In NOAA's management plan which was released in May of 1999, three reasons are listed for the creation of Thunder Bay National Marine Sanctuary and Underwater Preserve:
Over the course of over 100 years vessels with cargoes of fish, lumber, stone and supplies to provide for the needs of America's great westward expansion have all found their way to the bottom of the Thunder Bay area. Due to the preserving effects of the cold fresh water in which they sunk, their condition today is remarkable and unique in the world. Everything from wooden Schooners, Freighters, Barges, Victory Ships, Whales Back and Salt Water Freighters can be found. During the summer of 2001 and 2002 world-renowned Explorer Dr. Robert Ballard arrived to explore the Thunder Bay and it's shipwrecks. In 2002 Robert Ballard along with Robert Brooks video taped many of the known wrecks for a upcoming TV special. NOAA has pledged to "establish remote video hook-ups of researchers documenting the shipwrecks." This technology will provide visual access to shipwrecks for divers and non-divers alike. In short, in the coming years, Thunder Bay will become the hub spot for shipwreck diving. NOAA also committed to building a Interpretive Center devoted to exploring the history around the wrecks and the shipping history of the Great Lakes.
Other than the Shipwrecks Alpena County also offers an active karst system with sinkholes in Misery Bay, Lake Huron off Middle Island, and the State Forest west of RockPort. A large amount of Robert Ballard's IFE team's intrest was focused around off shre sink's found during their 2001 expedition. Wall dives can be had off the north shore of Thunder Bay Island which is part of the Niagra escarpment that extends from Niagra Falls to Lake of the Clouds in Michigan's Upper Pennisula. The chiseled carvings, by 100 years of lighthouse keepers on Thunder Bay Island, is worth exploring on a shore outing. The lighthouse its self is under the management of The Thunder Bay Lighthouse Preservation Society, a 509c3 organization. Membership is the only way to obtain legal access to the lighthouse properties, e-mail the web-master and he will gladly send out a membership brochure. Sugar Island is a larger island 1-2 mi. to the west of Thunder Bay Island and was also the home for early settlers. West of Sugar Island there is a 3-4 mi. expanse of dangerious waters that is about 15' deep but due to the many large boulders and rock piles that jump upward from the underling limestone sheets, this area should only be traversed with local knowledge.
Rockport was a active limestone quarry untill the 1930's and it loading docks make a worth while shore dive.Maritime history in Alpena goes back to 1832 to the establishment of a fishing community on Thunder Bay Island. The Island was chosen because of the Indian unrest which made the mainland too dangerous to settle. This appears to have been a wise decision as the first saw mill established in the area in 1836 was forced to relocate from the banks of the Thunder Bay River to Scarecrow Island in 1837 because of an Indian attack. Also in 1837 the first lighthouse was established on Thunder Bay Island to guide mariners around its dangerous shoals. In subsequent years additional lights were added at Presque Isle to the north and Sturgeon Point to the south.
The areas first fish hatchery was created in 1882 to shore up the already fading fishing industry. By 1886 the fishery in the area had collapsed by 2/3's due to the continued over fishing. Before that time Thunder Bay was providing 20% of the entire Lake Huron fish catch and was second only to Saginaw Bay in this regard. The lumber industry hung on until the 1890's providing for much of the lumber demand generated by the Civil War and the Great Chicago Fire. In 1901 with the creation of Huron Portland Cement Company changed the focus of commerce in Alpena to cement and limestone production. At one time Huron Portland grew to become the largest cement producer in the world and quarries were opened at Rock Port, Rogers City, and Stoneport for the production of Limestone to supply the needs of steel mills of Lake Erie, Indiana, and Illinois. The Rock Port quarry closed during the Great Depression but the quarry in Rogers City is currently still in operation, and is noted as being the largest limestone quarry in the world.