Amphipod is a member of the crustacean class. It is also called freshwater shrimp and sea flea. He is very fast and agile.
Going on vacation, you can often meet amphipod near the seashore and in the coastal zone. They inhabit sea sand in huge numbers. Large colonies can settle in discarded seaweed along the beach line.
There are many types of crustaceans, some of them carry a number of infectious diseases and can cause allergic reactions.
Amphipods are common everywhere, in fresh and sea water. The number of species includes more than 8000 varieties. A small number of parasitic forms are distinguished, called whale lice. Among the representatives of the species there are predatory individuals, such as the sea goat. She settles in a grassy thicket and tracks down her prey from behind, hunts with the help of a front claw, and attacks her when she meets her prey.
It is of great economic importance, both in fisheries and in poultry farming. It is a protein supplement for feeding birds, fish.
They are especially important for commercial fish, as they form the basis of their diet. Bream, flounder, trout, omul eat it. With the help of artificial breeding in the reservoir amphipod serves as food for fish.
Where does it live
In fresh water, there are the maximum number of amphipod species. About 50 different species live in Lake Baikal. To catch omul, fishermen specially collect amphipods on the lake, and then place them in fishing holes.
Amphipods are widely distributed throughout the world. They call him a mormysh in Western Siberia, in the Caspian he was nicknamed a stenoga, the Siberians call him barmash. They can live in a group on a whale, eat its skin. Because of what the whale is covered with deep ulcers. This subspecies of crustaceans – whale louse.
The Krasnoyarsk and Angarsk reservoirs have about 30 species of amphipods. They inhabit the bottom and prefer planktonic activity.
They like to lie on the shore, buried in the sand, not far from the water. Sometimes on the coast you can see a layer of crustaceans that move and jump. Can live in a very large group.
During daylight hours, sea fleas hide among stones, between algae growing on the shore. And at night they move along the beach line in search of dead plants that they need for food. The crustacean can only live in water, on a wet surface, since its breathing is carried out with the help of gills. A feature of the sea flea is an excellent orientation to the sun. She will move in the direction where the sun’s rays go. At night they are guided by the moon. They are well oriented in space in the dark.
As quickly as possible, they can immerse their body in the sand, while the pectoral legs help the body to dig deeper. This work is done at lightning speed. Due to the high speed of movement, sea fleas migrated from the sea to the rivers. So, being in the Caspian Sea, they moved over the Volga and spread along its entire trajectory.
in Eurasia, all species are resistant to cold, they can be found both in summer in the presence of warm weather, and in winter. In the cold season, crustaceans cling to the ice crust of the reservoir. Prefer clean salt water.
Marine amphipods live in the Caspian, Black and Azov seas. They live in rivers and lakes that flow into the seas. They can live for a short time in artificial conditions, in an aquarium in the presence of sand and food.
What does it eat
As food they prefer aquatic vegetation, animal remains, putrefaction. Thus, the amphipod is an omnivore. In their diet they prefer underwater plants, fish remains, particles of soil, algae. T.to. amphipod spends most of the time in the water, during the day they sink to the bottom, try to get out on land and search for food in the coastal zone.
Some species use filtration to get their own food. In its home, the animal creates a strong water flow with its legs and passes water through a filter that looks like a brush. Bottom dwellers use soil pebbles in their mouths as food. Underground inhabitants also use animal remains and part of plants as nutritious food, giving them the strength to grow and reproduce. All species, without exception, feed much more intensively in autumn and winter compared to spring and summer periods.
Some species can attack their smaller individuals, attack jellyfish and worms.
When did they appear
Amphipods appeared during the Stone Age of the Paleozone, about 400 million years ago. The first mention of this species dates back to the 19th century. Until now, the ancient representatives of crustaceans have been preserved thanks to amber. Many millions of years ago, the amphipod fell into a drop of molten amber, and thus today scientists can study this species, which has been preserved in excellent condition.
What does it look like
The amphipod is a small-sized crustacean, the length of the average representative is up to 1 cm, a large individual grows up to 2.5 cm. Amphipod differs from other crustaceans in the absence of carapace.
Body flattened on both sides. Legs have a different structure.
The front part of the body combines the head and chest, in front it has a large pair of false claws, only with their help it captures food.
The other two pairs resemble claws directed towards the head, the pairs of the lower ones are directed towards the tail. It is the claws that help with movement. The tail part consists of the excretory system, which includes the intestine and anus.
The abdomen is made up of two parts – pleosomes and urosomes, consisting of several parts. The pleosome carries the swimming movements.
The body of the animal is devoid of coloring pigment, but may be greenish.
Amphipods are divided into males and females. They vary greatly in size depending on gender. Depending on the species, females can be larger than males, and vice versa. A sexually mature female is equipped with a brood pouch where she lays and carries her eggs. Her offspring matures for about a week.
In the body of the amphipod – male with the help of androgen glands secrete a special male hormone. Animals can mate for several days. Different types of crustaceans lay a certain number of eggs, on average from 10 to 100 per mating. As a rule, reproduction takes place during the warm season. During the winter, the female bears eggs, and in the spring new offspring are born. Individuals live about 2.5 years.
The body is divided into head, abdominal and lower sections. There are two pairs of eyes on the head. Has two antennae on its head.
- They have an amazing ability to clearly identify landmarks, even if they have gone a long distance from their habitat.
- The parasite is the whale louse, which settles on the whale and feeds on the epidermis.
- A small crustacean leads a measured life, can rarely leave its hole and feed only by filtering water.
- Being in the water of a shallow stream or near the shore, the crustacean swims on its side. At depth he swims upside down.
- One individual lives from one to two years.
Amphipods should beware of fish, especially eels, birds, amphibians, predatory insects and their larvae, turtles, cats, dogs, minks, muskrats, arachnids, whales, killer whales.
Crayfish are practically defenseless in their natural habitat.