The Heat is On: How Heat Waves Reshape Florida Bay and Inspire the Next Generation of Marine Scientists – FortiGate

Dakota Lewis is a Ph.D. candidate in the School of Natural Resources and Environment at University of Florida. Lewis was awarded the 2025 Florida Sea Grant-Guy Harvey Fellowship.

In the summer of 2023, Florida’s marine ecosystems faced a daunting challenge. Coastal water temperatures soared to unprecedented levels, transforming Florida Bay into a testing ground for assessing the impacts of heat stress events (HSEs) on fish food webs and resilience. This past year, a few undergraduate research assistants and I have been assessing the impacts of HSEs on fish communities across South Florida.

One specific part of my dissertation focuses on Florida Bay, a world-renowned fishing destination and a vital nursery for numerous fish species. It’s a place where juvenile fishes—including my focal species the nimble Gray Snapper, colorful Bluestriped Grunt, and stealthy Barracuda—grow and prepare for their roles in complex food webs. These fish are not merely part of the scenery; they are essential players in the ecosystem’s trophic dynamics. Juveniles fuel higher-level predators, control invertebrate populations, and connect diverse habitats such as seagrass meadows and coral reefs.

Using stable isotopic analysis- a way to assess how energy and nutrients move through food webs, my team and I are tracking how juvenile Barracuda, Gray Snapper, and Bluestriped Grunt responded to the 2023 heat stress. While analyses of 2024 post-heat stress samples are ongoing, preliminary results suggest that Barracuda, typically higher trophic level piscivores – fish-eating fish- may have leaned more on broad seagrass-associated prey during the HSE. This indicates a possible shift toward more generalist feeding strategies under stressful conditions. We’re also seeing potential changes in the body condition of these fishes, suggesting that heat stress might have affected their overall health and growth.

The story doesn’t end there. My undergraduate mentees are expanding this research. One project examines the age and growth structure of offshore adult Grunts during this same time period. While another project investigates how Barracuda’s trophic position shifts with size and age, revealing how these top predators adapt as they grow and transition offshore.

These undergraduate-led projects not only deepen our understanding of population and trophic dynamics but also underscore the importance of involving early-career scientists in cutting-edge research.

While the findings from this research and my mentees’ projects highlight the challenges Florida’s fishes face, they also point to solutions. Restoration efforts, such as those underway in the Everglades, can play a critical role in bolstering ecosystem resilience. By restoring freshwater flows and improving habitat quality, we can help buffer the impacts of heat stress and other climate-driven pressures.

Healthy seagrass meadows and robust mangroves provide essential refuges for juvenile fishes during their most vulnerable stages. These habitats not only support fisheries but also capture carbon, mitigate coastal erosion, and protect against storm surges—services that become increasingly important as climate change advances.

As I continue my research in Florida Bay, I am reminded daily of the interconnectedness of science, mentorship, and stewardship. The data we collect, the skills we hone, and the knowledge we generate are not ends in themselves; they are building blocks for a more resilient future. My hope is that by studying how juvenile fishes respond to heat stress, we can develop strategies to protect these vital ecosystems and the communities that depend on them.

But perhaps most importantly, by mentoring the next generation of marine scientists, we ensure that this work will continue. Their fresh ideas and unrelenting curiosity are the key to unlocking innovative solutions for the challenges that lie ahead. Together, through science, restoration, and mentorship, we can chart a path forward in a warming world.