Channel catfish muscle tissue δ13C and δ15N value responses (black circles;mean±SE) to constant diets (gray triangles) of manufactured feed (A, B) and freeze-dried chironomid larvae (C, D) in the tank experiment, or live prey-only in the pond experiment (E, F; no-feeding treatment). Trophic enrichment factors (TEFs), defined as the‰difference between food
values (dash-dot lines) and their expression in fish tissue (dash lines), are displayed in each panel.