Thousands of dead fish float up in Melbourne Beach, Indialantic area

Thousands of dead fish floated up in Melbourne Beach and Indialantic this past weekend, the possible victims of an ongoing algae bloom in the Indian River Lagoon.

Among the dead: mullet, rays, puffer fish.

Thousands of fish died last month, too, in Malabar, after extreme heat and in the Sebastian area before that.

When an algae bloom dies, the rotting of its cells uses up available dissolved oxygen in the water, already low in the lagoon this summer due to hot water temperatures. Warmer water holds less oxygen because oxygen molecules move around more in hotterr water, so are more likely to escape into the atmosphere.

Numerous sensors throughout the lagoon have shown low dissolved oxygen levels driving fish kills this summer.

This month, Brevard County embarked on a $1 million pilot project to harvest algae from the Indian River Lagoon, via a barge and chemical process similar to what's used at drinking water treatment plants.

Scientists suspected heat also played a key role in killing a large number of fish in the Indian River Lagoon July 30 in Sebastian. That die-off involved a dozen species of saltwater and freshwater fish that floated for over a mile, from near the Sebastian River to Riverview Park, according to three people who reported the fish kill to the Florida Fish and Wildlife Conservation Commission's Fish Kill Hotline.

You can report a fish kill, diseased fish, or fish with other abnormalities by using our FWC Reporter app, FWC's web form, or by calling 1-800-636-0511.

Jim Waymer is an environment reporter at FLORIDA TODAY. Contact Waymer at 321-261-5903 or jwaymer@floridatoday.com. Or find him on X (formerly Twitter): @JWayEnviro.

This article originally appeared on Florida Today: Dead fish float up in Indian River Lagoon in Melbourne Beach and Indialantic