ANNA MARIA ISLAND – Local waters remained free of red tide last week, according to the Florida Fish and Wildlife Conservation Commission (FWC).
No trace of the toxic algae was found in water samples at the Rod & Reel Pier in Anna Maria or at the Palma Sola Bay bridge in Bradenton on Jan. 28, and only background concentrations were found at the Longboat Pass boat ramp in Bradenton Beach.
However, respiratory irritation was reported on Jan. 24-25 and Jan. 28-29 at Coquina Beach in Bradenton Beach and on Jan. 23-24 and Jan. 26 at Manatee Beach in Holmes Beach, according to the report.
Blooms of Florida red tide can be patchy, with varying concentrations of the toxin it produces, causing effects to be noticeable on one beach but not on a nearby beach. Red tide also can be carried by winds to areas where the water is clear of the algae.
One red tide-related fish kill was reported 30 miles off Longboat Pass on Jan. 30.
The bloom began in Southwest Florida in October 2017 and arrived in Anna Maria Island waters on Aug. 3.
Florida red tide, or Karenia brevis, is a type of microalgae that emits a neurotoxin when it blooms. Deadly to marine life, red tide also can make shellfish unfit to eat and can cause respiratory irritation in people.
Scientists say that salinity, currents, temperature and light play a part in the formation of blooms, as do nutrients from these sources:
- Florida’s natural phosphate deposits
- The Loop Current, which brings Caribbean seawater to Florida’s west coast
- The Mississippi River
- Saharan dust blown across the Atlantic Ocean to Florida’s waters
- Fertilizers and animal waste
