Atlantic sawtail catshark facts for kids
Quick facts for kids Atlantic sawtail catshark |
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| Conservation status | |
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| Genus: |
Galeus
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| Species: |
atlanticus
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| Range of the Atlantic sawtail catshark | |
| Synonyms | |
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Pristiurus atlanticus Vaillant, 1888 |
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The Atlantic sawtail catshark (Galeus atlanticus) is a type of catshark. It's part of the family called Scyliorhinidae. This shark lives in a small area of the northeastern Atlantic Ocean. You can find it near the Strait of Gibraltar and the Alborán Sea.
It usually lives on or near the ocean floor. This is on the continental slope, which is the part of the ocean floor that slopes down from the land. It mostly lives at depths of about 400 to 600 meters (1,300 to 2,000 feet).
This shark looks a lot like another shark called the blackmouth catshark (G. melastomus). For a long time, people thought they were the same species! Both are thin sharks. They have dark saddle-like marks and blotches along their backs and tails. They also have a special crest of rough skin, like tiny teeth, along the top edge of their tail fin. This crest looks a bit like a saw, which is how it got its name.
The Atlantic sawtail catshark is a oviparous animal. This means the females lay eggs. They can carry several eggs at once. These sharks mate and lay eggs all year round.
Fishermen sometimes catch this shark by accident. This is called bycatch. It happens when they are fishing for other deep-sea animals. Scientists are not sure how much fishing affects their numbers. This is because they are often counted as blackmouth catsharks. Because it lives in a small area, the International Union for Conservation of Nature (IUCN) says it is "Near Threatened". This means it could become endangered in the future.
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What is the Atlantic Sawtail Catshark?
The Atlantic sawtail catshark was first described in 1888. A French naturalist named Léon Louis Vaillant gave it the name Pristiurus atlanticus. He wrote about it in a science book. Vaillant studied a shark caught off Cape Spartel in northwestern Morocco. It was found at a depth of 540 meters (1,770 feet).
For many years, people thought this shark was the same as the blackmouth catshark. But in 1985, scientists Ramón Muñoz-Chápuli and A. Perez Ortega showed they were different. Later, in 2007, more studies confirmed this. They looked at the sharks' body shapes and their mitochondrial DNA. This DNA is like a special code that helps tell species apart.
Where Does the Atlantic Sawtail Catshark Live?
The Atlantic sawtail catshark lives in the ocean from Cape St. Vincent in southwestern Portugal. Its home stretches through the Strait of Gibraltar into the Alborán Sea. It goes as far as Cabo de Gata in southwestern Spain.
It is most common in the middle of the Alborán Sea. You can also find many around Isla de Alborán. This shark has been seen a few times off Morocco. It was also seen once off Mauritania. It might be very rare in those areas. Or, people might mistake it for the blackmouth catshark.
Scientists think its total home area is about 50,000 square kilometers (19,000 square miles). This area is split almost evenly between the northeastern Atlantic and the western Mediterranean.
This shark lives on the ocean floor. It prefers the continental slope. It lives at depths between 330 and 790 meters (1,080 and 2,590 feet). It is most common between 400 and 600 meters (1,300 and 2,000 feet). There is one rare record of it living in shallower water, less than 50 meters (160 feet) deep.
These sharks do not separate by sex or size. They also do not travel long distances during different seasons.
How to Identify an Atlantic Sawtail Catshark
The Atlantic sawtail catshark can grow up to 45 centimeters (18 inches) long. It has a thin, firm body. Its head is a bit flat with a medium-long, flat snout. Its head is shorter and narrower than the blackmouth catshark's. Its nostrils are also farther from the tip of its snout.
The nostrils have small, triangular skin flaps. Its eyes are shaped like horizontal ovals. They have small, protective third eyelids called nictitating membranes. There's a small ridge under each eye. A tiny hole called a spiracle is behind each eye.
Its mouth is large, wide, and curved. It has long grooves around the corners. Its small teeth have a narrow point in the middle. They also have several smaller points on each side. It has five pairs of gill slits, which help it breathe.
The first dorsal fin is above the back part of its pelvic fins. The second dorsal fin is above the back part of its anal fin. Both dorsal fins are angled and similar in size. Its pectoral fins are large and wide with rounded edges. The short pelvic fins are close to the anal fin. The anal fin is long and angled.
The part of its body before the tail, called the caudal peduncle, is flat from side to side. It is taller than in the blackmouth catshark. The caudal fin (tail fin) is low. It has a small lower part and a notch near the tip of the upper part.
Its skin is covered in tiny, tooth-like scales called dermal denticles. Each scale looks like a leaf with a ridge in the middle and three small teeth on the edge. A clear crest of larger scales runs along the front of the top edge of its tail fin.
The shark is gray on top and pale underneath. It has dark gray saddle-like marks or blotches along its back and tail. The dorsal fins are dark at the bottom and lighter towards the back edges. The back edge of the tail fin is black. The inside of its mouth is also black. The grooves at the corners of its mouth are dark. This is different from the blackmouth catshark, which has light grooves there.
Life and Habits of the Atlantic Sawtail Catshark
The Atlantic sawtail catshark is not as common as the blackmouth catshark. Both sharks live in the same areas. Scientists don't know much about the Atlantic sawtail catshark's daily life.
It reproduces by laying eggs. This is called being oviparous. They mate and lay eggs all year long. Females can have up to nine eggs developing inside them at one time. These eggs are split between two special tubes called oviducts.
The egg case is tough and reddish. It is shaped like a flask. It has a rounded bottom and two "horns" at the top. It measures about 3.1 to 3.8 centimeters (1.2 to 1.5 inches) long. It is about 1.1 to 1.3 centimeters (0.43 to 0.51 inches) wide. The egg case of the blackmouth catshark looks similar but is much bigger. Once the egg is laid, the baby shark hatches fairly quickly.
Male sharks become ready to reproduce when they are about 38 to 42 centimeters (15 to 17 inches) long. Females are ready when they are about 40 to 45 centimeters (16 to 18 inches) long. Some studies have found smaller mature males (33 cm or 13 in) and females (37 cm or 15 in).
Atlantic Sawtail Catshark and Humans
We don't have enough information about how many Atlantic sawtail catsharks are caught. This is because fishermen still record them as blackmouth catsharks.
These sharks are often caught by accident. This happens when deep-sea fishermen use longlines or bottom trawls. They are usually fishing for other animals. These include wreckfish, conger eel, Norway lobster, and red shrimp.
Most of the sharks caught are thrown back into the ocean. They likely die because they get hurt during fishing. Larger sharks are sometimes sold for people to eat.
The International Union for Conservation of Nature (IUCN) has listed this shark as "Near Threatened". This is because its home range is small. Also, there is a lot of fishing in that area.
Images for kids
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Atlantic sawtail catshark
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Range of the Atlantic sawtail catshark
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Dorsal and ventral views of the head of the Atlantic sawtail catshark.
