Sharks from ancient times instilled horror in man. They are associated with boundless sea, bloodthirstiness, death. Only one kind of such a creature is able to enter into a stupor, and if you hear the exclamation "Shark!", Being in the water, close to panic. People are afraid of these inhabitants of the depths, in many respects contributed to this fear numerous films about bloodthirsty monsters. But with what the shark cat is associated? The name evokes thoughts about the complete harmlessness of the fish. But is this creature safe?
People and Feline Sharks
Such sharks are not dangerous to humans absolutely. In the ordinary feline shark meat is edible, and in some countries it is popular with anglers. It is sometimes caught even with a bait, although it is mainly harvested from fishing vessels by nets. The meat of these fish is also used as bait to catch other fish that are more valuable to humans.
If the cat shark (the photo is in the article) comes across the net randomly, then in most cases the fishermen will release it. They are very tenacious, and after a long stay on land or trapped in networks, the percentage of their survival is more than 95.
The body of such sharks is used by scientists as a model organism in comparative analyzes of gastrulation. This is explained by the fact that the cat sharks are the most common of the plate-wad species. It is also possible to follow year round the development of the embryo. A shark's egg is placed in an aquarium with sea water and this water is constantly saturated with oxygen.
The number of feline sharks is stable and does not cause concerns about the possibility of extinction of the species.
Habitat extends from the southwestern shores of Scandinavia through the coastal waters of England, the Shetland Islands, Portugal and Spain to Senegal. Fish is almost universally found in the shelf zones of the Mediterranean and North Seas. Occasionally it appears in the Baltic Sea.
In the Black Sea, it was last observed in 1937.
The area covers areas with a temperate and subtropical climate. Ordinary feline sharks lodge mainly at depths of 10 to 400 m, in the Ionian Sea they are sometimes caught in deep waters up to 780 m.
The common cat shark is nocturnal. In the afternoon, she rests, lying on the seabed. Activity begins to appear with the arrival of twilight.
Fish prefers to hunt alone, but often gathers in flocks for joint hunting. As a rule, they are individuals of the same sex.
Vision in representatives of this species is poorly developed. They rely more on their sense of smell and on the ends of the muzzle of the electric sensors, which allow them to catch the slightest electrical impulses generated by living organisms.
The diet consists of various bottom living creatures. The sea dog feeds on crustaceans (Crustacea), mollusks (Mollusca) and small near-bottom bony fishes (Osteichthyes) living on the bottom. Octopuses (Octopus), squid (Cephalopoda) and echinoderms (Echinodermata) are eaten to a lesser extent.
In the daily menu of fry, polychaete worms (Polychaeta), sipunculides (Sipunculida) and larval-chordae (Urochordata) predominate. Adults feed mainly on decapods (Decapoda) and fish. The shells of the caught prey, they first eat through with their small bristle-shaped teeth, and then swallow.
The main natural enemy is Atlantic cod (Gadus morhua).
Sexual maturity in females occurs upon reaching a body length of 45-50 cm, and in males about 40 cm. Scyliorhinus canicula belong to the number of egg-laying fish. Spawning can be all year round. In the Mediterranean and northern latitudes, its peak occurs in the period from March to June. Off the western coast of Africa, mass spawning is observed from February to August.
After fertilization, the female lays 18-20 eggs in shallow water. It can spawn only once a year. Eggs are placed in an egg capsule with a hard, horny surface. The British call them the Mermaid’s Purses wallet.
Egg capsules have a size of approximately 5x2 cm and are equipped with thin filaments up to 1 m long, which are attached to algae, stones or shells of bivalve mytilidae mollusks (Mytilidae). Immediately after spawning, they are almost transparent, and over time they become milky. By the end of the incubation, which lasts from 5 to 9 months, the surface of the capsules becomes yellowish or dark brown.
Shark of 8-10 cm long are born. Babies in northern latitudes are larger than their southern counterparts.
During development, the embryos float in the capsule to increase the permeability of its walls and ensure the inflow of fresh water. Sometimes there are twins in one egg.
Hatched sharks feed on the remnants of the contents of the yolk sac, and then proceed to an independent search for food. They are a miniature copy of their parents, but they have larger spots on their bodies.
Keeping a cat shark in an aquarium
One adult is recommended to be kept in an aquarium with a minimum volume of 1500 liters. For a comfortable state of health she needs 5000 liters. For each new guest you need to add 500 liters.
