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Shark Week Episode: Dead Zone Impacting Fish in Indian River Lagoon

When scientists and film crews from “Shark Week” explored the Indian River Lagoon in May, they spent three days searching before finding a single living bull shark to which they could attach a sensor for water quality monitoring.

Bull sharks are typically abundant in the 156-mile-long lagoon, making it alarming for shark biologist Craig O’Connell to discover a dead zone filled with lifeless fish and diseased sharks in one of North America’s most biologically diverse estuaries.

“At first, I was hopeful,” said O’Connell, the “Shark Week” presenter. “I thought, ‘These bull sharks can tolerate everything,’ but then I saw this dead zone. There was no life, and it made me realize that this is an absolutely massive problem.”

The “Sharks of the Dead Zone” episode, which airs at 9 p.m. on Friday, investigates how water pollution and algae blooms create “eerie dead zones” in the lagoon. These dead zones can form naturally but are often exacerbated by human activities like nutrient pollution, as noted by the National Oceanic and Atmospheric Administration.

The Indian River Lagoon suffers from pollution, predominantly from nitrogen and phosphorus from sewage, urban and agricultural fertilizers, and discharges from Lake Okeechobee. When combined with warming waters, these pollutants fuel algae blooms.

“The algal growth increases more and more until you get this massive bloom that leads to a dead zone,” O’Connell explained. “All the oxygen gets sucked out of the water, and nothing can survive.”

Bull sharks, one of the few shark species that can live in freshwater, use the lagoon as a nursery. Juveniles can remain there for up to eight years before transitioning to the ocean, according to previous reports by TCPalm.

During their exploration, the “Shark Week” team encountered only two juvenile bull sharks: one was found dead with no signs of predation, and the other was alive but had its fins and reproductive organs covered in abnormal growths. O’Connell concluded that the lagoon’s adverse environment was affecting these sharks.

“I am a little bit fearful for the future of the Indian River Lagoon unless we change our ways,” he stated.

“Shark Week” will run from July 7-13, featuring 21 one-hour episodes that will air on the Discovery Channel starting at 8 p.m. each night. The episodes can also be streamed on Max.

The 36th edition of “Shark Week” will be hosted by John Cena, an actor, producer, and former professional wrestler.

Source: TCPalm, National Oceanic and Atmospheric Administration