What is a Menhaden?
Menhaden, also known as bunker, pogie, fat-back, alewife and bugmouth, is a species of small fish and a member of the herring family. This fish is an integral part of the ecosystems it inhabits, as it provides food for many larger species of fish and feeds off algae growing in the water. Without the menhaden, the health of coastal waters on the Atlantic side of the Americas likely would suffer.
Menhaden are silver and covered with lateral black spots. Most specimens have a large black spot just behind their gill opening as well as a variable number of smaller spots down the length of their backs. The fins of the menhaden lack spines that can be found in other species of herring, and they also lack teeth.
These fish live in the Atlantic ocean, from eastern Florida to Nova Scotia. They can also be found in the Gulf of Mexico and down the eastern coast of South America, as far south as Argentina. They live in shallow waters and spawn in the ocean. Menhaden fry spend their first year in the brackish water of bays and the mouths of rivers.
At one year old, the menhaden is approximately 6 inches (15 cm) long. The fish are fully grown at between two and three years of age. At this time they are 12 inches (about 30 cm) long and ready to spawn.
Like other herrings, the menhaden form large schools. They feed near the surface of the water, often lifting their mouths out of the water as they eat. In schools, they are easy to spot, as their mouths and fins create a disturbance on the ocean’s surface, making them easy for fishing boats to locate.
These small fish feed exclusively on plant plankton that they filter from the water. Menhaden are an important part of a healthy marine ecosystem. They feed on algae, which helps keep the ocean free from excessive algae, which can lower the amount of dissolved oxygen available in the water.
Though these fish are not eaten by humans, they are used for animal feed and as bait fish. They are also one of the sources of omega 3 fish oil which can be used as a dietary supplement. Overfishing of this species has caused populations of larger fish that feed on them to decline. The loss of menhaden has also caused a problem with shellfish populations, as the depleted oxygen levels adversely affect their populations.
New science has shown that menhaden eat phytoplankton (algae) as a primary food source only when they are young-of-the-year (juveniles). As adults, menhaden eat primarily zooplankton (animal) This can be found at Lynch et.al. 2010, Marine Ecology Process Series, Mar Ecol Progress Series,Vol. 401: 195–209, 2010.
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