Alosa pseudoharengus

The alewife (Alosa pseudoharengus) is an anadromous species of herring found in North America. It is one of the 'typical' North American shads, attributed to the subgenus Pomolobus of the genus Alosa. As an adult it is a marine species found in the northern West Atlantic Ocean, moving into estuaries before swimming upstream to breed in freshwater habitats, but some populations live entirely in fresh water. It is best known for its invasion of the Great Lakes by using the Welland Canal to bypass Niagara Falls. Here, its population surged, peaking between the 1950s and 1980s to the detriment of many native species of fish. In an effort to control them biologically, Pacific salmon were introduced, only partially successfully. As a marine fish, the alewife is a US National Marine Fisheries Service 'Species of Concern'. Alewives reach a maximum length of about 40 cm (16 in), but have an average length of about 25 cm (10 in). The front of the body is deep and larger than other fish found in the same waters, and its common name is said to come from comparison with a corpulent female tavernkeeper ('ale-wife'). In southwestern Nova Scotia, it is called a kiack (or kyack). In Atlantic Canada it is known as the gaspereau, from the Acadian French word gasparot, first mentioned by Nicolas Denys. William Francis Ganong, New Brunswick biologist and historian, wrote: Acadians named two rivers after the fish, the Gaspereau River in Nova Scotia and the Gaspereaux River in New Brunswick. In eastern Massachusetts, Alewife Brook flows through Arlington, Cambridge, and Somerville to the Mystic River. The brook gives its name to the Alewife Brook Parkway and the Alewife Brook Reservation. The Red Line (MBTA) of Boston's T ends at the Alewife station, so the name of this fish adorns the front of every northbound Red Line train. An extensive habitat restoration and education project, combined with a fish ladder with monitoring cameras, is yielding increasing numbers of Alewife back in the improving watershed. In the Southeast US, when sold and used as bait, the fish is often referred to as 'LY'. Both anadromous and landlocked forms occur. The landlocked form is also called a sawbelly or mooneye (although this latter name is more commonly applied to Hiodon spp.). Adult alewives are caught during their spring spawning migration upstream by being scooped out of shallow, constricted areas using large dip nets. They are the preferred bait for the spring lobster fishery in Maine, and are eaten by humans, usually smoked. Alewives are perhaps best known for their invasion of the Great Lakes by using the Welland Canal to bypass Niagara Falls. Alewives colonized the Great Lakes and became abundant mostly in Lake Huron and Lake Michigan. They reached their peak abundance from the 1950s through the 1980s. Alewives grew in number unchecked because of the lack of a top predator in the lakes (lake trout were essentially wiped out around the same time by overfishing and the invasion of the sea lamprey). For a time, alewives, which often exhibit seasonal die-offs, washed up in windrows on the shorelines of the Great Lakes. Various species of Pacific salmon (first coho, and later the Chinook salmon) were introduced as predators. Though marginally successful, this led to the development of a salmon/alewife fishery popular with many sport anglers.