Atlantic Herring (Clupea harengus)
Herring on the Ledge: Jeffreys Ledge is a critically important area for Atlantic herring, just as herring are critically important for the Ledge. They are the primary forage fish on which many other species of fish and marine mammals feed. Herring are a schooling fish, which usually occurs in the mid-water column during day, and nearer to the surface at night. Jeffreys Ledge is not only an important feeding area for herring, it is also the most important spawning ground of the Gulf of Maine herring stock. Each fall huge shoals of herring school together over the Ledge to lay their spawn, which can sometimes over the sea floor with egg beds up to a foot thick! Herring fishing on the Ledge has taken place for many years, either by seining (setting a surface net in a big circle at night) or specially permitted mid-water trawling. While Atlantic herring are not eaten in this country, agreements with eastern block nations allow herring to be sold for consumption in other countries. In addition, it is often sold domestically for fertilizer and pet foods.
Size: Herring can get up to 18 inches long, but most adults are less than one foot in length. They typically weigh less than two pounds. The fish is a silver color, sometimes with a green or bluish tint on top. Their tail is deeply forked.
Diet: Herring primarily eat animal plankton (zooplankton), especially copepods. However their diet will vary based on area and prey availability, and herring have been known to feed on a variety of animals, so much so that it has been said that they will feed on "anything that can fit in their mouth." Although they are typically "bite" feeders, they have even been known to use their gills to filter feed!
Habitat: Atlantic herring are found in a wide variety of habitat types, but are most common over rocky bottom areas of high relief. Some herring will come inshore to spawn, even spawning in eel grass beds along the coastline. Their eggs are deposited on objects such as kelp. Rocks, eel grass, or fishing gear. They hatch after two weeks, and spend the next several months in a larval stage before metamorphosizing into juvenile herring.
Predators: Herring are fed on by a wide variety of marine predators, including groundfish, tuna, sharks, squid, many species of sea birds, bluefish, seals, dolphins, and whales.
Range: From the mid-Atlantic United States to West Greenland, but most common between New York and Labrador. In New England, there are though to be two separate breeding stocks - one offshore (the "Georges Bank" stock), the other inshore (the "Gulf of Maine" stock). The Georges Bank stock was depleted to the point of near-extinction through over-fishing by foreign factory fleets in the 1960's-1970's, but has now recovered to near-pre-exploitation levels. The Gulf of Maine stock was never as heavily depleted, although some evidence indicates it has declined somewhat in recent years. The amount of mixing between the two stocks is unclear.
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