The main, or central, idea of the passage is Thanks to conservation efforts, Florida manatee populations...

The main, or central, idea of the passage is Thanks to conservation efforts, Florida manatee populations have increased. How does the detail in bold develop the main idea?
The Florida manatee, a subspecies of the West Indian manatee, is a large ocean mammal found in Florida's rivers and coastal areas. Unfortunately, the state's population of manatees has dwindled significantly over the years. Although the manatee has no natural predators, humans have contributed to many manatee deaths, mainly through boat collisions. The loss of warm-water habitats has also hastened the manatee's decline. Aerial surveys performed in the early 1990s found an estimated 1,267 manatees in Florida. Because of conservation efforts by several organizations, however, the number of manatees has rebounded recently. The creation of manatee protection zones—areas that boaters must avoid or drive through more slowly—has been particularly effective. As a result of these efforts, more than 6,000 manatees are found in Florida today.
It highlights a successful conservation strategy.
It anticipates a potential flaw in conservation strategy.