Alosa aestivalis (Mitchill, 1814)

Common Name: Blueback Herring

Synonyms and Other Names:

blueback shad, river herring

Duane Raver, US Fish and Wildlife ServiceCopyright Info

Identification: This fish is silvery in color, has a series of scutes (modified scales that are spiny and keeled) along its belly, and is characterized by deep bluish green backs. The most distinguishing characteristic of this species is the black to dusky in color of its peritoneum (the lining of the abdominal cavity). Blueback Herring and Alewife are difficult to distinguish from one another and are often regarded collectively as river herring. Alewife has larger eyes, greater body depth, and pearly to white peritoneal linings. Jenkins and Burkhead (1994); Owens et al. (1998); Page and Burr (1991); Smith (1985); Whitehead (1985). Comparisons between morphological and genetic identification methods found that identification between Blueback Herring and Alewife may be incorrect up to 16% of the time when using morphological methods alone (Kan et al., 2017).

Size: 40 cm

Native Range: Atlantic Coast from Cape Breton, Nova Scotia, to the St. Johns River, Florida. Ascends coastal rivers during spawning season (Page and Burr 1991).

Great Lakes Nonindigenous Occurrences: Blueback Herring was first collected in Lake Ontario in 1995 (Owens et al., 1998). They are established in Oneida Lake, the Oswego River in Minetto, Lake Champlain, and the upper Mohawk River upstream of Cohoes Falls, New York (Greeley 1935; Limburg et al. 2001; D. MacNeill and R. Owens, personal communication). Blueback Herring have been collected from Lake Champlain, Vermont (S. Good, personal communication).

Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Alosa aestivalis are found here.

Full list of USGS occurrences

State/ProvinceYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
New York197819954Lake Champlain; Lake Ontario; Oneida; Oswego
Vermont199719971Lake Champlain

Table last updated 9/30/2019

† Populations may not be currently present.

Ecology: Anadromous; living in marine systems and spawning in deep, swift freshwater with a hard substrate. Migrate to spawning grounds in the spring. In Connecticut, Blueback Herring spawn in 14–27oC temperatures. Usually spawns later in the spring than Alewife, when water temperatures are slightly warmer. During spawning, many eggs are deposited over the stream bottom where they stick to gravel, stones, logs, or other objects. Juveniles spend 3–7 months in freshwater, then migrate to the ocean (Yako et al. 2002). Blueback Herring are a planktivorous forage species (Winkelman and Van Der Avyle 2002).

The landlocked Lake Theo, Texas population attained a smaller maximum size and had a shorter life span than anadromous native populations (Schramm et al. 1991).

Means of Introduction: In most areas other than New York, these fish were intentionally stocked for forage. In New York these fish are expanding their range using ship locks and canals. Blueback Herring was first recorded in the Mohawk River upstream of Cohoes Falls in 1934 (Greeley 1935). They were reported from Lake Champlain on the New York side in the late 1970s, and from the Vermont side in 1997. Juveniles were apparently present in Oneida Lake by 1981 or 1982. Adults were first documented in 1994 by Cornell researchers based at Shackleton Point. Several thousand immature fish were also documented in 1994 at a power plant in Minetto on the Oswego River. Two immature fish caught in Lake Ontario near Oswego in October 1995 by were likely introduced by swimming up the Lake Erie Barge canal which connects Lakes Champlain and Ontario to the Mohawk-Hudson Rivers within the Blueback Herring’s native range (Owens et al., 1998). Blueback Herring in Jocassee and Keowee Reservoirs, South Carolina, were accidentally included in Threadfin Shad (Dorosoma petenense) stockings in 1972 and 1974 (Prince and Barwick 1981); the population in Lake Murray, SC, is likely the result of a bait bucket introduction.

Status: Established in New York, North Carolina, South Carolina, Tennessee, Vermont, and Virginia. Extirpated in Texas.

Great Lakes Impacts: Current research on the environmental impact of Alosa aestivalis in the Great Lakes is inadequate to support proper assessment.

The impact of blueback herring in Lake Ontario is largely unknown. 

This species is very likely to find suitable habitat throughout the Great Lakes system. GARP models predict it could find the entire region as suitable habitat, except possibly the deeper waters of Lake Superior (USEPA 2008).

If blueback herring became established throughout Lake Ontario and/or spread to other Great Lakes, it could impede recovery of depressed populations of native fishes such as cisco and lake trout (Owens et al. 1998). There is also speculation that blueback herring could displace rainbow smelt and/or native forage fishes (Marsden and Hauser 2009).

The introduction of blueback herring into Theo Reservoir in Briscoe County, Texas resulted in the elimination of large-bodied zooplankton such as Leptora sp., Epischura sp., Mesocyclops sp., and Daphnia sp., while small-bodied zooplankton such as Ceriodaphnia sp., Tropocyclops sp., and Bosmina sp. increased. There appeared to be little change in lengths of the zooplankton in the reservoir after herring introduction, but the community shifted from cladoceran to copepod dominance (Guest and Drenner 1991).

