How do you count two fish, three fish or even a school of fish? In Dry Tortugas National Park, located 70 miles from Key West, Florida, a group of scientists have joined forces to conduct a massive fish census. In this unprecedented collaboration, experts from four different agencies unite to count and analyze fish data from select sites. Changing Seas follows highly-skilled science divers as they determine the size of fish populations in hopes of better understanding how fishing pressures and environmental changes affect populations of marine resources within the park.

Bottlenose dolphins are a beloved Florida icon. But, recent studies show disturbing signs of immune system dysfunction and disease plaguing this charismatic mammal. These problems might be linked to legacy contaminants and other pollutants which bio-accumulate up the ocean food chain. Changing Seas meets with experts for an in-depth look at the health status of Florida's wild bottlenose dolphins.

An ancient species of flowering plants that grow beneath the surface of the world's oceans, seagrasses link coastal coral reefs with mangrove forests along the coastline. Today, these "prairies of the sea," along with mangroves, are declining globally. Scientists fear the diminishing vegetation could lead to an ecosystem collapse from the base of the food chain all the way to the top. Changing Seas joins experts in the field as they work to restore Florida's vital mangroves and seagrasses. Seagrasses and mangroves are "hotspots of biodiversity" since they attract and support a variety of marine life. However, damage and removal of these plants continue across the globe at a rapid pace. 'Changing Seas' journeys along Florida's coastline to better understand the significant roles mangroves and seagrasses play within the state.

In the turquoise blue waters of the Florida Keys, a new attraction is drawing scuba divers from around the world: The USNS General Hoyt S. Vandenberg. Laid to rest in the Florida Keys National Marine Sanctuary, the Vandenberg is the world's second largest intentionally sunk shipwreck. In her last mission as an artificial reef, this massive ship is already attracting a variety of fish and other marine life. Now, natural resources managers are trying to determine what impact this artificial reef has on fish populations and the health of the surrounding natural reefs.