Convoy Point: a walk out the jetty into Biscayne Bay

Welcome to Biscayne National Park, the largest marine park in the whole National Park System. It covers about a hundred and seventy-three thousand acres, and more than ninety-five percent of it is water: the bay, the islands, and a coral reef far offshore. The islands can only be reached by boat, so for anyone without one, this small point of land at Convoy Point is the place to start.

Today's walk is the jetty trail. It runs along the shore and out over the water to the end of a long jetty, partly on boardwalk and partly on gravel, and you come back the same way. The whole trip is less than a mile, with benches along the way, so take it slowly.

Before you start, have a look at the Fish Wall, by the visitor center's breezeway. The fish swimming along it stand for the nearly six hundred kinds of fish found in this park. The big one with the upturned mouth is a tarpon. That mouth helps it gulp air at the surface when shallow water runs low on oxygen.

I'll tell you a story at each spot along the trail and stay quiet in between. Keep an eye on the water and the sky as you go.

Here's the start of the jetty trail, right at the edge of Biscayne Bay. The simple launch here is where people with their own canoes and kayaks put in, any day of the year, from seven in the morning until five-thirty in the evening. On a windy day, you may see windsurfers out there too.

Look north, about a third of a mile out, and you may spot two small islands. They're called spoil islands, because they were built from the earth dug out when the canal just west of them was dredged. That canal is one of thousands of miles of canals cut across South Florida, when early developers set out to drain the land and build.

The canals did more than move water on the surface. They also disrupted the fresh water flowing underground, through the Biscayne Aquifer. That underground flow was once so strong that in places, fresh water visibly welled up in the bay. The canals changed this park forever, and Everglades and Big Cypress too. Today there are major efforts to restore a more natural flow of fresh water.

So the calm bay in front of you is still living with an older plan for this coast.

Here's the flagpole. It's a nautical flagpole, and the flag flies where the position of honor would have been aboard a sailing ship. That suits a park that protects hundreds of years of maritime history.

More than fifty of the park's cultural sites are shipwrecks. At times the park's eastern boundary takes in the Gulf Stream, a great current flowing north that has carried ships past this coast for centuries. Many never made it to port, especially when charts and navigation tools were primitive.

In the visitor center you can see artifacts from a British warship that sank here in 1748, before the United States even existed, including one of its cannons on the first floor.

Out on the reef, the park keeps the National Park Service's only underwater Maritime Heritage Trail: six shipwrecks and a lighthouse, reached by boat, with plaques underwater telling each ship's story. Most lie in ten to thirty feet of water. One of them, the Alicia, ran aground in 1905 loaded with silks and silverware. Some seventy different groups of wreckers fought over her cargo, and the battle led to a permanent rewriting of the nation's salvage laws.

Every wreck out there is a reminder that this bright, shallow water has never been simple to cross.

Now you're out over Biscayne Bay. All the water in front of you averages only about six to eight feet deep, and much of the bottom is covered in seagrass, a flowering plant that gives shelter to a whole community of life. Nearly seventy percent of South Florida's commercially important seafood starts life here in the bay. Young animals start out small and well hidden, so look closely. You might spot a barracuda, a blue crab hunting for dinner, or a southern stingray feeding in the shallows.

On the horizon to the east is a line of low islands, the northern Florida Keys. When Henry Flagler built his railroad south from Miami to Key West, he brought the tracks across where the Keys come closest to the mainland, at Key Largo, south of the park. These northern keys were bypassed, and they stayed almost undeveloped. With sharp eyes, or binoculars borrowed from the visitor center, you may pick out Elliott Key and Boca Chita Key. Both are reached only by boat.

Beyond them, out of sight, lies the northern end of Florida's coral reef. Corals need just the right warmth, saltiness and sunshine to grow. Leaving them untouched, and wearing reef-safe sunscreen, helps keep them alive.

Around you now are some remarkable trees: mangroves, living right in salt water. Most plants would die if you watered them with seawater, but mangroves have found ways to cope. Some keep the salt out at their roots, and others push the extra salt out through their leaves.

There are three kinds in the park. Red mangroves grow closest to the water, on long, arching prop roots that make the trees look as if they're walking out into the bay. The roots take on a reddish tinge when they're wet. Black mangroves grow a little higher up. Look on the ground for small, pencil-like roots poking up from the mud. They work like snorkels, taking in air even as the tide comes in. And white mangroves grow farthest inland. Their oval leaves have two tiny bumps at the base, glands that get rid of salt. Please look without picking: a mangrove leaf can stay on the tree for years.

These tangled roots help keep the park's water clear, and they shelter young fish, while the falling leaves feed the tiny creatures that start the food chain.

If you'd like a pause, there are benches at the quiet west end of the jetty. The park suggests sitting for a moment with your eyes closed, just listening. National parks protect sounds, too.

This is the end of the jetty. Out here the park keeps a bird sanctuary, so watch for shorebirds, terns and double-crested cormorants, especially in winter. In the mornings and evenings, hundreds of wading birds, mostly white ibis, fly overhead to and from their roosts on the park's islands to the south.

Now try to picture something else. In the 1950s and 60s, people saw these quiet keys as a place for hotels and roads. One plan would have dredged eight thousand acres of bay bottom for a jetport. Another called for an industrial seaport, with a forty-foot-deep channel cut through this clear, shallow water. In 1961, a group of landowners even voted to create their own city out on the islands.

A small group of locals had a different idea: a park made mostly of water. Lloyd Miller of the Izaak Walton League fought for it, even after, he said, opponents poisoned his dog. Miami Herald reporter Juanita Greene wrote story after story. As support grew, landowners bulldozed a six-lane strip seven miles long down the middle of Elliott Key. People called it spite highway. It didn't work. In October 1968, President Lyndon Johnson signed the bill creating Biscayne National Monument, and in 1980 it became a national park.

That's the end of our tour. Take your time on the walk back, and stop in at the visitor center for its films, exhibits and touch table. Thanks for walking out into the bay with me.