Physical Characteristics
The silver bream has a tall, strongly laterally compressed body, similar to the common bream but proportionally shorter and taller relative to length. The most important feature for distinguishing it from the common bream is the number of scales on the lateral line: the silver bream has 44-49 scales (the common bream has over 50), and counting scales from the dorsal fin to the lateral line, the silver bream has 9-11 rows (the common bream has 13 or more). The scales are large, thick, and well attached. The head is small with large, prominent eyes. The mouth is small, oblique, semi-inferior, lacking barbels. The pharyngeal teeth are arranged in two rows (in the common bream, in a single row).
Coloration is characteristically bright silver: greenish-bluish back tending towards brown or olive, silver-grey flanks with intense metallic sheen, bright white belly. The ventral and pectoral fins are yellowish or pale pink, becoming intense vermilion in males during the breeding period. Average dimensions are 12-25 cm and 60-200 grams.
Habitat & Distribution
The silver bream prefers still or very slowly flowing waters with muddy or sandy bottoms, being a benthic fish that spends most of its time on or near the bottom. In the Danube Delta, it is ubiquitous and extremely abundant in nearly all permanent and temporary lakes and ponds, channels with weak current, floodplains, the Razelm-Sinoe lagoon complex (tolerates low salinities), and the lower stretches of large rivers with gentle current.
Ideal habitat includes zones with moderate depths (1-5 meters), muddy or sandy bottoms, proximity to emergent vegetation (reed, cattail). The silver bream is gregarious and forms large shoals (50-200 specimens) of similar size. It tolerates a wide range of temperatures (0-28°C, optimum 15-22°C) and can survive in low-oxygen conditions.
Behavior & Feeding
The silver bream is an opportunistic benthic omnivore with an extremely varied and flexible diet, more diversified than the common bream. Food includes: benthic invertebrates (chironomid, mayfly, caddisfly larvae), small crustaceans, small mollusks, worms, aquatic and terrestrial insects, aquatic plants, seeds, plant debris, and occasionally fish eggs and fry. The feeding mode is characteristically benthic: the silver bream methodically searches the bottom, aspirating sediment and selecting edible particles.
Feeding activity is intense in the early morning and evening. Social behavior is moderate - shoals are smaller and more mobile than the common bream's. In autumn, feeding becomes frantic in preparation for winter. The silver bream can hybridize frequently with the common bream, carp, and other related cyprinids.
Life Cycle & Reproduction
The silver bream reaches sexual maturity relatively early: males at 2-3 years when 10-15 cm, females at 3-4 years when 12-18 cm. Reproduction takes place in late spring and early summer, between April and June, when water temperature exceeds 15°C (optimum 17-20°C). It migrates from deeper lakes to very shallow areas (20-80 cm) with dense vegetation. Males develop nuptial tubercles on the head, back, and fins, and coloration becomes intense with chest and ventral fins bright vermilion-red.
Fecundity varies considerably: a female lays between 17,000-110,000 eggs, average 40,000-60,000. Eggs are small (1-1.2 mm diameter), sticky, and adhere to submerged vegetation. Hatching occurs after 4-8 days. Growth is moderate: in the first year 5-8 cm, in the second 10-15 cm, in the third 15-20 cm.
Conservation Status
The silver bream is classified as "Least Concern" (LC) by IUCN, being one of the most abundant and widely distributed cyprinid species in Europe and Romania. In the Danube Delta, populations are extremely healthy, numerous, and stable, with the silver bream being one of the numerically dominant species in most lakes and ponds. It does not benefit from special protection measures, but is covered by the general spring reproduction prohibition (April-June).
It plays an important ecological role as an intermediate species: consuming benthic invertebrates and plants, controlling their populations, and serving as important prey for all predators. Threats are minimal due to great adaptability. Main potential threats include excessive eutrophication and severe chemical pollution.
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