How squid breed. Reproduction of squid. Names of squid in different languages
The common squid (lat. Loligo vulgaris) belongs to the cephalopod molluscs from the Decapodiformes order. It lives in salt waters. Its range lies in the eastern Atlantic Ocean from Ireland to Guinea, including the Mediterranean Sea.
These mollusks are usually found in shallow coastal waters, holding near the bottom or swimming in the water column. In many countries, their meat is considered an exquisite delicacy.
Commercial fishing for squids is carried out at night, when they begin a collective hunt for schooling fish.
Behavior
Common squids annually make seasonal migrations, swimming several thousand kilometers in search of food-rich areas of the oceans. In summer, they stay close to the surface of the water, and in winter they plunge into the depths.
Usually squids drift at a depth of 20-50 m, but individual individuals have been caught even at a depth of 500 m. These mollusks can lead both a solitary lifestyle and gather in fairly large groups. Groups hunt together, as if surrounding flocks of small fish with a dense hunting net.
During the day, squids lie quietly on the seabed, hiding in stones or in algae, and with the advent of darkness, they turn into energetic predators.
They grab their prey - fish and crustaceans - with two long tentacles and kill with poison, after which they methodically tear off piece by piece and swallow it with pleasure.
Squids themselves are a favorite delicacy of many marine life. Dolphins and sperm whales especially like to feast on them. To save their lives, they learned to change the color of their body and, as it were, dissolve in water, becoming invisible.
In the event of a threat, the mollusk shoots a stream of dark liquid at the aggressor, which envelops him in a kind of smoke screen. After such a chemical attack, he manages to hide from a dangerous predator in a matter of seconds.
Swimming in the water column, squids slowly flap their fins. To develop greater speed, the squid sucks water into the mantle cavity with rhythmic muscle contractions and forcefully pushes it out through the siphon, thereby creating a strong jet thrust.
Representatives of the species Loligo vulgaris, who prefer a solitary lifestyle, having met a smaller relative, often eat it without much remorse.
reproduction
Common squid breed all year round. They have a pronounced sexual dimorphism - males are much larger than females. Having met a female ready for spawning, the male begins to persistently swim around her, trying to demonstrate all his charms and virtues.
The female lays eggs in lumps hidden in gelatinous capsules and sticks them to underwater rocks, algae or objects drifting in the water. Often many females prefer to spawn as a group in one place.
Squid larvae are similar to adults, differing from them only in the ratio of body parts to each other.
At first, young squids with a body length of about 1 cm swim near the surface of the water in friendly flocks and feed on plankton. They grow very quickly and soon begin to hunt small crustaceans and small fish.
Description
Adult individuals reach a body length of 30-50 cm and a weight of up to 1.5 kg. The long body has a streamlined shape. The upper side of the body is colored reddish-brown.
Small dark specks are scattered on the lighter background of the lower side. The mollusk has 10 tentacles: 8 short and 2 long prehensile. Each of the tentacles is equipped with suction cups.
Between the tentacles and the head, clearly separated from the rest of the body, there is a mouth opening with strong jaws, with which the squid can easily crush the shells of its victims. In the pharynx is a special grater for grinding food.
The underdeveloped shell in the form of a horny shelf is completely hidden by the folds of the mantle. On both sides of the body are 2 sail-like fins.
A siphon is located on the underside, through which water is pushed out of the mantle cavity, creating jet thrust. This species has very large eyes, which are the most perfect organ of vision among all invertebrates.
The life expectancy of ordinary squids on average does not exceed 2-3 years.
Catching squid and octopus for most people living in the CIS, with the exception of residents of the Far East of Russia, is still a real exotic, more relevant for tourist trips to hot countries, where they can offer any fishing for money, including hunting for cephalopods shellfish during the day and evening. Often there is an impression that squids and octopuses themselves are not a cult object of amateur fishing in Russia and the CIS countries due to the fact that they are extremely rare in the daily diet. Well, admit it, when was the last time you ate squid or octopus? Half a year ago?! That's it!
Based on the foregoing, everyone who has caught, is catching and continues to constantly catch squid and octopus for a drive and for a great lunch or dinner deserves all respect and careful listening to the methods of harvesting these cephalopods using absolutely different devices and fixtures. Below in the text, we will give the floor to a professional sea fishing, as well as Igor King of Red Woman’s Heart, a passionate lover of squid and octopus hunting, and now we’ll digress, talking about potential targets for catching with scientific point vision.
