Fish face a summer DO-temperature squeeze in some reservoirs.

Example distribution

of habitat leading

to high survival

Example distribution

of habitat leading

to low survival

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Sturgeon are a bottom dwelling, cold-water species. They do not tolerate low dissolved oxygen or high temperatures. In storage reservoirs with high nutrient loadings from surrounding agricultural land, sturgeon may find themselves in what Chuck Coutant coined “the temperature-DO squeeze”. This is the type of habitat the animal needs. In the situation shown on the left, most of the habitat with suitably low temperatures has is anoxic and vise versa. Also this is total volume and doesn’t take into account that the fish needs to feed near the bottom. On the right, suitable conditions of the two factors coincide.