Danube bleak gravel bottoms. The females arrive later and deposit about twenty thousand eggs which stick to stones and gravel. These hatch after two or three days and the larvae stay among the gravel for another ten days before moving to backwaters and shallows where they feed on zooplankton, insect larvae and algae. The juvenile fish migrate down stream in the autumn or the spring of the following year. They may become mature in four to five years. Danube bleak The Danube bleak or Caspian shemaya ("Alburnus chalcoides") is a species of freshwater fish in the family Cyprinidae. It is found in
Atlantic horseshoe crab role in the local ecosystems, with their eggs providing an important food source for shorebirds, and the juveniles and adults being eaten by sea turtles. The other three extant (living) species in the family Limulidae are also called horseshoe crabs, but they are restricted to Asia. This group of animals is also known as horsefoot, or saucepan. Some people call the horseshoe crab a "helmet crab", but this common name is more frequently applied to a true crab, a malacostracan, of the species "Telmessus cheiragonus". The term "king crab" is sometimes used for horseshoe crabs, but it is more usually