The main types of squid caught in the oceans
squids
scientific classification
Kingdom: Animals Type: Mollusks Class: Cephalopods Subclass: Coleoids Superorder: Ten-armed (mollusks) Order: Squids
Latin name
TeuthidaSuborders and families
Loliginidae Australiteuthidae Ancistrocheiridae Architeuthidae (Гигантские кальмары) Bathyteuthidae Batoteuthidae Brachioteuthidae Chiroteuthidae Chtenopterygidae Cranchiidae (Кранхииды) Cycloteuthidae Enoploteuthidae Gonatidae Histioteuthidae Joubiniteuthidae Lepidoteuthidae Lycoteuthidae Magnapinnidae Mastigoteuthidae Neoteuthidae Octopoteuthidae Ommastrephidae Onychoteuthidae Pholidoteuthidae Promachoteuthidae Psychroteuthidae Pyroteuthidae Thysanoteuthidae Walvisteuthidae
Names of squid in different languages:
The name of the country | The name of the squid in the local language |
| Albanian | callamari |
| Albanian | kalmari |
| Albanian | lignja |
| Albanian | ulignja |
| Basque | txipiroiak |
| Catalan | calamar |
| Czech | krakatice |
| Danish | oligo |
| Dutch | gewone pijlinktvis |
| Dutch | pijlinktvis |
| English | Cape Hope squid |
| English | common squid |
| English | European squid |
| English | inkfish |
| English | lon-finned squid |
| English | sea arrow |
| Finnish | kalmari |
| French | calmar |
| French | calmar community |
| French | encornet |
| alician | lura txibia |
| German | Gemeiner Kalmar |
| German | gewohnlicher Kalmar |
| German | Kalmar |
| Icelandic | smokkfiskur |
| Italian | calamaro |
| Italian | totariello |
| Modern Greek (1453-) | Καλαμάρι |
| Polish | kal amarnice |
| Portuguese | lula-comum |
| Portuguese | lula-vulgar |
| Romanian | calmar |
| Scottish Gaelic | scuid |
| Slovak | kalmary |
| Slovenian | lignji |
| Spanish | calamar |
| Turkish | kalamar |
squid(name in Latin Teuthida- called in the world scientific classification (taxonomy) a detachment of decapod cephalopods living in the oceans. Typically, squids caught commercially in the Pacific and Atlantic have a size of 0.25-0.50 m, but giant squids living at great depths (up to 7-8 thousand meters) of the genus Architeuthis can reach a length of 20 meters (including tentacles) and are the largest invertebrates in the animal kingdom.
Squids live in almost all climatic zones, including the Arctic, but are most often found in temperate and subtropical waters. Squid living in the northern seas are small in size compared to their southern relatives and mostly do not have a bright color. Squids have five pairs of arms. The fourth pair has lengthened in the process of evolution. The location of the suckers on the arms (tentacles) of squid often varies and depends on the species. Squids have a streamlined torpedo-shaped body, which allows them to move in the water column with a high speed “tail” forward, the main method of movement is jet.
European squid
Loligo vulgaris
scientific classification Kingdom: Animalia Phylum: Mollusks Class: Cephalopods Order: Teuthida Genus: Loligo Species: Common squid Binomial name Loligo vulgarisA cartilaginous “arrow” runs along the entire body of the squid, supporting the body. It is called the gladius and is a vestige of the inner shell. The coloration of squids is extremely diverse, and depends on many factors: water temperature, depth of the water column, behavior (aggression, fear, etc.). It is noteworthy that some deep-sea squid species have an almost transparent body. The common loligo squid (Loligo vulgaris), of the Loliginidae family, of the Loligo genus, is a species of cephalopod mollusks from the order of ten-armed (Decapodiformes) most famous and widespread in commercial and amateur fishing. The popularity of this type of squid in the Mediterranean countries is so great that it is often called European squid there - European squid, catching only in the Adriatic annually from 1200 to 1500 tons of these individuals for the culinary needs of Italy, Slovenia, Croatia and Albania.
The length of the body of a loligo with tentacles in commercial catches often does not exceed 50 cm, and its weight is 1.5 kg. The length of the mantle is, as a rule, about 20 cm, but can also reach 40 cm, and the males of this species of cephalopods are larger than the females. This species is distributed in the coastal waters of the eastern North Atlantic from the North Sea to West Africa, as well as in the Mediterranean and Adriatic Seas. Loligo keeps at a depth of about 100 m or more, but can also be found at a depth of 400 to 500 m. in early spring after dark. Cephalopods arrive there in early June.
The loligo clutch consists of several oblong, sausage-shaped eggs, which are attached to a fixed substrate at a depth of about 30 m. These can be parts of the seabed, for example, a rocky ridge with seaweed, or sheer rock outcrops at a shallow depth. At the same time, several animals prefer to lay their eggs in a common place. Larvae are morphologically similar to adult specimens, differing in the ratio of body parts to each other. Their size at the time of emergence in June is less than 1 cm. The period of development of embryos until hatching at a temperature of more than 20 ° C is from 20 to 30 days, at a temperature of less than 15 ° C - from about 40 to 50 days.
Another extremely important commercial object of world fisheries is Argentine squid ( Illex argentinus) , of the genus Illex, from the Ommastrephidae family, is extremely popular with amateur anglers in Argentina and Uruguay.
Todarodes pacificus
(STEENSTRUP, 1880)
scientific classification Kingdom: Animals Phylum: Mollusks Class: Cephalopods Order: Squids Family: Ommastrephidae Genus: Todarodes Species: Pacific squid
On Far East Russia, of particular importance in the domestic fishery of all types of hydrobionts living in the Pacific is Pacific squid (lat. Todarodes pacificus) - a species of cephalopod mollusks from the order of ten-armed (Decapodiformes). The Pacific squid prevailing in catches usually has a size of 0.25 - 0.5 m, but can reach a length of 75-82 cm (including tentacles). This type squid is found throughout the Japanese, Yellow, East China Seas, off the eastern coast of the Japanese Islands to the island of Okinawa, in surface water layers to depths of no more than 200 m at a temperature of 0.4-28 ° C. In warm years, the northern boundary of the squid distribution expands to the Commander Islands, mass accumulations are observed up to 57°N. The Pacific squid feeds on large zooplankton and small fish. Sexual maturity occurs at the age of one year. It is believed that all squid of this species die after the first spawning. The Pacific squid is extremely popular with the inhabitants of Primorsky Krai and Sakhalin Island, who, along with catching ordinary sea fish, constantly catch squid, fishing from boats and boats in the Sea of Japan and the Sea of Okhotsk.
