A Review of the Impacts Associated from Florida's Red Tide Toxic Dinoflagellate, Gymnodinium breve, and Suggestions for Prediction, Management, and Control

Defense Date


Document Type


Degree Name

M.S. Marine Biology

Second Degree Name

M.S. Coastal Zone Management

First Advisor

Andrew Rogerson

Second Advisor

Curtis Burney


This paper is a comprehensive historical review and evaluation of Florida red tide events and their impacts on the natural ecosystem, commercial fisheries, regional economy, and the public health from 1946- 1999. Because of their potential severity, it is essential to determine if Harmful Agal Blooms (HABs), in particular red tides, are increasing in intensity, frequency, and geographic distribution, and if so what are the causes of this phenomenon.

The literature studied reveals several insufficiencies in our understanding of red tides. The lack of information on major red tide blooms in the past has made it difficult to determine the comprehensive impacts of red tides on Florida's ecosystems, commercial fisheries, coastal economy, and public health. The consensus finds that the fishing industry has suffered more economic losses than other businesses from red tide events. Scientists have uncovered many characteristics of the main toxic dinoflagellate in Florida, Gymnodinium breve, especially about its biochemistry, but still several questions concerning the initiation, maintenance, and termination of blooms remain unanswered by many scientists (Kusek, 1998). For example, it is still unknown whether this dinoflagellate has a benthic-resting cyst stage. The seed bed hypothesis proposed in the 1970's as the source of bloom initiation for Florida red tides requires further examination to determine if this theory is true. More importantly, the fundamental ecology and biology of G. breve requires more research to establish its role in bloom formations. Information on the recent emergence of Pfiesteria - like species in Florida is extremely unclear. Not enough research has been done to know about their possible impact on the natural ecosystem and people.

Ideas for prediction, management, and control of Florida red tides are offered in the closing stages of the paper. The use of GIS and satellite imagery are two of the most recent technologies available to facilitate in predicting red tides. Also, biological and chemical agents, such as predators and absorbent clays, have been introduced as a means of controlling the growth of red tides. Negative impacts from red tides could be avoided and/or controlled if there was increased close and continuous monitoring, public awareness, and long-term/large-scale research. These are the main issues that must be addressed in the fight against HABs.

A list of research questions is provided following the conclusions of this paper. Answers to these may take years of research and investigation. In the meantime, the problem of red tides in Florida remains ambiguous and citizens are becoming more frustrated by the effects of red tide left behind on beaches. Many are wondering how far scientists have come in their understanding of G. breve red tides (Kusek, 1998).

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