BioKIDS - Kids' Inquiry of Diverse Species, Alosa pseudoharengus, Anadromous alewives: INFORMATION Skip directly to main content . Kids' Inquiry of Diverse Species Alosa pseudoharengus What do they look like? Alewives have an overall silvery color with a grayish green back. A black spot at the eye level is directly behind the head. Adults have longitudinal lines that run along the midline of the body. Small alewives have a violet sheen on the sides while adults have a golden cast on their heads and upper parts. They are colored very much like skipjack herring . Scales along the middle of the belly form a raised edge. Females are bigger than males and generally live longer. The body is very rounded and flattened. The head is broadly triangular. The eyes are large and have structures that look like eyelids. The single dorsal fin usually has 13-14 rays but may have 12-16. The tail fin is forked. The anal fin is short and wide with 15-19 rays. Alewives that live at sea tend to be longer, ranging from 255 to 355 mm.

Alewives that live in freshwater are about 150 mm in length and mature faster than alewives that live at sea. Other Physical Features 3.94 to 13.98 in Where do they live? Alewives are native to the Atlantic Ocean and the lakes and streams that drain to it from Newfoundland to North Carolina. They are "anadromous", which means that they live most of their lives in the sea but migrate into freshwater rivers and streams to breed. They are present, but non-native, in all of the Great Lakes and many lakes in northern New York. In the Great Lakes they are now abundant in Lake Huron and Lake Michigan. Alewives don't do well in Lake Superior because the water is too cold and lake trout prey heavily on them there. They don't do well in Lake Erie because the lake is too shallow to provide suitable overwintering grounds for large numbers of fish. Several theories exist on how alewives could have become established in the Great Lakes. Scott and Crossman suggest that alewives may have been accidentally included in a batch of American shad that were used to stock Lake Ontario.

The alewives also could have migrated from Lakes Seneca and Cayuga in New York to the Great Lakes through the St. Lawrence River. A third argument for the current distribution is that alewives were native to Lake Ontario in small numbers but went unnoticed until a population explosion in 1873. Biogeographic Regions native What kind of habitat do they need? Alewives spend most of their time in coastal waters and most are caught in water 56 to 100 m deep at about 4°C. They are sensitive to light and tend to be in deeper waters during daylight hours. They follow the daily movements of zooplankton in the water column. Adults can withstand temperatures up to 25°C and young of the year can live in waters up to 30°C. These animals are found in the following types of habitat 183.73 to 328.08 ft How do they grow? Fertilized eggs are about 0.9 mm in diameter. Three to five days after hatching, the larvae begin to feed. They slowly transform into juvenile fish and remain in fresh water until the fall, growing to 3.8 to 12.5 cm.

How do they reproduce? Alewives spawn in the spring. The young swim to sea or to deeper parts of large lakes (including the Great Lakes). Migration to spawning grounds happens earlier in warmer areas. Spawning generally starts in April in the south and lasts until the end of May farther north. In all populations, females reach the spawning grounds first and older fish are the first to spawn. The oldest fish recorded at spawning sites were to 10 years old. Spawning occurs in groups of 3 or in pairs. Mating System polygynandrous (promiscuous) Females lay their eggs and males fertilize them at the same time. The eggs are sticky at first and may stick to plants or rocks. Within a few hours they settle to the bottom of the lake or river. Alewives lay their eggs over any type of substrate. The number of eggs per female may be 10,000 to 360,000. In populations that migrate to the sea, adult alewives spend most of their lives at sea but spawn in inland streams. Although they cannot jump obstacles such as dams, they can swim over rapids. Fish in these populations mature at 3 years for males and 4 years for females.

In freshwater populations, fish mature at 2 years for males and 3 years for females. These fish move close to shallow beaches or into streams to spawn. Eggs hatch in 3 to 6 days, depending on how warm the water is. Key Reproductive Features How often does reproduction occur? Alewives breed yearly. Spawning occurs during the spring. Range number of offspring Range age at sexual or reproductive maturity (female) 3 to 4 years Range age at sexual or reproductive maturity (male) 2 to 3 years Alewives do not have any parental investment in their young beyond spawning. The adults leave immediately after spawning in the spring and the young move to the open water in the fall. Parental Investment female How long do they live? Young alewives have a very high mortality rate. Less than 1% survive to migrate into the sea or large lake. About 70% of adult alewives die each year also. Most die during or shortly after the spawning season. Few alewives in freshwater populations live longer than 5 years. Range lifespan 5 (high) hours How do they behave? There is little information on the social behavior of alewives except for spawning behaviors and feeding patterns.