Berryteuthis magister
(Berry, 1913)
scientific classification Kingdom: Animals Type: Mollusks Class: Cephalopods Subclass: Coleoids Superorder: Ten-armed Order: Squids Family: Gonatidae Genus: Commander squids Species: Commander squids
A very significant place in the catches of Russian sailors is commander's squid(lat. Berryteuthis magister), of the genus Berryteuthis and the family Gonatidae, which currently prevails on the shelves of Russian stores and is one of the cheapest cephalopods of all available in retail. Maximum length Commander squid is 42-43 cm, and the weight can reach 2.2-2.6 kg. Sexual maturity occurs when reaching a length of 20-25 cm in males and 25-30 in females. Lives up to 2 years.
The Commander squid, reaching the usual size of 25-35 cm in length and weighing from 300 g to 1 kg, constantly lives at a depth of 30 to 1200 m. Juveniles are often found near the surface, adults stay near the bottom, but make daily migrations, rising at night into the water column. The squid feeds on small fish and zooplankton, does not disdain its own young, and itself serves as prey for large fish, sea birds, toothed whales and fur seals. The main fishing areas for the Commander squid are the Seas of Okhotsk, the Bering Sea and the Sea of Japan. Commander squid (about 30,000 tons per year), Russian vessels are harvested by bottom trawl during migration from the Pacific side of the Kuril Islands. There are very few places convenient for trawling, so the entire Russian fishing fleet gathers in small “patch patches”. Although the bottom there is plowed by trawls, the vast majority of other squid habitats are not affected by fishing. Significant stocks of the Commander squid are protected in the zone of the Commander State Reserve. At present, its main catch by the domestic fleet is carried out in only two areas from the Pacific side of the Kuril chain: near the islands of Ketoi and Simushir, Paramushir and Onekotan, since most other places where concentrations of Commander squid are formed are characterized by a complex bottom topography with numerous outcrops of sharp rocks, which limits the possibility of using bottom trawls, which are currently the only fishing gear for Russian vessels in the squid fishery. In the Kuril waters, it is timed to coincide with two spawning seasons and is conducted mainly in March-July and September-January.
Commander squid, caught by Russian vessels, processed on mother ships and sold on the territory of the Russian Federation with entrails, has the most disadvantageous presentation. Despite this, the Commander squid, according to many restaurateurs, is considered one of the most delicious of all other cephalopods caught in other regions of the world. Peruvian squid (Dosidicus gigas) - for example, without special processing it is inedible due to the strong ammonia taste. Therefore, the caught squid of this species (in Peru, the Central Reserve Bank confirmed since 2011 that squid has become the second leading category of the Peruvian seafood sector after anchovies), after freezing and briquetting, they are sent for processing to China, from where they are shipped around the world already cleaned.
Are there squids in the Black Sea?
Plenty of perfect different people in Russia, including amateur fishermen, a rather interesting question is often worried - are squids, octopuses, cuttlefish and other cephalopods found in the Black Sea? No, no cephalopods have been found in the Black Sea, and they are unlikely to appear there in the very near future. Why? I explain. According to ichthyologists, main reason lack of squid, octopus and cuttlefish in the Black Sea is the low salinity of the latter (from 12 to 22 ppm), which is much lower than the average salinity of the oceans (from 30 to 38 ppm). In the best case, even if some individuals of cephalopods get through the Bosphorus from the Sea of Marmara to the Black Sea, then more or less survive there long time They can not. On average, a 1.5 kg individual of the Mediterranean Loligo squid (L. vulgaris) after being in an aquatic environment with a salinity of 14-18 ppm can die in about 1-2 hours. Also, all cephalopods cannot bear offspring in the Black Sea water basin due to low salinity, which completely prevents the development of their offspring. It is gametes, eggs (spores, eggs in the case of algae) and larvae of marine organisms that die - the most unprotected, vulnerable stages of the life cycle. Of course, squids do not reproduce using fertilized eggs. Mating in cephalopods consists in the fact that the male passes the spermatophore to the female (this is a bag of sperm that looks like a narrow tube). They can be from a few millimeters to more than a meter. The spermatophore has a complex shell and an intricate apparatus for ejecting sperm at the signal of a sensitive hair, with the help of a powerful muscular spring and a special secret that instantly glues living tissues together in an aquatic environment with a salinity of 28 to 42 ppm. In an aquatic environment with low salinity (from 12 to 22 ppm), fertilization by the usual method does not occur, since the adhesive secret cannot provide the necessary adhesion. The spermatophores are located in a special organ (needham sac) in the male, and he passes them to the female with a specially modified hand (it is called "hectocotyl"), which is equipped with special clamps or tweezers to firmly grab the spermatophore and pass it to the female, placing it in the exact place where needed. The female squid can carry spermatophores for many months (up to six months), choosing the right moment for fertilization. Then she instructs the spermatophore to release sperm and "hatch" the fertilized eggs until her death. It should be noted that if fertilization in squid individuals occurred in the Black Sea, then the development of the eggs themselves in an aquatic environment with low salinity is virtually impossible.