There is little or no evidence to support that Alosa aestivalis has significant socio-economic impacts in the Great Lakes.

There is little or no evidence to support that Alosa aestivalis has significant beneficial effects in the Great Lakes.

One study in headwater lakes of Massachusetts indicates that this is a beneficial prey item for largemouth bass (Micropterus salmoides) introduced near the blueback’s native range (Yako and Mather 2000).


Regulations (pertaining to the Great Lakes region)
New York, under federal law, is required to follow the Interstate Fishery Management Plan for Shad and River herring established by the Atlantic States Marine Fisheries Commission (Enacted May 2009; ASMFC) and therefore are forced to close any non-sustainable commercial and recreational fisheries by January 1, 2012 until the Department can prove NY fisheries are self-sustaining (NYDEC 2012). Management plans are still in review and final amendments for each NY fisheries is unknown.   New York restricts the use of anadromous river herring (including blueback) as bait in most waters (6 NYCRR Part 19).  While not listed by name, in Ohio it is illegal for any person to possess, import or sell exotic species of fish (including Alosa aestivalis) or hybrids thereof for introduction or to release into any body of water that is connected to or otherwise drains into a flowing stream or other body of water that would allow egress of the fish into public waters, or waters of the state, without first having obtained permission (OAC Chapter 1501:31-19).

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Most management research relating to Alosa aestivalis appears focused on maintaining populations within the native range.  Little species-specific information is available on how to control this species where it is invasive.

There are no known biological control methods for this species.   Top-down control by salmonids is effective for the related species Alosa pseudoharengus.

There are no known physical control methods for this species.  

Of the four chemical piscicides registered for use in the United States, antimycin A and rotenone are considered “general” piscicides, but no studies have been found of their effects on Alosa aestivalis (GLMRIS 2012).

Increasing CO2 concentrations, either by bubbling pressurized gas directly into water or by the addition of sodium bicarbonate (NaHCO3) has been used to sedate fish with minimal residual toxicity, and is a potential method of harvesting fish for removal, though maintaining adequate CO2 concentrations may be difficult in large/natural water bodies (Clearwater et al. 2008). CO2 is approved only for use as an anesthetic for cold, cool, and warm water fishes the US, not for use as euthanasia, and exposure to NaHCO3 concentration of 142-642 mg/L for 5 min. is sufficient to anaesthetize most fish (Clearwater et al. 2008).

It should be noted that chemical treatment will often lead to non-target kills, and so all options for management of a species should be adequately studied before a decision is made to use piscicides or other chemicals. Potential effects on non-target plants and organisms, including macroinvertebrates and other fishes, should always be deliberately evaluated and analyzed. The effects of combinations of management chemicals and other toxicants, whether intentional or unintentional, should be understood prior to chemical treatment.  Other non-selective alterations of water quality, such as reducing dissolved oxygen levels or altering pH, could also have a deleterious impact on native fish, invertebrates, and other fauna or flora, and their potential harmful effects should therefore be evaluated thoroughly.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.

Remarks: One of the most common fish species in the Hudson River estuary (Hurst et al. 2004). Detection of a small population of Blueback Herring in Lake Ontario would be difficult because of the size of the Lake relative to the area routinely sampled and the herring's superficial similarity with Alewife, a fish sampled in large enough numbers that only a fraction of the adults are examined closely enough to distinguish between the two species (Owens et al. 1998). Owens et al. (1998) also asserted that colonizing a lake with resident population of Alewife, a fish that would be in direct competition with Blueback Herring for space and resources, and a surfeit of piscivores, both stocked and unstocked, may prove too difficult for A. aestivalis.

References: (click for full references)

Clearwater, S.J., C.W. Hickey, and M.L. Martin. 2008. Overview of potential piscicides and molluscicides for controlling aquatic pest species in New Zealand. Science & Technical Publishing, New Zealand Department of Conservation, Wellington, New Zealand.

Christmas, J., R. Eades, D. Cincotta, A. Shiels, R. Miller, J. Siemien, T. Sinnott, and P. Fuller. 2000. History, management, and status of introduced fishes in the Chesapeake Bay basin. Proceedings of the Conference of Biological Diversity, May 10-13, 1998. Annapolis, MD.

GLMRIS. 2012. Appendix C: Inventory of Available Controls for Aquatic Nuisance Species of Concern, Chicago Area Waterway System. U.S. Army Corps of Engineers.

Good, S. - Vermont Department of Fish and Wildlife, Pittsford, VT.

Greeley, J.R. 1935. Fishes of the watershed with an annotated list. Pages 63-101 in Moore, E. (ed.). A biological survey of the Mohawk-Hudson watershed. Supplemental to the 24th annual report of the New York State Conservation Department. Albany, NY.

Guest, W.C. 1983. Blueback herring evaluation. Federal Aid Project F-31-R-9.