They migrate up streams or to shallow waters to spawn. They make daily movements in the water column, moving up (closer to the surface) at night and down (into deeper waters) during the day. They generally travel in groups. Key Behaviors Alewives are not territorial. How do they communicate with each other? We don't know much about how alewives might communicate. Their large eyes probably help them find other alewives, their prey, and stay alert for predators. Communication Channels electric What do they eat? Little is known about the feeding habits of alewives that live at sea. Alewives in freshwater populations eat mostly zooplankton, especially small crustaceans such as copepods, cladocerans, mysids , and ostracods . When they grow larger than 11.9 cm, they feed mostly on larger, bottom dwelling crustaceans. Some spawning adults eat small fish or fish eggs when in shallow waters. Primary Diet zooplankton What eats them and how do they avoid being eaten? Alewives have many predators. In freshwater, their main predators are burbot , lake trout , eels , bass , walleye , and whitefish . Introduced predators include chinook and coho salmon.

Little is known about the predators of alewives that live at sea but their hatchlings have a high mortality rate. As few as one out of 80,000 will reach the sea. Known Predators coho salmon ( Oncorhynchus kisutch ) What roles do they have in the ecosystem? Alewives are now the most abundant planktivores in Lake Ontario and are the main prey of salmon in the Great Lakes. Their presence in the Great Lakes has caused the decline of many native fish species because of competition. There isn't much known about the parasites of alewives, but acanthocephalans , cestodes , trematodes , copepods, and nematodes have all been found in populations that live in the sea. Alewives that live in freshwater lakes don't have as many parasites. Commensal or parasitic species (or larger taxonomic groups) that use this species as a host nematodes Do they cause problems? Alewives have been considered a nuisance in the Great Lakes since their population explosion in 1873. Live fish can clog industrial intake pipelines and sometimes die in large numbers, resulting in lots of dead fish on beaches in the spring.

Coho salmon were introduced in the Great Lakes to control alewives and are now important sport fish in the region. Since alewives feed mainly on plankton and bottom-dwelling crustaceans, alewives are particularly good at accumulating DDT and other toxins in their fatty tissues. For this reason it is best not to eat too many of the fish predators of alewives, such as salmon from the Great Lakes. How do they interact with us? Alewives support an important commercial fishery in the Atlantic Ocean. They are packaged fresh, smoked, salted, or pickled for human food and are often sold as “river herring.” Fishermen use weirs, traps, gill nets, and dip nets for alewives, which they consider one of the easiest fish to catch. Alewives have other uses, including pet food, lobster and snow crab bait, and processing into fishmeal and fish oil. Alewives are not usually fished in the Great Lakes since these are small and too bony to eat. However, recently there has been a trend to use them for pet food and fish meal. Ways that people benefit from these animals: body parts are source of valuable material Are they endangered?

Alewives not listed as an endangered species, but in many places in their natural range, their habitat is threatened by dams along spawning rivers. On the other hand, their introduction into the Great Lakes and other areas resulted in declines in native fish in those areas. No special status Some more information... Alosa pseudoharengus was formerly classified as Alosa pseudoharengus . Common names for A. pseudoharengus include alewife, gaspereau, sawbelly, kyak, kiack, river herring, and glut herring. Alewives have some interesting cultural and historical connections. Alewives are the fish the Native Americans in New England buried with crops as fertilizer (Grosvenor, 1965). The silvery coating on the scales is sometimes used in making costume jewelry and is called pearl essence by the jewelry industry (Grosvenor, 1965). ( Grosvenor, 1965 ) Contributors Vanessa Tobias (author), University of Michigan-Ann Arbor, William Fink (editor, instructor), University of Michigan-Ann Arbor, Renee Sherman Mulcrone (editor). References Daniels, R. 2001.

Untested assumptions: the role of canals in the dispersal of sea lamprey, alewife, and other fishes in the eastern United States. Environmental Biology of Fishes, 60: 309-329. Grosvenor, M. 1965. Wondrous World of Fishes. Washington, DC: National Geographic Society. Klumb, R., L. Rudstam, E. Mills. 2003. Comparison of Alewife Young-of-the-Year and Adult Respiration and Swimming Speed Bioenergetics Model Parameters: Implications of Extrapolation. Transactions of the American Fisheries Society, 132: 1089-1103. Madenjian, C., J. Holuszko, T. Desorcie. 2003. Growth and Condition of Alewives in Lake Michigan, 1984-2001. Transactions of the American Fisheries Society, 132: 1104-1116. Maine Department of Marine Resources, 2004. "Maine Department of Marine Resources" (On-line). Fact Sheet- Anadromous Alewife.

