Introduction: Why do fish lay so many eggs?

Fish are known for producing a large number of eggs, and this is a characteristic that distinguishes them from other groups of animals. The sheer number of eggs produced by fish can be staggering, with some species laying millions of eggs at a time. This raises the question of why fish lay so many eggs, and what evolutionary and ecological factors have contributed to this reproductive strategy.

Evolutionary origins of high egg production

The high egg production seen in fish is thought to have evolved as a response to the high mortality rates experienced by their offspring. By producing large numbers of eggs, fish are able to maximize the chances of at least some of their offspring surviving to adulthood. This reproductive strategy is known as “r-selection,” and is characterized by the production of many small offspring with little parental investment. In contrast, “K-selection” involves producing fewer offspring with greater parental investment. Fish that live in unpredictable and challenging environments are more likely to exhibit r-selection, while those in more stable environments may adopt a K-selection strategy.