The alewife is a much-misunderstood fish, and some of its life is still a mystery.

Each spring, alewives migrate upstream from the sea, in great numbers, to spawn. It’s a huge orgy, “the fish version of creation,” said Naomi Shalit of Alna, an alewife advocate head of a group called Maine Rivers. At a recent meeting in Damariscotta, she explained that for years alewives have been in decline. For a while, the legal harvesting of these fish was halted along traditional runs such as Damariscotta Mills in Nobleboro, and the Medomak River in Waldoboro. Other rivers and streams, some named for the fish, no longer support alewife runs in late April and May.

Shalit said the culprits are dams, pollution and overfishing, despite state laws that allow municipalities to regulate the taking of alewives. In Waldoboro, the alewife harvest was banned for years, then allowed on a limited basis last year.

The Damariscotta Mills stone fish ladder is a perennial tourist attraction, and that alewife run is one of Maine’s most robust. Historically, the alewife run in Nobleboro – from Great Salt Bay up an 19th century fish ladder to Damariscotta Lake – has been a very profitable business, with salted fish packed in barrels to be shipped. The Kennebec River has an alewife run that was extended by 20 miles several years ago with the demolition of Edwards Dam in Augusta. An 1852 history reports alewives on the Kennebec “were so plentiful there at the time the country was settled, that bears, and later swine, fed on them in the water. They were crowded ashore by the thousands.”

In 1809, selectmen in Benton, on the Sebasticook River, ordered a mill dam removed because it blocked the shad and alewife runs. Today, another dam blocks the Sebasticook, which empties into the Kennebec at Winslow.

Shalit said research indicates a correlation between the alewife decline and the disappearance of deep-sea species of fish in coastal waters. The alewife run also offers cover for salmon smolt, allowing the young salmon to grow, as well as to another endangered species: the alewife floater mussel. Salmon is king in the public’s mind, Shalit admits, but she says the lowly alewife deserves “civil rights” too.

Shalit has investigated alewives with Lois Winter, a biologist with the U.S. Fish & Wildlife Service, and Gail Wippelhauser, scientist with the Maine Department of Marine Resources. What’s still not known about alewives is where they go after spawning, when they migrate to saltwater. Alewives have been found as far south as Georgia, but many of them may stay in the Gulf of Maine.

In both estuaries and at sea, alewives are food for striped bass, haddock and cod. Scientists believe the recovery of these species depends on a healthy alewife population. A decade-long Department of Marine Resources study showed that stocking alewives in Lake George, in Canaan, had no ill effect on existing species such as smallmouth bass, brown trout, pickerel or perch.

This sort of knowledge didn’t stop the Maine Legislature from passing a law in the 1990s to block alewife passage around dams on the St. Croix River. Local guides feared alewives would ruin their bass-based livelihoods, since bass disappeared from Spednic Lake and they blamed – apparently without any hard evidence – the alewives. Canadian and U.S. Fish & Wildlife authorities objected, but the law stuck. The St. Croix alewife population sank from 2.5 million in the 1980s to about 1,000 in 2002. Shalit has documented that battle, which has so far been a defeat for biologists and conservationists.

Shalit said too few people appreciate that alewives provide meals for bald eagles and osprey, great blue herons, otter, mink, fox, turtles, even whales.

For generations, alewives have been a cheap source of bait for lobstermen, and there are those people who actually take the time to cook and eat the alewife. Until recently, alewives were smoked and sold for eating. Native Americans and early European settlers used alewives to fertilize crops. Alewives were shipped to the West Indies to feed slaves on Caribbean plantations. The fish were traded for molasses and rum.

As for where these “river herring” got their name – that’s still a mystery.