A new invader is threatening the Everglades. Biologists have confirmed that invasive swamp eels, first detected in South Florida in the early 2000s, are spreading through the wetlands and wiping out key food sources for native wildlife.

What's happening?

Recent research led by Florida International University scientists revealed that in Taylor Slough — a vital Everglades marsh — populations of crayfish and small fish have dropped by 80% due to predation from these snake-like fish. 

These prey species are crucial for nesting wading birds like ibises and egrets. Without them, the birds struggle to raise their young, unraveling a food web that Everglades restoration projects have spent decades and billions of dollars trying to preserve.

"This is not something that we think is a normal phenomenon," said Nathan Dorn, FIU aquatic ecologist. "It's a really novel predator with some novel traits and it's a new sort of loss factor for our fish in the system."

Why are swamp eels important?

Swamp eels may look unassuming, but their presence could reshape the Everglades in lasting ways. 

Unlike native fish, they can survive droughts by burrowing into mud and breathing air, waiting for water levels to return. That resilience, paired with their voracious appetite for small aquatic species, allows them to outcompete native predators.

The ripple effects reach far beyond the Everglades' birds. Healthy wetland ecosystems protect South Florida's water supply, filter pollution, and buffer communities from flooding. As invasive species push out native ones, those natural benefits weaken — putting both wildlife and people at risk.

The story is part of a wider pattern. Other regions have struggled with destructive non-native species, from invasive lionfish decimating reef ecosystems to alien fish spreading in the Mediterranean. In each case, invasive animals disrupt balance, drain resources, and jeopardize the survival of native species.

What's being done about swamp eels?

For now, researchers warn that prevention is the best tool. Once invasive species become established, removing them is costly and often impossible. Instead, scientists suggest policies that limit imports of non-native animals and stricter enforcement around pet and food trades that often introduce them.

Locally, Everglades restoration projects may need to adapt by incorporating invasive predators into their models, ensuring future strategies account for today's altered food web. 

For everyday people, supporting native plants and habitats in their own backyards can help strengthen ecosystems against invasive threats.

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