Catch-up growth and swimming performance in threespine sticklebacks (Gasterosteus aculeatus): seasonal changes in the cost of compensation

Compensatory growth is a phase of unusually rapid growth following a period of growth depression. This response allows animals to achieve the same size-for-age as continuously fed contemporaries. We tested the hypothesis that a period of poor growth followed by compensation reduces the swimming abilities of threespine sticklebacks (Gasterosteus aculeatus), even after the period of rapid growth had ceased; we also investigated how the time of year in which the rapid growth occurred affected the possible costs in swimming performance. The threespine sticklebacks showed a compensatory growth response after a period of food shortage, both in winter and in spring. This change in growth trajectory subsequently caused a reduction in ability to withstand high flows, but only when the period of rapid growth occurred just prior to the breeding season. We suggest that threespine sticklebacks may be willing to incur the swimming costs of catch-up growth just prior to the breeding season to maximize their expected reproductive success.