Compensatory Growth

Compensatory growth is the phase of accelerated growth — driven by elevated appetite (hyperphagia) and improved feed efficiency — that follows a period of feed restriction, poor water quality, or other growth-limiting stress, during which the animal partially or fully recovers the size deficit relative to continuously fed contemporaries. The effect rests on physiological reallocation: restricted animals suppress costly processes (immune function, gonadal development) and prioritize maintenance, then after refeeding convert feed to somatic growth at rates above normal for a window of weeks. Commercially, farms exploit this deliberately: short, controlled restriction periods — seasonal in cages exposed to winter low temperatures, or scheduled in tilapia and salmon smolt protocols — can produce equal final weights with lower total feed consumption, improving overall feed conversion ratio and cutting feed cost per kilogram. The effect has hard limits. Restriction that is too severe, too early (during early larval stages, where stunting is essentially permanent), or too long leads to irreversible size reduction, impaired immune status, and higher subsequent mortality rather than catch-up; and compensatory growth typically does not fully restore condition factor, gonad quality, or filet lipid content even when weight catches up. Protocols therefore require species- and stage-specific validation: the recovery window, its duration, and the maximum safe restriction depth all vary. When used correctly, compensatory growth is a powerful feed-economics tool; used blindly, it manufactures runts.