Why are menhaden cosiderate a keystone species?

Menhaden are considered a keystone species because they play a crucial role in the marine ecosystem by serving as a primary food source for various predators, including larger fish, birds, and marine mammals. They help maintain the health of coastal ecosystems by filtering plankton from the water, which contributes to water quality and clarity. This filtering process also supports the overall balance of marine life, making menhaden essential for the ecological stability of their habitats. Their decline or absence can lead to significant disruptions in the food web and overall ecosystem health.