Fighting for their food, the fish eagles lock talons in a dizzying display. But landing in the water puts one eagle in grave danger.

Excerpts from NATURE examine interrelationships between sharks and other species in the marine ecology. Human impact in the ecosystem includes the shark fin industry.

This video-enhanced lesson focuses on symbiosis and ecological relationships. Using sharks and marine species as examples, students will investigate the many ways that species that live in close proximity to each other might interact in an ecosystem, and will then explore the ways that ecosystems can be thrown out of balance, often as a result of human action. (Grades 9-12)

Starting in County Cavan, the Shannon River tumbles and twists 200 miles to the Atlantic Ocean. For anglers, it is the salmon that draws them to the Shannon.

Download superfish wallpaper for your desktop.

Find additional billfish resources online and in print.

View the production credits for NATURE's "Superfish."