Asynchrony of Gambierdiscus spp. Abundance and Toxicity in the U.S. Virgin Islands: Implications for Monitoring and Management of Ciguatera

• Published in: Toxins Vol. 13; no. 6; p. 413
• Main Authors: Liefer, Justin D, Richlen, Mindy L, Smith, Tyler B, DeBose, Jennifer L, Xu, Yixiao, Anderson, Donald M, Robertson, Alison
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 10.06.2021; MDPI
• Subjects: Algae; Algal blooms; Animals; Caribbean; Cell Line, Tumor; Cell Survival - drug effects; Ciguatera; Ciguatera Poisoning; ciguatoxin; Ciguatoxins - analysis; Ciguatoxins - toxicity; Coastal fisheries; Coral reefs; Dictyota; dinoflagellate; Dinoflagellates; Dinoflagellida; Ecosystem services; Environmental conditions; Environmental factors; Environmental Monitoring; Eutrophication; Fish; Fisheries; Fishery resources; Food chains; Food webs; Gambierdiscus; Islands; Mice; Microorganisms; Monitoring; Nutrients; Poisoning; Precipitation; Principal components analysis; Quotas; Salinity; Seasonal variations; Seasons; Seawater; Substrates; Toxicity; Toxins; Trends; Trophic levels; United States Virgin Islands; Water temperature; Weather; United States Virgin Islands; Dictyota; ciguatoxin; harmful algal bloom; ciguatera poisoning; algal toxin; benthic algae; Caribbean; dinoflagellate; Gambierdiscus
• ISSN: 2072-6651; 2072-6651
• DOI: 10.3390/toxins13060413

Ciguatera poisoning (CP) poses a significant threat to ecosystem services and fishery resources in coastal communities. The CP-causative ciguatoxins (CTXs) are produced by benthic dinoflagellates including and spp., and enter reef food webs via grazing on macroalgal substrates. In this study, we report on a 3-year monthly time series in St. Thomas, US Virgin Islands where spp. abundance and Caribbean-CTX toxicity in benthic samples were compared to key environmental factors, including temperature, salinity, nutrients, benthic cover, and physical data. We found that peak abundance occurred in summer while CTX-specific toxicity peaked in cooler months (February-May) when the mean water temperatures were approximately 26-28 °C. These trends were most evident at deeper offshore sites where macroalgal cover was highest year-round. Other environmental parameters were not correlated with the CTX variability observed over time. The asynchrony between spp. abundance and toxicity reflects potential differences in toxin cell quotas among species with concomitant variability in their abundances throughout the year. These results have significant implications for monitoring and management of benthic harmful algal blooms and highlights potential seasonal and highly-localized pulses in reef toxin loads that may be transferred to higher trophic levels.