The primary impact of overfishing on marine ecosystems is the depletion of fish populations, which disrupts the natural balance of the food web. As targeted species diminish, the entire ecosystem can be thrown off balance, affecting predator-prey relationships and leading to species extinction. Additionally, overfishing may cause an increase in the population of less desirable species, known as bycatch. This imbalance jeopardizes the health of marine environments and economic resources for communities dependent on fishing.