Classification of life histories based on juvenile survival, fecundity, and age at reproductive matu

They called the three endpoints on their surface “opportunistic,” “equilibrium,” and “periodic” life histories. The opportunistic strategy, by combining low juvenile survival, low numbers of offspring, and early reproductive maturity, maximizes colonizing ability across environments that vary unpredictably in time or space. It is important to keep in mind, however, that while the absolute reproductive output of opportunistic species may be low, the percentage of their energy budget allocated to reproduction is high. Winemiller and Rose's equilibrium strategy combines high juvenile survival, low numbers of offspring, and late reproductive maturity. Finally, the periodic strategy combines low juvenile survival, high numbers of offspring, and late maturity. Among fish, periodic species tend to be large and produce numerous small offspring. By producing large numbers of offspring over a long life span, periodic species can take advantage of infrequent periods when conditions are favourable for reproduction.