Florida's Red Tide Decimating Stone Crab Populations

What lobster is to Maine and king crab is to Alaska, the stone crab is to Southwest Florida. But it seems that regional specialty could be in serious danger.

Fishermen in the Gulf Coast area—such as Everglades City—are recording record lows as the scourge of harmful algae, dubbed the red tide, devastates the region. The plant-like alga, technically known as Karenia brevis, produces toxins that cause gastrointestinal and neurological problems when eaten. It also consumes oxygen at night, suffocating sea life below the surface.

Thousands of fish (catfish, mullet, trout, and grouper), turtles, manatees, dolphins, even a 26-foot long juvenile whale shark have washed up on Florida beaches, in what National Geographic calls a "wildlife massacre of massive proportions."

The New York Times is reporting that the latest red tide bloom (named for its signature rust-red color) can be traced back to October 2017, and has picked up intensity in the last few months. Although the Gulf has seen ebbs and flows of the toxic algae for centuries (there have been documented cases dating back to the 1500s), this is considered the worst bloom in over a decade. Currently, it stretches 100 miles along the Southwest coast, as well as miles offshore.

And that's where it's particularly problematic for stone crab trappers.

What sea life hasn't already died, has fled the area. Heather Barron, head veterinarian at Florida’s Clinic for Rehabilitation of Wildlife tells National Geographic that "It’s like a ghost town." That includes stone crabs, which are less adept swimmers than blue crabs, and have to scuttle across the ocean floor using their oversized claws.

Stone crabs are also extremely perishable. Unlike blue or Dungeness crabs, which are valued for their abdomen and leg meat, stone crabs are only harvested for their claws (which fishermen remove, returning the animal to the water to regenerate). And those claws have to be cooked dockside before they spoil. The further out stone crabs travel to avoid the perils of the encroaching red tide, the more it becomes logistically impossible for fishermen to return with a safe catch.

A seven-month-a-year industry off the coast of the Florida Everglades, fishermen are only bringing in a fraction of previous years' (and generations) hauls. A typical daily catch can hover around 400 pounds, except in 2018, where crabbers are struggling to break triple digits. Figuring in the cost of gas, bait, dockage fees, and crew hours, they’re hemorrhaging money.

That ripple effect is now being seen by consumers, where pricing and scarcity is skyrocketing. Stephen Sawitz, the fourth-generation owner of Joe's Stone Crab in South Beach (perhaps the most famous purveyor of stone crabs in the country), tells The New York Times that supply is off 40 percent, forcing them to "subtly" steer customers to Alaskan king crab and other alternatives. Not only have they pushed their signature dish to the appetizers page (rather than an entrée), they're struggling to appease disgruntled guests when the kitchen inevitably runs out.

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Scientists are still split on the exact culprits behind this prolonged occurrence of red tide. A percentage of Karenia brevis is naturally occurring in the wild, but most agree that extreme blooms are exacerbated by human activities such as development, manufacturing, and agricultural pollutants.

What's more, Richard Bartleson, a biologist at Sanibel-Captiva Conservation Foundation, tells National Geographic that explosive red tide years seem to follow in the wake of massive storms. That was true in 2004 and 2005 when multiple hurricanes ripped across the state, as well as in the aftermath of 2017's Hurricane Irma. And those storms are becoming more frequent and intense due to climate change.

While the red tide has finally shown signs of weakening, there are significant consequences for the commercial fishing industry around the Florida Keys (the second-largest, standalone economic-generator, according to the Miami Herald). Higher concentrations of the algae not only amount to escalating mortality rates, it kills off crab larvae, jeopardizing future harvests. And that has many fishermen seriously questioning the long-term viability of their livelihoods on Florida waters.