How many species of skates are there

The smallest skate is the starry skate Raja stellata which only reaches a maximum total length of 30 inches 76 cm. Are rays and skates related to sharks? Rays, skates, and sharks all belong to the class Chondrichthyes Greek, chondro meaning cartilage and ichthos meaning fish. Characteristics of Chondrichthyes include a skeleton made of cartilage, jaws, paired fins, and paired nostrils. The subclass Elasmobranchii includes sharks, rays, and skates.

Elasmobranchs are characterized by cylindrical or flattened bodies, five to seven pairs of gill slits, an upper jaw not fused to the cranium, and placoid scales. Placoid scales, also referred to as dermal denticles, have the same structure as a tooth consisting of three layers.

These scales are arranged in a regular pattern on sharks and irregular patterns on rays and skates. Is it easy to distinguish rays and skates from sharks?

The primary characteristic of dorso-ventrally flattened bodies makes rays and skates easy to distinguish from sharks.

Where in the world do rays and skates live? Rays and skates live in oceans throughout the world. Most rays and skates are benthic while some are pelagic. Some rays also live in freshwater habitats. In Florida, the Atlantic stingray Dasyatis sabina is known to live in freshwater along the St.

Johns River waterway as well as inland freshwater lakes. These populations of the Atlantic stingray are unique in that they spend their entire life cycle in freshwater. Are stingrays dangerous to humans? Stingrays have venomous spines along or near the base of the tail. See the full list of sharks and fishes species. The reef manta ray. Follow the links to profiles on each of the fishes with full information and pictures.

Dasyatis americana. Dasyatis brevicaudata. Dasyatis centroura. Dasyatis kuhlii. Dasyatis margarita. Dasyatis sabina. Dasyatis say. Pteroplatytrygon violacea. Jennifer Kennedy, M. Updated August 31, Featured Video. Cite this Article Format. Kennedy, Jennifer. Skate Characteristics and Information. Little Skate Characteristics and Information. Your Privacy Rights.

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Although oviparous species provide no parental care in the form of nutrients after the egg is deposited, little is known about "parental care" in oviparous elasmobranchs. None are known to actively guard their eggs or build nests, but it is possibel that egg-laying elasmobranchs select appropriate substrate for their eggs so as to maximize the chances of survival of the developing embryos. The females of at least one species of bullhead shark family Heterodontidae are known to pick up their eggs in their mouths and then wedge them into rocks and marine vegetation.

Northwest Atlantic skates in a holding tank at BIO. Skates are oviparous, laying tough egg cases also called "mermaids purses" on the seafloor from which miniature skates hatch.

A newly hatched thorny skate Amblyraja radiata. Note the swelling of the body cavity, indicating the presence of an internal yolk sac. The egg capsule of a thorny skate Amblyraja radiata , with one wall cut away to reveal a developing embryo. Mating behaviour has been observed in the wild in very few species of elasmobranch.

Only five of the more than species of batoids have been observed copulating in the wild, leaving most aspects of their natural sexual behaviour unknown.

Female receptivity to copulation likely depends on hormonal status. For example, the process of parturition might produce some form of sexual pheromone or olfactory attractant for male rays. Precopulatory mating behaviour i. For example, male eagle rays Aetobatis narinari dive upon and gouge the back of females during courtship, and the copulatory bites of the male roughtail stingray Dasyatis centroura , round stingray Urolophus halleri and the bullseye stingray Urolophus concentricus - among others - can inflict lasting scars on the female.

Mating and insemination is often a long, drawn-out process, especially in batoids, where copulation can last for several hours.

In some species of elasmobranch, sperm are then stored in the nidamental gland of the female, in some cases for months or longer, before they are released to fertilize ovulated ova. A barndoor skate Dipturus laevis captured aboard a commercial longline vessel. Many species of skates are rays are becoming increasingly important in fisheries around the world.

Skates, for example, have edible "wings", the flesh of which is firm, white, sweet and similar in texture and taste to that of scallops. In the eastern Atlantic , skate meat is esteemed, and skate wings are eaten fresh, salted, or smoked.

In the northwest NW Atlantic, on the other hand, skates were fished primarily for use in fish meal and pet food, and occasionally in the preparation of imitation scallops, until declines in traditional groundfish species - such as Atlantic cod Gadus morhua - brought about an increase in "alternative" fisheries. Today, NW Atlantic skates are considered quality food items, with commercial fisheries aimed primarily at winter skate Leucoraja ocellata and thorny skate Amblyraja radiata.

These two species are caught with longlines, gillnets, and trawls, and their large pectoral fins are commercially marketed up and down the coast of North America as well as overseas in Europe. Figure from Recovery potential assessment of 4T and 4VW winter skate Leucoraja ocellata : biology, current status and threats. Swain, J. Simon, L.

Harris, and H. Unfortunately, along with capture in directed fisheries, NW skates have and continue to be subjected to enhanced mortality through indirect fishing pressure. Skates are caught unintentionally i. Annual discards of skates have fluctuated in most areas, although in some areas such as the northeast coast of the US, the biomass of total discards was estimated to be two to eight times the reported landings It is currently not known whether the skates that are discarded survive, and if so, how many.

Moreover, in Canada, skate landings are not consistently identified by species, but are instead classified as "skates unspecified", making it difficult to access the status of each skate species separately.