Description and characteristics
The European perch (Perca fluviatilis) is a freshwater predatory fish, easily recognised by its robust and laterally compressed body. It has a characteristic colouration: olive-green back, green-yellow flanks with dark vertical bars (5–7 of them) and orange-red ventral and anal fins. The scales are small and rough, and the mouth has numerous small teeth.
Habitat and distribution
The perch inhabits a wide range of freshwater and brackish habitats in the Danube Delta: lakes, arms, canals and flooded areas. It prefers waters rich in aquatic vegetation, where it finds shelter and food. It is a highly adaptable species, present in calm waters as well as in faster currents.
Diet and behaviour
It is an opportunistic predator, feeding on aquatic invertebrates, insect larvae, worms and, as it grows, mainly on small fish. When hunting, perch often form packs that herd schools of small fish into vegetation or shallow water.
Reproduction
Spawning occurs in spring at water temperatures of 8–12°C. The female lays eggs in pale-yellow ribbons attached to vegetation, reeds or other underwater surfaces. The eggs are numerous and the fry grow quickly.
Economic and ecological importance
Perch is an important sport and semi-commercial species in the Danube Delta, valued for its tasty flesh. Ecologically, it helps regulate populations of small fish and invertebrates.
Threats and conservation
Populations are affected by water pollution, loss of wetland habitats and fishing pressure. Responsible management, protection of spawning areas and respect for catch limits are essential for conservation.
Fishing and legal minimum size
Perch is sought by sport anglers in the Danube Delta and other inland waters. In the table of minimum legal sizes, the perch (Perca fluviatilis) has a minimum legal size of 12 cm, measured from the tip of the snout to the base of the caudal fin.
Conclusion
The European perch is an important piece of the Danube Delta biodiversity, playing a dual role: a fishing resource and an element of balance for aquatic ecosystems.