How catching 'junk' fish cleans up Central Florida lakes
This week, the St. Johns Water Management District wraps up its annual gizzard shad harvest — a unique program that teams government and businesses to extract the nutrients that fuel fish-killing toxic algae blooms. The program helped cut Lake Apopka's nitrogen and phosphorus levels in half over the past two decades. It's a direct, cheaper way to remove the two algae-fueling nutrients from Florida waters where shad reign supreme, especially compared to stormwater projects, sewer plant upgrades or septic tank removals. And it proves that sometimes just getting the shad out can be a vital piece of the ecological restoration puzzle.
"The lake has really rebounded remarkably," Dean Dobberfuhl, a bureau chief at the water management district, said this recent day out on a placid Lake Apopka. "In terms of a restoration technique, it's very cheap."
The district's program has removed almost 25 million pounds of gizzard shad from Lake Apopka since 1993, reducing nitrogen and phosphorus levels in the lake by more than half, in combination with other nutrient reduction methods.
The program typically removes about 1 million pounds of shad from the 31,000-acre lake annually.
Harvesting gizzard shad from Lake Apopka has been a cheaper way to reduce phosphorus into the lake. Fertilizers from Lake Apopka's surrounding farms and homes feed algae blooms that cloud sunlight to bottom plants — vital nurseries for bass and other important sport fish. Waters low in nitrogen and phosphorus are clear, a tad tea-colored, and team with underwater plants that fish need to feed, breed and hide in.