In this chapter we discuss the relationship between the ecology, specifically rates of reproduction of living marine resources, and regime formation to manage those resources. The main point to look for is that when the rate of reproduction is high, other things equal, there is a better chance of agreeing sensible management rules, compared with when the rate of reproduction is low. The key variable is the rent-maximizing harvest, H*, compared with the environmental carrying capacity of a species, K – that is, H*/K.