Why do female trout lay so many eggs?

Trout, like many other species of fish, have what is known as a high fecundity rate. This means that females can produce a large number of eggs during their reproductive season. Trout often do so to offset potential losses in offspring. While many trout species can lay tens of thousands of eggs or more at once, most of the young won't actually live out this stage at all--falling prey to hungry birds, large fishes, and many other types of animals. By laying a great number of eggs, the chances of a few of those tiny creatures surviving the dangerous time between their birth and adulthood improves drastically. This evolutionary adaptation helps ensure continued survival of their specie despite such low odds.