Marine reserves are areas where people are not allowed to fish, helping marine species recover from overfishing. Studies in New Zealand and Chile show that marine reserves can bring fish populations back to healthy levels similar to the past. By comparing current fish numbers to historical levels, we can see the impact of human fishing on marine ecosystems. Marine reserves are important for conservation and management, helping to rebuild overexploited fish stocks and restore ecosystems to a more natural state. They also help us understand how human activities affect the entire ecosystem, which is crucial for managing coastal resources effectively.