Fish population dynamics is the study of change in a fish population over time. Fundamentally, a population size after some time interval equates to the population size before that interval plus births (i.e., recruitment) and immigration and minus mortality and emigration. Many fish populations follow a logistic pattern of density-dependent growth. Beginning with a population size where space and food are not limiting, the population grows rapidly in an exponential pattern; at a certain population density, population growth slows and stabilizes at a given carrying capacity.
Density-dependent factors governing fish population dynamics include competition, predation, disease, and parasitism. Fish population dynamics can also be driven by density-independent abiotic factors such as temperature, dissolved oxygen, and water chemistry.