Muscle tissue isotope δ value transition rates (i.e., half-lives, t1/2) varied according to estimated growth rates for each treatment. Fish in the tank treatments of chironomid larvae only and feed only grew slower in the first three weeks of the experiment (chironomid larvae only, SGR = 4.7%/d; feed only, SGR = 12.5%/d) as compared to fish in the no-feeding treatment in the pond experiment that had access to live prey only (SGR = 15.4%/d). These growth patterns resulted in slower isotopic transitions (i.e., longer t1/2) in the chironomid larvae only and feed-only treatments (t1/2=9 and 12 d, respectively) as compared to fish in the no-feeding treatment in ponds (t1/2=5d). Regardless of treatment, however, the onset of isotope δ value transitions was immediate, and muscle tissue approached steady-state values to the
new diet in 2–4 weeks.