Accessed October 27, 2004 at . Scott, W., E. Crossman. 1998. The Freshwater Fishes of Canada. Oakville, Ontario, Canada: Galt House Publications Ldt.. Scott, W., M. Scott. 1988. Atlantic Fishes of Canada. Toronto, Canada: Canadian Bulletin of Fisheries and Aquatic Science (University of Toronto Press). Smith, S. 1970. Species Interactions of the Alewife in the Great Lakes. Transactions of the American Fisheries Society, 4: 754-764. Trautman, M. 1957. The Fishes of Ohio. Baltimore, Md.: Ohio State University Press (Waverly Press). U.S. Department of Agriculture, N. 2004. "Invasivespecies.gov A gateway to Federal and State invasive species activities and programs" (On-line). Accessed October 27, 2004 at . Alewife - definition of alewife by The Free Dictionary Alewife - definition of alewife by The Free Dictionary (āl′wīf′) n. pl.

ale·wives (-wīvz′) A fish (Alosa pseudoharengus) of North American Atlantic waters and some inland lakes, which swims up rivers to spawn. [Originally North American English, probably from alteration (influenced by alewife , because the fish's relatively big belly distinguishes it from the herring) of obsolete English aloes, allowes, a type of shad (Alosa alosa), from French alose, shad, from Old French, from Late Latin alausa, of Gaulish origin.] ale·wife 2 n. pl. ale·wives (-wīvz′) A woman who keeps an alehouse. alewife (ˈeɪlˌwaɪf) n, pl -wives (Animals) a North American fish, Pomolobus pseudoharengus, similar to the herring Clupea harengus: family Clupeidae (herrings) [C19: perhaps an alteration (through influence of alewife, that is, a large rotund woman, alluding to the fish's shape) of French alose shad] ale•wife1 n., pl. -wives.

a North American fish, Alosa pseudoharengus, similar to a shad. [1625–35, Amer.; earlier allowes, perhaps influenced by alewife 2, probably < French alose shad < Gallo-Latin alausa] ale•wife2 a woman who owns or operates an alehouse. [1350–1400] 1. alewife - flesh of shad-like fish abundant along the Atlantic coast or in coastal streams Alosa pseudoharengus , Pomolobus pseudoharengus , alewife - shad-like food fish that runs rivers to spawn; often salted or smoked; sometimes placed in genus Pomolobus fish - the flesh of fish used as food; "in Japan most fish is eaten raw"; "after the scare about foot-and-mouth disease a lot of people started eating fish instead of meat"; "they have a chef who specializes in fish" 2.

alewife - shad-like food fish that runs rivers to spawn; often salted or smoked; sometimes placed in genus Pomolobus alewife - flesh of shad-like fish abundant along the Atlantic coast or in coastal streams Translations Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: Critical thermal maxima of captive-bred Devils River minnows (Dionda diaboli) Seven species are introduced in the Chicago region: Common Carp (Cyprinus carpio), Alewife (Alosa pseudoharengus), Goldfish (Carassius auratus), Chinook Salmon (Oncorhynchus tshawytseha), Redear Sunfish (Lepomis microlophus), White Perch (Morone americana), and Round Goby (Neogobius melanostomus), but many others owe their presence in Wolf Lake to human intervention.

'The road less travelled' In turn, Diporeia was fed upon by many fish species, including the commercially important lake whitefish, and forage fish such as alewife, bloater, and sculpin that serve as prey for larger piscivores (salmon, trout) (Scott and Crossman 1973, Wells 1980). Recent disappearance of the Benthic Amphipod, Diporeia spp., in the Great Lakes: spatial patterns, potential causes, and ecological implications That contrasted with an alewife who was based in Foregate Street, an area of the town filled with drinking establishments - in the late 1480s, there were 21 brewers and 33 places that sold ale. Restoration of the Alewife | Natural History Magazine Restoration of the Alewife By Clinton B. Townsend Visitors observe alewives congregating in the historic Damariscotta Mills fish ladder that is undergoing restoration in Nobleboro, Maine. In the spring of 2012 more than 400,000 alewives passed through the ladder, located about sixteen miles inland from the Gulf of Maine, on their annual spawning migration to Damariscotta Lake.

AP Photo/Råobert F. Bukaty Before 1492, there was probably not a waterway in eastern North America that did not support great runs of alewives, a species of herring that is anadromous, that is, is born in freshwater, spends most of its life in the sea, and returns to freshwater to spawn. Aboriginal people feasted on them, as shown by fish bones found in ancient fire pits and middens dating as far back as 4,000 years. In historical times alewives have ranged from South Carolina to Labrador (in Canada they are known as gaspereaux). The species (Alosa pseudoharengus) is one of the most important members of the herring clan, part of a large family of fish, collectively known as Clupeidae, that are widely distrib­uted in both fresh and salt water. Other members of the East Coast “river herring” division include the closely related blueback herring (A. aestivalis)—even experts find it difficult to tell the species apart—as well as the larger American shad (A.

