OXYGEN AND CATS
Q: Have there been studies on the oxygen needs of catfish? They become more difficult to catch during the peak of summer in my river, and I'm wondering if their feeding slows as the water warms and the current decreases, lowering the oxygen content.
-Member Jay Richey/Cleveland, Tennessee
A: Actually, quite a bit is known about channel catfish oxygen requirements and temperature-feeding relationships, because millions of dollars in catfish harvest is on the line every summer when warm water and high catfish oxygen demand creates a precarious situation in stocked production ponds.
Channel cats stop feeding when dissolved oxygen concentrations fall below 2 parts per million. High water temperatures will reduce feeding- a channel cat's food intake peaks at about 85 degrees and then declines.
Water flow, by itself, is not an issue. But in muddy rivers and streams, algae, phytoplankton and aquatic plants produce little oxygen. Thus, lack of flow could mean low dissolved oxygen.
How can you tell if oxygen is low? Lacking an expensive oxygen meter, look for activity of other fish, except gar, which gulp air at the surface. If sunfish are active and can be caught, oxygen is not affecting catfish.
-Dr. Hal Schramm