What the edges are. No cold edge published. No warm edge published. These are not one consistent quantity across species. A measured avoidance temperature is where fish were seen leaving; a water-quality maximum is a regulatory ceiling written to prevent a kill, and it sits well above the point a day gets difficult.
Source. International Pacific Halibut Commission, Pacific Halibut (Hippoglossus stenolepis): Stock Status and Biology; survey conditions from Sadorus, L.L., R.A. Webster & M. Sullivan 2024, Marine and Freshwater Research 75(5):MF23175. Read it.
Warmwater species swing their preference ten degrees or more between winter and summer in the same laboratory. One band per species is a summer simplification, and it is why the drawing shows a band rather than a line.