sapidissima), made famous by John McPhee as “The Founding Fish.” An osprey makes off with an alewife Dave Maher Feeding primarily on the tiny invertebrate organisms known as zooplankton, alewives seldom grow more than twelve inches long at ma­turity, which males generally reach at age four and females at age five. What they lack in size they make up in numbers. Adults and juveniles are eaten by almost every living creature that shares their environment. In the sea, they are an important part of the prey base for resident groundfish (fish that live on, in, or near the bot­tom) such as cod and haddock, as well as for transient migrants such as striped bass, bluefish, and tuna. They are pursued by marine mammals, including seals, dolphins, porpoises, and whales. In their spring migra­tions into rivers to spawn, the mature adults are eaten by gulls, ospreys, and eagles. The juveniles migrating out to the ocean in the summer and fall are consumed by resident fish, birds, and mammals. River herring enter rivers to spawn on a time gradient from March in the southern part of the range to June in Canada.

Alewives typically are the first to arrive, followed by blueback herring and American shad. From the earliest colonial times, alewives have been economically important. With their high fat content, their arrival when other food stocks were low made them valuable as a food source, eaten fresh or salted and smoked. In New England, many coastal communities provided free alewives to their poor or elderly citizens. There was a flourishing trade in smoked salted alewives sent to the West Indies to feed the slave populations of the “sugar islands” of the Caribbean. In Maine, alewives are widely used as lobster bait, particularly in the spring when other bait supplies are low. But from Colonial times to the present day, the biological riches of the Atlantic seaboard have been under assault through overfishing on marine and anadromous stocks, the erection of dams without fish passage, and pollution from the dis­charge of municipal and industrial wastes. None of those problems went unnoticed. There are numerous re­cords documenting the loss of anadromous fisheries, dating back almost 300 years. Hundreds of petitions were made to governing authorities setting forth the dismay and outrage of citizens at the wanton destruction of resources upon which they were dependent for a livelihood.

Yet by and large, preventing the losses received only lip service. The frontier mentality that a resource lost in one location might yet be found just over the horizon pervad­ed the eighteenth, nineteenth, and early twentieth centuries. Foresight­ed people failed to stem the tide be­cause of lack of public support and a mindset that considered resource de­struction in the name of “progress” to be inevitable and acceptable. By the middle of the twentieth century, most anadromous fish runs in the rivers flowing to the Atlantic Ocean had been wiped out. Many groundfish stocks, such as cod and haddock, were reduced from overfishing and from the loss of the forage base furnished by juvenile anadromous fish. After the end of World War II in 1945, things began to change. The United States had become the world’s greatest industrial power. An era of prosperity set in. At the same time, it was increasingly clear that the price of prosperity in terms of harm to water, air, wildlife, and human health was high and growing higher.

In the decades between 1950 and 1980, great strides were made toward understanding the collateral consequences of industrialization and establishing a framework to address them. At the federal level, the National Marine Fisheries Service (NMFS), part of the National Oceanic and Atmospheric Administration in the Department of Commerce, was charged with management of the nation’s coastal and offshore waters and the species that inhabit them. It was given the legal tools and funding to start restoration of lost or depleted marine and anadromous fishery resources. The federal restoration of anadromous fisheries was specifically mandated by the Anadromous Fish Conservation Act of 1965. States were encouraged to develop the political structure to deal with fishery issues, in the belief that operating within the overall framework of federal legislation, each state could best identify its own needs and could best develop the processes appropriate for dealing with its own fish stocks. Significant federal funds were made available to that end. Each state has an agency responsible for setting and enforcing the regulations necessary to manage fisheries in its coastal waters. The Atlantic States Marine Fisheries Council plays a coordinating role between the federal agencies and the states.

Fishery managers have learned to think in terms of ecosystem management rather than single species management, because, as John Muir pointed out more than a century ago, “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” For one thing, restoration of depleted groundfish and migratory fish populations is dependent upon an adequate forage base for the species, available either year round or seasonally. Alewives are a major part of the underpinning for marine and freshwater ecosystems. Another critical role for alewives is as a buffer for other species against predation. As an example, it is no coincidence that juvenile Atlantic salmon (known as smolts) migrate downriver to the sea at the same time that adult alewives migrate upriver to spawn. Since there are many more alewives than smolts, any given Atlantic salmon smolt has a better chance of avoiding being eaten by a hungry osprey, cormorant, or seal than it would have if migrating in isolation. So those people who are in charge of restoring Atlantic salmon are also busily restoring alewives. Unfortunately, despite more than forty years of effort, alewife populations from southern New England to the Carolinas remain severely depleted.

