Which is higher in mercury, tuna or swordfish?
                                
                                
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                                    3 min read                                
                            
                                According to the U.S. Food and Drug Administration (FDA), swordfish has a significantly higher average mercury concentration (1.00 ppm) than many varieties of tuna. This difference is primarily due to the natural process of biomagnification, where larger, longer-living predatory fish like swordfish accumulate more mercury over time.