Description and characteristics
Crayfish (Astacus sp.) are freshwater crustaceans with a hard exoskeleton, five pairs of legs, one pair with strong claws. They have a long, muscular tail ending in a fan. Colouring varies from brown-green to reddish when cooked.
Habitat and distribution
They inhabit clean fresh waters with stony or muddy bottoms and shelters — canals, branches and lakes of the Danube Delta. They hide under stones, roots and in burrows.
Diet and behaviour
They are omnivorous, feeding on invertebrates, larvae, vegetation, organic debris and even small fish. They are active especially at night, leaving shelters to search for food.
Reproduction
Reproduction occurs in autumn, with females carrying fertilised eggs attached to the abdomen until hatching in spring. The young grow gradually through successive moults.
Economic and ecological importance
Crayfish have great economic and culinary value, appreciated for their delicate flesh. Ecologically, they help clean the bottom and are part of the food web.
Threats and conservation
They are sensitive to pollution and to crayfish plague, a disease that has decimated European populations. Protection of clean waters and fishing management are essential.
Fishing and legal minimum size
Crayfish are caught with traps and hoop nets. In the table of minimum legal sizes, crayfish (Astacus sp.) have a minimum size of 9 cm.
Conclusion
Crayfish are valuable freshwater crustaceans, important for gastronomy and ecological balance in the Danube Delta.