Climate-driven browning reduces visibility in 871 North American and European lakes, shifting communities toward sensory-adapted predators

Freshwater browning increases dissolved organic carbon from soils, reducing light penetration and altering prey detection. The reviewed studies combined meta-analyses of growth rates with community surveys in 303 Canadian lakes and population data from 871 lakes spanning North America and Europe. Species with large eyes or vibration-sensing systems gained relative abundance; visual foragers declined. This produces not isolated color changes but systematic species turnover that reconfigures predator-prey size spectra and energy flow through pelagic and littoral food webs.

Mainstream coverage treats browning as an aesthetic or local water-quality issue. The data instead show consistent directional change in economically important fisheries, with slower individual growth rates scaling to lower recruitment in unstocked populations. Brook trout proved an exception, indicating trait-specific thresholds rather than uniform stress. These patterns align with earlier DOC loading experiments and long-term monitoring in boreal catchments that documented similar sensory filtering of fish assemblages.

Management responses must therefore move beyond stocking visual predators. Lure selection favoring vibration or scent already reflects the sensory shift; broader adaptation requires revising harvest models and habitat protection to account for compressed visual foraging ranges. Continued warming will likely accelerate carbon mobilization, pushing more lakes past visibility thresholds that favor pike and walleye dominance within 20–30 years.

Next steps include coupled hydrodynamic-DOC models validated against the existing 871-lake dataset to forecast tipping points where walleye biomass exceeds 30 % of total fish production.