Atlantic menhaden

Atlantic Menhaden
Atlantic Menhaden (Brevoortia tyrannus)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Clupeiformes Family: Clupeidae Subfamily: Alosinae Genus: Brevoortia Species: B. tyrannus
Binomial name
Brevoortia tyrannus (Latrobe, 1802)

The Atlantic menhaden (Brevoortia tyrannus) is a silvery, highly compressed fish in the herring family, Clupeidae.^[1][2] A filter feeder, it lives on plankton caught in midwater. Adult fish can filter up to four gallons of water a minute; and they play an important role in clarifying ocean water. They are also a natural check to the deadly red tide.^[3]

Menhaden historically occurred in large numbers in the North Atlantic, ranging from Nova Scotia, Canada to central Florida, USA, although their presence in northern waters has diminished in the 20th Century. They swim in large schools, some reportedly up to 40 miles (64 km) long. As a result of their abundance they are important prey for a wide range of predators including bluefish, striped bass, cod, haddock, halibut, mackerel, swordfish, and tuna.^[3]

The menhaden is also called pogy, mossbunker, bug fish, alewife, shad, greasetail, bunker, bunker fish and fat back.^[4]

Life Cycle

Atlantic menhaden, Brevoortia tyrannus, are found in estuarine and coastal waters from northern Florida to Nova Scotia and serve as prey (food) for many fish, sea birds and marine mammals.

Sexual maturity begins just before age three. The majority of spawning occurs primarily offshore during winter. Buoyant eggs hatch at sea and larvae are carried into estuarine nursery areas by ocean currents. Juveniles spend most of their first year of life in estuaries, migrating to the ocean in late fall. Adult and juvenile menhaden migrate south in fall/winter, and migrate north in spring.

Menhaden feed by straining plankton from the water, their gill rakers forming a specialized basket to efficiently capture tiny food. Menhaden provide a link between primary production and higher organisms by consuming plankton and providing food for species such as striped bass, bluefish, and weakfish.

Commercial fishing

The Atlantic menhaden is popular for use as live or dead bait. The fish is notorious for its rapid deterioration when caught, as well as its bony and oily makeup. As a result, they are primarily used for the production of fish meal, oil and fertilizer. It was likely the fish that Squanto taught the Pilgrims to bury alongside freshly planted seeds as fertiliser. It went on to be used for this purpose on a large scale on farmland on the Atlantic coast, though this process was stopped after it was realized that the oily fish parched the soil.^[4][3]

Menhaden B. tyrannus from the Chesapeake Bay

In recent years their population is considered to be sustainable coastwide, though a possibility for a localized depletion exists in the Chesapeake Bay due to a concentrated harvest.^[5] Omega Protein, a Houston, Texas-based company, has a virtual monopoly on the menhaden reduction industry in the United States.^[6] The company uses a process known as purse-seining to corral and remove from the water entire schools of menhaden, often numbering in the hundreds of thousands.^[6] Purse seining has been outlawed by every Atlantic coast state except Virginia and North Carolina. Tremendous algal blooms that starve the bay of sunlight and oxygen have been attributed to a diminished menhaden population due to the menhaden's important role as a filter feeder of algae and other phytoplankton. Significant malnutrition and disease in one of its primary predators, the striped bass, is also widespread in the Chesapeake.^[6]

Management

Menhaden is managed with limits on fishing in order to help the species population grow. The main problem with the management of menhaden is that they are a prey species of many other fish, and the management of one affects the other. Organizations managing the species continue to work on the understanding and management of menhaden and their predators.

References

1. ^ Brevoortia tyrannus (TSN 161732). Integrated Taxonomic Information System. Retrieved on 30 January 2006.
2. ^ "Brevoortia tyrannus". FishBase. Ed. Ranier Froese and Daniel Pauly. 10 2005 version. N.p.: FishBase, 2005.
3. ^ ^{a b c} H. Bruce Franklin (March 2006). "Net Losses: Declaring War on the Menhaden". Mother Jones. http://www.motherjones.com/news/feature/2006/03/net_losses.html. Retrieved on 21 February 2006.  Extensive article on the role of menhaden in the ecosystem and possible results of overfishing.
4. ^ ^{a b} George Brown Goode (1887). The Fisheries and Fishery Industries of the United States. Section V. History and Methods of the Fisheries. Washington, D.C.: U.S. Government Printing Office. 
5. ^ ASMFC 2005
6. ^ ^{a b c} Franklin, H. Bruce (2007) The Most Important Fish in the Sea: Menhaden and America Island Press. ISBN 9781597261241