Climate change is warming freshwater fish thermal habitats. Here, the authors examine daily temperature profiles from 12,688 lakes and thermal habitats of 60 fish species, finding that cold-water fishes are losing preferred thermal habitats at a faster rate than warm-water fishes are gaining them.

Water quality impacts by harmful algal blooms co-occur with anthropogenic chemicals and waste pollution. We need to embrace multidisciplinary approaches to advance the science and improve the practice of water quality assessment and management.

Human changes to freshwater flows affect marine ecosystems, but such impacts are rarely considered in development plans involving dam building and water abstraction from rivers. Now research shows how approaches that integrate flow management and marine fisheries can improve both freshwater and coastal ecosystem sustainability.

We examined the interactive effects of temperature and the presence of apex fish predators on food web structure in Icelandic geothermal streams. Fish suppressed the biomass of invertebrates and thus released algae from grazing pressure, but only at higher temperatures, which illustrates how the combination of warming and apex predators triggers this trophic cascade.