The Atlantic menhaden (Brevoortia tyrannus) is a North American species of fish in the herring family, Clupeidae.
Atlantic menhaden are found in North Atlantic coastal and estuarine waters from Nova Scotia south to northern Florida. They are commonly found in all salinities of the Chesapeake Bay and Mid-Atlantic water. They swim in large schools that stratify by size and age along the coast. Younger and smaller fish are found in the Chesapeake Bay and southern coastline while older, larger fish are found along the northern coastline.
Characteristics
Atlantic menhaden are silvery coloured fishes characterized by a moderately compressed body and a black spot on their shoulder behind their gill openings. They can reach a size of approximately 15 inches.
Biology
Diet
The Atlantic menhaden is a filter feeder, which that it collects food by filtering water through modifications of the branchial apparatus (gill arches and gill rakers). Its diet depends on the size of their gill rakers, which change as menhaden age. When the rakers are smaller, which generally correspond to when they are under the age of 1, Atlantic menhaden feed primarily on zooplankton. As they age and their gill rakers grow larger, menhaden shift their diet to primarily consume phytoplankton.
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". 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.
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. Atlantic menhaden can live up to 10 to 12 years.
Predators
Atlantic menhaden are preyed upon by fish such as striped bass, weakfish and bluefish, and by birds such as ospreys and eagles. Humpback whales off the coast of New Jersey feed on Atlantic menhaden. Other cetaceans, such as fin whales and dolphins also eat menhaden. Dolphins can eat up to 20 pounds of Atlantic menhaden a day.
Fisheries and management
Historical uses
Menhaden have historically been used as a fertilizer for crops. It is likely that menhaden is the fish that Squanto taught the Pilgrims to bury alongside freshly planted seeds as fertilizer. Other uses for menhaden include: feed for animals, bait for fish, oil for human consumption, oil for manufacturing purposes and oil as a fuel source.
In the early years of the United States, Atlantic menhaden were being harvested by thousands of fishing ships. The Atlantic coastline was lined with processing facilities to quickly transform the fish into a product of worth, typically oil but later fish meal became more popular. Tragedy of the commons set in and the menhaden population began to dwindle. Many of these small companies could not manage, which left only a handful of menhaden fishing companies to remain on the Atlantic coast.
While many sources today claim that the menhaden is inedible, the fish were once consumed as sardines might be, or fried. Maine fishermen, for example, would eat fried pogies for breakfast. The fish that were not sold for bait would be sold to the poorer classes for food.
Commercial fishery
In the Atlantic, menhaden are targeted by two types of fisheries, a reduction fishery and a bait fishery. They are also taken directly by recreational fishing for use as bait.