On the example of eggs from ordinary fish, you can imagine how and why this happens. The egg (although they are large) is just one living cell, it has a more or less strong, depending on the type of animal, protective shell surrounding the cell membrane, consisting of two mobile, fluid layers of lipids; a variety of special proteins are built into the membrane - they carry substances and salt ions through the membrane, perform other functions. On the outside, cell membranes are reinforced and protected by more rigid, branched carbohydrate (sugar) molecules. For the question - why the caviar of hydrobionts of the World Ocean with a higher salinity dies in the low-salinity Black Sea - it is important to know the following.
Ions of some salts (we remember that salts in solution break down into charged halves - positively charged - metal cations, and negative - anions) can penetrate the cell membrane unhindered, but most of them are transported through specially regulated ion channels - large protein molecules similar to tubes that pierce the membrane, and with the help of real, energy-requiring protein machines - ion pumps. This complex system is needed to ensure that the concentrations of various ions necessary for its normal life are always maintained in the cell. But water molecules pass through all cell membranes freely, and faster than they work ion pumps. The total concentration of ions of all salts and the sum of the charges of other molecules in the caviar is the same as in its native sea water. This sum of charges is a more accurate and important value than the concentration of salts, but usually, the total concentrations of salts in the egg and the water around it are close. Now we can imagine the following. a pair of sea urchins crawled into the Black Sea, or a pair of swordfish sailed - and spawned. The concentration of salt in the caviar is close to oceanic, and the salinity around is half as much. What will happen? What physicists and chemists call the phenomenon of osmosis will happen: particles (molecules, ions) of a substance always move to where their concentration is lower. Ions cannot pass through the membrane, but water can; concentration of water in the egg sea urchin, squid eggs - lower than in the Black Sea water, which means that the water will rush into the cage. A cell - an egg - will first swell, and then burst. Therefore, squids can appear in the Black Sea for an extremely short time, but they will not be able to reproduce. If they do not develop special adaptation to low salinity conditions - as, for example, it happened with the Pacific snail, which breeds beautifully in the Black Sea water basin.
The type of molluscs is divided into 7 classes: shellless, monoplacophores, armored, spadefoot, bivalves, gastropods and cephalopods.
Shellless (Aplacophora) mollusks have a worm-like body up to 30 cm long, completely covered by a mantle, there is no shell. On the ventral side, they have a groove with a roller - a rudiment of the leg. There are no nephridia. This group of molluscs are hermaphrodites.
Breeding and breeding squid
| The class has been known since the Cambrian. About 150 families and 20,000 species. Marine and freshwater bivalves feed on plankton and detritus by filtering water through siphons at the back of their shells. Some drill through hard rock and wood (using sharp shell teeth or by dissolving the rock with acid). The shipworm damages the bottoms of ships and piers by cutting long passages into them. Some bivalves(oysters, mussels, scallops) are eaten. The sea squirt is one of my favorite sea creatures. Imagine my surprise when he splashes me right in the eye! The creature is well named, but there's more to this amazing animal than its "syringe gun." Sea spray belongs to a remarkable group of underwater animals called shells. Although it was hard to tell by looking at their soft bodies, sea spray is also part of the chordate phylum - a group of animals that includes fish, birds, reptiles and mammals! This is because, in their larval stage, sea squirts have many vertebrate anatomical features. The shells of gastropods (Gastropoda) mollusks are twisted into a spiral and are distinguished by a wide variety of shapes. In some mollusks, the shell is immersed inside the body or is absent altogether. The head has a pair of tentacles with eyes. In the course of evolution, gastropods have lost their bilateral symmetry. In many species, the symmetrical organs located on the right side of the body were reduced. Some species have a kind of lung - a cavity filled with air or water with oxygen dissolved in it. There are both hermaphrodites and dioecious forms. Marine syringes come in an amazing variety of shapes and colors. On the surface, they may look like sponges. Or they may look like rubber blobs when they live in colonies. Or they may even look like grapes. If you want to see some of the best marine syringe images on the internet, then you should stop by Madang - Bilun Mi Ples. This is a wonderful photo essay by my friend Jan Messersmith. Sea spray Images from the reefs of Papua New GuineaSea spray really has their brainsAfter the ability to blow you in the eye, probably the most common syringes are "eat their brains". What happens is not as much as it seems, but the life cycle of marine syringes is "extreme" and fascinating nonetheless.Sea squirt larvae begin to consume all the tadpole-like parts that made them chords. Where sea squirt larvae once had gills, it develops a habit and contains siphons to help it bring water and food into its body. It absorbs its twitching tail. He absorbs his primitive eye and his vertebral nasal sign. Finally, he even absorbs the vestigial little "brain" he used to swim and find his attachment spot. So, yes, in general, the sea syringe “eats its own brain”, such as it is. But since the sea syringe no longer needs a brain to help it swim or see, it's not a big loss for the creature. This is to use this now redundant body material to help develop its digestive, reproductive, and circulatory organs. The remains of the shell are sometimes preserved under the skin in the form of a horny plate; the outer shell was mainly in extinct