16-02-2025
Documentary explores devastating sea lampreys of Great Lakes
Feb. 15—With their eel-like bodies, vampire teeth and suction cup mouths, the main characters of a new documentary resemble something out of the "Dune" science fiction films.
The sea lamprey nearly destroyed fishing in the Great Lakes. The new 90-minute film "The Fish Thief: A Great Lakes Mystery," narrated by Academy Award-winning actor J.K. Simmons, tells the story of those who tackled the mystery of why lake trout, one of the most prized fish in the Great Lakes, nearly vanished.
The near cataclysm destroyed jobs and businesses and devastated towns and Indigenous communities in the U.S. and Canada. As one expert says in the film, "The effort invested in lake trout recovery is probably the largest scale species recovery program ever. It exceeds by quite a margin the amount of federal effort invested in any species recovery in the country."
But the effort to find a solution to control sea lampreys faced hurdles and several setbacks were recorded before a remedy was found.
"If you don't care about fishing, know nothing about the Great Lakes or care about the Great Lakes, this is a story about human perseverance and persistence," "Fish Thief" writer, director and producer T. Lindsey Haskin said in a phone interview. "These researchers were given a task to basically find a needle in a hay stack and a way to solve this issue in order to save small town economies, jobs and small businesses on both sides of the Great Lakes in Canada and the U.S."
"The Fish Thief" has been showcased at regional, national and international film festivals, where it earned multiple awards. On Feb. 1, it became available on Apple TV and Amazon Prime Video.
Haskin, founder of California-based Skyhound Media, grew up in a suburb of Detroit and his father was an avid fisherman. "I grew up fishing, boating and all that sort of thing," he said. "This film is deeply personal to me."
The first recorded observation of a sea lamprey in the Great Lakes was in 1835 in Lake Ontario, according to the Great Lakes Fishery Commission, which worked with Skyhound Media to produce the film. The parasitic fish, native to the Atlantic Ocean, have remained largely unchanged for more than 340 million years and have survived through at least four major extinction events. Sea lampreys attach to fish with their suction cup mouths then dig their teeth into flesh for grip. In their native Atlantic Ocean, thanks to co-evolution with fish there, sea lampreys are parasites that typically do not kill their host. In the Great Lakes, where no such co-evolutionary link exists, sea lampreys act as predators, with each individual capable of killing up to 40 pounds of fish over their 12-18 month feeding period.
Sea lampreys eventually detach from their host. Afterwards, they migrate up freshwater tributaries to spawn.
Before the sea lamprey invasion, Canada and the United States harvested about 15 million pounds of lake trout in the upper Great Lakes each year. By the late 1940s, sea lamprey populations had exploded. They fed on large numbers of lake trout, lake whitefish, and ciscoes — fish that were the mainstays of a thriving Great Lakes fishery. By the early 1960s, the catch had dropped dramatically, to approximately 300,000 pounds — about 2% of the previous average.
Travels and research
"The Fish Thief" is a product of nearly eight years of research and production, with Haskin working closely with indigenous communities, anglers, biologists, historians, environmental agencies and conservationists.
"We went all the way from the eastern end of Lake Ontario to Duluth, Minnesota and up into Ontario, north of Minnesota and all the way down to Chicago," Haskin said. "We were in small towns all over the place and going out with tribal communities, First Nations and fishermen in different places. It was a very involved effort."
Filming also took place aboard scientific research vessels, commercial fishing tugs, trap net vessels and the boats of sports anglers. Haskin, who has written, produced or directed more than 400 productions, also made use of archival film and records.
"We combed historical societies, university archives, state and provincial archives and any kind of places where we could find archival images from the day," he said.
The film shows how overfishing, dam building and industrial dumping decimated fish populations in parts of the Great Lakes. But nothing compared to the effects of the sea lamprey.
Safe passage
Niagara Falls had served as a natural barrier to sea lampreys, confining the parasites to Lake Ontario and preventing them from entering the remaining four Great Lakes.
However, in the late 1800s and early 1900s, improvements to the Welland Canal, which bypasses Niagara Falls and provides a shipping connection between Lakes Ontario and Erie, allowed sea lampreys access to the rest of the Great Lakes. They entered Lake Erie by 1921, Lakes Michigan and Huron by 1936 and 1937, and Lake Superior by 1938, according to the Great Lakes Fishery Commission.
By the 1950s, lake trout were wiped out in Lake Ontario due to uncontrolled fishing and sea lamprey predation. Other Great Lakes saw a similar depletion or massive drops in the number of lake trout.
The GLFC, a binational organization, was created at the 1954 Convention of Great Lakes Fisheries to control sea lampreys.
"The Fish Thief" documents the discovery of "strange eel-like creatures" discovered in Lake Erie in 1921 and their spread.
Different methods were tried to control the sea lamprey invasion, including electrical barriers.
But experts settled on a search for a chemical to use as a remedy.
Early results were discouraging. But after testing more than 5,000 compounds, it was discovered in 1958 that TFM (3-trifluoromethyl-4-nitrophenol) was highly effective in controlling sea lampreys without significantly impacting other species. It continues to be the primary means by which sea lampreys are controlled. The GLFC says about 250 Great Lakes tributaries are treated at regular intervals with the lampricide.
Sea lampreys are most vulnerable during their larval stage, when TFM is applied to streams, not to the open waters of the Great Lakes. Studies by GLFC has shown it does not accumulate in the aquatic environment and it breaks down in a matter of days.
The control of the sea lamprey led to another issue. The parasites decimated predatory fish, causing another invasive species, the alewife, to explode.
Lakes exceeded their carrying capacity for alewives, leading to massive die-offs of the fish that washed up on shores and discouraged tourism. Alewife control was needed, and the stocking of salmon in the 1960s was seen as the answer.
"The Fish Thief" explores how the stocking of salmon and other fish created a booming sports fishing industry in all of the Great Lakes.
"This story is about an instance where government and science were the last resort to save fishing in the Great Lakes," Haskin said. "It was government, and it was science that got us to this point. I don't think that people should blanket trust government. We have to hold our government officials' feet to the fire to make sure they are being honest, not corrupt and not telling us things that are not true. It's the same thing with scientists. Their data can be questionable and whoever is funding them may be influencing their conclusions."
But "The Fish Thief," Haskin said, documents how "science and the government came to the rescue."
"We still have fish in the Great Lakes and a very lucrative sports fishery came out of this that wouldn't exist without sea lamprey control," he said.
"Since the Great Lakes Fishery Commission was established in 1955, Canada and the United States have worked together to carry out one of the most successful aquatic invasive species control programs in the world," said GLFC commissioner Ethan Baker. "Despite the success, not everyone knows about the commission's work or even sea lampreys. This documentary is an exciting and lively way to remind people that the world-class, $6 billion Great Lakes fishery that we enjoy today, is the result of an unwavering commitment to work together across borders. The lessons learned over the past seven decades serve as an important reminder of the havoc caused by invasive species and why we need to be vigilant stewards of our Great Lakes."
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THE DETAILS
WHAT: "The Fish Thief: A Great Lakes Mystery."
PRODUCED BY: Skyhound Media and Great Lakes Fishery Commission.
RUNNING TIME: 90 minutes.
SYNOPSIS: When fish began disappearing far from industrial cities, scientists discovered what proved to be the most destructive marine species to ever invade the Great Lakes.
WHERE TO WATCH: For rent or purchase on the Apple TV app and it can be watched for free on Amazon Prime Video, which requires a subscription. GLFC says screenings are planned throughout the Great Lakes region.
