Lake Erie fish gather near low-oxygen zones as climate change reshapes habitat

Lake Erie can look deceptively uniform from the surface. Beneath it, however, temperature, oxygen and nutrients divide the water into shifting layers, creating habitats that can change over surprisingly short distances. During the warmer months, parts of the lake’s deeper water can become depleted of dissolved oxygen, forming seasonal hypoxic zones that restrict where fish can remain. Scientists studying Lake Erie expected those conditions to alter how fish species used the water and interacted with one another. What they observed was less straightforward. Rather than simply retreating from oxygen-poor water, fish often gathered along the boundary of the hypoxic zone, occupying the narrow area where oxygenated and depleted waters met. That behaviour matters because it changes how scientists interpret fish distributions, food-web interactions and even fisheries data.How Lake Erie hypoxia changes fish habitat and food websAs per the US Geological Survey project, climate-related environmental changes could reshape aquatic food webs across the Great Lakes. Lake Erie was used as a representative system because it combines strong nutrient gradients, seasonal hypoxia and fish communities ...