forms. The only modern cephalopods that still retain an outer spiral shell are nautiluses. The circulatory system is well developed; The blood is blue in color due to hemocyanin, which is part of the erythrocytes. Cephalopods breathe with gills, some are capable of a long stay on land (several hours or even days) thanks to the water stored in the mantle cavity. A sea squirt is basically a large stomach inside a bag. The bag pumps water on its own, filtering the food carried by the sea currents. Water enters one siphon and descends into a large basket resembling a pharynx. The pharynx has numerous lattice slits for the passage of incoming water. The plankton in the incoming water gets caught in the sticky mucus lining the throat, and the small hairy cilia help move the plankton into the stomach for digestion. Filtered water and waste are removed through a second siphon. Sea squirts are fascinating animals. They may look primitive, but they are actually one of the most advanced marine invertebrates. They start out looking like tadpoles and end up looking like beautiful leather bags and drops. In the process, they "lose their minds" so to speak! At the entrance to the mantle cavity there is a funnel (siphon), which is the second part of the modified leg. Due to the reactive force arising from the water ejected from it backwards, the animal moves forward with the rear end of the body. Muscle contractions occur at a very high frequency, which ensures uniformity of movement. This is achieved, in particular, by the high conductivity of the nerves - in some squids, their thickness reaches 18 mm. Squids have been recorded moving at 55 km/h. Cephalopods can also swim using their tentacles to help themselves. Some squids, pushing water out of the siphon near the sea surface, can rise several meters into the air. In the larval stage, the sea squirt has characteristics that make them part of the same chordate type to which all fish, birds, reptiles and mammals belong. In adult form a sea syringe is more than a water pump, pumping water into the vascular system, extracting nutrients, and pumping out water. Truly, the sea syringe has one of the most extreme and unusual life cycles any animal. It is certainly one of the most unusual and oddly beautiful creatures in our oceans. There's a lot of great science in it, with a lot of discussion about how sea spray spreads. Brief introduction to the biology of cephalopods. The organs of vision are perfect. Human-like eyes have a lens and a retina; in giant squids, their size exceeds 40 cm. There are also miniature thermolocators on the fins. The sensitive organs of smell (or taste) are concentrated on the inner surface of the tentacles and on the suckers. Developed organs correspond to a large brain. For passive protection from enemies, autotomy is used (cephalopods “throw away” the tentacles by which they are grabbed by the enemy) and ink curtains, possibly poisonous, are sprayed to the side. In addition, special cells scattered over the skin - chromatophores and iridiocysts - allow you to change the color of the body, "adjusting" to the environment. Some cephalopods are capable of luminescence. Cephalopods can grow to gigantic sizes - 18 m or more (their mass can reach several tons). There are numerous stories about giant octopuses (krakens), supposedly dragging ships to the bottom. All cephalopods are dioecious. Male octopuses transfer sperm into the mantle cavity of the female with a special tentacle - hectocotylus. Often it breaks away from the body and swims independently in search of a female. The female usually incubates the eggs, sometimes building nests. Cephalopods live in the seas (up to a depth of 5 km), preferring warm water bodies. Some forms live among the coastal rocks, others - at great depths. Some swim in the water column, others crawl along the bottom. Almost all are predators, feeding on fish, crustaceans, and other mollusks; prey is caught with tentacles, killing it with the secret of poisonous glands. Many cephalopods (squid, cuttlefish, octopus) are eaten by humans. The class is divided into two subclasses: four-gill (extinct ammonites and the only surviving nautilus genus) and two-gill (cuttlefish, squid, octopus and extinct belemnites). About 600 modern species. |
Biologist Henk-Jan Hoving from the University of Groningen is interested in how squid reproduce Decapodiform cephalopods. In addition to this cephalopod, Hoving studied at least ten more species of squid and cuttlefish - from a 12-meter giant squid to a mini-squid no more than 25 mm long.
As Hoving says, studying deep-sea squid is still very difficult, because it is very difficult to get to them. To observe these cephalopods in their natural environment requires a special technique. Therefore, the biologist had to reconstruct the sexual habits of squids, content with already dead specimens and descriptions of other specialists. But still, the Dutchman managed to make some discoveries.
As the biologist himself says, "reproduction is not fun, especially if you are a squid."
In the mollusk species Taningia danae, males, during mating, injure the body of females with their beaks and hooks to a depth of five centimeters. And all because this type of squid simply does not have suckers. But from such "self-mutilation" partners derive considerable benefit. In cuts, males put "bags" containing spermatozoa - spermatophores.
The same method is used by representatives of another variety of deep-sea "multi-armed" - Moroteuthis ingens. True, the process of such a peculiar fertilization in these squids is more peaceful. Spermatophores penetrate the skin without damaging it. According to Hoving, the males have some kind of substance, most likely an enzyme, that allows you to "melt" the skin.
Hoving found evidence that spermatophores penetrate the skin on their own. The biologist managed to see this process in freshly caught squid. Moreover, Japanese doctors have registered a case of squid spermatophores growing into human tissue. Not so long ago, in the Land of the Rising Sun, an operation was performed, during which “sperm bags” of a cephalopod were removed from the throat of some sashimi lover.
