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These Prehistoric Fish Are Making a Slow Comeback in the Midwest

Animals
Two ice fishers with a truck cut a hole in the ice near an ice fishing hut on frozen Lake Winnebago.
Richard Hamilton Smith / Corbis NX / Getty Images

By Susan Cosier

Come February in Wisconsin, almost everything will be covered in ice and snow. In little shanties on frozen Lake Winnebago, a 30-by-13-mile lake in the eastern part of the state, fishers will keep watch over rectangular holes cut into the ice with a chainsaw. When they spot a fin passing below, they'll jab their spears down deep. The lucky ones will earn themselves a lake sturgeon, a species that has prowled the earth's waters for more than 150 million years.


Lake Winnebago is one of only two locations in the world where people can spearfish lake sturgeon. These armored fish, also distinguished by whiskerlike barbels growing from their chins, can live as long as a century, weigh as much as 200 pounds, and grow more than seven feet long. Every year, people gather on the lake for a 16-day fishing event. Just 500 licenses exist, a number that keeps overfishing in check while allowing nearly 1,000 sturgeon to be taken for their caviar (for those lucky enough to catch a female) and meat (delicious when smoked).

The sturgeon spearing event will mark its 80th season this year. And with the fish listed as threatened in 19 of the 20 states where it's found, Wisconsin wildlife officials consider the event one of a number of tactics that help educate people about the fish. (Another is an adoption program allowing members of the public to sponsor and hand-release young fish, reared at a state hatchery, into Lake Michigan and the Milwaukee River, part of the annual SturgeonFest.) Efforts to revive their populations have been somewhat successful, but it's been slow going: Female lake sturgeon don't start reproducing until they're at least 20 years old.

This biological fact, combined with overfishing, pollution, and habitat degradation, has resulted in their plight today. An estimated 15 million sturgeon used to exist in the Great Lakes, with fishers bringing in upwards of four million pounds per year between 1879 and 1900. The trade took a serious toll on the species. By 1929, commercial sturgeon fishing had closed in Lake Michigan due to too few fish. And by the end of the century, fishers had taken 80 percent of the sturgeon out of Lake Erie. Meanwhile, dams and development ruined habitat and kept the fish from reaching key spawning grounds. In response to the population crash, most states instituted protections and mandated hunting limits in the 1990s and early 2000s.

Today, only 1 percent of the lake sturgeon's population remains. In addition to the states that list them as threatened, the United States Fish and Wildlife Service announced in August that it would study whether to list the fish as federally threatened or endangered.

“The Right Thing for the Great Lakes”

Ryan Koenigs, a fisheries biologist with the Wisconsin Department of Natural Resources (DNR), is among those dedicated to bringing the lake sturgeon back. He's part of a team that keeps track of every individual caught, and he helps run the registration stations where fishers who spear a sturgeon in Lake Winnebago must go before taking their catch home. Koenigs and his colleagues look for a passive integrated transponder (PIT) tag, which offers information about the fish. These tags are implanted in each fish reared or caught and released by the agency. Some individuals caught in the past few years were tagged decades ago. "I'm reaping the benefits right now of what the biologists two generations before me did in the 1970s," Koenigs says.

Restoration efforts also exist in many other states bordering the Great Lakes. In New York, the Department of Environmental Conservation, the U.S. Fish and Wildlife Service, and the Saint Regis Mohawk Tribe harvest sturgeon eggs from the St. Lawrence River and send them to hatcheries in the central part of the state and in Wisconsin. In Michigan, fisheries biologists, researchers, and state agencies successfully protected the sturgeon population in Black Lake and now use the data collected from their efforts to guide their restocking of nearby lakes and streams.

These types of projects replenish waterways with the fish, but the species' recovery has a long way to go. Should conservationists succeed, the fish could end up benefiting the entire ecosystem, notes Ed Baker, a fisheries biologist in Michigan. "If we have a native species fish community that's been degraded, that's a sign that its environment is no longer healthy," he says. "If we can restore lake sturgeon to their prominence, or at least somewhat close to what their prominence was before we started harvesting them, that's a sign that we're doing the right thing for the Great Lakes."

