A few weeks ago, I wrote about sturgeon — those strange, prehistoric giant fish that leap out of the Androscoggin River in late spring.

They are bigger than many people and weigh an impressive amount due to their heavily-scaled bodies. But, there’s a smaller, more numerous fish that makes a similar journey from fresh to salt water every year. The homely alewife is a fellow anadromous fish, meaning that it spends most of its life in salt water, but is born in fresh water, then returning there a few years later when they are mature enough to spawn.

Alewives are a beacon of spring each year. While they don’t splash impressively like the sturgeon, and they typically measure up to only about 6 inches (versus 6 feet for sturgeon), the impressive thing about alewives is their mass migration up rivers to spawn. For this reason, the species we have in Maine, Alosa pseudoharengus, is commonly called “river herring”. They are also known as “sawbellies” due to the little series of scales along their silvery bellies that looks like a saw. Their backs are gray-green to help camouflage them, and they have an eye-spot behind their actual eye to distract predators.

Like many anadromous fishes, alewives have suffered a similar fate of having their passage from fresh to saltwater blocked by the building of dams along Maine’s riverways to harness power for mills or electricity. As many of these have been removed in recent years, and also as fish ladders have been built to assist with upstream migration, fish like alewives have once again been able to complete their life cycles. There are many places to see this migration – both in the upstream and the downstream directions, with a couple of weeks in between as they hang out to spawn.

Close to Brunswick, the Nequasset fish ladder in Woolwich, is an easy place to see alewives as they travel up via the ladder to Nequasset Lake. The Kennebec Estuary Land Trust (KELT) runs a citizen science program there where people can become official alewife counters for a set period of time at the ladder. It’s pretty exciting to see these little fish work hard to make their way up, pool by pool, to the top and then swim off into the lake. If you’re interested in participating, you can find more information at: https://www.kennebecestuary.org/fish-counting. If you go to the Nequasset ladder, you can also take home some smoked alewives from the on-site smokehouse to try, as this is one of a small handful of alewife runs where commercial harvest is allowed. Aside from smoking, alewives are also used as lobster bait and are important prey species for many native birds and larger fish.

If you’re willing to venture a little further afield, there is an impressive alewife run down near Portland. Recently, the Gulf of Maine Research Institute (GMRI) partnered with the Presumpscot Regional Land Trust to highlight the biggest alewife migration from Casco Bay, which goes up the Presumpscot River through Mill Brook to their spawning area in Highland Lake. Every year, thousands of alewives come through Westbrook’s Mill Brook Preserve, which is a great place to observe all of the activity. There are trails there that take you to several great viewing spots. They recently released an online guide that tells about alewives, their ecology, and their migration patterns. It is available here.

Susan Olcott is director of strategic initiatives for Maine Coast Fishermen’s Association.