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Exploring Thunder Bay National Marine Sanctuary

This year, Scuba Diver Life is partnering with the National Oceanic and Atmospheric Administration (NOAA) to bring you images and stories from each of the United States’ 11 dive-able marine sanctuaries. This month, we bring you to Thunder Bay National Marine Sanctuary.

For more than 40 years, national marine sanctuaries have worked to protect special places in America’s oceans and Great Lakes waters, from the Hawaiian Islands to the Florida Keys, from Lake Huron to American Samoa. Backed by one of the nation’s strongest pieces of ocean-conservation legislation, the National Marine Sanctuaries Act, the sanctuaries seek to preserve the extraordinary beauty, biodiversity, historical connections and economic productivity of our most precious underwater treasures. And — lucky for you — most of these places are accessible to recreational divers. Sanctuary waters are filled with unique ecosystems, harboring a spectacular array of plants, animals and historical artifacts, all waiting to be explored. National marine sanctuaries belong to everyone, so dive in.

Thunder Bay National Marine Sanctuary

Dive into the cold waters of Lake Huron and you’ll lay eyes on one of the best-preserved and nationally significant collections of shipwrecks in the United States. Explore the hull of an old wooden schooner; admire the pristine condition of an early steel-hulled steamer; and even descend to a modern, 500-foot-long freighter.

Thunder Bay National Marine Sanctuary encompasses 4,300 square miles of northwestern Lake Huron and protects over 200 shipwrecks within its boundaries. Nicknamed “Shipwreck Alley,” this area of the Great Lakes experiences unpredictable and intense weather, including heavy fog, high winds and sudden blizzards. As one of the world’s busiest waterways for the last 150 years, fire, ice, collisions and storms have claimed many vessels here. And not only is there an impressive number of shipwrecks here, but also the diversity of shipwreck types makes Thunder Bay a unique and exciting place to dive.

The variety of Thunder Bay’s shipwrecks allow divers of all experience levels, from first-time wreck divers to highly technical divers looking for a new thrill, to enjoy this national marine sanctuary. Visiting the sanctuary with friends or family who don’t dive? You can experience Great Lakes maritime history while snorkeling on shallow wrecks like the wooden steamer Albany, in just over five feet of water. The crystal-clear water of Lake Huron also means that many of the shipwrecks are visible from a kayak or glass-bottom boat.

Lake Huron’s cold, fresh water makes Thunder Bay’s shipwrecks some of the best-preserved in the world, with many sites virtually unchanged since they sank. Still, invasive species like zebra and quagga mussels are altering the appearance of some. Most likely brought to the region in the ballast water of ships, these marine invertebrates are now a fairly common sight on Thunder Bay National Marine Sanctuary’s shipwrecks. By inspecting and washing your boat and dive gear, you can help protect these historic wrecks.

You can also help protect these unique maritime heritage resources by using the sanctuary’s mooring buoys to prevent damage to the shipwrecks by boat anchors. Additionally, make sure to always keep a safe distance from all parts of the shipwrecks by streamlining your equipment; in this way divers can contribute positively to their continued preservation for years to come.

Experience the wonders of Thunder Bay National Marine Sanctuary and other national marine sanctuaries via our photos, and see more at

By guest writers Allison Randolph and Elizabeth Weinberg, NOAA Office of National Marine Sanctuaries

Cover image credit: David J. Ruck/NOAA