Hurricane Michael’s ’underwater landslide’ moved scores of artificial reefs in Bay and Gulf counties

Before the Category 5 Hurricane Michael blasted Mexico Beach last October, it wrought havoc across a huge swath of the Gulf of Mexico, causing underwater changes that are much less noticeable than blue tarp-covered roofs and trees snapped like matchsticks.


Storm-caused waves of more than 20 feet tall displaced numerous publicly accessible artificial reef structures, including a 50-foot tall radio tower that was dragged more than 1,000 feet along the seafloor, according to the Florida Fish and Wildlife Conservation Commission.


Besides forcing many other changes, Michael birthed an "underwater landslide or sandstorm" that intensified the scouring away of sand on one side of the popular dive site known as the "Shady Lady" shrimp boat, said Bob Cox, president of the Mexico Beach Artificial Reef Association.


The 110-foot vessel, which had been laying on its side since being deployed in 2007, stands in about 95 feet of water around 17 nautical miles from the Mexico Beach Canal, Cox said.


SEE coordinates of artificial reefs near Mexico Beach


MAP of reef sites near Mexico Beach.


During the storm, the shrimp boat was pushed upright in a newly carved depression in the sand. The portion of seafloor that had long been covered by the boat revealed several large tree stumps that experts say might be more than 10,000 years old, Cox said.


The thousands of artificial reefs in the Gulf along the Panhandle provide habitat for numerous game and tropical fish species and other wildlife.


In Bay County and Gulf County portions of the Gulf of Mexico churned up by Michael, reefs in deeper water held their positions much better overall than those in shallower water. According to the FWC, the displacements are not entirely problematic.


Shifting sand


Last February, biologists with the Fisheries-Independent Monitoring program from the FWC’s Fish and Wildlife Research Institute used side-scan sonar to map more than 50 square nautical miles of sea floor near Michael’s path in the Northern Gulf, according to the FWC.


These assessments are meant to inform Gulf-wide, reef-fish survey efforts, but specific habitat changes have not yet been fully quantified, according to Michelle Kerr, spokeswoman for the Fish and Wildlife Research Institute.


Last December and January, the FWC’s Division of Marine Fisheries Management artificial reef group examined three artificial reef permitted areas totaling 7 square nautical miles in Bay County. Its work aims to determine the impacts of various artificial reef designs from a direct pass of a large hurricane, Kerr said in an email.



Among other findings, researchers saw that in the nearshore Bell Shoals reef site, the storm had moved 144 of the 226 concrete, 8-foot tall triangular pyramid-shaped reef modules at least 100 feet. Most of those modules were toppled over.


The Bell Shoals site is in less than 30 feet of water and its closest point from shore is about 1 nautical mile.


Each triangular, pyramid-shaped module weighs more than 6,000 pounds. One of them was moved about 950 feet. Some of them were relocated up to about a half-mile away.


The post-storm Bell Shoals site also reveals more secondary use and reefball modules that were uncovered due to sand movement during the hurricane. Overall, the reefballs at this site received no damage and were moved only slightly during the storm.


Biologists did not observe any movement/damage to artificial reefs in the Sherman and Carbody sites, which stand in more than 70 feet of water. The Sherman site’s closest point to shore is just more than 6 nautical miles and the Carbody’s is about 3 nautical miles.


New locations


After being displaced by Michael, the reefs at the Bell Shoals site that previously stood in tight clusters at distinct locations are more spread out.


"This may make finding the current individual module locations more difficult until we are able to publish the new locations," Kerr said. "On the other hand, the more widespread distribution also provides more equally distributed fishing destinations throughout the site. It will also be interesting to see how the fish respond to the different reef configuration, such as accessing greater forage area from the wider spread of materials, or utilizing more ledge space for shelter from the toppled modules."


While the storm has moved many reefs, Cox doesn’t think their new spots will be hard to find.


Reefs in shallow waters, like those at the Bell Shoals site, usually are easy to spot from a boat because they stand out on the white sandy bottom, while the use of fish-finding equipment and other technology provide great assistance in locating reefs in deeper waters, he said.



While a lack of oxygen from hurricane-caused runoff pollution might have contributed to a decline in various fish populations, Cox said he is starting to see more juvenile snapper, grouper and aquarium/tropical types of fish in the Gulf.


Also, "In our area, (invasive) lionfish were practically gone" right after the hurricane, he said. "We’re starting to see some back now. We used to see 100 a day. Now we see about 15 a day."


The Mexico Beach Artificial Reef Association has deployed more than 150 artificial reefs since it formed in 1997. Many of those reefs are pyramid-shaped memorial reefs that honor people’s late loved ones.


This past summer, Cox found three of the handful of memorial reefs at the Bell Shoals site that were displaced by Hurricane Michael. One of the relocated reefs he found contains the cremated remains of his brother and one contains the cremated remains of his grandparents.


He and other divers are intent on finding each of the other displaced memorial reefs, one of which contains his father-in-law’s cremains.