Guest, W.C., and R.W. Drenner. 1991. Relationship between feeding of blueback herring and the zooplankton community of a Texas reservoir. Hydrobiologia 209(1):1-6.

Howells, R.G. 1992. Annotated list of introduced non-native fishes, mollusks, crustaceans and aquatic plants in Texas waters. Texas Parks and Wildlife Department, Management Data Series 78, Austin, TX. 19 pp.

Hurst, T.P., K.A. McKown, and D.O. Conover. 2004. Interannual and long-term variation in the nearshore fish community of the mesohaline Hudson River Estuary. Estuaries 27(4):659-669.

Jenkins, R.E., and N.M. Burkhead. 1994. Freshwater fishes of Virginia. American Fisheries Society, Bethesda, MD.

Kan, C, J. Lichter, V. Douhovnikoff. 2017. Genetic population structure and accuracy of morphological assessment in Alosa aestivalis (Blueback Herring) and A. pseudoharengus (Alewife). Northeastern Naturalist 24(4):483-498

Limburg, K.E., I. Blackburn, R. Schmidt, T. Lake, J. Hasse, M. Elfman, and P. Kristiansson. 2001. Otolith microchemistry indicates unezpected patterns of residency and anadromy in blueback herring, Alosa aestivalis, in the Hudson and Mowhawk rivers. Bulletin Français de la Pêche et de la Pisciculture 362-363:931-938.

MacNeill, D. - New York Sea Grant, State University of New York at Brockport, Brockport, NY.

Marsden, J.E., and M. Hauser. 2009. Exotic species in Lake Champlain. Journal of Great Lakes Research 35(2):250-265.

Menhinick, E.F. 1991. The Freshwater Fishes of North Carolina. North Carolina Wildlife Resources Commission. 227 pp.

Negus, J. - Tennessee Wildlife Resources Agency, Morristown, TN.

New York State Depertment of Environmental conservation (NYDEC). 2012. NY River herring management. Accessed 29 July 2012.

Owens, R. - U.S. Geological Survey, Oswego, NY.

Owens, R.W., R. O'Gorman, E.L. Mills, L.G. Rudstam, J.J. Hasse, B.H. Kulik, and D.R. MacNeill. 1998. Blueback herring (Alosa aestivalis) in Lake Ontario: First record, entry route, and colonization potential. Journal of Great Lakes Research 24(3):723-730.

Page, L.M., and B.M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. The Peterson Field Guide Series, volume 42. Houghton Mifflin Company, Boston, MA.

Prince, E.D., and D.H. Barwick. 1981. Landlocked Blueback Herring in two South Carolina reservoirs: reproduction and suitability as stocked prey. North American Journal of Fisheries Management 1(1):41-45.<41:LBHITS>2.0.CO;2.

Rohde, F.C., R.G. Arndt, J.W. Foltz, and J.M. Quattro. 2009. Freshwater fishes of South Carolina. University of South Carolina Press, Columbia, SC.

Schramm, H.L., Jr., G.A. Conley, and W.C. Guest. 1991. Age and growth of a landlocked population of blueback herring and management implications. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 45:323-332.

Smith, C.L. 1985. The Inland Fishes of New York State. New York State Department of Environmental Conservation, Albany, NY. 522 pp.

U.S. Environmental Protection Agency (USEPA). 2008. Predicting future introductions of nonindigenous species to the Great Lakes. EPA/600/R-08/066F. National Center for Environmental Assessment, Washington, DC, 138 pp.

Whitehead, J.P. 1985. FAO Species Catalogue. Vol. 7. Clupeoid Fishes of the World (Suborder Clupeoidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, anchovies and wolf-herrings. Part 1 - Chirocentridae, Clupeidae and Pristigasteridae. FAO Fisheries Synopsis (125) Vol. 7, Pt. 1:303 pp.

Winkelman, D.L., and M.J. Van Der Avyle. 2002. A comparison of diets of blueback herring (Alosa aestivalis) and threadfin shad (Dorosoma petenense) in a large southeastern reservoir. Journal of Freshwater Ecology 17(2): 209-221.

Yako, L.A., and M.E. Mather. 2000. Assessing the contribution of anadromous herring to largemouth bass growth. Transactions of the American Fisheries Society 129(21):77-88.

Yako, L.A., M.E. Mather, and F. Juanes. 2002. Mechanisms for migration of anadromous herring: An ecological basis for effective conservation. Ecological Applications 12(2): 521-534.

Author: Fuller, P., G. Jacobs, J. Larson, A. Fusaro, and M. Neilson

Contributing Agencies:

Revision Date: 9/12/2019

Peer Review Date: 6/26/2014

Citation for this information:
Fuller, P., G. Jacobs, J. Larson, A. Fusaro, and M. Neilson, 2020, Alosa aestivalis (Mitchill, 1814): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI,, Revision Date: 9/12/2019, Peer Review Date: 6/26/2014, Access Date: 2/27/2020

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.