Gymnodinium pulchellum (from: http://www.floridamarine.org/features/view_article.asp?id=12339

This species often blooms in estuaries.

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Takayama pulchella (formerly Gymnodinium pulchellum has been identified from Australia, Florida, and Japan. It is a coastal/estuarine toxic species associated with fish kills, human respiratory irritation, and ichthyotoxins (fish poison) within the cell.

Does it produce a bottom resting stage? Probably! Recurrent blooms of dinoflagellates in the same place year after year typically indicates a benthic seed population.

In Florida, this species has occurred in bloom proportions at one dock on the Indian River Lagoon twice in the last decade.

A distinctive characteristic of T. pulchella is a sigmoidal (S-shaped) apical groove along the top of the cell.

World Distribution
Australia, Florida, Japan, and the Mediterranean

Distribution in Gulf of Mexico
Florida

Habitat
Estuarine

Toxins
Reported to be brevetoxins

Associated Impacts
Animal Mortality: Fish kills
Animal Disease: Unknown
Ecological Impact: Unknown
Shellfish Poisoning: Unknown
Human Impact: Possible respiratory irritation

What we know

• In high concentrations, G. pulchellum has been associated with fish kills
• There are limited accounts of people experiencing respiratory irritation when G. pulchellum is blooming
• There are similar species with similar apical grooves

What we don't know

• The basic biology, ecology and impacts are unknown
• Do different geographic strains have different toxicity?
• What toxins does G. pulchellum produce?
• How do human activities affect species distribution?
• What is the global distribution?

Technical Identification

• Unarmored dinoflagellate; approximately 25 µm in width
• Broadly oval cell that is slightly dorso-ventrally compressed
• Cingulum is displaced to 1.5x
• Epitheca has characteristic apical groove that is reversed "S" shape that starts ventrally to the right of the sulcal intrusion and extends onto the dorsal surface
• Nucleus ellipsoidal and located on the left side
• Chloroplasts present, yellow-green cell
• Planktonic with potential resting cysts

Selected G. pulchellum References

Hallegraeff, G.M. 1991. Aquaculturists Guide to Harmful Australian Microalgae. Fishing Industry Training Board of Tasmania/CSIRO Division of Fisheries. Hobart.

Larsen, J. 1994. Unarmored dinoflagellates from Australian waters. I. The genus Gymnodinium (Gymnodiniales, Dinophyceae). Phycologia 33: 24-33.

Onoue, Y. et al. 1985. Occurrence of a toxic dinoflagellate, "Gymnodinium type 84K" in Kagoshima Bay. Bull. Jpn. Soc. Fish. 51: 1567.

Steidinger, K.A., J.H. Landsberg, E.W. Truby and B.S. Roberts. 1998. First report of Gymnodinium pulchellum (Dinophyceae) in North America and associated fish kills in the Indian River, Florida. Journal of Phycology 34: 431-437.

Taylor, F.J.R., Y. Fukuyo and J. Larsen. 1995. Taxonomy of Harmful Dinoflagellates. In Manual on Harmful Microalgae (G.M. Hallegraeff, D.M. Anderson and A.D. Cembella, editors). IOC Manuals and Guides 33. UNESCO, France.

Impaired Waters list status for C-25 and North St. Lucie County Indian River Lagoon

Basin Group Name	Water Segment Name	Waterbody Type	Waterbody Class	Parameters Assessed Using the Impaired Waters Rule (IWR)	Concentration Causing Impairment^1	Priority for TMDL Development^2	Projected Year for TMDL Development^2	Comments^3 (# Exceedances/# Samples) PP=Planning Period VP=Verified Period
Southeast Florida Coast	C-25 EAST SEGMENT	STREAM	3F	Nutrients (CHLA)	TN = 1.438 mg/L TP = 0.145 mg/L	Medium	2008	PP - No Data; VP - Verified, with one annual mean chl a value above 20 ug/L. Colimiting of nitrogen and phosperous based upon TN/TP ratios [TN median = 1.438 mg/L and TP median = 0.145 mg/L. PP median TN/TP ratio = 10.46 (327 values), VP median TN/TP ratio = 10.11 (291 values).
Southeast Florida Coast	NORTH COASTAL	ESTUARY	3M	Nutrients (CHLA)	TN = 0.93 mg/L TP = 0.056 mg/L	Medium	2008	PP - Potentially Impaired; VP - Verified, with two annual mean chl a values above 11 ug/L. Both phosphorous and nitrogen identied as limiting nutrients based on TN/TP ratios. TN median = 0.93 mg/L, TP median = 0.056 mg/L. PP TN/TP ratio median = 12.5 (357 values), VP = 14.87 (230 values).