitic Isopoda (Crustacea ) of Chondrichthyes // Boletim do Instituto Oceanográfico. - T. 27 , no. 2 . - P. 95-152. - ISSN 0373-5524 . - DOI : 10.1590 / S0373-55241978000200005 .
- Species Dipturus laevis (English) in the World Register of Marine Species .
