In 2009, Key West sank the 523-foot Vandenberg in 140 feet of water; one year later, REEF monitoring had documented 123 fish species on the former ship

A former 523-foot missile-tracking ship, the Gen. Hoyt S. Vandenberg, was sunk off the coast of Key West, Florida, on May 27, 2009. It wasn’t an accident; city officials and conservation groups intentionally sank the retired vessel seven miles offshore in about 140 feet of water to create a new reef for fish, divers, and anglers. The plan worked faster than most people expected, according to the Reef Environmental Education Foundation (REEF), which tracked the ship’s transformation. REEF’s Advanced Assessment Team began surveying the wreck shortly after it settled onto the seafloor and documented 123 fish species on the reef within a year of its sinking.

Why this particular wreck matters

The Vandenberg is not just another sunken ship. At 523 feet long, it is the largest artificial reef in the Florida Keys National Marine Sanctuary and the second largest intentionally sunk reef in the world, according to REEF. Its deck is 71 feet wide at its widest point, and it creates layers of habitat from about 45 feet below the surface to the sandy bottom at 140 feet. It took years of planning to get it there. The City of Key West worked with the Artificial Reefs of the Keys, Florida Fish and Wildlife Conservation Commission and Florida Keys National Marine Sanctuary to purchase, clean and sink the ship, an effort that reportedly cost some $8.6 million. Florida’s wildlife agency then contracted with REEF to study fish movement in and around the wreck.


Counting fish one dive at a time

Between May 2009 and December 2010, the team made five separate monitoring trips to the wreck, REEF said. Divers employed a method known as the Roving Diver Technique, which involved swimming through the site and recording every species they observed. That approach produced a tally of 123 fish species within a year of the sinking, but the project didn’t stop there. REEF continued to monitor the site through 2012, then returned for another round of surveys in 2014 and 2015. The team also scanned for unwelcome visitors on the way, such as invasive lionfish and other nonnative species that can disrupt a new reef.

The science behind why ships attract fish so quickly

It might seem surprising that a bare steel hull could attract more than 100 species of fish in just 12 months, but this pattern is seen again and again, say researchers who study artificial reefs. A 2020 synthesis study led by scientists at NOAA’s National Centers for Coastal Ocean Science, which reviewed 39 peer-reviewed studies comparing artificial and natural reefs worldwide, found that artificial reefs can support fish numbers and diversity comparable to nearby natural reefs, but the researchers stressed that this pattern is not universal: how well an artificial reef performs depends heavily on its geographic setting and the material it's built from, meaning results should be read as location-specific rather than a guaranteed outcome. Sunken ships give fish something reefs often lack in busy coastal waters: hard structure and shelter. Algae and invertebrates settle on the bare steel first, providing an initial source of food and cover. Small fish move in next, drawn by those crannies and the food supply building up on the hull. From groupers to sharks, bigger predators follow once there's prey around.

Can volunteer divers really be trusted with the data

Many of the fish counts for REEF are done by trained volunteer divers, not full-time scientists, which raises a fair question about how reliable that kind of data really is. This was put to the test in a study titled 'Assessing the value of citizen scientist observations in tracking the abundance of marine fishes,' published in Conservation Letters by researchers Dan Greenberg, Christy Pattengill-Semmens, and Brice Semmens, in conjunction with REEF. The team compared 25 years of fish data gathered by REEF's volunteers in Key Largo with a separate, federally funded survey of the same waters, tracking population trends for dozens of reef fish species. Most species, including groupers and snappers, tracked closely between the two datasets, the researchers found. Study co-author Brice Semmens has said the results suggest that citizen scientists can serve as effective sentinels of ecological change, that is, divers armed with slates and fish ID cards can produce numbers that stand up to professional fisheries surveys.

What the Vandenberg story tells us

Seventeen years after it hit the seafloor, the Vandenberg has become one of the most visited dive sites in the Florida Keys. Its story contains a simple but hopeful lesson: ocean life can move into new spaces surprisingly fast given the right conditions. One ship, carefully sunk and closely monitored by scientists and volunteers, became a bustling underwater habitat in under a year.