How many grams is a sea urchin? Unraveling the weight differences
                                
                                
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                                    4 min read                                
                            
                                A typical commercial-sized red sea urchin, measuring about 3.5 inches in diameter, weighs approximately 454 grams, or one pound. This weight, however, is not a fixed number, as the question of how many grams is a sea urchin can vary dramatically depending on several biological and environmental factors.