The Great Alewife Invasion

John Hmurovic
August 2021

They landed on the beaches of Whiting and Hammond. Most residents were caught by surprise. They came by the millions and quickly took control of every inch of beachfront. No one dared to come near the beach because they were quickly repelled by the invaders. The invaders were only seven to ten inches in size, and every one of them, millions of them, were dead. They were the alewives.

Whiting and Hammond were not alone. Virtually every community along Lake Michigan was dealing with the same problem, from Wisconsin and Illinois, to neighboring Indiana communities and all along the Michigan coastline. Alewives were washing up dead, piled inches deep on the shore, rotting in the summer sun. The smell was horrendous.

“One report,” according to an article in the Hammond Times in the summer of 1967, “said the solid, silvery carpet of dead fish stretches forty miles along the shore in Gary, Hammond and Chicago area.” William Svetic, who was the superintendent of the Indiana Dunes State Park warned a visitor about walking on the alewife-covered beach. “You’ll never get rid of that stink on your shoes,” he said. “We have to wash down our trucks three times daily after the wheels pass over these fish carcasses. The smell is really awful.”

The alewife is native to the North American coast of the Atlantic Ocean. As far back as anyone remembers, they were abundant off the shores of Maine. They were very familiar to fishermen in towns like Warren and Damariscotta Mills, especially when the fish would swim up rivers along the coast to spawn. In 1890, a reporter from the New York Tribune, watching the alewives crowd into the Damariscotta River, was fascinated by what he saw. “An alewife run is…a marvelous sight,” he wrote. “They come all at once down the river. With startling suddenness, a queer sort of tidal wave seems to form. It moves rapidly upstream, extending from bank to bank. The waves roll a foot high. And it is a wave of fish--alewives!”

An alewife is not considered edible by most humans, and although there were attempts to use them as fertilizer and pet food, and to use their scales to make artificial pearls, their main value was that some bigger fish liked to eat them.   

As early as the 1870s, alewives worked their way into Lake Ontario, the easternmost of the Great Lakes, probably via the St. Lawrence River. From there, they spread into smaller lakes in upper New York state. A few made their way into Lake Erie, Lake Ontario’s neighboring Great Lake, but most were kept out by the formidable barrier of Niagara Falls. The falls were also a barrier for humans who wanted to open shipping between the Atlantic Coast to the Great Lakes. To allow ships to bypass Niagara Falls, the humans built the Welland Canal in Ontario, which opened a new connection from Lake Ontario into Lake Erie. The alewives appreciated that.

The first reports of alewives in Lake Michigan were in 1949 in the upper lake, and 1954 in the southern part. The lake trout enjoyed having them around. Trout gobbled them up, keeping their numbers under control. But the alewife wasn’t the only fish that discovered the Welland Canal. The sea lamprey, sometimes known as the “vampire fish,” also made its way from the Atlantic Ocean. Sea lamprey attach their sharp teeth to the bodies of other fish and suck the insides out of them. In Lake Michigan, they virtually wiped out the population of lake trout.

With the trout gone, the alewives were secure enough to become fruitful and multiply. That is something that comes naturally to an alewife. Typically, one female alewife lays 10,000 to 360,000 eggs. Quickly, the lake was dominated by the small, silver fish.

There were hints of a problem in the early 1950s, particularly in Lake Huron. By the end of the decade, towns like Sarnia, Ontario, on the far southern tip of Lake Huron, were dealing with millions of dead alewives. The local conservation officer said that the only thing to be done is to burn them, “because even sea gulls won’t touch them.” On Lake Michigan, by 1961, fishermen using nets reported that they were pulling up 800 pounds of alewives out of every thousand pounds of their catches. The beaches of Indiana Dunes State Park also began to see numerous dead fish.

Each summer, the problem grew. It reached its peak in 1967. By that time, Whiting and Hammond were already acquainted with the unwelcome visitors. Thousands littered the beach in July of 1964. That same year, in Chicago, the park district switchboard was jammed with calls from citizens complaining about the smell. The dead fish also got sucked into Chicago’s water intakes, clogging them, and lowering water pressure in much of the city to dangerous levels.

In 1965, it was estimated that by weight alone, the tiny alewives accounted for 95-percent of all the fish in the Great Lakes. Fifteen-thousand pounds of alewives were scraped off Chicago’s water intakes in just one hour. They soon were replaced on the intakes by more alewives. By 1966, it was estimated that the number of alewives in the lake was four times greater than the year before. At the Commonwealth Edison plant in Hammond, on the state line with Illinois, more than four tons of alewives were removed from the power plant’s water intakes in May 1966.

Hammond’s water intakes were not badly affected, but the park departments from both Whiting and Hammond struggled with the job they faced. In 1967, a spokesperson for the Hammond Parks Department said they were hauling them away as fast as possible, but basically threw his hands up in the air and said that some of the fish “will just have to rot.” All along the lakeshore, beachgoers stayed away. “Swimmers have been afraid to dive in the alewife-filled water,” said Dunes State Park Superintendent William Svetic, “because of the good possibility of coming up with a mouthful of dead fish.”