The optimum temperature is 10 ° -16 ° C. It is advisable to constantly adhere to the same its value. This can be achieved with the help of thermostats and special cooling devices.
Sharing with tropical sharks is unacceptable.
At temperatures above 18 ° C, the immunity of fish is sharply reduced, so they quickly become ill with fungal diseases and are affected by various parasites, primarily the nematodes Proleptus obtusus. They often refuse to eat and die even after a slight overheating.
Increasing the salinity of the water, using antibiotics and regularly cleaning the skin helps to fight parasites. With a lack of iodine, goiter is often formed.
The average body length is 60-80 cm. Weight ranges from 1000 to 1500 g. Individual specimens grow to 100 cm and weigh over 2000 g.
The thin body has a wedge-shaped shape and is covered with fine hard scales resembling sandpaper. On its upper part, gray and brown spots are well visible, the belly is whitish and most often without spots. The general background color is sandy brown.
The muzzle is short, rounded. On the sides of the head are elongated oval eyes without blinks. The nostrils are closed with wide nasal valves, which stretch all the way to the mouth and are divided in half. The extended tail fin is equipped with a developed upper and underdeveloped lower lobe. The dorsal fins are located at the back of the torso.
Sprinklers are behind the eyes. Small sharp teeth are arranged in rows in a small curved mouth. In females they are smaller than in males.
The life span of an ordinary feline shark is about 8 years.
Why is the shark called feline?
The name "cat" sharks were not for nothing: all representatives perfectly see in the dark and are night predators.
And all this is not due to the excellent vision, although the eyes of sharks are large and bulging, but due to the presence of photosensitive sensors (located near the eyes), through which the shark senses electrical signals emanating from another living creature, in particular, fish.
The color of the family members is in many ways similar - a gray-coal, almost black back or dark brown, with medium-sized dark spots and a light yellowish or sandy belly, but the skin resembles emery paper.
The shark's body is slim and truly possesses feline flexibility, however, the head is massive and flattened.
Since the cat shark feeds on crustaceans, it accordingly leads to a near-bottom lifestyle - which is what it is adapted for: the nostrils, which are in front of the head, are covered with skin valves.
Watch video - Feline sharks:
The sense of smell of a shark is well developed and helps to find prey even in the dark.
Teeth small, dull, but can grind shells. Gill slits are indistinguishable. The tail fin is long and has almost no lower lobe, and dorsal fins begin closer to the tail fin.
All members of the family do not favor tropical heat and prefer moderate latitudes.
Amazing variety of feline sharks
The spotted or black-necked cat shark, she is a shark-tail shark, (Galeus melastomus) has chosen the range from the Adriatic to the North Sea. The name of the fish speaks for itself - the upper part of the fin has notches.
The common cat shark (Scyliorhinus canicula) is found both off the coast of North Africa and off the coast of Norway and is a typical member of the family. Basically, the size of the fish is not more than 60-70 cm, but sometimes there are meter specimens.
The California cat shark, which is also swelling (Cephaloscyllimn ventriosum), lives off the coast of California. The shark got its name due to one particular feature: when it is caught, then on the shore the shark swallows air and inflates the belly - perhaps trying to defend and frighten the enemy.
Sometimes inflated sharks swim on the surface of the water in this form.
Watch the video - Swell shark:
The Australian coral shark (Atelomycterus macleayi), up to 60 cm in size, prefers warm waters and lives on the coast of North-West Australia among coral reefs, feeding on mollusks. In addition to dark spots, like all representatives, there are bright saddle-shaped marks.
A black-spotted cat shark (Aulohalaelurus labiosus) also lives near the coast of Australia. It is not a deep-sea species and hunts at a depth of 5 meters.
Since it lives in shallow reef, it is not very accessible for fishing, although representatives of this species are not eaten, but often caught for keeping in aquariums.
The Tasmanian spotted cat shark lives off the coast of South Australia (Asymboius vincenti), the main difference of the species is the shape of the head: small and round.
The Australian spotted cat shark (Asymboius analis) lives far from the coast, and thus has its own, different from others, habitat.
Watch the video - Spotted cat shark:
There is also the Madeira black cat shark (Apristurus maderensis) living in the northern part of the Atlantic, and the brown cat shark (Apristurus brunneus) in the temperate waters of the Pacific Ocean, all of which are typical representatives of the family.
