Story highlights The Indian River Lagoon in central Florida littered with dead, rotting fish

"All up and down the coast, it's the same story," fisherman Mike Conner says

Warmer temps allowed toxic algae bloom and brown tide to deplete water of oxygen

(CNN) Florida may be the fishing capital of the world, but you'd never know it from the latest scenes around the state's Indian River Lagoon.

Usually idyllic beaches, waterways and estuaries near the massive, biodiverse ecosystem along central Florida's Atlantic coast are littered with scores of dead, rotting fish; an estimated hundreds of thousands of them are floating belly up in brackish, polluted water as far as the eye can see.

"The heartbreaking images can be seen for miles," said Mike Conner, who has been fishing the area since the 1970s. "All up and down the coast, it's the same story, and it could get worse before it gets better."

But the devastation isn't merely what is visible on the surface; it runs far deeper.

El Nino has soaked Florida recently, even during its usual "dry season."

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