Ciguatoxin in Hawai'i: Fisheries forecasting using geospatial and environmental analyses for the invasive...

Invasive species can precede far-reaching environmental and economic consequences. In the Hawai'ian Archipelago Cephalopholis argus (family Serranidae) is an established invasive species, now recognized as the dominant local reef predator, negatively impacting the native ecosystem and local fishery. In this region, no official C. argus fishery exists, due to its association with Ciguatera seafood poisoning (CP); a severe intoxication in humans occurring after eating (primarily) fish contaminated with ciguatoxins (CTXs). Pre-harvest prediction of CP is currently not possible; partly due to the ubiquitous nature of the microalgae producing CTXs and the diverse bioaccumulation pathways of the toxins. This study investigated the perceived risk of CP in two geographically discrete regions (Leeward and Windward) around the main island of Hawai'i, guided by local fishers. C. argus was collected and investigated for CTXs using the U.S. Food and Drug Administration (FDA) CTX testing protocol (in vitro neuroblastoma N2a-assay and LC-MS/MS). Overall, 76% of fish (87/113) exceeded the FDA guidance value for CTX1B (0.01 ng g^-1 tissue equivalents); determined by the N2a-assay. Maximum CTX levels were ≅2× higher at the Leeward vs Windward location and, respectively, 95% (64/67) and 54% (25/46) of fish were positive for CTX-like activity. Fisher persons and environmental understandings, regarding the existence of a geographic predictor (Leeward vs Windward) for harvest, were found to be (mostly) accurate as CTXs were detected in both locations and the local designation of C. argus as a risk for CP was confirmed. This study provides additional evidence that supports the previous conclusions that this species is a severe CP risk in the coastal food web of Hawai'i, and that ocean exposure (wave power) may be a prominent factor influencing the CTX content in fish within a hyperendemic region for CP.