Menhaden

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Menhaden

Gulf menhaden, Brevoortia patronus
Atlantic menhaden, Brevoortia tyrannus
Pacific menhaden, Ethmidium maculatum

A menhaden, also known as mossbunker, bunker, and pogy, is any forage fish of the genera Brevoortia and Ethmidium, two genera of marine fish in the family Clupeidae. "Menhaden" derives from a Native American word for fertilizer.[1] It is generally thought that Pilgrims were advised by Squanto to plant the fish with their corn crops.[1]

Physical characteristics

Gulf menhaden and Atlantic menhaden are small oily-fleshed fish, bright silver and characterized by a series of smaller spots behind the main, Humeral spot. They tend to have larger scales than Yellowfin menhaden and Finescale menhaden. Menhaden are flat, have soft flesh, and a deeply forked tail. In addition, Yellowfin menhaden tail rays are a bright yellow in contrast to those of the Atlantic menhaden. Menhaden's maximum length is 15 inches with a varied weight range.

Taxonomy

This article is
one of a series on
Commercial fish
Large pelagic
billfish, bonito
mackerel, salmon
shark, tuna

Forage
anchovy, herring
menhaden, sardine
shad, sprat

Demersal
cod, eel, flatfish
pollock, ray
Mixed
carp, tilapia

Recent taxonomic work using DNA comparisons have organized the North American menhadens into large-scaled (Gulf and Atlantic menhaden) and small-scaled (Finescale and Yellowfin menhaden) designations.[2]

The menhaden consist of two genera and seven species:

  • Genus Brevoortia T. N. Gill, 1861
    • Brevoortia aurea (Spix & Agassiz, 1829) (Brazilian menhaden);
    • Brevoortia gunteri Hildebrand, 1948 (Finescale menhaden);
    • Brevoortia patronus Goode, 1878 (Gulf menhaden);
    • Brevoortia pectinata (Jenyns, 1842) (Argentine menhaden);
    • Brevoortia smithi Hildebrand, 1941 (Yellowfin menhaden);
    • Brevoortia tyrannus (Latrobe, 1802) (Atlantic menhaden).
  • Genus Ethmidium W. F. Thompson, 1916
    • Ethmidium maculatum (Valenciennes, 1847) (Pacific menhaden).

Distribution

  • The various species of menhaden occur anywhere from estuarine waters outwards to the continental shelf. Menhaden grow in less saline waters of estuaries and can be found in bays, lagoons, as well as river mouths. Adults appear to prefer water temperatures near 18 °C.

Life cycle

Atlantic menhaden can spawn year round in inshore waters off the Atlantic coast, with the highest spawning rates near North Carolina in the late fall. The eggs hatch in the open ocean and the larvae drift to sheltered estuaries via ocean currents. The young spend a year developing in these estuaries before returning to the open ocean. At this early stage, they are commonly known as "peanut bunker". The Atlantic menhaden usually do not become sexually mature until the end of their second year, after which they reproduce until death. A young, sexually mature female can produce roughly 38,000 eggs, while a fully mature female can produce upwards of 362,000.[3]

Eggs are buoyant and hatch within 2 to 3 days depending on the temperature. The larvae will spend 1 to 3 months in waters over the continental shelf. The Chesapeake Bay is a popular nursery for juvenile menhaden. Larval fish will enter the Bay in late winter and early summer. The larval fish will move into lower salinity waters in estuarine tributaries while juvenile and immature fish remain in the Bay until the fall.

Ecology

Menhaden are omnivorous filter feeders, feeding by straining food particles from water. They travel in large, slow-moving, and tightly packed schools with open mouths. Filter feeders typically take into their open mouths "materials in the same proportions as they occur in ambient waters".[4] Menhaden primarily eat phytoplankton (microscopic plants); although, since they are omnivorous, they take in a small portion of zooplankton (microscopic animals). Even though most other related fish (in the family Clupeidae) eat zooplankton, "Menhaden primarily consume phytoplankton, that is, algae and other drifting bits of vegetable matter. The ecological significance of this difference can hardly be overstated."[5]

Human intake

Fisheries

Global commercial capture of menhaden in million tonnes 1950–2010[1]
Capture of menhaden in 2010 reported by the FAO[1]

According to James Kirkley of the Virginia Institute of Marine Science (VIMS), there are two established commercial fisheries for menhaden. The first is known as a reduction fishery. According to the Omega Protein Corporation, this fishery's output produces omega-3 oils for human consumption, and for aquaculture, swine, and other livestock feeds.[6] The second is known as a bait fishery, which harvests menhaden for the use of both commercial and recreational fishermen. Commercial fishermen, especially crabbers in the Chesapeake Bay area, use menhaden to bait their traps or hooks. The recreational fisherman use ground menhaden chum as a fish attractant, and whole fish as bait. The total harvest is approximately 500 million fish per year.[7] Atlantic menhaden are harvested using purse seines.

As food

Purse seine boats encircling a school of menhaden

Menhaden were prized in America for their delicate but rich flavors in the mid 18th century. Mark Catesby (1682–1749), an English naturalist, wrote of the menhaden as an "excellent Sweet Fish, and so excessive fat that butter is never used in frying or any other preparation of them....[menhaden were] much esteemed by the Inhabitants for their delicacy."[citation needed] Colonel William Byrd II, the founder of Richmond, Virginia, commended menhaden as food fit for a gourmet writing of the menhaden as a "small, but splendid fish when it is baked." Over a century later George Brown Goode (1851–1896) praised the menhaden for its flavor, saying it is "superior in flavor to most of the common shore-fishes," and notes that menhaden sold at a "price nearly as high as that of striped bass, the favorite fish in Washington."[citation needed]

Presently, menhaden are an important input for fishmeal and fish oil, with both of these "reduction" products being used as feed for livestock and aquaculture, such as salmon, shrimp, tilapia, catfish. Fish oil made from menhaden is also used as a dietary supplement, and as a raw material for products such as lipstick.[7] Atlantic menhaden are an important link between plankton and upper level predators. Because of their filter feeding abilities, "menhaden consume and redistribute a significant amount of energy within and between Chesapeake Bay and other estuaries, and the coastal ocean."[8] Because they play this role, and their abundance, menhaden are an invaluable prey species for many predatory fish, such as striped bass, bluefish, mackerel, flounder, tuna, Drum (fish), and sharks. They are also a very important food source for many birds, including egrets, ospreys, seagulls, northern gannets, pelicans, and herons.

