Every May and June, rivers and streams all around the state are busy with migrating fish. Guided by their sense of smell, Alewives are members of the hearing family and these fish live in the western North Atlantic Ocean. They are also known as river herring because they swim up rivers and streams from the ocean to their spawning grounds in ponds and lakes. These incredible and persistent swimmers face many challenges along the way dodging hungry predators and human-made obstacles.