Update from Miami-Dade County on recent fish kill

The Department of Regulatory and Economic Resources, Division of Environmental Resources Management (RER-DERM) has received multiple reports of a fish kill across the northern basin of Biscayne Bay. RER-DERM staff has responded and is investigating. This release includes an update detailing the response effort underway and the ways the community can help.

“Since the massive fish kill event in August 2020, Miami-Dade has doubled down on its commitment to protecting our precious waters and especially Biscayne Bay,” said Miami-Dade Mayor Daniella Levine Cava. “Our Bay is very fragile, from decades of neglect and climate change. It will take years to reverse the damage, but we have already implemented many changes, including an annual report card. We will continue to invest in critical, long-term, comprehensive solutions to improve Biscayne Bay’s wellbeing – such as the septic to sewer transition, water infrastructure upgrades, pollution reduction policies, and more.”

Fish kill response

By the end of yesterday, DERM staff responded to various areas, both land and water side, to begin their investigation. Based on preliminary findings, estimates indicate that over a thousand dead fish were dispersed in the northern part of the Bay. DERM activated the biomass removal contractor and is working with both the City of Miami and the City of Miami Beach to prioritize those areas that had the bulk of dead fish.

As a part of the investigative efforts, the DERM team continues to analyze water quality data trends in these areas to determine baseline conditions (prior to the fish kill event). Preliminary sampling activities were conducted yesterday and will continue for the remainder of the week. DERM is reviewing all potential sources that may have led to this incident, which include the heavy rains that impacted our watershed last week, the pumping activities associated with the King tides, and a recent sanitary sewer overflow event that occurred this weekend that may have impacted this same area of the Bay.

Yesterday, DERM also participated in a coordination call to discuss initial field work findings and to refine a plan of action for this and potential future responses. The coordination meeting includes local and state government agencies, local universities, and local stakeholders all working together on collecting water samples and analyzing data.

Today, DERM teams are out again on both water and land to sample during slack tide (ambient bay water) to best characterize the bay’s waters without tidal influence from canal/ river discharges. These sampling efforts will help us determine if the discharges from the rivers themselves were a direct causative factor to this fish kill and to show any stratifications that are occurring in the rivers.

In addition, DERM field teams will report back to the contractor on accumulation areas of dead fish to remove, and transmit any visual data, take pictures of their activities, and have handheld probes to get immediate data back on the water column itself (Dissolved Oxygen, Temperature, Salinity, etc.).

FLDEP, FIU, NOAA and UM will all also be sampling, and a coordinated effort will be made to conduct more groundwater sampling (at a higher frequency) and running analyses with everyone's data to model the decoupling of dissolved oxygen and salinity so we can better understand the freshwater canal influence versus freshwater from groundwater since the river/ canal flows are correlated, but not causative.

Given that another tidal cycle will have taken place when staff is back on the water, the DERM team will provide preliminary reconnaissance activities to further identify the extent of biomass that will need to be removed and to determine if any more fish kills are found north of this incident.

How the community can help protect the Bay

Residents have a number of options for reporting a fish kill. The DERM hotline, 305-372-6955, and email, [email protected], are available 24/7.  Residents can also report via 311. Use the 311Direct App (Android or Apple), 311 Online: www.miamidade.gov/311direct or, simply call 311. DERM is best able to respond quickly when they are contacted directly and the information includes an address or precise location. Photos and videos are also helpful.