In Canada, the federal agency Fisheries and Oceans Canada (DFO) has documented similar declines of alewives in the Maritime Provinces. Many states from Massachusetts to North Carolina have imposed moratoriums on the harvest of alewives. The NMFS listed alewives as a “Species of Concern” in 2006. And last year, a petition was filed by the Natural Resources Defense Council seeking listing of alewives as a threatened species under the federal Endangered Species Act. The Maine Department of Marine Resources (DMR) has been working at restoring alewife populations for more than forty years. Even so, the restoration program has had its share of controversy. Although alewives are a native species, they are seen in some quarters as undesirable intruders. There is no better example of this conflict than the St. Croix River, which forms the boundary between the United States and Canada. That river has the potential to host the return migration of up to 25 million spawning alewives. In 1985, as the result of DMR efforts, 2.5 million fish were entering the system.

Then a raging controversy arose because certain local angling guides who favor nonnative smallmouth bass thought that alewives were responsible for a population crash of bass. In fact, a series of dry years and massive drawdowns (for hydroelectric power generation) of impounded lake waters along the St. Croix destroyed shallow-water bass spawning beds. But it was easier to accuse alewives than to take on a major economic force in the region. Alewives were called evil predators, even likened to piranhas, in testimony and debate within the Maine legislature, despite the fact that they are plankton eaters. In 1995—over the opposition of state and federal fishery managers, the Canadian federal government, and the New Brunswick provincial government—the Maine legislature enacted a statute barring alewives from access to the fish passage facilities at the two lowest dams on the St. Croix River. In 2007, Maine Rivers, an independent advocacy organization, issued a study of the interaction between alewives and smallmouth bass that showed definitively that plankton-eating alewives are not detrimental to piscivorous smallmouth bass at any life stage, and in fact all life stages of smallmouth bass thrive on a diet of alewives.

The following year the statute was amended to allow access through the lower of the two dams, but the small area to which alewives were granted access is low-quality habitat and amounts to only about 2 percent of their historic range in the St. Croix system. The result has been a population crash; in some years fewer than 1,000 fish returned. Meanwhile, from 2001 to 2007, the Canadian DFO resorted to trapping alewives below the dams and trucking them upriver. That is probably the reason that there are any alewives in the system at all. The battle to restore alewives to the St. Croix has raged in the Maine legislature and before the International Joint Commission created by the 1909 Boundary Waters Treaty between the United States and Canada, and it continues in the courts. A recent filing by the Conservation Law Foundation in the United States District Court for the District of Maine asserts that the exclusion of native alewives from their natural habitat is a violation of the Federal Clean Water Act.

In latebreaking news, on July 10, in a landmark letter to the Attorney General of Maine, the Environmental Protection Agency’s Office of Ecosystem Protection agreed, finding that the artificial exclusion of alewives, a native species, has indeed “caused the habitat to be degraded.” Since there is no known “sound scientific rationale” for such exclusion, the EPA instructed Maine authorities to “take appropriate action to authorize passage of river herring” farther up the St. Croix. The next move is Maine’s. In other areas, the state of Maine has already experienced the benefits of alewife restoration, overcoming the irrational prejudice against the river herring. Many Maine lakes suffer from summertime algal blooms, making them unattractive to cottage owners. The real cause of these blooms is lack of proper sewage disposal systems and the fertilizing of lawns too close to the water, resulting in too much phosphorus in the lakes, and consequent eutrophication. Because adult alewives bring in a certain amount of “marine-derived nutrients” to the lakes, many lake associations have accused alewives of being the cause of algal blooms, and many water districts using lakes as their water source have opposed alewife restoration for the same reason.

Fortunately, recent studies have shown that in fact juvenile alewives are net exporters of phosphorus out of the lakes. At Sebasticook Lake in the Kennebec River drainage, a lake long notorious for algae, blooms have sharply diminished in recent years following alewife introductions. The Kennebec Water District, which draws drinking water from China Lake, has recently reversed its position and is actively supporting alewife restoration in that lake. Nevertheless, old habits die hard, and there are still those to whom alewife restoration is anathema. There have been successes in Maine rivers as well. The removal of the Edwards Dam from the Kennebec River in 1999, followed a decade later by removal of the Fort Halifax Dam at the mouth of the Sebasticook River, a major tributary, has led to the rejuvenation of the anadromous fisheries of that system, including alewives and shad. The Kennebec River currently has the largest run of alewives on the eastern seaboard, estimated at more than 3 million fish in 2012, with the potential to triple that number when alewives gain access to all the lakes that constituted their historic habitat.

