anadromous
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...
species of
herring
Herring are forage fish, mostly belonging to the family of Clupeidae.
Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, i ...
found in
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
''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
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
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".
Description
Alewife 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").
Etymology and folklore
In southwestern Nova Scotia, alewife are referred to as kiacks (or kyacks). In
Atlantic Canada
Atlantic Canada, also called the Atlantic provinces (french: provinces de l'Atlantique), is the region of Eastern Canada comprising the provinces located on the Atlantic coast, excluding Quebec. The four provinces are New Brunswick, Newfoundlan ...
Gaspereau, or Gasparot. Name of a common salt-water fish of Acadia
(also called alewife), first used, so far as I can find, by Denys in
1672. Nowhere can I find any clue to its origin. It seems not to be
Indian.
Acadians named two rivers after the fish, the Gaspereau River in Nova Scotia and the Gaspereau 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
Alewife Brook Parkway is a short parkway in Cambridge and Somerville, Massachusetts. It is listed on the National Register of Historic Places. It begins at Fresh Pond in Cambridge (linking to Fresh Pond Parkway via Concord Avenue), and heads nor ...
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 Mystic River watershed.
Both
anadromous
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...
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 alewife 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.
In the North American Great Lakes
Alewife are known for their invasion of the Great Lakes by using the Welland Canal to bypass Niagara Falls. Alewife colonized the Great Lakes and became abundant mostly in
Lake Huron
Lake Huron ( ) is one of the five Great Lakes of North America. Hydrology, Hydrologically, it comprises the easterly portion of Lake Michigan–Huron, having the same surface elevation as Lake Michigan, to which it is connected by the , Strait ...
and
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America. It is the second-largest of the Great Lakes by volume () and the third-largest by surface area (), after Lake Superior and Lake Huron. To the east, its basin is conjoined with that o ...
. They reached their peak abundance from the 1950s through the 1980s. Alewife grew in number unchecked because the lakes lacked a top predator ( lake trout were essentially wiped out around the same time by
overfishing
Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...
and the invasion of the sea lamprey).
For a time, alewife, 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.
In spite of such biological control methods, alewife remain implicated in the decline of many native Great Lakes species. It is also a common predator of numerous native and non-native zooplankton taxa ('' Bythotrephes longimanus'', ''
Leptodiaptomus ashlandi
''Leptodiaptomus ashlandi'' is a calanoid copepod zooplankton native to the Laurentian Great Lakes and their basin.
Distribution
''Leptodiaptomus ashlandi'' is a zooplankton species widely distributed across Canada and the northern half of the U ...
'', ''
Leptodiaptomus minutus
''Leptodiaptomus ashlandi'' is a calanoid copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), ...
'', ''
Leptodiaptomus sicilis
''Leptodiaptomus sicilis'' is a calanoid copepod native to the Laurentian Great Lakes and its basin.
Distribution
The species is found all over North America, north of Missouri, in fresh and saline waters. It is found in all the Great Lakes bu ...
'', and ''
Leptodora kindtii
''Leptodora'' is a genus containing two species of large, nearly transparent predatory water fleas. They grow up to long, with two large antennae used for swimming and a single compound eye. The legs are used to catch copepods that it comes int ...
'').
Conservation
Alewife populations have seen big declines throughout much of their range. Several threats have most likely contributed to their decline, including loss of habitat due to decreased access to spawning areas from the construction of dams and other impediments to migration, habitat degradation, fishing, and increased predation due to recovering striped bass populations.
In response to the declining population trend for alewives, the states of Massachusetts, Rhode Island, Connecticut, Virginia, and North Carolina have instituted moratoria on taking and possession.
The alewife is a US National Marine Fisheries Service Species of Concern, about which the National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the US
Endangered Species Act
The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...