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Leucoraja erinacea

(Little common skate)

Overview

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Family : Skates ; Usually on sandy or gravelly bottoms from shoal waters to 90 m depth[1]. Mostly inactive during daylight, but active under dark conditions[2]. Oviparous . Distinct pairing with embrace. Young may tend to follow large objects, such as their mother [3]. Eggs are oblong capsules with stiff pointed horns at the corners deposited in sandy or muddy flats[3]. Egg capsules are 4.6-6.3 cm long and 2.7-4.8 cm wide, about 10-35 eggs are laid annually[4]. Possesses an electric organ located in the tail region[2]. Electric organ discharge (EOD) activity is intermittent [5] and seemed more frequent during dark periods[6]. The individual EOD of this species is monophasic, head-negative, and lasts 70 ms[5].

Near Threatened

Threat status

Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in Danish:

Lille rokke

Common Names in Dutch:

Kleine rog

Common Names in English:

common skate, Little common skate, little skate, Little summer skate, Raie-Chardon, summer skate

Common Names in French:

Raie Guitare, Raie H, raie hérisson, Raie-H, raie-hérisson, Raie-hérisson

Common Names in Mandarin Chinese:

猬鳐, 蝟鰩

Common Names in Polish:

Raja kanadyjska

Common Names in Portuguese:

Raia-De-Ver, Raia-de-verão

Common Names in Rumanian:

Vatos mic

Common Names in Swedish:

Igelkottsrocka

Description

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Physical Description

Species Leucoraja erinacea

Distinctive Features: The little skate has a very rounded snout and wings with a blunt nose. The two dorsal fins are located close together on the tail. The tail length for newly hatched young is about 1.1 times the length of the body (from snout to cloaca ) but decreases as they reach adulthood to about 0.85 to 0.95 the length of the body.

The little skate possesses an electrosensory known as ampullae of Lorenzini. This organ is found on the head and consists of many tiny gel filled canals. This organ allows it to detect weak electric fields produced by its prey . It is also believed that this organ might function like a compass with the earth's magnetic field. This species also has electric organs on the tail that consists of electrocytes but it produces weak electric fields. It is suspected that these electric organs are used more for conspecific communication and possibly mate location.

There has been one unusual specimen found near Fisher's Island, NY that showed hermaphroditism , which is extremely rare among elasmobranch fishes . The left side of the body contained large well-developed testis , vas deferens, and functional clasper while the right side had tiny/abortive clasper, adolescent ovary, shell gland , and a mature oviduct .

Dentition: The teeth of the little skate consist of about 38 to 66 series on jaw plates . The teeth are round shaped with faint transverse cutting edges . They use the teeth for grinding food between the two plates.

Denticles : When it is fully-grown, they are relatively small and no thorny spines are present along the midline of the back (unlike the young of this species). Females have spines scattered on the upper surface that are prominent on the head, snout, shoulders , and sides of the tail. Typically, spines are not found on the midline, back of the shoulder girdle but there have been exceptions to this generalization. Males tend to have fewer spines than the females since males lose most of the thorns from the inner parts of the pectorals and some from the mid-dorsal ridge as they mature. The spines that are located on the tail, shoulder, and on either side of the ridge of the back are quite strong in both sexes.

Color:

The dorsal surface ranges from grayish to dark brown or clouded light and dark brown. The edges of the pectoral fins are paler. There are usually small round darker spots found on the dorsal surface. The ventral surface is white or grayish. The tail has either irregular dusky blotches or dark gray lower surface.

Size/Age/Growth

The little skate commonly reach 16 to 20 inches (40.6-50.8 cm) long but a maximum size of 21 inches (54 cm) has been recorded. The disc is about 1.2 times as wide as it is long. At 16 to 17 inches (40.6-43.2 cm), they weigh about 3/4 to 1 pound (0.34-0.45 kg ) and can weigh from 1 1/3 to 2 pounds (0.59-0.91 kg) at 18 inches long. Little skates that are 8 inches (20 cm) long may be 1 to 1 1/2 years old, 11 3/4 to 12 inches (30 cm) 2-3 years, 15 3/4 to 16 inches (40 cm) 3 to 4 years, 19 3/4 to 20 inches (50cm) 6 to 8 years old. The mortality rate for this species seems to be very high after five years since very few that have been captured are longer than 18 to 19 inches. Females reach sexual maturity at 12 1/2 to 17 inches (32-43 cm), while males reach it at about 14 to 17 1/4 inches (35.5-43.8 cm) long.

Habitat

This species is typically found on sandy or gravely bottoms from shallow waters to 295.28 feet (90 m ) deep. They are most active during daylight hours. The little skate can tolerate a wide range of temperatures , from 89.6ºF (32ºC) to 158ºF (70ºC). The little skate can tolerate salinity ranges of 27 0/00 to 33.8 0/00 but their optimal range is 29 0/00 to 33 0/00. There are no reports of this species being found in freshwater and ones that have been placed in freshwater show physiological problems. The little skate does not appear to have large-scale migrations but they do move to shallower water during the summer and move to deeper water in fall or early winter.

Typically found in water with a depth of 0 to -5,095 meters (0 to -16,716 feet).[7]

Ecology: Habitat ranges from shallow shoal waters to 90 m depth, usually on sandy or gravelly substrates. This species reaches a maximum size of 60 cm total length (TL ) (Johnson 1979). Males and females mature at 35?50 cm TL and size at birth is 9.3?10.2 cm TL (McEachran 2002, Richards et al. 1963). Females produce 28?33 eggs per year after a gestation period of 9?12 months (Richards et al. 1963, Johnson 1979).

