Fish Kill and Algae Bloom in Biscayne Bay

We are passing a tipping point for the Bay not being able to support any life — literally overnight, the Bay became a deadzone. On Monday morning, August 10th, Miami Waterkeeper’s samplers and members of the public encountered about a dozen dead fish while conducting our weekly fecal indicator bacteria monitoring at Morningside Park. Miami-Dade County DERM monitoring groups conducted their routine monthly sampling nearby, noted very high water temperature (~90 F), and low dissolved oxygen levels. Many species of fish and marine life have been killed, including pufferfish, toadfish, eels, shrimp, trunkfish, pinfish, lizardfish, hogchoker, hogfish, barracuda, parrotfish, angelfish, blue crab, horseshoe crab, seahorses, octopus, lobster, grunts, mangrove snapper and more. 

(Fish kill near Morningside Park, Miami, FL. Source: Kathryn Mikesell)

(Map of community reports of fish kill impacts, updated in real-time. Red dots are fish kill reports; Green dots are algae bloom reports)

The kill seems to have an epicenter near Morningside Park, but dead fish have been seen from North Miami to Virginia Key. We notified the proper agencies and are sending water samples to FWC to check for harmful algae bloom toxins. Many species of fish were killed, including pufferfish, toadfish, eels, shrimp, trunkfish, pinfish, lizardfish, hogchoker, and more. 

On August 12, 2020, Pelican Harbor Seabird Station reported an aggregation of rays nearshore. Scientists believe that this aggregation may be due to low oxygen levels in the water, making it hard for the rays to breathe. Agencies are working on a rapid response to avoid a ray die-off in this area. View the video here. 

On August 15, 2020, Miami Waterkeeper mobilized an emergency aeration effort for Biscayne Bay. In coordination with Miami Dade County and PortMiami, fireboats were sent to oxygen-starved areas of the Bay. Anecdotal evidence seems to suggest that this was an effective temporary measure. Oxygen readings from those areas increased by 30% in the direct vicinity of the fireboats and increased by 15% approximately 100 yards from the boats’ aeration areas. In the days that followed, the City of Miami mobilized an emergency aeration response by converting stormwater pumps to help aerate nearshore areas throughout the City, including hot spot locations such as Morningside Park. Anecdotally, these aeration efforts seemed to have been effective as a temporary measure to increase oxygen in these areas. 

(Photo credit: Christy Raynor)

On August 15, 2020, Miami Waterkeeper mobilized an emergency aeration effort for Biscayne Bay. In coordination with Miami Dade County and PortMiami, fireboats were sent to oxygen-starved areas of the Bay. Anecdotal evidence seems to suggest that this was an effective temporary measure. Oxygen readings from those areas increased by 30% in the direct vicinity of the fireboats and increased by 15% approximately 100 yards from the boats’ aeration areas. In the days that followed, the City of Miami mobilized an emergency aeration response by converting stormwater pumps to help aerate nearshore areas throughout the City, including hot spot locations such as Morningside Park. Anecdotally, these aeration efforts seemed to have been effective as a temporary measure to increase oxygen in these areas.