And here is the mini squid Heteroteuthis dispar decided to raise the birth rate. Females of this species fertilize their eggs on their own, inside the body. According to Hoving, they developed a special pouch for storing sperm, which is directly connected to the internal cavity of the body and reproductive organs.
When mating, males fill this container with sperm. And so generously that its stock can be up to 3% of the body weight of the female. According to the biologist, this method has a lot of advantages for both sexes. Females can grow eggs for a long time and gradually fertilize them as they mature. And the “bombed out” males still have a guarantee that their girlfriends will have completely specific spermatozoa.
Found Hoving among squids and "effeminate" males. Squids are not snails, they usually do not have hermaphroditism. But Ancistrocheirus lesueurii found small glands that are involved in the production of eggs in females. The body length of these non-males also turned out to be not quite standard - more than that of normal "men".
Hoving cannot explain this phenomenon and believes that it is the result of exposure to hormones and hormone-like substances from human pills. Which are first with sewage fall into the coastal zones of the ocean, and then to the depths. But, the biologist adds, this may also be the squid's own "invention" - a kind of way to get closer to women.
The scientist hopes that his research will not only help to learn more about deep-sea cephalopods, but will also save them from human greed. After all, not only research probes penetrate into the depths, but also new fishing trawls.
Squids are the largest and most mobile cephalopods. About 300 species of these animals are known in nature, among which there are amazing life forms. Their closest relatives are octopuses and cuttlefish. A special systematic position is occupied by the infernal vampire squid, singled out in a separate detachment. In fact, it is an intermediate form between squid and octopus.
Southern Sepioteuthis squid (Sepioteuthis australis).
The general physique of squid is similar to that of octopuses and cuttlefish. Their internal organs are placed in a cavity bag - mantle. A large head in front is crowned with a bunch of 8 arms. In addition, there are two more trapping tentacles near the mouth, armed with powerful suckers, in some species the suckers turn into hooks.
Squid with outstretched arms and tentacles.
Beak-shaped jaws hide between the tentacles. The blood of these molluscs is blue. The excretory organs of squid produce ammonia, which gives a specific smell to their meat. Like cuttlefish and octopuses, squids are highly intelligent, their brain is enclosed in a cartilaginous box - a kind of prototype of the skull. True, their chromatophores (pigmented skin cells) are very poorly developed, so squids cannot change body color and thus transmit signals to their relatives. But their intelligence is manifested in the ability to quickly process information, which is very important for such mobile animals. These mollusks have the thickest nerve fibers among all living things, their thickness (and hence the speed nervous system) is 100 times the thickness of human nerves!
The eyes of squids are relatively large and in structure approach the eyes of vertebrates. They also have binocular vision, which allows them to focus their eyes on prey and determine the distance to it with great accuracy.
Squids differ from other cephalopods in their oblong-cylindrical body shape. They do not have membranes between the tentacles, but on the sides there are small diamond-shaped outgrowths-wings. In some species, they can stretch almost the entire length of the body, and this makes squids similar to cuttlefish. Wings play a supporting role in swimming. Forward movement is carried out by pushing water out of a special siphon tube, thus creating a very powerful jet stream. Squids can turn the siphon in different directions and instantly change the direction of movement, back up, moreover, if necessary, many species are able to jump out of the water and fly from a dozen meters above the waves.
Bartram's flying squids (Ommastrephes bartramii) glide above the waves on outstretched tentacles and wings.
The hellish vampire squid looks very unusual. This is the only species of these molluscs that has a real membrane between the tentacles. Because of this, it was first considered an octopus, and only later did scientists discover signs of squid in this species. Now this species is separated into a special order and occupies an intermediate position between real squids and octopuses. This relic inhabitant of great depths got its hard-hitting name because of its bright red color and the ability to phosphorescent in the dark; nothing else unites it with hell, let alone vampires.
The hellish vampire squid (Vampyroteuthis infrnalis) reaches a length of only 37 cm and has nothing demonic in its appearance.
Most squids are not too brightly colored, they are more often white, bluish, pinkish in color. Their body is devoid of complex patterns, but many of them are able to glow in the dark in purple or blue. This glow is provided by special bacteria that live in the tissues of mollusks. A cluster of many phosphorescent squids is a fabulous sight! The sizes of these animals also vary in a wide range. Most species of squid are small, their length is from 25 cm to 1 m. But there are exceptions to this rule. The smallest species is the dwarf piglet squid, barely reaching a length of 10 cm, and the largest is the giant squid. The existence of these animals has been known since ancient times. northern peoples there are many legends describing the kraken - a monster with tentacles that attacks entire ships. Scientists for a long time could not find a giant squid, so the kraken was declared a fiction. And only from the second half of the 20th century, due to the development of the ocean, researchers began to come across first huge pieces of tentacles, and then whole remains of colossal mollusks. Of course, they do not attack ships, but the size of the giant squid is amazing: it reaches 18 m in length, of which about 12 m are tentacles!
The pygmy pig squid (Helicocranchia pfefferi) gets its name from its barrel-shaped body and tiny snout, which is actually a photophore.
