Menhaden, also known as mossbunker, bunker, and "the most important fish in the sea", are forage fish of the genera Brevoortia and Ethmidium, two genera of marine fish in the order Clupeiformes. Menhaden is a blend of poghaden (pogy for short) and an Algonquian word akin to Narragansett munnawhatteaûg, derived from munnohquohteau ("he fertilizes"), referring to their use of the fish as fertilizer. It is generally thought that Pilgrims were advised by Tisquantum (also known as Squanto) to plant menhaden with their crops. In southeastern South America they are called "savelhas" or "saracas."
Description Menhaden are flat and have soft flesh and a deeply forked tail. They rarely exceed 15 inches (38 cm) in length, and have a varied weight range. 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. In addition, yellowfin menhaden tail rays are a bright yellow in contrast to those of the Atlantic menhaden.
Taxonomy
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. The menhaden consist of two genera and seven species:
Genus Brevoortia T. N. Gill, 1861 Large-scaled Brevoortia aurea (Spix & Agassiz, 1829) (Brazilian menhaden) Brevoortia patronus Goode, 1878 (Gulf menhaden) Brevoortia pectinata (Jenyns, 1842) (Argentine menhaden) Brevoortia tyrannus (Latrobe, 1802) (Atlantic menhaden) Small-scaled Brevoortia gunteri Hildebrand, 1948 (Finescale menhaden) Brevoortia smithi Hildebrand, 1941 (Yellowfin menhaden) Genus Ethmidium W. F. Thompson, 1916 Ethmidium maculatum (Valenciennes, 1847) (Pacific menhaden)
Distribution Argentine menhaden and Brazilian menhaden range from Bahía Blanca, Argentina to Rio de Janeiro state, Brazil Finescale menhaden range from the Yucatán to Louisiana. Yellowfin menhaden range from Louisiana to Virginia. Gulf menhaden range from the Yucatán Peninsula, Mexico, to Tampa Bay, Florida. Atlantic menhaden range from Jupiter Inlet, Florida, to Nova Scotia; Atlantic menhaden seasonally migrate along the coast; in June, mature adults typically are in the northern portion of the coastline with sub-adults and juveniles located in the southern portion. The various species of menhaden occur anywhere from estuarine waters outward to the continental shelf; menhaden grow in less saline waters of estuaries and may be found in bays and lagoons, as well as at river mouths; adults appear to prefer water temperatures near 18 °C.
Ecology Menhaden are filter feeders that 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". Menhaden have two main sources of food: phytoplankton and zooplankton. A menhaden's diet varies considerably over the course of its lifetime, and is directly related to its size. The smallest menhaden, typically those under one year old, eat primarily phytoplankton. After that age, adult menhaden gradually shift to a diet comprised almost exclusively of zooplankton. Menhaden are omnivorous filter feeders, feeding by straining plankton and algae from water. Along with oysters, which filter water on the seabed, menhaden play a key role in the food chain in estuaries and bays. 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 the Chesapeake Bay and other estuaries, and the coastal ocean." 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, drums, and sharks. They are also a very important food source for many birds, including egrets, ospreys, seagulls, northern gannets, pelicans, and herons. In 2012, the Atlantic States Marine Fisheries Commission declared that the Atlantic menhaden was depleted due to overfishing. The decision was driven by issues with water quality in the Chesapeake Bay and failing efforts to re-introduce predator species, due to lack of menhaden on which they could feed. Menhaden are crucial not only because of their keystone species-status in the food web, but also because of their ecological services. The way menhaden filter feed on phytoplankton helps to mitigate toxic algal blooms. These algal blooms, which are often detrimental to a number of fish, bird, and marine mammal species, create hypoxic conditions. The phytoplankton being preyed upon are photosynthetic organisms, converting sunlight into energy which is then transferred to menhaden and then to bigger species of fish or other larger marine organisms such as birds or mammals. The consequence of this behavior is that if menhaden are eliminated or significantly decreased, there are limited means of energy transfer among trophic levels – making menhaden a true keystone species with ecological services that are invaluable to humans.
Habitat Menhaden are a pelagic schooling fish that migrate inshore during the summer and off-shore in the winter months. The juvenile and larval menhaden migrate to shore and inland waterways through currents during summer months to grow while feeding on the phytoplankton and eventually zooplankton once they have matured. Commercially caught menhaden have been recorded in waters of around 5 to 24 ‰, as well as in hypersaline waters around 60 ‰.
Reproduction Menhaden reproduce in open oceans externally, however, the female does not carry eggs with them during the process as they are released into the water column at the planktonic level as gametes and sperm. Currently, functional hermaphroditism is unknown to the species and identification of sex of the individual organism cannot be determined externally due to the lack of accessory reproductive organs. These fish breed during the winter months through December to March and the eggs and juveniles navigate towards estuaries and inland waterways through tides and currents.
… excerpt ends here. Continue reading the full article.
