Iran's endangered caviar industry

Iran has been working for 35 years to prevent the extinction of wild sturgeon and preserve caviar production. The country releases 10 million baby sturgeon annually into rivers leading to the Caspian Sea. The process is slow, with some species taking up to 18 years to mature. Challenges include poaching, pollution, and dams blocking spawning routes. Iran urges neighboring countries to release sturgeon and control poaching. Despite less than 1% reaching maturity, the effort generates significant caviar revenue.

What is the relationship between sturgeon population decline and poaching or pollution?

What is the estimated cost of releasing sturgeon into the wild each year in Iran?