Asp

Back dark olive to bluish-black; sides silvery and shiny; ventral side whitish with a metallic luster. Pectoral, pelvic, and anal fins are often greyish to reddish-tinted.

Large, superior mouth reaching below the eye. The lower jaw has a prominent tubercle that fits into a corresponding notch in the upper jaw. The anal fin is deeply falcate (concave).

Chub (Squalius cephalus) – which has a convex anal fin; Ide (Leuciscus idus) – which has a smaller, terminal mouth.

During the spawning season, males develop fine nuptial tubercles on the head and scales of the anterior part of the body.

Barbel zone and Bream zone; also enters the brackish waters of the Baltic Sea.

Pelagic; prefers the upper water layers (epipelagic) of large rivers and lakes.

Rheophilic; prefers flowing areas in large rivers, but also occurs in standing waters.

Gravelly to sandy; requires clean gravel bars in strong currents for reproduction.

Moderate to high; as an active predator, it depends on a good oxygen supply.

Performs distinct upstream spawning migrations to reach suitable gravel spawning grounds in high-flow sections.

Gravel and stones in strong current (lithophilic).

After hatching, the larvae drift into calm shore zones, where they develop in shallow water areas.

None; eggs are deposited in the gravel and the parents leave the spawning site immediately.

Predatory fish; the only primarily piscivorous representative of the cyprinids in Central Europe.

Zooplankton, small insect larvae, and crustaceans; at a length of approx. 8-10 cm, the switch to fish prey occurs.

Predominantly small fish (e.g., bleak, roach, perch), occasionally terrestrial insects (allochthonous input).

Active hunter; often hunts spectacularly at the water surface, striking into schools of small fish with great force.

Juveniles live in schools; adult animals are often solitary or hunt in small, coordinated groups.

Apex predator in the open water of large river systems; regulates populations of small fish such as bleak.

Pike, Wels catfish, cormorant, and otter; juveniles are also preyed upon by perch and other predatory fish.

Pike-perch and pike (food competition); in the juvenile stage, competition with other cyprinids for zooplankton.

Infestation by various trematodes (e.g., Posthodiplostomum cuticola) and parasitic crustaceans (Ergasilus sieboldi).

Indicator for the ecological connectivity of watercourses and the presence of intact gravel spawning habitats.

Regulated by regional fishery ordinances; often includes minimum sizes and closed seasons; additionally protected by the Habitats Directive.

Varies regionally, usually within the period from April 1st to May 31st.

Low importance as a food fish due to many Y-bones; however, very high importance as a target species for recreational fishing.

Transverse structures prevent spawning migration; loss of spawning habitats due to siltation and bank stabilization; water pollution.

Stable to slightly increasing in Central Europe, favored by restoration measures and improved water quality.

Restoration of connectivity (fish ladders); protection and revitalization of gravel bars; compliance with Habitats Directive management plans.