Pacific Ciguatoxins in Food Web Components of Coral Reef Systems in the Republic of Kiribati

Abstract

Ciguatera fish poisoning (CFP) is a foodborne illness caused by consumption of coral reef fishes contaminated by ciguatoxins (CTXs); of the known CTX congeners, the Pacific ciguatoxins (P-CTXs) are the most toxic. Little is known about the trophodynamics of P-CTXs in coral reef systems. The present study explores the distribution, transfer, and trophic magnification of P-CTX-1, -2, and -3 in coral reef systems with high (ciguatoxic) and low (reference) ciguatoxicity in a CFP-endemic nation by use of liquid chromatography-tandem mass spectrometry (LC-MS/MS). In ciguatoxic coral reef systems, P-CTXs were detected in 54% of herbivorous fishes [total P-CTXs <0.500-1670 pg/g wet weight (ww)], 72% of omnivorous fishes (<0.500-1810 pg/g ww), and 76% of carnivorous fishes (<0.500-69 500 pg/g ww), as well as a lobster ( Panulirus penicillatus ; 2.36 pg/g ww) and an octopus (Octopodidae; 2.56 pg/g ww). The dominant P-CTXs in grazers and piscivorous fishes were P-CTX-2 and -1, respectively. No significant correlation between P-CTX levels and lipid content in three target predatory fishes indicated that accumulation of P-CTXs does not depend on fat content. A weak but significant positive relationship was observed between δ(15)N and P-CTX-1 levels, but further investigation is required to confirm its biomagnification potential.

Ciguatoxin Occurrence in Food-Web Components of a Cuban Coral Reef Ecosystem: Risk-Assessment Implications

“…These results are in agreement with the common knowledge of ciguatera in the region. They also corroborate a study in the Pacific that found a positive correlation between CTX1B levels and δ 15 N, suggesting biomagnification may be occurring due to biotransformation of P-CTX2 and P-CTX3 precursors (aka 52-epi-54-deoxyCTX1B and 54-deoxyCTX1B, respectively) [45]. In the Pacific, P-CTXs are known to become more potent with metabolization and oxidation as they move up the fish food chain, resulting in a greater risk of ciguatera with large predator fish [37].…”

Climate change, food security and health in Kiribati: a narrative review of the literature

“…Most of the items examining this theme were reports that stressed the inherent vulnerability of Kiribati on account of its geography, its population pressures and its problems in terms of environment, economics and isolation. Peer reviewed articles focused on the health impacts of climate change [16,23], and on food security and risks posed by climate change [24][25][26][27][28][29][30]. Migration and sociocultural issues impacted by climate change in Kiribati were also explored, further showcasing the complexity of the subject [31,32].…”

“…The toxins are not removed on cooking. Ciguatera seems to be of increasing concern in Kiribati, with three peer-reviewed articles exclusively focusing on the problem [27,28,30].…”

Harmful Algal Blooms in Benthic Systems: Recent Progress and Future Research

“…Progress has been slow for CTX (e.g., Mak et al, 2013) and PLTXlike compounds (Brissard et al, 2014;Biré et al, 2015). Ecotoxicology tests are revealing a distinctive sensitivity of model organisms to these toxins (e.g., Giussani et al, 2015).…”