Little Skates make no extensive migrations, although where it occurs inshore the species moves onshore and offshore with seasonal temperature changes (Collette and Klein-MacPhee 2002). Common prey items include hermit and other crabs, shrimps, worms, amphipods , ascidians (sea squirts), bivalve mollusks, squid, small fishes , and even some copepods (Collette and Klein-MacPhee 2002). [8].

List of Habitats:

Biology

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Diet

Common prey items include hermit and other crabs, shrimps, worms, amphipods , ascidians (sea squirts), bivalve mollusks, squid, small fishes , and even some copepods .

Reproduction

Little skates are oviparous (egg layers). The male uses two long claspers , along the pelvic fins, to aid in transmitting sperm . They are known to copulate many times throughout the year and frequently. There seems to be a higher frequency of pregnant little skates from October to December and April to May while there is a low frequency from August to September and February to March. Eggs are laid throughout the year but appear to be highest from October to January and June to July. The egg capsule is amber or golden yellow when they are first laid. The oblong capsules have stiff pointed horns at the corners and are either deposited on sandy or muddy flats or attached to seaweed. The egg capsules are 1.8-2.5 inches (4.6-6.3 cm) long and 1-2 inches (2.7-4.8 cm) wide, and the female lays about 10-35 eggs annually. Yolk within the egg capsule contains all of the organic materials necessary for development until hatching . It takes about 5 to 6 months for the young to hatch under aquarium conditions. It is expected to be longer in nature, especially during autumn and early winter because of cooler temperatures . The young skates emerge from the capsule through a transverse opening at the edge with the longer pair of horns. The length of the young when hatched is about 3 ¾ to 4 inches (10 cm), its abdomen is still swollen with yolk, and the whiplash-like extension on the tail disappears within a few days. The whiplash-like embryo tail is believed to be used for water circulation in the capsule. After the young skates have hatched, the empty black capsules wash ashore.

Behavior

Predators:

Predators of the little skate include sharks (especially the sandbar shark ), other skates (including the winter skate), and gray seals.

Parasites:

The little skate is plagued by a variety of parasites. Protozoan parasites include Caliperia brevipes, Haemogregarina delagei, and Trypanosoma rajae. Chloromyxum leydigi and Leptotheca agilis are members of Myxosporida parasites. Pseudanisakis tricupola is the only species of nematodes to parasitize them. Eudactylina corrugata and Lernaeopodina longimana are members of Copepoda that have been found as well.

Taxonomy

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Synonyms

Leucoraja erinacea • Megathopomima magnifica • Megathopomima magnifica Balthasar • Megathopomima magnifica BALTHASAR, 1939 • Raia erinacea Mitchill • Raja erinacea Mitchill • Raja erinaceus • Raja erinaceus Mitchill

Notes

Name Status: Accepted Name .

Last scrutiny: Data last modified by FishBase 30-Sep-1999

Sympatric to the Winter Skate (Leucoraja ocellata), immature Little Skates are often confused with immature Winter Skates (especially females). However, the probability of misidentification decreases with skate size as they mature . Skates originally identified as little skate in the Gulf of St . Lawrence were later confirmed as winter skate.[8].

Similar Species

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While the winter skate (Leucoraja ocellata) typically has oscillated spots, individuals that lack these spots are often confused with little skates.

Members of the genus Leucoraja

ZipcodeZoo has pages for 17 species and subspecies in this genus:

L. caribbaea (Maya Skate) · L. circularis (Cuckoo Ray) · L. compagnoi (Tiger-Tail Skate) · L. erinacea (Little Summer Skate) · L. fullonica (Shagreen Ray) · L. garmani (Rosette River Stingray) · L. garmani garmani (Freckled Skate) · L. garmani virginica (Leopard Skate) · L. lentiginosa (Speckled Skate) · L. leucosticta (Whitedappled Skate) · L. melitensis (Maltese Skate Or Ray) · L. naevus (Butterfly Skate) · L. ocellata (Winter Big Skate) · L. pristispina (Sawback Skate) · L. virginica (Virginia Skate) · L. wallacei (Yellospotted Skate) · L. yucatanensis (Yucatan Whiteskate)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 29, 2008:

Identifiers

Footnotes

  1. Robins, C.R. and G.C. Ray (1986). A field guide to Atlantic coast fishes of North America. Houghton Mifflin Company, Boston, U.S.A. 354 p. [back]
  2. Bratton, B.O. and L.J. Ayres (1987). Observations on the electric organ discharge of two skate species (Chondrichthyes: Rajidae) and its relationship to behavior. Environ. Biol. Fish. 220:241-254. [back]
  3. Breder, C.M. and D.E. Rosen (1966). Modes of reproduction in fishes. T.F.H. Publications, Neptune City, New Jersey. 941 p. [back]
  4. Bor, P. (2002). Egg-capsules of sharks and skates. www.rajidae.tmfweb.nl/rogtabel.html [back]
  5. Moller, P. (1995). Electric fishes: history and behavior. Chapman & Hall, London. 584 p. [back]
  6. Mortensen, F.J. and R.H. Whitaker (1973). Electric discharge in free-swimming female winter skates (Raja ocellata). Am. Zool. 13:1266. [back]
  7. Mean = -212.340 meters (-696.654 feet), Standard Deviation = 517.350 based on 8,310 observations. Ocean depth information for each observation from British Oceanographic Data Centre. [back]
  8. Sulikowski, J., Kulka, D.W. & Gedamke, T. 2009. Leucoraja erinacea. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 01 February 2012. [back]
Last Revised: 7/15/2012