This inquiry uses evolutionary game theory to assess the stability of various sex ratio strategies and evolutionarily stable strategies (ESS) to identify the advantages and downsides of sex ratio changes on Sea Lamprey populations. We constructed the TOPSIS indicator model, selected three positive and three negative indicators, and calculated the total score to assess pros and cons. For issue three, this study constructs an ecological network model with several species and trophic levels, solves differential equations numerically, and explains their relationships. A TOPSIS indicator model with four influencing components is built, and a comprehensive ecosystem assessment indicator is generated. Sex ratio affects Sea Lamprey ecological stability, and stability improves as men to females approach 1.This question answers issue four by creating an ecological model of multi-species interactions and using differential equations to describe food web interactions. An ecosystem with Sea Lamprey populations with variable sex ratios can benefit all four using numerical methods to solve differential equations and TOPSIS to assess sex ratio variation, competitive relationship complexity, parasite population variation, and food web complexity with a threshold value of 0.6.The study finishes with model sensitivity and strengths and weaknesses analyses.