a woman giving a presentation to a group of people
Monroe County artificial reefs director Hanna Koch outlines a ‘holistic, science-based approach’ to creating artificial reef structures for fish at various life stages. ALEX RICKERT/Keys Weekly

An outline of the future for Monroe County’s artificial reef program was met with a mixture of anticipation, caution and debate at the April 16 meeting of the Florida Keys National Marine Sanctuary Advisory Council (SAC).

Advisory council members gathered in Marathon listened to the highly-anticipated presentation from newly-hired artificial reefs director Hanna Koch, who began her new post this month after six years with Mote Marine Lab as a staff scientist and coral reproduction research program manager. The program she’s tasked with directing was made possible with an August 2023 award of $10 million from the state explicitly for the purpose of establishing artificial reefs. An additional award of $5 million, awaiting Gov. Ron DeSantis’ signature, will extend the program from its initial 2028 time frame to 2029 if signed.

Koch aims to provide artificial support structures to help combat habitat deficits for fish and invertebrate species throughout the Keys, acknowledging that grant language directly states an intent to provide additional recreational fishing and diving locations, reducing conflicts among user groups and alleviating pressures on natural reefs.

“I realize that there will probably be a variety of projects and structures with different intentions,” she said. “We need to consider sustainability on all levels, whether it’s the materials we’re using or how our work and our structures impact fisheries and resources and how we manage them.

“I’m well aware that this is a conversation that’s been going on well before I arrived on the scene, and I want to assure everyone that my arrival is not a reset button,” she concluded.

A robust comment period from council members followed, praising Koch’s hire and adding appreciable debate on balancing the program’s environmental benefits with clear recreational and economic implications.

“My concern is that we use this system to enhance the environment, and not to increase extraction,” said council member Mimi Stafford. “My training and my view is that we aren’t really going to increase biomass, we’re just going to concentrate it and make it easier to harvest. … There is a place for this, because we’re losing our reefs – I’ve seen them collapsing, and that’s a great concern because of increased wave action.”

“I’m really happy that finally this tool is completing our toolbox,” said charter captain Will Benson. “Speaking as a fisherman, when you look back to the world records … we had an entire fishery that was created by structure that is no longer there. It’s my belief, and the belief of a lot of other captains, that over the years as we’ve watched that structure decline, we’ve seen a corresponding decline in our fish.”

“Anything we can do to give these divers an option other than to go to a different reef … I think that would just pull so many more people off our reefs and (decrease) the pressure,” said Gary Jennings, from the American Sportfishing Association. “Our reef tract down here, we’re just loving it to death unfortunately, and I don’t know how much more it can sustain.”

“I think my biggest concern is that I’m not sure how throwing some stuff out there improves an ecology that’s going downhill now,” said SAC chair George Garrett. “It’s the milieu that this is all sitting in that is somehow, I’m going to say, a bit sick right now. That needs to be changed, and that’s a much bigger playing field.”

Tuesday’s discussion did not include any specific projects, though one of the program’s first moves is expected to involve a series of decommissioned power poles acquired by the county last summer from the Florida Keys Electric Co-op. Koch said that while other specific projects are in early stages of development, preliminary discussions have supported networks of habitat structures to support fish at various life stages, with some locations of reef installations possibly remaining undisclosed.

“We’re already thinking about doing this in a sustainable way – not just putting things out there where everyone can go and everyone can take,” she said.

FWC’s CJ Sweetman delivers an update to the Sanctuary Advisory Council on continuing efforts to explain unusual fish behavior and sawfish mortalities throughout the Florida Keys. ALEX RICKERT/Keys Weekly

Algal toxins still leading culprits for spinning fish

Tuesday’s session closed with updates from partner organizations working to diagnose and combat the root causes of unusual “spinning fish” behavior and a mortality event that has claimed the lives of at least 40 critically endangered smalltooth sawfish to date since late 2023.

FWC’s CJ Sweetman confirmed that working groups continue to evaluate the role of toxins produced by benthic microalgae, multiple of which have been identified in collected water samples and symptomatic fish. Species in the Gambierdiscus algae family, mentioned for weeks as a prime suspect in producing the harmful toxins, continue to test at elevated levels in areas with affected fish.

Sweetman said more than 430 abnormal behavior reports have documented impacts to more than 50 species of fish. Oxygen levels, salinity, pH and water temperatures have yet to show cause for concern, and necropsy data has not yielded signs of communicable pathogens or bacterial infections. Affected fish appear to be targeted through their gills, he said, an idea supported by investigators’ findings that quickly-afflicted animals can recover nearly as fast when placed in clean water. 

“Preliminary fish bioassays show swimming abnormalities within 20 minutes of exposure to this waterborne microalgae extract, and then recovery of that fish within 28 minutes when placed in clean water,” he said.

“Basically, we have tested for every human-made chemical pollutant that we can,” added DEP sanctuary liaison Nicholas Parr. “It doesn’t appear that what is affecting the fish directly is of human origin … but we’re going to continue to look at anything we can to make sure we’re not missing something.”

“It’s possible, but we’re not certain, that the abnormal fish behavior and the sawfish mortality are related based on fish necropsy data and what we’re seeing from the sawfish,” Sweetman concluded, acknowledging that the end of the unprecedented mortality event’s timeline, or a deadline to identify the cause, are still both unknown.

“I assure you that we’re working around the clock tirelessly on this,” he said. “If you don’t know what you’re looking for, it’s a little challenging to get to the bottom of this. … So many people are dropping everything to focus on this and try and get some answers.”
Reports of unusual fish behavior, complete with detailed locations, are still critical for agencies’ understanding of this unprecedented event. To report sightings of healthy, sick, injured or dead sawfish, contact FWC’s Sawfish Hotline at 844-472-9347 or sawfish@myfwc.com. Report sightings of other abnormal fish behavior or fish kills to the Fish Kill Hotline at 800-636-0511.

Alex Rickert
Alex Rickert made the perfectly natural career progression from dolphin trainer to newspaper editor in 2021 after freelancing for Keys Weekly while working full time at Dolphin Research Center. A resident of Marathon since 2015, he fell in love with the Florida Keys community by helping multiple organizations and friends rebuild in the wake of Hurricane Irma. An avid runner, actor, and spearfisherman, he spends as much of his time outside of work on or under the sea having civil disagreements with sharks.