Why few brown trout live to be over two years?

It's not accurate to say that few brown trout live to be over two years. While it's true that brown trout have a high mortality rate in their first few years, they can live much longer than two years.

Here's why it might seem like few live past two years:

* Predation: Young brown trout are vulnerable to a wide range of predators, including larger fish, birds, and mammals. This high predation pressure leads to a significant drop in population during the first year or two.

* Competition: Brown trout fry and young-of-the-year compete for food and space, further increasing mortality rates.

* Environmental factors: Factors like water temperature, habitat quality, and food availability can also influence survival rates.

However, brown trout can live for many years:

* Maximum lifespan: Brown trout can live up to 15-20 years in ideal conditions.

* Age at maturity: Brown trout typically reach sexual maturity at 2-3 years old.

* Survival beyond two years: While many die before reaching two years, a significant number survive beyond that age and continue to grow and reproduce.

It's important to remember that mortality rates vary depending on the specific environment and conditions faced by a brown trout population. In some areas, brown trout may have higher survival rates, leading to older fish being more common.