Why can't big pike just go deep in summer where the water is cold?
In many lakes they try — and run into the summer squeeze: the cold water below the thermocline in fertile lakes loses its dissolved oxygen as the season wears on, so the layer with the right temperature has unbreathable oxygen, and the layer with breathable oxygen is too warm. Big pike get pinched into a narrow band along the thermocline or onto deep weedlines where plants still pump oxygen by day. Infertile, clear, cold lakes — classic Canadian Shield cisco water — keep oxygen deep all summer, which is one big reason the giant summer pike of the far north live where they do.
The full story
This answer is one piece of a longer lesson — setups, diagrams and the reasoning behind it.
More questions about Breathing & oxygen
Same topic, other species
- Why are summer crappie pinned to one exact depth band? — Crappie
- How does the thermocline affect where largemouth hold in summer? — Largemouth Bass
- Why do muskie suspend over open basins in summer? — Muskellunge (Muskie)
- Is there enough oxygen in the deep basin under the ice? — Yellow Perch
- Does a summer smallmouth have to move deep? — Smallmouth Bass
- Why do trout lakes need to be deep or spring-fed? — Trout (Rainbow · Brook · Lake)
- How does the thermocline decide where summer walleye live? — Walleye