Dr. Mike Larkin | Why Fish DON'T Migrate FL to Bahamas | Tom Rowland Podcast Ep. 859

Dr. Mike Larkin is a marine biologist and fisheries scientist with extensive experience studying fish behavior and migration patterns in Florida and the Bahamas. In this conversation, he challenges one of the most widely believed concepts in saltwater fishing: that fish swim from Florida to the Bahamas and back. Using tagging data, oceanographic science, and decades of research, Dr. Larkin reveals why this popular theory doesn't hold up under scrutiny. He breaks down the science of fish movement, explains how ocean currents actually work, and shares what tagging studies have really shown about where fish go. If you've ever wondered whether that permit or tarpon you caught in the Keys could have come from Bimini, this conversation will change how you think about fish migration.

The Science Behind the Migration Myth

Tom opens the conversation by presenting the widely accepted theory he's heard for years: that fish like permit, bonefish, and tarpon swim from Florida to the Bahamas and back, following the Gulf Stream and using ocean currents as underwater highways. It's a romantic idea that many anglers and even fishing guides have repeated for decades. Dr. Larkin immediately pushes back on this notion, explaining that while it sounds logical on the surface, the actual oceanography tells a very different story. He describes how the Gulf Stream current runs north along Florida's coast with tremendous force, creating a barrier rather than a bridge. The conversation sets up a fascinating challenge to conventional wisdom, with Dr. Larkin promising to explain exactly why the tagging data contradicts what so many people believe. The full breakdown of why this theory doesn't work starts at the opening of the episode.

What Tagging Data Actually Reveals

Dr. Larkin dives into the hard data from years of tagging studies conducted on both sides of the Florida Straits. He explains how researchers have tagged thousands of fish in Florida waters and thousands more in the Bahamas, yet the recapture data tells a compelling story about limited movement between these areas. When you look at where fish are actually caught after being tagged, they tend to stay within their regional populations. Dr. Larkin describes specific examples of fish that were tagged and recaptured multiple times, showing local movement patterns rather than long-distance migrations. He addresses the question of whether fish could make the crossing but simply aren't being recaptured on the other side, and explains why the statistical probability makes that scenario unlikely given the fishing pressure and tagging efforts on both coasts. The detailed tagging evidence that challenges conventional wisdom is discussed throughout the middle portion of the episode.

Understanding Ocean Currents and Fish Movement

The conversation shifts to the mechanics of how ocean currents actually affect fish movement. Dr. Larkin explains that the Gulf Stream isn't just a gentle river in the ocean that fish can ride across—it's a powerful current that moves at significant speed and creates real challenges for fish trying to cross it. He breaks down the oceanographic realities of the Florida Straits, including current velocity, direction, and the energy expenditure required for a fish to successfully navigate these waters. Tom and Dr. Larkin discuss whether fish could theoretically make the crossing if they tried, and what physical and behavioral factors would influence their ability to do so. The discussion reveals why the simplistic maps showing arrows between Florida and the Bahamas don't capture the complexity of what's actually happening in the water column. The oceanography lesson that explains why the crossing is more difficult than it appears unfolds in the middle section of the conversation.

Why Anglers and Guides Believe the Migration Story

Tom and Dr. Larkin explore why this migration theory has persisted for so long despite the scientific evidence to the contrary. They discuss how the visual simplicity of looking at a map makes the crossing seem logical and straightforward—the distance doesn't look that far, and the presence of similar species on both sides of the straits seems to support the idea of movement between them. Dr. Larkin explains how confirmation bias plays a role, where people remember the stories that support their existing beliefs while discounting contradictory evidence. The conversation touches on the role of anecdotal observations versus scientific data, and why fishing guides and experienced anglers might genuinely believe they're seeing migrating fish when the actual explanation for fish presence and absence is more localized. The discussion about why this myth has such staying power in the fishing community happens later in the episode.

Final Thoughts from Tom

I've been hearing the Florida-to-Bahamas migration story my entire fishing career. It's one of those things that everyone just accepts as fact because it makes sense when you look at a map and because respected anglers and guides repeat it. Having Dr. Larkin walk through the actual science and tagging data was eye-opening. It's a perfect example of how the fishing world sometimes relies on stories and assumptions rather than looking at what the research actually shows.

What I appreciate about this conversation is that Dr. Larkin doesn't just say "you're wrong"—he explains why the theory doesn't hold up, walks through the oceanography, and shows what the tagging studies have actually revealed over years of data collection. It's the kind of conversation that makes you rethink assumptions you didn't even know you were making. Whether you fish Florida, the Bahamas, or neither, understanding how fish actually move through their environment makes you a better angler.

This is one of those episodes where the science is fascinating and the implications for how we think about fishing are significant. Listen to the whole thing—Dr. Larkin's explanations are clear, data-driven, and genuinely interesting even if you're not a marine biology nerd.