Impact of Energy Allocation on Fish's Age and Weight at Maturation by Mathematical Models

The age and weight at maturation are crucial traits in an organism’s life cycle, influencing its growth, survival, and reproduction. We propose a biphasic energy allocation model, distinguishing pre-maturity and post-maturity, to study the mechanisms of maturation and estimate the age and weight at maturation. This model is parameterized for female lake whitefish (Coregonus clupeaformis). We compare different functions involved in the model, estimate parameters, and do sensitivity analysis. Our results indicate that (i) weight at maturation is positively related to the fraction of energy allocated to growth which, by data fitting, is almost a constant; (ii) age at maturation is highly sensitive to the coefficient and exponent in the energy assimilation rate; (iii) higher energy conversion efficiency to weight can lead to earlier maturation with larger weight. Additionally, the results offer new insights into the ratio between asymptotic weight and mature weight across populations.