Narrow-clawed crayfish (lat. Astacus leptodactylus) is part of the Decapod order, has another common name crayfish tailor. This is due to its specific shape of the claw, it resembles tailor’s elongated scissors.
Description
A narrow-toed variety of crayfish is awake only at night, during the daytime it hides securely in its shelter. During night hunting, moving along the bottom of the reservoir, he collects pieces of algae that have come off. From vegetation prefers pondweed, elodea and hornwort.
Carrion is considered any food. If it is absent, then narrow-clawed crayfish attacks amphibians, small fish, small invertebrate representatives of the water element. How does he eat food?
Food is captured by large claws;
Tries to break as much as possible, reaching small segments;
Then, with the help of small claws, he collects these pieces, additionally crushes and sends them to the oral cavity.
If danger is approaching, narrow-clawed crayfish tries to defend itself with claws and shows aggression.
Appearance
Unlike its close relatives (broad- and thick-clawed crayfish), the narrow-clawed crayfish has long and narrow claws. Moreover, there is no notch on the fixed finger.
Other Features:
The surface of the shell is marble-like;
Color from light sand to light brown;
Telson angular;
Body type slender;
Aantsir thin;
Carapace expanded like an egg or pear;
Sides with spines;
Epistoma apical, without spines;
Chest has 8 segments;
Abdomen 6 segments;
Paws 10 pcs.;
Length male 18 cm, female 17 cm.
Where does it live
Narrow-clawed crayfish prefer stagnant fresh water. In Europe, it is found to a greater extent in the Eastern and Central parts, in Eurasia it is the Caspian and Black Seas, lakes of the Trans-Urals. Today, narrow-clawed crayfish are also common in other regions where the reservoir meets the requirements for maintenance:
thickening with algae;
Many secluded places;
Thick sandy-silty bottom;
Minimum depth 2 m;
Maximum 15-30 m;
The acidity of the water is from 7.8 to 8.5 pH;
The level of oxygen saturation is from 5 to 10 mg/l;
The temperature of the reservoir is from +18 to +23°C, but they can also exist with a run-up from +1 to +28°C.
Narrowfingered crayfish are too sensitive to chemical compounds, so they cannot live in ponds with chemical pollution.
Reproduction
Sexual maturity occurs after a year in males, after 2 years of life in females. The mating period falls on October, November and December.
Other features:
Marriage time from September to early November;
Working fertility-250 eggs, absolute-330-340;
The number of eggs laid varies from 100 to 200 pcs., but only 35-40%hatch;
Caviar larvae appear in May or June;
Metamorphosis lasts from 3 to 9 days (this is a period when larvae cannot eat on their own);
The first molting of fry is noted after 5-6 days, the second-from 11 to 15;
Incubation period-5-6 months;
Crustaceans hatch up to 1 cm in size;
For about 2 months they live on Rachikha, clinging to the legs near the abdomen.
Immediately after fertilization, the female begins the time of laying eggs. To do this, she rolls over onto her back and arches it so that a “capacity” forms on her abdomen, where the eggs are hatched. They are immediately fixed on the belly and legs.
Interesting Facts
Narrow-clawed crayfish are amazing arthropods, there is a lot of cognitive in their development and life.
There are some interesting facts:
Before the process of molting, the shell is separated from the body due to the fact that carbon dioxide compounds dissolve in water. After that, the crayfish begin to rub themselves with their paws and thus end up on their backs;
Sharp gusts contribute to the cracking of the carapace, starting from the areas of combination of the belly and cephalothorax. Then he removes the shell from his head, then pulling out everything else. Before the formation of a fresh shell, the cancer hides in a shelter. This takes about 10 days;
In 1860, a massive death of narrow-toed crustaceans was noted in Italy. This happened against the background of the entrance to the port of American ships, which lowered ballast water contaminated with bacteria. This infection led to the fact that arthropods began to develop crayfish plague;
Until the end of the 19th century, more than half of this type of crayfish was infected, as a result of which they rapidly died;
After the 50s of the 20th century, the number of narrow-clawed crayfish has sharply decreased. The reason for this is the use of mineral and pesticide fertilizers in agriculture;
Life expectancy is as much as 25 years, but under favorable conditions.
Narrow-toed crayfish in Eastern Europe is under control, so it is forbidden to catch it during mating seasons, spawning and growth of crustaceans. This time is from the end of October to the beginning of August.