The Great Works Dam, one of two lower dams being dismantled on the Penobscot River, was breached on June 23, 2012. It was a milestone moment in the Penobscot River Restoration Project, a comprehensive effort to open up habitat for alewives and other anadromous fish (those that migrate to and from the sea) while maintaining or even increasing hydropower production. Penobscot River Restoration Trust At the Penobscot River, the restoration of eleven species of anadromous fish, including Atlantic salmon, shad, alewives, and sturgeon, is the goal of removal of two dams in the lower river. This unique $60 million project is supported by the Penobscot River Restoration Trust, a consortium comprising American Rivers, the Atlantic Salmon Federation, Maine Audubon, the Natural Resources Council of Maine, The Nature Conservancy, Trout Unlimited, and the Penobscot Indian Nation, as well as DMR, NMFS, and the U.S. Fish and Wildlife Service and other partners. It will open up more than 1,000 miles of river habitat.

It is thought that several million alewives will return to spawn when the project reaches its full potential. The Great Works Dam, one of two dams being dismantled, was breached on June 23, 2012. In addition, there are dozens of smaller Maine coastal river systems that have existing alewife runs or the potential for future runs. Many Maine communities have retained the right, dating back to colonial times, to license the harvesting of alewives in the rivers that pass through them. The thousands of dollars the licenses bring in annually go to support the municipal governments. Other river communities are looking at the potential for licensing fees when alewife runs increase to the point where local harvest is environmentally and economically sound. Every dollar raised from licensing alewife harvest is a dollar that does not need to be raised by taxation. Once Maine’s river systems achieve their full potential for alewife production, spawning runs are expected to be in the range of 50 million fish annually. It has been estimated that each spawning female can produce as many as 1,000 juvenile alewives that survive to migrate to the sea (and surviving adults may return to spawn for several years). That translates into 50 billion fish added to the marine forage base.

Only two in 1,000 need to survive to spawn in order to maintain a self-sustaining run. The other 998 are available to be eaten by groundfish and migratory fish species, birds, marine mammals, and other predators. It is this extreme fecundity that makes the alewife such an important component of the forage base for all the creatures that depend upon it for their own continued existence. The result of reestablishing alewives and the commercial ground fisheries of the Gulf of Maine will be the revitalization of currently impoverished coastal communities and the recovery of a way of life deeply rooted in history. Today only a shrunken population of commercial fishermen eke out a difficult living while facing a mind-numbing set of rules that limit their number of days at sea, types of gear, and the timing and location of their efforts. That could change with the restoration of a viable commercial groundfish industry. In that regard, the tiny alewife can play not only an important biological role, but a sociological and economic one as well.

Illustration of an alewife prepared as part of the 1927–1940 New York Biological Survey conducted by the Conservation Department (the predecessor of today’s New York State Department of Environmental Conservation) Ellen Edmonson and Hugh Chrisp/Provided by New York State Department of Environmental Conservation Recent Stories alewife | fish | Britannica.com Alewife Alternative Titles: Alosa pseudoharengus, branch herring, gaspereau, grayback, Pomolobus pseudoharengus, sawbelly Similar Topics bristling Alewife, also called sawbelly, grayback, gaspereau, or branch herring, (Pomolobus, or Alosa, pseudoharengus), important North American food fish of the herring family, Clupeidae. Deeper-bodied than the true herring, the alewife has a pronounced saw-edge on the underside; it grows to about 30 cm (1 foot). Except for members of a few lake populations, it spends several years along the Atlantic coast of North America before ascending freshwater streams (possibly the parent stream) to spawn each spring in ponds or sluggish rivers. Alewives entered the Great Lakes through the St.

Lawrence Seaway and the Welland Canal . In the 1960s they multiplied so rapidly that they became a nuisance, threatening the native fishes by competing for the same food sources. Importation of coho and king salmon brought the alewife population into balance in the Great Lakes in the 1970s. Alewife (Alosa pseudoharengus), Montrose Harbor, Lake Michigan, … © Rich Pallardy Welland Canal waterway in southern Ontario, Can., that provides navigation for large vessels between Lake Erie to the south and Lake Ontario to the north and forms an important link in the St. Lawrence Seaway. The canal was necessary because the Niagara River, the natural connection between Lakes Erie and... coho (Onco rhyn chus kisutch), species of salmon, family Salmonidae, prized for food and sport. The coho may weigh up to 16 kg (35 pounds) and is recognized by the small spots on the back and upper tail-fin lobe. Young coho stay in fresh water for about one year before entering North Pacific waters;...

chinook salmon (Oncorhynchus tshawytscha) prized North Pacific food and sport fish of the family Salmonidae. It weighs up to 60 kg (130 pounds) and is silvery with round black spots. Spawning runs occur in spring, adults swimming as far as 3,200 km (2,000 miles) up the Yukon. Young chinook salmon do not enter the... 2 References found in Britannica Articles Assorted References Corrections? Updates? Help us improve this article! Contact our editors with your feedback. MEDIA FOR: You have successfully emailed this. Error when sending the email. Try again later. Edit Mode Submit Tips For Editing We welcome suggested improvements to any of our articles. You can make it easier for us to review and, hopefully, publish your contribution by keeping a few points in mind. Encyclopædia Britannica articles are written in a neutral objective tone for a general audience. You may find it helpful to search within the site to see how similar or related subjects are covered. Any text you add should be original, not copied from other sources.