At a depth of more than 600 meters in all oceans, you can find only black feline sharks (Apristurus), they correspond to their name - they have an almost black coloration of the back. Perhaps the presence of a shovel-shaped head (wide and flattened) is directly related to the habitat.
All members of the cat shark family are egg-laying, depending on the species they lay 2-22 eggs in a hard capsule, which are attached to the ground.
Watch the video - Cat shark lays eggs:
Perhaps significant fertility helps the family to retain a sufficient number of individuals.
After all, a person, realizing that feline sharks cannot harm him by their size, in every way destroys good-natured predators: eats (though not on commercial scales), catches for aquariums, for fun for tourists and just for hunting.
Feline is called the vast group of selachs that make up the Karkharinoobraznyh sharks. This predator community is the most numerous in terms of species composition; it consists of three families - striped cat sharks, in which there are eight species and one without a scientific description, false cat sharks, in which only one species and real cat sharks, numbering almost 130 species in their ranks, united in 15 genera.
The epithet "cat" entrenched behind these predators because of the characteristic shape of the head, resembling the head of land cats. In addition, they have a flexible and mobile body, like cats.
All these predators are combined with external signs, structural features of the organism and lifestyle. All feline sharks are benthic predators. Many of them are more active at night, preferring to rest in a shelter during daylight hours. The appearance of feline sharks has characteristic features - a long and slender body, a large rounded head, oval eyes with a blinking membrane, above which brow arcs usually rise. There are sprinklers behind the eyes. Gill slits in cat sharks are short, located behind the head in five pairs on the sides. Nostrils large, antennal and nasal grooves not. The teeth of different species differ, but more often they are small and sharp, forming a seta.
The fins of feline sharks also have characteristic outlines and forms - the tail, as a rule, is long, its lower share is very poorly developed. The dorsal fins are shifted to the tail. The pectoral fins are very developed, rounded. The abdominal and anal fins are smaller.
Body color of cat sharks can be the most diverse. Some species are very colorful and beautifully painted, but there are also monotonously colored varieties.
Among the feline sharks there are no large fish - only the humpback and the false feline sharks can boast impressive body sizes, reaching three meters in length and even more. The rest of the sea cats rarely grow to the meter strip.
The habitat of these predators is quite wide, but they are not found in the cold waters of the Arctic Ocean. The common cat shark Scyliorhinus canicula is found in the Far Eastern seas, and in the summer it sometimes visits the Black Sea from the Mediterranean.
In our northern waters, there may be a spotted, or black-necked, cat shark (Galeus melastomus), also called a shark-tail shark due to a sawtooth serration on the upper part of the caudal fin. This species is commonly found off the coast of Europe from the Adriatic Sea and the western part of the Mediterranean Sea to the North Sea and Norway.
In Russian waters, the black-necked shark is known from a single specimen caught more than 100 years ago off the coast of the Kola Peninsula.
This small shark, whose length does not exceed 1 m. It dwells in coastal waters, near the bottom and rarely descends to a depth of more than 400 m. Small black fish and crustaceans serve as food for the black-necked cat shark, it is not dangerous for humans.
The basis of the diet of feline sharks are small fish, cephalopods (mainly squid), crustaceans and other benthic invertebrates, as well as larvae of marine animals.
They hunt mainly from an ambush, which they arrange in thickets of aquatic vegetation or stones, but sometimes they also show activity in pursuit of prey. They can perfectly find their prey in the dark thanks to their sharp eyesight, smell, sensitive lateral line and electroreceptor perception.
Because of their small size, cat sharks often fall prey to larger predators - sharks, rays, large sea fish, octopuses and cetaceans.
These predators reproduce, mainly, egg-laying, but some species are egg-feeding, i.e. the female does not lay eggs, but carries them in her body the whole period of development of the embryo.
There is no consensus on the taste qualities of cat shark meat between gourmets. Some consider it very tasty and tender, others - tough and lean. On tastes, as they say, do not argue, however, the meat of shark cats is edible and can be eaten in a different form - salted, dried, fried, etc.
The main consumers of feline shark meat are European countries bordering the seas. On the Adriatic coast, sharks make the traditional dish "Antipasto burrida".
Commercial value of them is small.
Public aquariums and some private aquarists keep feline sharks as exotic fish. They are unpretentious, take up little space in the aquarium and are very beautifully painted.
