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Scientists turn to high-tech tracking to learn more about Lake Erie sturgeon

You might say a 100-year-old lake sturgeon has seen it all.

Then the metal cylinders began appearing on the bottom of Lake Erie.

The devices – acoustic telemeters anchored to concrete weights – began appearing along the bottom of Buffalo Harbor over the last year or so and are now electronically tracking and logging the movements of the threatened lake sturgeon as they pass through Buffalo Harbor and other spots in the lake.

It’s part of a collaborative effort of federal and state scientists to learn more about this fish species that swam the earth’s waters at the same time Tyrannosaurus Rex was wreaking havoc on land.

The lake sturgeon could play an important role in the comeback of the Great Lakes.

Although a bottom-feeder not known as a particularly predatory carnivorous fish, lake sturgeon feed on two major invasive species – the round goby and zebra mussel. It’s part of the reason why its recovery may be much more important than just an interesting sideshow.

“There are a lot of questions that need to be answered,” said Jonah Withers, a fish biologist with the U.S. Fish and Wildlife Service.

Some answers that scientists seek involve sturgeon population, migration patterns, spawning locations and habits of juvenile sturgeon. It’s the first step toward allowing scientists to launch habitat restoration programs that will aid the fish in regaining the sort of numbers they enjoyed in the late 19th century before overfishing and pollution threatened them with extinction.

“Their numbers were reduced to low levels,” said Christopher Legard, a scientist with the state Department of Environmental Conservation. “Through most of our careers, they’ve been fish we didn’t know a lot about.”

Tracking sturgeon

In a sense, it’s a tale of 21st-century technology meeting the prehistoric world.

Over the last four years, scientists tagged more than 130 lake sturgeon with identifying numbers during their spawning season in Buffalo Harbor.

In May, for the first time, 22 of the sturgeon also were tagged with trackable devices – some with acoustical tags, others with satellite tags and some with both.

Telemeter receivers – small, data-logging computers in metal cylinders attached to concrete anchors – were placed in the lake, each equipped to pick up information from acoustic tags attached to passing lake sturgeon.

About three dozen receivers are arranged in a grid pattern across Buffalo Harbor. Another couple are set up in the Buffalo River and the upper Niagara River near Strawberry Island. Farther away, lines of telemetry devices are also in place from the shoreline near Sturgeon Point in Evans; Dunkirk; near the Pennsylvania state line; Erie, Pa.; Cleveland and the Lake Erie Islands in Ohio – forming a line stretching across Lake Erie to the Canadian shore.

“We’ll be able to see where the fish are moving all throughout the lake,” Legard said. “How far do they travel? We don’t really know.”

Population estimates of sturgeon in Lake Erie are also still tough for scientists to measure.

“We don’t know how many are actually out there,” said John Sweka, another fish biologist with the U.S. Fish and Wildlife Service. “We’re finding more of them, but we’re also looking harder for them.”

What scientists do know is that the ancient fish are certainly out there. They congregate in Buffalo Harbor during their spring spawning season and the same fish don’t come around every year.

“Sturgeon are so long-lived they don’t return to spawn every year,” Legard said. “Every year, you have the potential to only see a small subset of the population.”

Besides pinpointing exact spawning locations of the lake sturgeon, scientists hope to learn what they do in between, what their home range is, where they migrate, where their spawning areas are and what types of habitats they use.

The acoustic telemetry technology is cutting-edge, but comes with limitations. Scientists cannot gather the data in real time.

“It’s not like we can get on our computers and watch the fish,” Sweka said.

When a sturgeon with a specially numbered acoustic tag passes near a receiver, the device records that identification number as well as the time, date, depth and temperature. About twice a year, the receivers are retrieved so the information can be downloaded into computers.

Some fish are also tracked with satellite markers. While the acoustic tags remain on the sturgeon, the satellite markers are designed to pop off the fish and surface. Those tags then wirelessly relay data to satellites which can include detailed information about location, movement, temperature and depth of the fish’s journey in the lake.

Keystone fish

When all the data finally does start pouring in, probably sometime later this year, it will make for instantly groundbreaking research.

“We might find out they spend their entire year in Buffalo, we might find out they swim to Michigan and back,” Legard said. “This is going to be a really interesting project to see.”

Females, which can live 80 years or more, don’t reach reproductive maturity until they’re between 14 and 23 years old and then spawn only every four to six years, according to DEC data. The oldest lake sturgeon ever recorded was 154 years old and weighed 208 pounds when it was caught in Canadian waters north of Minnesota in the 1950s.

“This is an ancient, keystone fish,” Withers said. “This is one of the oldest freshwater species in North America.”

The lake sturgeon was once so plentiful along New York’s Lake Erie shoreline, legend had it you could walk on top of the water because of their sheer numbers below the surface.

“It was once a nuisance species in the late 1800s,” Withers said. “It kind of started plummeting, and numbers have been low over the past 50 years.”

Before scientists can get to work on restoring the habitat that lake sturgeon thrive in the most, they agree there’s a lot of learning to do.

“The information we’re getting here is basic life history on a charismatic fish that was once very important and driven down by overexploitation, habitat loss and water pollution,” Sweka said.

“We have to know more about the habitat they use,” Legard said.

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Lake sturgeon fact sheet

Scientific name: Acipenser fulvescens

New York status: Threatened

Size: Mature adults average 3 to 5 feet in length but can grow to larger than 7 feet

Weight: Range between 10 to 80 pounds, but can weigh more than 300 pounds

Nickname: The “living fossil”; a keystone species on earth, the lake sturgeon belongs to a family of aquatic creatures stretching back 135 million years

Life span: Up to 80 years or more for females, about 55 years for males

Sexual maturity: 14 to 23 for females, 8 to 19 years for males; mature female sturgeon can lay hundreds of thousands of eggs during one spawning season

Spawning season: Late spring

Distinguishing characteristics: Ancient lake sturgeon look the part. They appear primitive, with bony plates protecting their torpedo-shaped bodies. Their snouts are sharp and cone-shaped, and are equipped with four smooth barbels.

Diet: Bottom feeders, lake sturgeon use the barbels under their snouts to find food. They consume leeches, snails, clams and small fish. Also included in their diet are the invasive round goby fish and zebra mussels.

email: tpignataro@buffnews.com