At the bottom of the article, feel free to list any sources that support your changes, so that we can fully understand their context. (Internet URLs are the best.) Your contribution may be further edited by our staff, and its publication is subject to our final approval. Unfortunately, our editorial approach may not be able to accommodate all contributions. Submit Thank You for Your Contribution! Our editors will review what you've submitted, and if it meets our criteria, we'll add it to the article. Please note that our editors may make some formatting changes or correct spelling or grammatical errors, and may also contact you if any clarifications are needed. Uh Oh There was a problem with your submission. Please try again later. Close Date Published: May 31, 2016 URL: Access Date: January 19, 2017 Share Alewife Alewife by Ethan Nedeau In the recreational anglers' hierarchy of fishes, the alewife, Alosa pseudoharengus, is situated somewhere between the white sucker and creek chub. Bait.

Sure, you can eat them during lean times, and maybe the old hands will wax poetic about smoked and salted alewife, but nowadays the fish are likely to be used for pet food, fertilizer or lobster bait. Yet their importance may be far greater than most of our other native fishes. Alewives bring an enormous influx of marine-derived nutrients to freshwater ecosystems. They are a forage fish for many predators and they are the only known host for the freshwater mussel Anodonta implicata, the alewife floater. Alewives were once a prominent-albeit seasonal-member of the native fish community in Atlantic coastal watersheds. They traversed streams from South Carolina to Newfoundland, seeking spawning areas in lakes, ponds and slow-moving portions of rivers. Small coastal ponds might have supported a few thousand fish, whereas a large watershed such as the Penobscot River could have supported tens of millions. Today, some rivers still support abundant populations of spawning alewives, yet man-made obstructions and pollution confine alewives to a small percentage of their ancestral spawning areas. In the St. Croix River watershed, alewives historically swam into Spednic Lake.

Scientists estimate that the watershed might have supported 14 to 38 million spawning alewives and their anadromous look-alike, the blueback herring, Alosa aestivalis. Collectively, these two species are called river herring, or gaspereau. After closure of the Vanceboro dam in 1987, the Grand Falls Dam in 1991 and the Woodland Dam in 1995, nearly the entire watershed was inaccessible to these fish, and in 2002 only 900 river herring returned from the sea to spawn. Spawning alewives present nutrients to freshwater ecosystems in the form of eggs, excreted materials and their dead and decaying bodies. Each female produces 60,000 to 467,000 eggs annually and may spawn up to seven or eight years in her lifetime. In a single lake, billions or trillions of eggs, as well as a huge volume of sperm, may be released into the water each spring-essentially "protein packets" for aquatic animals such as zooplankton, bryozoans, clams and insect larvae.

The alewives that die before returning to the sea, which may be 25 percent of the spawning population in the Northeast U.S., but greater than 75 percent of the population in mid-Atlantic watersheds, are eaten by scavengers such as crayfish, turtles, eels, raccoons, gulls and bald eagles. Ospreys, bald eagles, cormorants and great blue herons prey heavily on migrating alewives each spring, at a time when some of these birds are nesting and rearing their chicks. In polluted rivers, organic chemicals and heavy metals (such as PCBs, dioxin and mercury) bioaccumulate in the tissues of resident fish, and these toxins are then passed to birds that consume them. Alewives are a healthier prey item for fish-eating birds than resident freshwater fish because they have not accrued these toxins in their bodies. Thus, a large alewife run will help to curtail the harmful effects of biomagnification on fish-eating birds. Some anglers worry that anadromous alewives might have a detrimental effect on sport fisheries, but nothing could be further from the truth.

Adult anadromous alewives do not compete with freshwater fish because they essentially stop feeding during the migration and spawning period, and do not resume feeding until they reach brackish water on their way back to sea. Since alewives are planktivores, the vast majority of their food is zooplankton, small crustaceans and insect larvae. Even at sea, fish comprise a miniscule proportion of an alewife's diet. One 1994 study published in the Fishery Bulletin, examined 1,215 alewife stomachs and found that larval fish represented only 1.4 percent by volume of total prey items. Migratory alewives and their offspring are key forage for fish predators. Striped bass, northern pike, pickerel and lake trout are among the fish that consume adult alewives in freshwater or estuaries, in addition to the large number of predators in the marine environment. Striped bass will follow migrating alewives for many miles up estuaries and rivers, providing a recreational fishery in May and June.