Squids live exclusively in salt waters - from the warm tropics to the Arctic regions. In the seas and oceans, they have mastered all niches: some species live in the water column at a depth of 100-500 m, others prefer to stay near the surface, others are found exclusively at great depths (up to 1500 m) and never see the sun. Deep-sea squids are often solitary, but small species that live near the surface live in flocks. All species of squid are very mobile and spend their whole lives swimming, they do not have permanent habitats. Moreover, many species make daily vertical migrations, rising at night to the surface of the water, as well as annual spawning migrations. In the latter case, in three months of travel, squids cover more than 3000 km, that is, on average they swim 30 km per day! Not surprisingly, their migrations take place at cruising speed. Flying squids are especially mobile, many of their species can reach speeds of up to 70 km / h! The smallest species, on the contrary, are planktonic; instead of actively swimming, they drift with the flow. This drift provides another amazing ability of these animals - neutral buoyancy. In the body of planktonic squids there is a bladder filled with ammonium chloride (ammonia). This liquid is lighter than water, so the mollusks do not sink even when they are motionless.
The body of the Hawaiian short-tailed squid (Euprymba scolopes) is colored with symbiotic luminescent bacteria (Vibrio fischeri).
Depending on the size of the squid itself, its prey can be both small planktonic organisms and relatively large animals: fish, pteropods, squid of other species, and even its own juveniles. Giant squid prey on large deep sea fish. Cases of attacks on sperm whales are often attributed to this mollusk, motivating it large size, however, this is not true, since even the largest squid weighs up to 800 kg, and sperm whales - 30-50 tons. It is clear that even with long tentacles, the giant squid is not able to cope with such prey. Contrary to the tales of sailors, he also never attacks ships, since he lives at great depths. No one has yet seen a live healthy giant squid, only dead or dying individuals fell into the hands of researchers. Squids catch their prey with the help of tentacles (not to be confused with hands), and in some mollusks the tentacles can significantly lengthen and shorten. Throwing this kind of fishing rod, the squid is able to catch prey without coming close to it. Fluorescence also serves to lure prey.
This is what phosphorescent squids look like in complete darkness.
Reproduction in squid usually occurs once a year in certain spawning areas with a favorable hydrological regime. During this period, the males wrap their arms around the female and present her with a spermatophore. The female places this bag of sperm next to her eggs and immediately rushes to the bottom. One female lays up to several dozen eggs, similar to oblong white balloons. Sometimes the female hides them in a shelter, sometimes attaches them to algae, and more often she places them on a flat bottom. In places of mass spawning of squid, many clutches form a continuous carpet, which fantastically sways under the influence of currents. The larvae of many squids at first are not very similar to their parents, but they grow very quickly and reach sexual maturity by 1-2 years.
Mating Tasmanian squid (Euprymna tasmanica).
Since squids are mass species of animals, they are hunted in the sea by all and sundry. Smaller species are eaten by gulls, albatrosses, petrels, as well as larger squids. The larger mollusks are preyed upon by dolphins, and the largest and deepest species are the main food of sperm whales. To protect themselves from enemies, they use many tricks. Firstly, squids, like octopuses, have an ink bag with a dark liquid that is released in case of danger, disorienting the enemy. Secondly, fast-swimming species rely on speed, including flight, which saves them from many fish. Finally, in deep-sea species, photophores (luminous organs) serve as a deterrent. It turns out that squids are able not only to passively glow, but also to regulate the glow, suddenly flashing bright lights. Moreover, the squid magic lamp is capable of releasing a luminous liquid: while the enemy wanders in a sparkling cloud, the squid quietly disappears from view.
A newborn squid in front of eggs, inside of which its fellow embryos are visible.
Squid are mass-produced in almost all fishing areas. Their meat is used in the cuisine of many countries, it is nutritious and tasty, quickly cooked and easily digested. The harvest of these animals must be regulated to avoid overfishing. Many deep-sea species are still little studied and are known from single randomly obtained specimens.
Mollusks are widespread secondary cavities, invertebrates. Their body is soft, undivided, in most it is divided into the head, trunk and leg. The main features of mollusks are the presence in most species lime shell And robes- a skin fold that covers the internal organs. The oral cavity of molluscs is filled with parenchyma. The circulatory system is not closed. Over 130,000 modern species and about the same number of fossil species are known. Mollusks are divided into classes: gastropods, bivalve, cephalopods.
class gastropods
class gastropods- this is the only class whose representatives have mastered not only water bodies, but also land, therefore, in terms of the number of mollusk species, this is the most numerous class. Its representatives are relatively small in size: Black Sea mollusk rapana up to 12 cm tall, grape snail - 8 cm, some naked slugs- up to 10 cm, large tropical species reach 60 cm.
A typical class representative is big pond snail living in ponds, lakes, quiet backwaters. Its body is divided into a head, a torso, and a leg that occupies the entire ventral surface of the body (hence the name of the class).
The body of the mollusk is covered with a mantle and enclosed in a spirally twisted shell. The movement of the mollusk occurs due to the wave-like contraction of the leg muscle. A mouth is placed on the underside of the head, and on the sides are two sensitive tentacles, at their base are eyes.
The pond snail feeds on plant foods. In his throat there is a muscular tongue with numerous teeth on the underside, with which, like a grater, the pond snail scrapes off the soft tissues of plants. Through throat And esophagus food gets into stomach where it begins to digest. Further digestion takes place in liver and ends in the intestines. Undigested food is expelled through the anus to the outside.