As the lake sturgeon populations rebound, they could help biologists beat back some new threats, too. Notably, they eat invasive zebra and quagga mussels that now blanket the lake beds. They also eat invasive round gobies. All three of these marine species hail from faraway waters and snuck their way in through the ballast water used to balance ships' hulls.

Mysteries Unsolved

In 1995, Baker was tasked with finishing and implementing Michigan's new sturgeon rehabilitation plan. He observed reach after reach, finding only a few places were the fish still existed. One of those was the Upper Peninsula's Black Lake. Locals still spearfished sturgeon, and the population appeared to be falling. In 2001 Baker and Kim Scribner of Michigan State University set out to study the fish and get a rough population estimate. They concluded that over a 25-year period, sturgeon numbers had declined by more than 60 percent.

The state's Department of Natural Resources decided sturgeon spearfishing could continue, but fishers could harvest no more than five fish a year. Baker and his team stocked the lake, too, and the sturgeon population grew. The limit is now up to 14. Still, the population isn't recovering as quickly as expected.

To figure out why, Baker and Scribner continue their research. They also use the information they collect on basic sturgeon biology, genetics, and behavior to inform conservation efforts in other Michigan water bodies.

One major question they hope to answer concerns the timing of the sturgeon's reproduction. As with steelhead and salmon, it appears that the river where sturgeon spend the first summer of life, between May and October, is imprinted on the fish, and they come back to that place to spawn. Confirming this would help in their stocking efforts—especially in reaches where the fish haven't swum for decades.

In addition to the hatchling adopt-and-release program that takes place in September in Milwaukee, Wisconsonites get another opportunity to help biologists in April, when Koenigs does his stock assessments. On the Wolf River near Lake Winnebago, hundreds of thousands of sturgeon ranging in size from four to seven feet long swim along the waterline. Koenigs and his team stand at the ready with nets to pull the fish out of the water, then weigh, measure, and tag them.

When the team finds fish with those tags implanted during the February spearfishing season, they track the data to get a tagged to non-tagged fish ratio, which is then used to set harvest limits. The data collected at each event helps inform how best to manage the species.

"We're on the right path," says Koenigs, who is now prepping for the spearfishing season that begins on Feb. 8. "The work that's being done through these various efforts seems to be showing some pretty promising signs."

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Guillain-Barre syndrome occurs when the body's own immune system attacks and injures the nerves outside of the spinal cord or brain – the peripheral nervous system. Niq Steele / Getty Images

By Sherry H-Y. Chou, Aarti Sarwal and Neha S. Dangayach

The patient in the case report (let's call him Tom) was 54 and in good health. For two days in May, he felt unwell and was too weak to get out of bed. When his family finally brought him to the hospital, doctors found that he had a fever and signs of a severe infection, or sepsis. He tested positive for SARS-CoV-2, the virus that causes COVID-19 infection. In addition to symptoms of COVID-19, he was also too weak to move his legs.

When a neurologist examined him, Tom was diagnosed with Guillain-Barre Syndrome, an autoimmune disease that causes abnormal sensation and weakness due to delays in sending signals through the nerves. Usually reversible, in severe cases it can cause prolonged paralysis involving breathing muscles, require ventilator support and sometimes leave permanent neurological deficits. Early recognition by expert neurologists is key to proper treatment.

We are neurologists specializing in intensive care and leading studies related to neurological complications from COVID-19. Given the occurrence of Guillain-Barre Syndrome in prior pandemics with other corona viruses like SARS and MERS, we are investigating a possible link between Guillain-Barre Syndrome and COVID-19 and tracking published reports to see if there is any link between Guillain-Barre Syndrome and COVID-19.

Some patients may not seek timely medical care for neurological symptoms like prolonged headache, vision loss and new muscle weakness due to fear of getting exposed to virus in the emergency setting. People need to know that medical facilities have taken full precautions to protect patients. Seeking timely medical evaluation for neurological symptoms can help treat many of these diseases.

What Is Guillain-Barre Syndrome?

