Christian et al. 2024 — Mercury in Caribbean fish and invertebrates
More than 1,600 samples of 108 unique species of fish and aquatic invertebrates collected between 2005 and 2023 from eleven countries or territories in the wider Caribbean Region were compiled and analyzed for total mercury (tHg). The study finds wide variability in tHg concentrations: 55% of samples were below the 0.23 µg/g wet weight (ww) FDA/EPA guideline for 2-3 weekly servings, while 26% exceeded the 0.46 µg/g ww guideline associated with adverse health effects from continual consumption, particularly for sensitive populations. Significant relationships were found between tHg concentrations and taxonomic family, sampling country, fish length, and trophic level. The dataset represents baseline mercury data collected partly through the Caribbean Region Mercury Monitoring Network (CRMMN), established in 2022 under Minamata Convention obligations.
Key numbers
Total samples: >1,600; species: 108 unique; countries/territories: 11 (Anguilla, Antigua and Barbuda, Dominica, Grenada, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, Belize, Honduras, Guatemala, Suriname); collection period: 2005-2023. Key thresholds applied: FDA/EPA guideline for 2-3 servings/week = 0.23 µg/g ww; FDA/EPA guideline for adverse effects from continual consumption = 0.46 µg/g ww. 55% of samples below 0.23 µg/g ww; 26% exceeding 0.46 µg/g ww. Species with highest tHg were large pelagic predators (yellowfin tuna, barracuda) at higher trophic levels. Around 75-95% of total mercury in fish muscle is in the form of MeHg; tHg is used as proxy for MeHg throughout this study.
Note: this study reports total mercury (tHg). MeHg was not separately quantified, though the authors note the tHg:MeHg ratio in fish muscle is well established in the literature.
Methods (brief)
Compiled dataset from multiple monitoring programmes across the wider Caribbean Region. Total mercury measured in fish muscle (and other tissues for some species). Reference thresholds from FDA/EPA Fish Advice (2022). Statistical analysis included mixed-effects models examining tHg vs. family, country, fish length, and trophic level.
Implications
Certification: Caribbean region fish/seafood mercury data; relevant for products containing Caribbean-sourced seafood. The 26% exceedance rate above 0.46 µg/g ww is a signal that regional sourcing matters for mercury exposure.
Courses: valuable teaching case on tHg as proxy for MeHg, Minamata Convention monitoring obligations, and fish consumption advisories for SIDS populations.
App: tHg values by species and trophic level support species-specific fish contamination estimates for Caribbean species.