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Benthic Zone

Freshwater Rivers (Lotic)

Flowing freshwater systems - streams, creeks, and rivers - where current shapes every aspect of fish adaptation and community structure.

Depth: 0-200m Light: Sunlight

📖 Overview

Lotic (flowing) freshwater systems support 40% of the worlds fish species despite covering less than 0.01% of the surface. Fish adapt via streamlining, strong swimming muscles, and lateral-line rheotaxis. Riffles-pools-runs sequences create habitat mosaics. Salmonids, catfish, cyprinids, and centrarchids dominate temperate systems; characins and cichlids dominate tropical.

🌿 Ecology

Detritus and drift-based food web. Invertebrate drift feeds trout. Salmonid spawning gravels. Reef structure from wood snags and rocks.

⚠️ Threats

Dams (blocking migration), pollution, water diversion, invasive species, warming waters.