The American eel (Anguilla rostrata) has a catadromous life cycle, that is, it spawns in the ocean and migrates to fresh water to grow to adult size. As adult eels mature, they leave the brackish/freshwater growing areas in the fall (August to November), migrate to the Sargasso Sea and spawn during the late winter. The Sargasso Sea is a large area of the western North Atlantic located east of the Bahamas and south of Bermuda. After spawning, the adult eels die. The eggs hatch after several days and develop into a larval stage (leptocephalus) which is shaped like a willow leaf. The larvae drift in the ocean for several months and then enter the Gulf Stream current to be carried north toward the North American continent. As they approach the continental shelf, the larvae transform into miniature transparent eels called "glass eels". As glass eels leave the open ocean to enter estuaries and ascend rivers they are known as elvers. This migration occurs in late winter, early spring, and throughout the summer months. Some elvers may remain in brackish waters while others ascend rivers far inland. Eels may stay in growing areas from 8-25 years before migrating back to sea to spawn.
There are two fisheries for eels in Maine which relate to two different life stages. The glass eel/elver fishery harvests small eels returning to rivers from their ocean spawning areas. This fishery utilizes fine mesh fyke nets (a funnel shaped net) or dip nets to collect elvers as they ascend to fresh water. The yellow eel fishery occurs for eels which are growing in brackish and fresh waters. These eels are typically more than 2-3 years old, but not yet mature. Harvesting gear in this fishery includes baited eel pots and fyke nets. The silver eel fishery, which occured in late summer and fall and consisted of weirs across streams and rivers to collect out migrating sexually mature eels that are moving downstream to go to the Sargasso Sea to spawn, was closed in 2014 in response to Addendum III of the Atlantic States Marine Fisheries Commission's (ASMFC's) Fishery Management Plan (FMP). Maine's glass eel/elver fishery and yellow eel fishery are managed under Addendum V of the ASMFC's FMP.
Fisheries for yellow and silver eels have a long history in Maine, having occurred since the earliest colonial settlements. The elver fishery is relatively recent, having begun in the early 1970?s to 1978 and recommenced in the early 1990's. The fishery was nonexistent from 1979 to the early 1990's due to a collapse in market demand for elvers. In recent years, market demand has increased dramatically. Elvers are highly valued in the far east (Japan, China, Taiwan, and Korea) where they are cultured and reared to adult size for the food fish market. Due to recent intense market demand, elvers have now become the most valuable marine resource in terms of price per pound which, in 2019, was over $2,000.
The fishing season for elvers runs from March 22 through June 7, although the fishery may be closed earlier if Maine's quota, as established by the ASMFC, has been met. Harvest methods are restricted to hand dip nets, fyke nets, or Sheldon eel traps. Concerns about elver fishing relate to impacts of fyke nets on other species migrating and spawning (smelt, alewives, trout and salmon) in Maine rivers, potential over harvest of eels, and the significance of eels to the ecosystem.
The Department of Marine Resources held lotteries for elver licenses until 2013, when the Legislature suspended any further lotteries after that season because of an overall state quota established by the ASMFC, which reduced the amount available for every licensed harvester. However, in 2017, the legislature authorized the Department of Marine Resources to renew the lottery but capped total licenses at 425.
DMR staff monitor the Maine elver fishery to collect information on the harvest and fishing effort, bycatch of other species in elver nets, and the impact of this fishery on adult eel abundance in Maine waters. In addition, DMR has funded a number of eel research projects with the University of Maine at Orono to investigate various life history aspects of the American eel.
For more information on eel and elver biology, fishery management, or monitoring and assessment, see the American eel/elver profile, stock status, habitat, assessment, and management plan c/o ASMFC or see the links and contact information on our eel/elver home page.