Why do smaller fish species generally accumulate less mercury than larger predatory fish?

Smaller fish species tend to accumulate less mercury than larger predatory fish higher up the food chain

A key consideration for consumers incorporating fish regularly into their diet is the potential for exposure to environmental contaminants, primarily mercury. The biological mechanism affecting mercury concentration relates directly to the fish's position within the aquatic ecosystem and its size. Generally, mercury accumulates progressively as it moves up the food chain through a process known as biomagnification. Consequently, smaller species, which often feed lower down the chain or have shorter lifespans, naturally accumulate lower overall concentrations of mercury in their tissues compared to larger, older, apex predators that have consumed many contaminated organisms over extended periods.