Barney crayfish: photo, lifestyle

Most people who used to be on the beach, most likely, paid attention to small volcanic formations of snow-white color. They, as a rule, densely cover coastal stones and underwater fragments of various structures. These formations are shells of various crustacean species.

Kinds

Today we will talk about the crabs of the barnacles, and they are also called sea acorns. Subclass Crustaceans. Barnacles are representatives of the following crustaceans:

• Thoracica - these include sea ducks and sea acorns.
• Acrothoracica are small boring forms that live in shells of mollusks.
• Apoda - zooparasites of individual representatives of the order Thoracica.
• Kornegolovye (Rhizocephala) - biophytes of decapod crayfish.

Habitat

Barnacles, of which there are about 1200 species, are found all over the world and live in the seas. The greatest number of different types can be found in saline coastal waters. The size of the crayfish begins at a height of 3 mm (in the Chthalamus species) and reaches a diameter of 70-100 mm and a height of 120-150 mm (in the genus Balanus nubilus).

Certain species of large barnacles croaks settle only on rocks immersed in water. For example, cancers living on the Pacific coast of the United States of America can reach a mass of 1.5 kg.

Barnacles: a way of life

These individuals are the only of all their relatives who lead a "settled life". One of the main functions of barnacles is the ability to produce a sticky special substance that helps them to stick to almost any surface. It quickly hardens in a humid environment and is persistently retained under extreme temperature and pressure. Sea acorns reliably braid piles, stones and other hard surfaces.

Barnacles are attached to frozen objects that are immersed in water, for example, to the bottoms of ships in the port. They can be seen on shells of mollusks, shells of crabs and skin of whales.

Long stay in the air, low temperature or fresh water are fatal for the barnacles, but their conical conchs continue to cling to the last until they erode. At low tide, the crayfish hide in a multilayered carapace, which consists of calcium carbonate.

Reproduction

The larva of urogenital cancer is part of the plankton, the initial link in the food chain. Barnacles are very prolific marine animals. Studies conducted on the north-west coast of England found that crayfish that live near the coastline produce a trillion larvae per year.

Tropical crayfish begin to multiply at three weeks of age and produce about 10 thousand larvae three times a year - and so throughout their existence (for 4-5 years).

The born crustaceans emerge from the shells of their parents and almost immediately become food of planktivorous animals. Those who managed to survive in a couple of weeks find a new place of residence. Settling on the ground, they begin to secrete sticky substance. After several hours it hardens, and the final transformation of the larva into adult cancer occurs.

Within 5-10 days, the young cancer completely locks itself into a cone consisting of six layers of lime petals lumped together.

Nonparasitic barnacles

Nonparasitic barnacles are divided into two main species - sea ducks and sea acorns. Their body is shrouded in a mantle that emits calcareous plates in the shells. The body of the crustaceans is divided into the head, chest and belly.

On the head are antennas (antennae), which serve in most cases for touch. Antennae in lower crustaceans are also organs of movement.

On the chest are six pairs of bifurcate legs, with the help of which the cancer collects in the mantle cavity water with food particles - microorganisms. Shaking the legs, the cancer attracts plankton, absorbs oxygen from the water.

These animals do not have gills, and the only eye can distinguish only darkness from light. Most of the barnacles are hermaphrodites.

Parasitic barnacles have a saccate body, there is no shell, intestine and limbs.

Sea ducks

On the Spanish, Italian and Greek coasts there is another species of barnacles - these are sea ducks. They cause less inconvenience than their other species - marine acorns. Ducks are attached to floating objects, such as pieces of rotten wood. At the initial stage of development, the larvae of sea ducks and sea acorns lead the same mode of existence. When the deposition period comes, they also stick together in one place, but they have a little more freedom in reproduction and nutrition.

Cleaning vessels from sea acorns

Since ancient times, barnacles (photos of which are presented below) are a problem of millions of ship owners.

Their removal from the bottoms of ships is a long and complex process, during which millions of dollars are spent.

In warm waters, the slowing of the vessel's progress, caused by a six-month fouling, causes the owner to spend fuel 40% more to maintain the normal pace of traffic.

Any decrease in speed leads to additional costs, such as:

• Cleaning the bottom of the ship;
• Purchase of additional fuel.

Military vessels become the most vulnerable to enemies in case of attachment to the body of barnacles. They turn a combat ship into an object, which, due to distortion of the echo, becomes easily audible hydroacoustic devices.

According to the calculations of experts, only in the United States of America millions of dollars are annually spent to clean fouling on the bottoms of civil and military vessels.

Protection of the bottom of vessels

As soon as people began to study the oceans and seas, they tried to find a means that prevents the joining of barnacles to the ships. The Phoenicians tried to use tar. The Greeks tried wax and tar, but no means helped until they began using copper to cover the wooden cases.

However, for modern large vessels, copper is a very expensive substance, for this reason, paints containing copper oxide are currently used.

After leaching a chemical from the paint, it forms a toxic film that protects the vessel from the larvae of marine animals.

One of the last is barnacle cancer, larva (photo above), it is attached to a specific place of the vessel, subsequently forming a shell. On average, the paint protects the bottom of the vessel for three years.

The Mystery of the Adhesive

Despite the fact that the bugs bother the bathers and upset shipowners, they have for centuries attracted the interest of scientists. Charles Darwin spent more than eight years of his life exploring them.

Scientists believe that if you know the composition of the released adhesive, it will be possible to synthesize a similar adhesive product that could be successfully used in dentistry, orthopedics, surgery, traumatology, and also in industry.

However, the sticky substance does not hurry to reveal its secrets. In the solid state, it can not be dissolved by strong acids or organic solvents. It is beyond the influence of bacteria and can withstand temperatures above 200 ° C.

Interesting Facts

According to paleontologists, barnacles first appeared 400 million years ago. Since the Jurassic period, the main sign of them was tenacity. Their remains, dating back to that period, show the barnacles still anchored to the planes on which they settled 150 million years ago.

For a long time, the barnacles treated mollusks, and only thanks to the discovery of the free-floating larva, it was possible to determine their relationship to other crustaceans.

The use of barnacles in food

A steamed crab has the taste of a crab and a lobster at the same time. It is served with a special sauce made from seafood. This dish is appreciated by gourmets around the world. Barnacles can be eaten raw, and they can be fried or boiled.

Such uneasy and peculiar sea inhabitants are barnacles.