Why are smaller, shorter-lived species like sardines often recommended over large predators regarding contaminant risk?

Contaminants like mercury accumulate up the food chain, making larger fish riskier.

A key strategy for mitigating potential exposure to environmental contaminants, especially mercury, involves careful selection of fish species based on their position in the marine food web. Mercury does not degrade and tends to bioaccumulate, meaning it concentrates in greater quantities in organisms higher up the food chain that consume smaller, contaminated prey over many years. Consequently, very large, long-lived predatory fish accumulate higher toxin loads. Conversely, smaller species like sardines and anchovies are shorter-lived and occupy lower trophic levels, resulting in significantly lower mercury accumulation, thus making them safer for more frequent consumption.