The effects of feeding history and environment on condition, body composition and growth of bluegills Lepomis macrochirus.

Initial relative mass (W(R), low v. high) and energetic trajectory in time (starved v. fed) were experimentally manipulated in bluegill Lepomis macrochirus. Fed fish starting at low W(R) grew more and gained more W(R) than fed fish starting at high W(R). Similarly, starved fish starting at high W(R) lost more mass and W(R) than did starved fish starting at low W(R). Temporal changes in other variables did not consistently match that of W(R), but, by the end of the experiment, proximate composition showed a high correlation to W(R). Regression slopes of W(R) on proximate composition increased with time in the laboratory. Differences between wild and laboratory fish appeared to result from relaxation of environmental stress. When excess resources are available such that L. macrochirus grow, condition indices will increase, but individual response will depend on initial values and thus past environmental experience.