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Rays are a family of animals with more than 200 species worldwide .
Rays are commonly found in abundance in the world's waters, and they are often caught as a by-product of fishing trawlers, so some species are now critically endangered. When prepared properly, the meatiness of the skates complements the consistency and flavor of the scallops. In fact, ice skating dishes are now on the menus of many Michelin-starred restaurants.
3 Surprising Facts:
- A gigantic liver: Rays have one of the largest livers in the animal kingdom! Its liver makes up a quarter of its body weight. In comparison, the human liver makes up 2% of body weight! This large liver helps the ray stay close to the bottom of the ocean.
- Spiny Defense: While stingrays utilize their barbed tails for defense, rays' bodies are made of a "thorny" material that helps protect them.
- "Mermaid pouch:" Unlike stingrays that give birth live, rays lay eggs. The pouches containing these eggs are called "mermaid pouches". It's not uncommon to find them washed up on beaches around the world!
Rays are cartilaginous fish that belong to the class Chondrichthyes, which also includes sharks, stingrays, and chimeras. Although these fish have no bones, leaving limited fossil evidence, modern skates are believed to have evolved during the Jurassic period (200 to 145 million years ago).
However, more than 400 million years ago, the first animals to leave the ocean and start walking on land were related to rays, the last common ancestor of sharks and mammals. Gene and brain studies have shown that roller skates have the makings of walking animals, and they can still "walk" on the ocean floor.
Rays belong to the order Rajiformes , which contains more than 200 species distributed in four families. These other families include smooth-nosed skates, soft-nosed skates, and midget skates.
The largest ray family is Rajidae, with 159 described species in 16 genera at the end of 2020. An example of a scientific name for a specific skate species is the big skate, which was named Raja binocular.
Knowledge of skateboarding taxonomy continues to grow. Because these bottom dwellers typically live at depths as deep as 8,900 feet, new species and genera will likely continue to be discovered in the coming years. In fact, in the past ten years (2011-2020), six new skates have been discovered!
The geographic range of most rays is relatively narrow . For example, eight different species of rays are endemic to the waters around New Zealand.
Some notable ray species include:
- Big Skate : Found from Baja California all the way to Alaska, the Big Skate is one of the largest species of skates, reaching up to 8 feet in length and weighing up to 200 pounds.
- Deep Sea Skate : A type of skate that lives on the bottom of continental slopes and has been found living at depths of 8,900 feet!
- Arctic skate : Widely distributed skate that lives in the frigid waters off Greenland and the frigid waters off Antarctica.
- Common Skates : Contrary to its name, common skates are now critically endangered.
Rays can come in extremely unique shapes, colors, and even sizes! While large rays can reach lengths of up to 8 feet and weigh up to 200 pounds, most rays are less than 3 feet long and weigh 10 pounds or less.
There are about 200 species of rays, all of which vary widely in appearance. The most common color is a "brownish" hue that helps the species blend into the seafloor; however, some skate varieties have dots or other markings. Additionally, skates tend to have "diamond" or even round body shapes.
Comparison with Stingray
Skates and rays look very similar, but they have some key differences that separate them into separate families.
- Eggs and Live Birth: Rays lay eggs, which they keep in protective pouches called "mermaid pouches," and the rays give birth to offspring.
- Different Tail: The tail of the ray has a sharp barb at the end, which is used for defense. Rays do not have such barbs on their tails, but instead use "spiny" skin as their primary defense against predators.
- Dorsal Fin: Skates usually have one or two dorsal fins (fins used for stability). Rays either lack a dorsal fin or have a small stump.
- Size: Skates are usually smaller than rays. The largest species of ray—the giant manta ray—can have a wingspan of 29 feet and weigh up to 3,600 pounds. Compare that to the biggest skates that only weigh about 200 lbs!
In addition to these differences, rays and skates also have important differences in their teeth and habitat (rays generally prefer to live in deeper waters).
Distribution and Habitat
Rays are found in the world's oceans. Different skating species inhabit environments ranging from the shallow mouths of river deltas all the way to depths of up to 8,900 feet on the outer continental shelf.
There are skates for both cold and temperate climates. The species can be found near the equator all the way to Antarctica in the southern hemisphere and Greenland in the northern hemisphere. When rays lie on the bottom of the ocean, they breathe through blowholes located behind their eyes. These specially evolved openings allow the rays to breathe oxygenated water while buried in the sand near the ocean floor.
Reproduction, Eggs, and Lifespan
The rays reproduce with eggs placed in "mermaid pouches" made of collagen, which provide extra protection from bottom predators. Skate embryos usually live in these pouches for about 3 months (12 weeks) before breaking free. When they are ready to leave the protection of the bag, they will grow to about twice the size of the bag (usually about 4 inches to 6 inches).
Since skates mostly live in deeper environments and are difficult to observe, estimating their exact lifespan is a challenge. However, scientists put the lifespan of the common ray at 50 to 100 years. Other species may have shorter lifespans. For example, the useful life of winter skates is estimated to be about 20 years.
Some rays are very long-lived, meaning it can take 10 years or more to reach maturity, making repopulation challenging. Most rays lay many eggs (the common ray lays about 40), but very few of these eggs lead to a mature ray.
Most ray species are considered abundant, but trawling has led to a reduction in the estimated biomass of many rays.
Common skates are now listed as critically endangered and protected in the European Union. The spiked skate is on the decline in the United States, but in 2017 the Department of Fisheries ruled that it didn't need protection under the Endangered Species Act. Although the species is in decline, the final report on its status states that populations of thorn rays are still estimated to be in the hundreds of millions.
Many rays are abundant and are often caught as by-products by fishing trawlers. Traditionally, rays are not cooked as often as other fish, but its use in cooking is increasing.
One of the challenges of cooking rays is that, like other cartilaginous fish such as sharks, rays carry urea in their tissues. This can lead to an ammonia-like smell if not prepared properly. Most skates with this foul smell are the result of improper storage and handling.
Skateboards can now be found on the menus of Michelin-starred restaurants like Le Bernardin in New York City. Additionally, rays are considered a delicacy in other cultures in different preparations. In South Korea, the city of Mokpo is known for its pungent-smelling ice skating discs filled with fish.
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Rays feed primarily on small invertebrates that live on the ocean floor. Their diet consists of shrimp, crab, fish, clams and molluscs.
The biggest challenge in eating ray is getting the meat properly processed without the "ammonia-like" smell. If you can find skates that are handled properly, the flavor is often on par with scallops, and is featured in several high-end restaurants. Rays are often served with brown butter or other sauces that go well with the fish.
Sea ray is just another name for ray. They are also known as "skateboard wings" and other names. Importantly, a ray is not a ray, and there are very significant differences between the two fish families.
Most of the 200 species of rays are abundant. Over the past 40 years, many species have suffered biomass losses from trawling, which often results in them being caught as by-products. The common skate is listed as a critically endangered species and is protected across the European Union.
Skate Fish belongs to Kingdom Animalia.
Rays lay eggs.
Although both are cartilaginous fish, there are major differences between rays and stingrays. First, the stingray is dangerous, while the other is relatively harmless. The tail of a ray is usually thicker and shorter than that of a stingray. They also have different teeth and even reproduce and give birth in completely different ways. But that's not all there is to know about these fascinating fish.