Given the months long red tide bloom on the southwest coast of Florida, many of our residents and visitors have questions and concerns about consuming and harvesting shellfish. We asked Becky Lazensky, MPH, an Epidemiologist with the Aquatic Toxins Program, Public Health Toxicology, Bureau of Epidemiology, Division of Disease Control and Health Protection, Florida Department of Health, if she could address these questions. She shared the following information with us.
Shellfish harvesting is one of the many outdoor activities in which Floridians and visitors to our state can partake, but it is important to check local conditions and regulations before venturing out for a day on the water. You can visit the Department of Agriculture and Consumer Services Aquaculture Shellfish Harvesting website at: http://www.floridaaquaculture.com/SEAS/SEAS_intro.htm to check the status of shellfish harvesting sites throughout the state. Once you are at the website, click on ‘Area Maps’ on the left sidebar to view an interactive map or click on ‘Area Information’ for a list of each site. Next, click on the location you plan to visit to see whether the site is ‘conditionally approved’ (shown in green) or ‘closed temporarily’ (shown in red).
There are several reasons why it may be necessary to close a shellfish bed. While aquatic toxins can pose a threat to the safety of shellfish, other contaminants, bacteria, and viruses may also accumulate in shellfish tissue. When a red tide is present, toxins produced by the red tide algae, Karenia brevis, may accumulate in filter-feeding bi-valves such as clams, oysters, whelks, and mussels. While some people choose to only consume shellfish while it is very ‘fresh’, this practice will not reduce the presence of these aquatic toxins as they would already be concentrated in the shellfish meat when harvested. Because the red tide toxins are heat-stable, cooking shellfish does not remove or de-activate the toxins, although cooking shellfish does reduce your risk of getting sick from other illnesses including vibrio infections. Environmental conditions can change rapidly and it is important to consult the shellfish maps for your local area before enjoying Florida shellfish.
If you would like to learn more about protecting yourself from harmful algal blooms, please visit the Florida Department of Health’s Aquatic Toxins web site at: http://www.myfloridaeh.com/medicine/aquatic/index.html