Common bleak small shellfish and plant detritus. It is found in streams and lakes. The bleak prefers open waters and is found in large numbers where there is an inflow of food from pumping stations or behind weirs. The bleak spawns near the shore in shallow waters. Some are found in deep water. The substrate is not important. The bleak is an important food source for predatory fish. It is more sensitive to pollution than other cyprinids, which might explain the decline in North-Western Europe. Bleak are used as bait for sport-fishing for larger fish. In 1656 in Paris, a Mr. Jaquin
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