The pond snail breathes with the help lung- a special pocket of the mantle, where air enters through the breathing hole. Because the pond snail breathes atmospheric air, he needs to rise to the surface of the water from time to time. The walls of the lung are braided with a net blood vessels . This is where the blood is enriched with oxygen and carbon dioxide is released.
Heart pond snail consists of two chambers - atrium And ventricle. Their walls alternately contract, pushing blood into the vessels. From large vessels through capillaries blood enters the space between the organs. This circulatory system is called open. From the body cavity, blood (venous - without oxygen) is collected in a vessel suitable for the lung, where it is enriched with oxygen, from where it enters the atrium, then into the ventricle and then along arteries- vessels carrying blood enriched with oxygen (arterial) enters the organs.
The excretory organ is bud. The blood flowing through it is freed from toxic metabolic products. From the kidney, these substances are excreted through the opening located next to the anal.
The nervous system is represented by five pairs ganglions located in different parts body, from them nerves depart to all organs.
Prudoviki are hermaphrodites, but their fertilization is cross. Eggs are laid on the surface of aquatic plants. They develop into juveniles. Development is direct.
The gastropods include slugs, named because of the abundant secretion of mucus. They don't have sinks. They live on land in humid places and feed on plants, fungi, some are found in vegetable gardens, causing harm to cultivated plants.
The herbivorous gastropods are grape snail also damaging agriculture. In some countries it is used as food.
Among the numerous species of gastropods, sea shells are especially famous for their beautiful shells. They are used as souvenirs, buttons are made from the mother-of-pearl layer, and some peoples of Africa and Asia make money and jewelry from the shell of a very small kauri mollusk.
Bivalve class- exclusively aquatic animals. Through their mantle cavity, they pump water, choosing from it nutrients. This type of food is called filtration. It does not require special mobility of organisms, therefore, representatives of the class have some simplification in structure compared to representatives of other classes. All molluscs of this class have bivalve sink(hence the name of the class). The shell flaps are connected by a special elastic ligament located on the dorsal side of the mollusk. Muscles attached to shell valves contactors, their contraction contributes to the convergence of the valves, the closing of the shell, when they are relaxed, the shell opens.
Representatives this class are , barley, oysters, mussels. The largest marine mollusk tridacna weighing up to 300 kg.
The most common mollusk in fresh water bodies of the country is. The body of a toothless, consisting of torso And legs, covered with a mantle hanging from the sides in the form of two folds.
Between the folds and the body there is a cavity in which gills And leg. Toothless has no head. At the posterior end of the body, both folds of the mantle are pressed against each other, forming two siphon: lower (input) and upper (output). Through the lower siphon, water enters the mantle cavity and washes the gills, which ensures breathing. With water, various protozoan unicellular algae, the remains of dead plants are brought. Filtered food particles pass through the mouth into stomach And intestines where they are exposed enzymes. The toothless is well developed liver whose ducts empty into the stomach.
Bivalves are used by humans. Mussels, oysters - are eaten, others, for example, are bred to obtain pearls and mother-of-pearl: pearl oyster, barley.
class cephalopods
Modern cephalopods There are about 700 species, exclusively inhabitants of the seas and oceans with a high concentration of salts, so they are not found either in the Black or in the Sea of Azov.
Cephalopods are medium to large sized predators. Their body is made up of torso And big head, the leg turned into tentacles that surround horn. Most of them have 8 identical tentacles, for example octopuses or 8 short and 2 long, like squid.
On the tentacles are suckers, with the help of which prey is retained. Only one tropical species does not have suckers - nautilus, but has a large number of tentacles. On the head of the representatives of the class there are large eyes resembling human eyes. Below, between the head and the body, there is a gap that connects with the mantle cavity. A special tube opens into this gap, called watering can, through which the mantle cavity is connected to the environment and is a modified part of the leg.
Many representatives of cephalopods do not have a shell, only the cuttlefish has it located under the skin, and the nautilus has a multi-chamber shell. The body is located in one of them, the others are filled with air, which contributes to the rapid buoyancy of animals. In many cephalopods, thanks to the jet mode of movement, the speed reaches 70 km per hour (squid).
The skin of many representatives of cephalopods is able to instantly change color under the influence of nerve impulses. The coloration can be protective (disguised as the color environment) or threatening (contrasting coloration, often changing). This is due high level development of the nervous system, which has a complex brain, protected by a cartilaginous sheath - " scull", the sense organs that cause complex behavior in particular, the formation of conditioned reflexes.
For example, in case of danger, the salivary glands secrete poison that kills prey, or the ducts of the ink gland secrete a liquid that forms in water black spot, under his cover, the mollusk runs away from enemies.
Cephalopods are dioecious animals. They are characterized by direct development.
Cephalopods are of great industrial importance: they are used as food (squid, octopus, cuttlefish), cuttlefish and squid are made from the contents of the ink sac of cuttlefish and squid brown paint- sepia, natural Chinese ink. In the intestines of sperm whales, a special substance is formed from the undigested remains of cephalopods - ambergris, which is used in the perfume industry to impart stability to the smell of perfume. Cephalopods are a food base for marine animals - pinnipeds, toothed whales, etc.
