On Jan 5, 2011, the USS Kittiwake was scuttled off Grand Cayman; five years later, 120,800 divers and snorkelers had visited as fish, corals, and other marine life moved in

On Jan. 5, 2011, the 251-foot former U.S. Navy vessel, having spent about 17 years in naval mothballs since her decommissioning, made its way under the turquoise waters of Seven Mile Beach off the west coast of Grand Cayman. According to a 2016 Cayman Compass report, the total number stood at 120,800 (53,000 divers and 67,800 snorkelers) of those who had visited the site over the past five years to observe what happens when a decommissioned warship becomes part of a coral reef ecosystem.

Meet the USS Kittiwake

The ship in question, USS Kittiwake (ASR-13), was a submarine rescue vessel of the Chanticleer class that was launched on July 10, 1945, commissioned on July 18, 1946, and decommissioned on September 30, 1994, a run of roughly 48 to 49 years between her launch and decommissioning, helping submarine crews and monitoring underwater rescue drills. She's also frequently, and incorrectly, credited with sinking on purpose to recover the "black box" from the Space Shuttle Challenger disaster. Neither half of that claim holds up: the Space Shuttle never carried a crash-survivable flight recorder of the kind airliners use, so there was no "black box" to find, and Kittiwake herself was still a fully active Navy vessel in 1986, decades away from her own eventual scuttling. What actually happened is that she was diverted from a routine training mission in early 1986 to assist in the Challenger search-and-recovery effort off Cape Canaveral, where Navy records show she helped recover a large piece of one of the shuttle's Solid Rocket Boosters from about 175 feet of water, not any kind of flight recorder.

After years of being left unused, the Kittiwake was transferred by the US Maritime Administration to the Cayman government, which spent about a decade removing PCBs, asbestos, and lead-based paint before towing her from Virginia to sink upright about 800 yards off Seven Mile Beach. Scuba Diving's detailed history of the project indicates that her depth was purposefully shallow (about 15 to 65 feet) for both new divers and snorkelers to be able to reach her. The plan was successful, and Grand Cayman had an attraction that was tailor-made almost overnight.

There's a catch

The story gets more interesting than "coral grew on a boat" here. Artificial reefs such as the Kittiwake do attract fish and invertebrates, but the species arriving on these structures may not be the same as those found on a nearby natural reef, and most previous studies have measured change in species composition on the reefs for too short a time to determine whether the reefs are having a positive conservation effect beyond simply providing a new place for wildlife to sit.

A 2020 study titled “Shipwrecks help invasive coral to expand range in the Atlantic Ocean,” in the journal Marine Pollution Bulletin, compared the species richness of a shipwreck from the 1600s to the natural reef adjacent to it, and they were able to determine that there was a significantly lower diversity of species on the shipwreck, concluding that even after hundreds of years of existence, a manmade reef is no match for the natural reef. A 2016 study titled “Ecological carrying capacity assessment of diving site: A case study of Mabul Island, Malaysia,” published in the Journal of Environmental Management, from a similarly popular dive spot in Malaysia discovered that coral damage increases rapidly when the number of divers exceeds a certain threshold for a year in a single location.

Why this matters

The Kittiwake remains a popular dive site. According to most traveller accounts, it's actually a very good one: shallow enough for beginners, moody enough for an adventure, and also newsworthy for swimming through the remnants of the ship's mess hall and engine room. The broader lesson for travelers interested in sustainable tourism is more complicated. These wrecks can provide, over time, some biodiversity and some tourist dollars for a location such as Grand Cayman, but the studies above indicate they remain a patch, not a cure, for the ongoing loss of natural reefs.