Silver Bream
Blicca bjoerkna
The silver bream is a widespread European freshwater fish belonging to the cyprinid family. It is characterized by a deep, laterally compressed body and a shiny silver coloration. Compared to the common bream, it has noticeably larger eyes and often reddish bases on its pectoral and pelvic fins. It prefers slow-moving or standing waters with soft substrates and abundant vegetation.
Details
Identification
Large eyes (diameter larger than snout length), reddish bases of pectoral and pelvic fins, 19-23 branched rays in the anal fin, two rows of pharyngeal teeth.
Social behavior
Gregarious shoaling fish, often forming mixed shoals with common bream or roach.
Diet
Opportunistic omnivore feeding on zooplankton, insect larvae (especially chironomids), small snails, mussels, and detritus.
Hunting strategy
Bottom-feeding by rooting in the mud as well as searching aquatic plants for edible organisms.
Spawning substrate
Phytophilous; eggs are deposited on submerged aquatic plants, roots, or flooded grass.
Overwintering
Gathers in large shoals in deeper, low-current areas or hollows on the water bottom and reduces food intake.
Ecology
Ecological role
Important primary consumer and link in the food web; serves as significant prey for larger predatory fish.
Natural predators
Northern pike, pike-perch, wels catfish, cormorant, grey heron, Eurasian otter.
Competitor species
Common bream (Abramis brama), Roach (Rutilus rutilus), Ruffe (Gymnocephalus cernua).
Ecosystem service
Contributes to nutrient cycling in the sediment and is a relevant fish for recreational angling.
Threats
Loss of shallow water zones and spawning habitats due to bank stabilization; extreme eutrophication and oxygen depletion.
Scientific profile
Morphology & ID
Coloration
Silvery shining flanks, back olive-greenish to blue-grey; paired fins (pectoral and pelvic) often have a reddish or orange tint at the base.
Distinguishing features
Large eyes (eye diameter usually larger than snout length), pharyngeal teeth in two rows (formula 2.5-5.2), 43-48 scales along the lateral line, reddish fin bases.
Confusion species
Common Bream (Abramis brama): has smaller eyes, dark fin bases, and more scales (51-60) on the lateral line. Blue Bream (Ballerus ballerus): has a significantly longer anal fin.
Sexual dimorphism
Males develop fine-grained spawning tubercles on the head and scales of the anterior body during the breeding season.
Habitat
Fish region
Bream zone (Metapotamal)
Preferred zone
Benthic and littoral; prefers areas near the bottom of vegetation-rich shore zones.
Flow preference
Limnophilous to eurytopic; prefers stagnant waters or very slow-moving river sections.
Substrate preference
Fine substrates such as mud, detritus, or sand, often associated with macrophyte stands.
Oxygen requirement
Moderate; tolerant of temporary oxygen depletion in eutrophic waters.
Migration
Migration behaviour
Potamodrom; führt kurze Wanderungen zwischen Fresshabitaten, Überwinterungsplätzen und flachen Laichgebieten durch.