Below is a description of some species of feline sharks.
Common Cat Shark (Scyliorhinus canicula)
It is very common on the Atlantic coast of Europe (in the north comes to Norway) and North Africa. It is also found in the Mediterranean and Marmara seas, from which it may also enter the Black Sea. This shark usually does not exceed 60 cm in length, but sometimes larger specimens, up to 1 m long, are also encountered.
It lives at the bottom at shallow depths of the coastal zone, and feeds mainly on benthic invertebrates - crustaceans, mollusks, worms and, to a lesser extent, fish.
Propagated by egg-laying. The female lays from 2 to 20 eggs enclosed in a hard capsule, at the corners of which there are long horny threads. With their help, the egg is attached to the ground. Embryo development continues for about nine months.
The common cat shark has edible meat and in some places it is hunted by local fishery. For a person is not dangerous.
Australian coral cat shark (Atelomycterus macleayi)
Slender with a narrow head predatory fish of variegated color. Light saddle markings on the back, covered with numerous black spots.
Very little is known about this shark. She lives in shallow water on sandy and rocky soils. Size: Up to 60 cm.
Распространение: тропические воды Северо-Западной Австралии.
Основу рациона составляют, вероятно, донные беспозвоночные и мелкая рыба. Размножается яйцекладкой.
Чернопятнистая кошачья акула (Aulohalaelurus labiosus)
Эта прибрежная донная акула активна по ночам. Тело цилиндрическое, удлиненное, с темными седловидными отметинами, кожа толстая и прочная. Спинные плавники одинаковой величины, глаза небольшие. Размер: до 67 см.
Распространение: Юго-Восточная Австралия.
Питается мелкой рыбой, кальмарами, ракообразными, креветками и другой мелкой донной живностью.
Тасманийская пятнистая кошачья акула (Asymboius vincenti)
A small shark with a short rounded snout and a chocolate-brown body covered with numerous white spots. Coastal bottom species occurring at depths of up to 220 m.
Size: Up to 60 cm.
Oviparous, lays at the same time one egg 5 cm long with long tendrils. For the person is absolutely not dangerous.
Australian spotted cat shark. (Asymboius analis)
Small shark with an elongated body. In the coloring of the body there are reddish spots and light brown saddle markings on the sides. Snout short and round, teeth small.
In males, the ventral fins grow together, forming a skin process around the copulatory organ. It is found in temperate waters far from the shore, and leads a benthic lifestyle.
Size: up to 60 cm.
Distribution: Southeast Australia.
Little is known about food preferences. Probably, the basis of the diet is benthic invertebrates.
Madeira black cat shark (Apristurus maderensis)
Slender shark with a wide, flattened snout and big eyes. The body is black, smooth.
The small dorsal fins are shifted to the back of the body.
Lives on the bottom, on the continental slopes, at depths from 700 to 1500 m. Size: Up to 68 cm.
Distribution: North-East Atlantic and Madeira, to the north, possibly to Iceland.
Food preferences are unknown, most likely bottom animals and small bony fish.
Brown Cat Shark (Apristurus brunneus)
A small cat shark with a large round head. Size: Up to 68 cm. The body color is even dark brown. The edges of the fins are bright.
Distribution: tropical and temperate waters of the eastern Pacific Ocean. It is found on the continental shelf, at depths of up to 950 m. Food: mainly shrimps and squid.
Reproduction: the female lays one egg 5 cm long.
California Blowing Shark (Cephaloscyllimn ventriosum)
Distributed in coastal waters off the Pacific coast of Mexico and the United States.
It is quite brightly colored in yellow-brown color and has black spots and stripes on the body. This shark, reaching a length of 1 m, feeds on fish, sometimes capturing rather large prey.
Being extracted from the water, the Californian shark can swallow air and strongly inflate its belly, which gives it a very strange look. Sometimes swollen sharks were observed floating on the surface of the water.
Among the deep-sea members of the family can be noted black feline sharks (genus Apristurus), of which there are about 20 species. These are small sharks, less than a meter long, having a wide and flattened head, resembling in its form an ordinary shovel. They all have a dark brown or even almost black color.
Black cat sharks are found in all oceans. They live at the bottom and are sometimes present in deep-sea trawls or other gear, raised from a depth of 600 - 1500 m.