Sea turtles are large, graceful reptiles that swim in the world's oceans. Unfortunately, sea turtle numbers are in decline, and some sea turtle species are now endangered. Conservation biologists have several suggestions to help reverse the decline in sea turtle populations. One suggestion is to protect sea turtle eggs from predators by building metal fences around their nests. Sea turtles typically migrate long distances to lay their eggs on specific beaches, guided in their migration by a well-developed magnetic sense. But the unprotected eggs are often eaten by predators such as dogs. If conservationists erected protective wire fences around the eggs, it would keep predators away and allow young turtles to hatch safely from the eggs. A second threat to sea turtles is plastic bags, such as those used to carry groceries. Many sea turtles eat these bags, mistaking them for jellyfish (a food source), and die because the plastic blocks their digestive tract. One way of helping sea turtles would be to ban plastic bags, requiring shoppers to use reusable or paper bags instead. This simple change could drastically reduce the number of plastic bags that end up in the ocean, thus removing one of the major threats to sea turtles. Finally, many sea turtles are killed accidentally when fishing vessels catch them in their nets. Sea turtles breathe air, so when they are trapped in a fishing net that remains underwater for hours, they drown. Fortunately, new nets have been designed with devices called turtle excluders. A turtle excluder allows fish to pass into the net, but it stops large animals like sea turtles. Laws requiring fishers to use turtle excluders would prevent sea turtles from being killed accidentally in the nets.