Words can’t describe how bad the smell was. Instead of taking a leisurely drive on Lake Shore Drive in Chicago with your car windows open, motorists rolled up the windows and sped off as quickly as possible to get away from the stench. The dead and rotting fish also attracted swarms of flies.

All along the lake, tourism suffered. A Chicagoan who kept a summer cottage one block from the beach at Beverly Shores, said alewives were piled up two feet deep. The smell and the flies kept him away. Michigan estimated that it lost 55-million dollars in tourist revenue due to the alewife. Wolf Lake in Hammond, which had a swimming beach at the time, saw a huge leap in the number of bathers. With no connection to Lake Michigan, Wolf Lake was relatively alewife free, although some of the fish still found a way to get there.

The 1967 invasion began in late April and was still a problem in late June. Abe Mills, who worked for the city of Whiting, said that every year since 1964, the die-off would begin sooner and would be more intense. By 1967, it was estimated that beaches all along Lake Michigan were inundated with billions of dead alewives. Every day, Mills said, a five-man city crew daily cleaned the beach, “but the fish keep drifting in every day.” Chicago had a ninety-person crew working around-the-clock to clear the shores. Most of the dead fish were buried in commercial landfills. In Chicago alone, the dead alewives formed a pile 500-feet high, nearly the size of two football fields. The amount of fish disposed of in Chicago was four times greater than one year’s worth of garbage collected by the city. The story was the same all along Lake Michigan.

By mid-July of 1967, the problem tapered off. In Whiting, having work crews doing nothing but clean up dead fish was “digging into our budget,” said Sylvester O’Connell, the Whiting parks superintendent. Yet, despite the additional cost, the city was interested in buying a piece of property from the railroads that was north of Atchison Avenue. It wanted to turn that land into an alewife burial ground. Whiting had been dumping the alewives in a landfill but getting there meant truckloads of rotting alewives had to pass through town. No one, said Mayor Frank Harangody, wanted trucks filled with dead fish to come through any part of the city.

Hammond didn’t need to worry as much about beach clearing in 1967, because its Lake Michigan beach was closed due to polluted waters. Pollution was the first guess many people had as the reason for the fish die-off. It was a major issue in the 1960s. But the experts quickly ruled that out as the cause. There was much debate about the cause, but the reasons given by most experts were that alewives were not adapted to life in fresh water, and the water temperature of the lakes were warmer than they were accustomed to. Because the alewife reproduces in massive numbers, even with millions dying, billions more were ready to replace them.

Eventually, humans came up with a plan. Part of that plan was already underway. A major effort to get rid of the sea lamprey was making progress by the early 1960s. With the threat of the blood-sucking lamprey diminished, an effort began to stock Lake Michigan with salmon and trout. With alewife high on their menu, both salmon and trout flourished. There were still alewives showing up on beaches, but the massive alewife die-offs became a thing of the past in the 1970s.

In more recent times, invasive species like the alewife and sea lamprey have taken a back seat to the zebra and quagga mussels, two other species that are not native to the Great Lakes. More than thirty years ago, they were carried here by ships from Eastern Europe. To maintain stability on their ocean-crossings, ships arriving in the Great Lakes are often loaded with what’s called ballast water. After reaching their destinations, crews would sometimes empty the ballast water into the lake. Unfortunately, that water sometimes contains organisms that are not native to North America. That was the case with the zebra and quagga mussels. They arrived here in an environment that didn’t have any of their natural enemies. In the prime years of the alewife invasion there were no zebra or quagga mussels in the lake, but the latest estimate is that Lake Michigan is now home to 300-trillion of these stamp-sized creatures.

The mussels clog water intakes, damage boats and docks, and they’ve made the waters of Lake Michigan seem clearer. But they’ve done that by changing the mix of nutrients in the water which in turn has allowed sunlight to reach new depths in the lake, which in turn has created a lush growth of harmful algae at the lake’s bottom, which in turn has had a harmful impact on other fish.   

When the alewife came on the scene, other fish species suffered. The alewife, for example, went after the same food source that the perch and whitefish depended on, leading to a decline in both of those species. Likewise, the arrival of the zebra and quagga mussels have changed the balance of nutrients that alewife depend on. That has contributed to a decline in the number of alewife, which has affected the population of salmon, which depend on alewife as a primary food source.

There are no signs that the beaches of Whiting and Hammond will experience anything like the alewife die-offs of the 1960s. But before 1950, who ever imagined that there would be billions of alewives in Lake Michigan? Before 1990, who ever imagined that there would be 300-trillion mussels residing on the bottom of Lake Michigan? There are now more than 185 non-native species in the lake. So, who can predict what the future may bring to our Lake Michigan doorstep?