When you hear the word "eel," what comes to mind? For many people, eels are repulsive, slimy creatures to be avoided. But to fishermen and crabbers, eels are an important commodity, either as bait or to be exported for human consumption. Whatever one might think of them, eels are extraordinary fish and are considered a delicacy worldwide.
A few summers ago, I had the opportunity to taste eel. Acquaintances from Poland, now living in Maryland, smoked some eel and offered me a sample. Though it looked unappetizing, I discovered that eel is quite tasty.
American eels are found in freshwater rivers and lakes, bays, coastal areas and open ocean. No other fish matches the eel's ability to exist in such a diversity of habitats. They range from the southern tip of Greenland, along the entire Atlantic Coast of North America, into the Gulf of Mexico and south to the northeastern portion of South America. In the Chesapeake Bay, they can be found in the mainstem and most tributaries.
Much myth and mystery surround this fish. Tribes in the Philippines once thought eels were the souls of the dead. Some Europeans believed that skin rubbed with eel oil caused one to see fairies. Because no one had ever seen a female eel with eggs, the Greeks once believed that baby eels were produced by spontaneous generation. This myth was dispelled in 1922 when a scientist, Johannes Schmidt, discovered the spawning ground for American and European eels in the Sargasso Sea, near Bermuda.
This discovery led to a greater understanding of the eel's life cycle. The American eel, Anguilla rostrata, is the only catadromous fish in the Bay, which means it lives most of its life in fresh and estuarine water, and migrates into saltwater to spawn. Before their fall migration, adult eels undergo changes that adapt them for life in the ocean. These changes include an accumulation of fat and the degeneration of the gut.
Spawning migration takes place between August and December, with eels being most active at night. American eels spawn in the western Sargasso Sea between January and March. A female eel may lay between 400,000 and 2,500,000 eggs. Parents die after spawning.
The eggs hatch and the young, which look like transparent ribbons, are seized by ocean currents and transported to the mouth of the Chesapeake Bay and other inlets of the Atlantic Ocean. This journey can take months or even years. After their first year, the young change, taking on the form of tiny, unpigmented eels, known as glass eels.
Glass eels become pigmented as they move to coastal areas. Their bodies turn dark brown and their metamorphosis is complete. They are now called elvers. The elvers continue the journey upstream into brackish and freshwater rivers, streams and creeks. Elvers are found in the Chesapeake Bay in April and May.
When elvers stop migrating, they undergo a period of growth and are called yellow eels. Yellow eels stay in the Bay and its tributaries eight to 24 years.
While in estuaries and rivers, yellow eels have small home ranges in which they feed. Voracious feeders, they consume a variety of fish, insects, crayfish and worms.Yellow eels are more active at night, retiring into burrows, bottom mud or other cover during the day.
In the spring, the eels migrate into estuaries and come summer and autumn, move back up into rivers. They hibernate in the mud during the winter.
About one year before reaching sexual maturity, eels undergo their last transformation before spawning, resulting in the silver eel phase.
Although considered a hardy fish, the status of the eel in the Bay is not clear.
There are two eel industries; a bait market for crab trotliners and a live eel market for human consumption. Eels are used as bait throughout Maryland. In Virginia, the amount used as bait is smaller and is confined to recreational crabbers.
It is hard to determine how much the bait fishery affects the eel population because the number of eels harvested for crab bait has not always been reported. In 1974, eel harvest figures for Maryland and Virginia were 145,300 pounds and 1,453,048 pounds, respectively; in 1984 these figure dropped to 109,558 pounds and 786,462 pounds; and in 1994 eel harvests were down again, 295,867 pounds and 355,746 pounds, according to the Maryland Department of Natural Resources and Virginia Marine Resources Commission.
These harvest figures, though important to gauging the Chesapeake Bay eel population, do not provide a complete picture.
The information does not currently report fishing effort, which includes such data as the number and types of fishing gear used. Effort data, combined with harvest numbers, gives a truer account of the population status. For instance, the same amount of eels may be harvested each year but the effort to catch those eels may increase. This could indicate a decline in the overall eel population. Fishery managers are considering ways to retrieve effort data.
Some countries raise eels to meet the demand for meat. Eel meat can be fried, jellied, stewed or smoked. Foreign interests trying to get elvers for eel culture could impact Chesapeake Bay eel stock.
Other factors can affect the eel population. Because of their bottom-feeding behavior, contaminants in bottom sediments and low, dissolved oxygen levels can negatively impact eels.
Probably the biggest threat eels face is the blockage of important habitats by dams and other obstructions. Even though elvers are known to, when necessary, leave the water and scale low dams or move over moist grass, this is not an efficient way for them to pass. It leaves them open to predation and many elvers do not survive their daring climbs.
Efforts to remove blockages from important fishery habitats are occurring throughout the watershed. Where removal is not possible, different techniques are used to help fish migrate. These include fish elevators, fish ladders or partially removing the blockage.
By ensuring safe fish passage, reducing pollutants and monitoring populations, eels, and many other valuable fish, will continue to flourish in the Chesapeake Bay.