Two companies harvest menhaden in the United States:

  1. Omega Protein Inc., Houston, Texas, with operations in Virginia, Louisiana, Mississippi, and Alabama which takes 90% of the national total;[7] and
  2. Daybrook Fisheries, Empire, Louisiana.

Management and overfishing

According to the Atlantic States Marine Fisheries Commission, while the stock of menhaden is not considered overfished, overfishing has occurred in 32 of the past 54 years and was occurring in 2008, the latest year in the Atlantic menhaden stock assessment.[9] According to Paul Greenberg, who has called for a ban on fishing menhaden in US federal waters and the Chesapeake bay, the continued overfishing of menhaden (especially by Omega Proteins) is having detrimental effects on the population, which in turn is affecting populations of fish and birds that feed on menhaden and especially on water quality:[7]
The muddy brown color of the Long Island Sound and the growing dead zones in the Chesapeake Bay are the direct result of inadequate water filtration — a job that was once carried out by menhaden. An adult menhaden can rid four to six gallons of water of algae in a minute. Imagine then the water-cleaning capacity of the half-billion menhaden we "reduce" into oil every year.

There is increasing concern, especially from recreational fisherman and conservationists, that the Chesapeake Bay’s population is declining significantly.[10] This concern is shared by anglers from Maine to Florida who have watched this vital forage fish species vanish from its upper and lower ranges.Grassroots efforts by conservation minded fisherman like Menhaden Defenders are working hard to unite anglers and to get the word out about rebuilding the Atlantic Menhaden stock levels which is currently at its lowest point in history. Currently, non sustainable methods of fishing continue on an industrial scale, using spotter planes to target older, oil rich menhaden, and direct enormous refrigerated seawater vessels to the fish. Small net boats then circle the purse seine net around the giant schools and the ship vacuum pumps them aboard. The ASMFC has determined that this fishery has been overfishing for 52 out of the past 54 years.

The Chesapeake Bay’s major menhaden fishery is located in the southern (Virginia) portion. According to the Chesapeake Bay Program:

"Chesapeake-specific population estimates for menhaden are not currently produced; estimates are only made for the entire Atlantic coast stock, which appears to be healthy. Still, scientists are concerned about what appears to be a low abundance of menhaden in the Bay, which is one of the fish's key nursery areas.
Fisheries-independent data from seine surveys in Maryland and Virginia through 2004 suggested that menhaden recruitment—the number of juveniles that grow to a "catchable" size—was possibly declining in the Bay. Coast-wide recruitment is considered to be at median historic levels.
The exact causes of the decline in recruitment remain unknown. While additional scientific knowledge is necessary to understand the variability of menhaden recruitment, scientists have cited several possible contributing factors, including:
- Heavy fishing on the adult menhaden stock.
- Possible increases in mortality by predators.
- Changing environmental conditions, such as climate change or poor water quality, in menhaden nursery areas."[11]

Menhaden have been called 'the most important fish in the sea'.[12] H. Bruce Franklin’s most recent book, The Most Important Fish in the Sea: Menhaden and America is an interdisciplinary study of the role of menhaden in American environmental, economic, social, political, and cultural history from the seventeenth into the twenty-first centuries.[5]

Notes

  1. 1.0 1.1 Richard Conniff. "The Oiliest Catch". Conservation Magazine. Retrieved 2013-01-18. 
  2. Anderson, Joel (2007). "Systematics of the North American menhadens: molecular evolutionary reconstructions in the genus Brevoortia (Clupeiformes: Clupeidae)". Fishery Bulletin 105 (3): 368378. Retrieved 10 February 2011. 
  3. "引越し完全マニュアル" (in Japanese). Archived from the original on 30 January 2009 
  4. GSMFC 2002
  5. 5.0 5.1 Franklin, H. Bruce (2007). The Most Important Fish in the Sea: Menhaden and America. Island Press. ISBN 978-1-59726-507-2. OCLC 74569179. 
  6. Omega Protein (home page). Omega Protein 
  7. 7.0 7.1 7.2 7.3 Greenberg, Paul (15 December 2009). "A Fish Oil Story". The New York Times. Retrieved 10 February 2011. 
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  8. "Maryland Department of Natural Resources". Dnr.state.md.us. 2012-12-31. Retrieved 2013-01-07. 
  9. . NOAA Chesapeake Bay Office http://chesapeakebay.noaa.gov/fish-facts/menhaden. Retrieved 27 June 2013.  Missing or empty |title= (help)
  10. The Most Important Fish in the Sea Article about the multiple problems of menhaden overfishing from Discover (magazine)
  11. "Chesapeake Bay Program (homepage)" 
  12. Discover Magazine. "menhaden". Andromeda.rutgers.edu. Retrieved 2013-01-07. 

References

Fisheries Commission. Available: http://www.asmfc.org/speciesDocuments/menhaden/reports/stockAssessments/2006StockAsses smentReport.pdf

External links

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