These trends are under close investigation in southern Lake Michigan and else where around the state. For example, in the inner half of Saginaw Bay, yellow perch are still very abundant. Sport harvest alone exceeds 1 million fish in many years and a commercial fishery persists there today. This is exactly where the bay's long term harvest historically averaged. In fact, during the late 1980s there were actually too many yellow perch in Saginaw Bay.
Yellow perch are an intermediate predator in the food chain.
This means they are both a predator on other fish and aquatic organisms but are also prey for other predators. A characteristic of fish lower in the food chain is that they have the ability to achieve explosive reproduction when conditions are right. They are not very often eaten by predators any more since the invasion of soft rayed exotics like alewife. Alewife together with gizzard shad account for the preferred prey of most predators in the bay. Also perch need large invertebrates to grow well.