Comparison of four clones of the ichthyotoxic flagellate Prymnesium

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Melissa A. Clouse (Creator)
The University of North Carolina Wilmington (UNCW )
Web Site:
Carmelo Tomas

Abstract: Since the mid 1980s blooms of the ichthyotoxic flagellate Prymnesium parvum have resulted in recurrent fish kills in Texas lakes, rivers, and reservoirs. South Carolina experienced a bloom of P. parvum in a brackish golf course pond in summer 2001. No dead fish were reported since the pond had no resident fish. The following year at Artesian Aquafarms in N.C., all hybrid striped bass perished to blooms of P. parvum. In the present study, clonal cultures from each of these blooms were grown in laboratory studies to determine response variation with nutrient-stressed (N-limited, P-limited) and replete cells for growth, hemolytic activity, and ichthyotoxicity. A congener, P. calathiferum originally isolated from a New Zealand bloom, was used for comparison. Of the P. parvum clones, the TX clone overall grew slower (0.21-0.31 div.d-1), had lower hemolytic activity (40-7164 units), but had the highest ichthyotoxicity (1 hr to kill fish in P-limited, 3 hrs in Replete and N-limited). This clone was the most sensitive to nutrient stress and conditioning was reduced to 1 week. In contrast, overall growth and hemolytic activity were greater in the NC (0.21-0.56 div.d-1, 77-21399 units) and SC clones (0.20-0.70 div·d-1, 45-20795 units) with lower ichthyotoxicity for both (>4 hrs in N-&P-limited). Prymnesium calathiferum showed substantially lower hemolytic activity (8-779 units), but grew faster (0.30-0.73 div.d-1) than the P. parvum clones. Nitrogen-deficient cultures were similar to or more hemolytic than P-deficient cultures for P. parvum, but the P-deficient cultures were the most ichthyotoxic. Under nutrient-replete conditions, P. calathiferum was the most ichthyotoxic of the clones with fish mortality occurring in one hour as compared to three hours for the TX clone. Toxicity in P. parvum is a complex interaction of hemolytic and ichthyotoxic components.

Additional Information

A Thesis Submitted to University of North Carolina Wilmington in Partial Fulfillment Of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Algal blooms--Research, Algal blooms--Toxicology, Algal toxins--Research, Algal toxins--Toxicology, Chrysophytes--Toxicology, Fish kills--North Carolina, Fish kills--South Carolina, Fish kills--Texas, Prymnesium, Prymnesium parvum, Toxic algae--Research
Fish kills -- North Carolina
Fish kills -- South Carolina
Fish kills -- Texas
Prymnesium parvum
Algal blooms -- Toxicology
Algal blooms -- Research
Algal toxins -- Research
Algal toxins -- Toxicology
Chrysophytes -- Toxicology
Toxic algae -- Research

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