Some scientists have speculated that damming of coastal rivers contributed to the collapse of the cod fishery in the Gulf of Maine by reducing the abundance of alewives, one of the cod's principal prey items. Restoration of pelagic and groundfish stocks in the Gulf of Maine would likely benefit from restoration of alewife populations. Young-of-the-year alewives present a spring, summer and fall picnic for our important game fish. They live in freshwater for three to seven months and grow two to five inches before descending the watershed and entering the ocean. They are eaten by many fish such as perch, bass, salmon and trout. In studying both blueback herring and alewife in Massachusetts coastal lakes, scientists determined that Alosa was the most important fish prey consumed by largemouth bass (based on number in individuals consumed), and that Alosa are an energy-rich prey that provide a high growth potential for largemouth bass.

The scientists concluded that "Our simulations show that the presence of 'trophy' largemouth bass found in southeastern, coastal Massachusetts was not solely related to water temperature across the state but rather was related to predator diet and, specifically, to the presence of anadromous herring in largemouth bass diets." The freshwater mussel connection Freshwater mussels are large bivalved molluscs, superficially resembling a marine quahog, which inhabit large permanent waterbodies throughout North America. They are one of the most endangered groups of animals on Earth. In North America alone, nearly 75 percent of the 297 native species are listed officially as Special Concern, Threatened or Endangered in all or parts of their range, including eight of the thirteen species native to coastal New England and the Canadian Maritime provinces. The larvae of freshwater mussels are obligate fish parasites. Female mussels release larvae into the water, where they must find a suitable host fish and attach to its fins or gills. Mussels are often specific about the fish they can parasitize, and if environmental factors change the abundance or availability of the host fish, then mussel reproduction is compromised.

The alewife is the only known vertebrate host for the freshwater mussel Anodonta implicata (alewife floater), though the blueback herring and American shad, Alosa sapidissima, are also suspected hosts. The alewife floater is often abundant in Atlantic coastal rivers and lakes, and its distribution is closely tied to, and dependent upon, the alewife. If a dam blocks alewives from reaching historical spawning grounds, then the alewife floater will go extinct in upstream areas. Some evidence suggests that the alewife floater was extirpated in several coastal watersheds in the last four centuries. For example, it is noticeably absent in rivers and lakes of southern coastal Maine, where dams were built as early as 1634. Anadromous fish migrations were halted decades and even centuries before scientists could document fish or mussel populations in some watersheds.

A quotation from the 1867 Fish Commissioner's Report, referring to salmon in the Saco River, is particularly telling: "We could obtain no estimate of their numbers in former times, as they had ceased to be plenty beyond the recollection in the present generation." Freshwater mussels are filter feeders that remove large amounts of algae, zooplankton, bacteria and sediments from the water. Scientists have estimated that freshwater mussels in the tidal Hudson River filtered 5.3 million gallons of water per day! Mussels store enormous amounts of nutrients and minerals in their tissues and shells, such as carbon, nitrogen, potassium and calcium. Freshwater mussels usually comprise the greatest proportion of animal biomass in aquatic systems, far outweighing all other animals combined, including fish. They are a food item for suckers, sturgeon and catfish, as well as mammals such as otters, muskrats and raccoons. Mussels are sensitive to environmental changes and pollution, and are ideal biomonitors for assessing the health and recovery of aquatic ecosystems. Elimination of alewives will eliminate these many services that the alewife floater provides.

The productivity, diversity and health of coastal freshwater habitats depend in part on an unimpeded spring migration of alewives, and in the same way, the Gulf of Maine depends on an unimpeded summer and fall migration of alewives back to the ocean to fuel marine food webs. By blocking and degrading the conduits that connect headwaters to the sea, we have severed the two-way flow of energy between the ocean and its watershed. It is difficult to imagine how any creatures-from mussels living in our lake and river bottoms, to striped bass that follow alewives from sea to rivers, to eagles and cormorants that gather at spawning rivers each spring in hungry anticipation of Alosa-have not been affected by the disruption of alewife reproduction in the Gulf of Maine. Restoration of alewives will involve removing dams or installing better-designed fishways that allow both upstream and downstream passage, dealing with pollution problems and maintaining adequate stream flow. This article was reprinted with permission from the summer 2003 issue of the Gulf of Maine Times (find at: Ethan Nedeau is a science translator for the Gulf of Maine Council on the Marine Environment. He can be reached at ejnedeau@attbi.com.

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Question: What type of creature is an alewife?
Answer: Fish