There is little information about ciguatera and the dinoflagellates responsible for it in Venezuela. The object
of this study was to evaluate the presence of epibenthic dinoflagellates in Turpialito Bay, located on the southern coast of the
Gulf of Cariaco. Surface sea water salinity and temperature were measured. Sampling was done fortnightly during the period
May-November 2012. The organisms were collected from Thalassia testudinum (Banks ex König) leaves, macroalgal thalli,
and plastic bottles (350 ml). All samples were fixed with formaldehyde (40%). A subsample was used to identified the organisms
and the other was used to quantified them following Utermöhl´s method. Salinity and temperature varied in the intervals 37
- 39 and 27 - 31 °C, respectively. Individuals belonging to two genera and nine species were identified. According to their
frequency in the samples, these were: Ostreopsis siamensis, Prorocentrum lima, P. mexicanum, P. concavum, P. minimum,
Prorocentrum sp., Ostreopsis sp., P. micans and P. cf. compresum. The maximum number of species (six) was found on T.
testudinum while the minimum (two) was found on Cauerpa racemosa. On other hand, the species with the greatest relative
abundance were: O. siamensis (86% or 44 x 103 org g-1) on the macroalgae Sargassum sp. and P. mexicanum (61% or 22 x
103 org g-1) on C. sertulariodes. It was determined that tidal state had a significant influence on the abundance of P.
mexicanum (KW = 5.10; p < 0,05), while the type of substrate had a significant influence on the abundance of P. lima (KW
= 36.60; p < 0,05). The results indicated that epibenthic dinoflagellates were present in all the samples collected throughout
the study. The variability in the presence and abundance of the species was attributed to natural changes and differences in the
type of substrate.