Guillain-Barre syndrome occurs when the body's own immune system attacks and injures the nerves outside of the spinal cord or brain – the peripheral nervous system. Most commonly, the injury involves the protective sheath, or myelin, that wraps nerves and is essential to nerve function.

Without the myelin sheath, signals that go through a nerve are slowed or lost, which causes the nerve to malfunction.

To diagnose Guillain-Barre Syndrome, neurologists perform a detailed neurological exam. Due to the nerve injury, patients often may have loss of reflexes on examination. Doctors often need to perform a lumbar puncture, otherwise known as spinal tap, to sample spinal fluid and look for signs of inflammation and abnormal antibodies.

Studies have shown that giving patients an infusion of antibodies derived from donated blood or plasma exchange – a process that cleans patients' blood of harmful antibodies - can speed up recovery. A very small subset of patients may need these therapies long-term.

The majority of Guillain-Barre Syndrome patients improve within a few weeks and eventually can make a full recovery. However, some patients with Guillain-Barre Syndrome have lingering symptoms including weakness and abnormal sensations in arms and/or legs; rarely patients may be bedridden or disabled long-term.

Guillain-Barre Syndrome and Pandemics

As the COVID-19 pandemic sweeps across the globe, many neurologic specialists have been on the lookout for potentially serious nervous system complications such as Guillain-Barre Syndrome.

Though Guillain-Barre Syndrome is rare, it is well known to emerge following bacterial infections, such as Campylobacter jejuni, a common cause of food poisoning, and a multitude of viral infections including the flu virus, Zika virus and other coronaviruses.

Studies showed an increase in Guillain-Barre Syndrome cases following the 2009 H1N1 flu pandemic, suggesting a possible connection. The presumed cause for this link is that the body's own immune response to fight the infection turns on itself and attacks the peripheral nerves. This is called an "autoimmune" condition. When a pandemic affects as many people as our current COVID-19 crisis, even a rare complication can become a significant public health problem. That is especially true for one that causes neurological dysfunction where the recovery takes a long time and may be incomplete.

The first reports of Guillain-Barre Syndrome in COVID-19 pandemic originated from Italy, Spain and China, where the pandemic surged before the U.S. crisis.

Though there is clear clinical suspicion that COVID-19 can lead to Guillain-Barre Syndrome, many important questions remain. What are the chances that someone gets Guillain-Barre Syndrome during or following a COVID-19 infection? Does Guillain-Barre Syndrome happen more often in those who have been infected with COVID-19 compared to other types of infections, such as the flu?

The only way to get answers is through a prospective study where doctors perform systematic surveillance and collect data on a large group of patients. There are ongoing large research consortia hard at work to figure out answers to these questions.

Understanding the Association Between COVID-19 and Guillain-Barre Syndrome

While large research studies are underway, overall it appears that Guillain-Barre Syndrome is a rare but serious phenomenon possibly linked to COVID-19. Given that more than 10.7 million cases have been reported for COVID-19, there have been 10 reported cases of COVID-19 patients with Guillain-Barre Syndrome so far – only two reported cases in the U.S., five in Italy, two cases in Iran and one from Wuhan, China.

It is certainly possible that there are other cases that have not been reported. The Global Consortium Study of Neurological Dysfunctions in COVID-19 is actively underway to find out how often neurological problems like Guillain-Barre Syndrome is seen in hospitalized COVID-19 patients. Also, just because Guillain-Barre Syndrome occurs in a patient diagnosed with COVID-19, that does not imply that it was caused by the virus; this still may be a coincident occurrence. More research is needed to understand how the two events are related.

Due to the pandemic and infection-containment considerations, diagnostic tests, such as a nerve conduction study that used to be routine for patients with suspected Guillain-Barre Syndrome, are more difficult to do. In both U.S. cases, the initial diagnosis and treatment were all based on clinical examination by a neurological experts rather than any tests. Both patients survived but with significant residual weakness at the time these case reports came out, but that is not uncommon for Guillain-Barre Syndrome patients. The road to recovery may sometimes be long, but many patients can make a full recovery with time.

Though the reported cases of Guillain-Barre Syndrome so far all have severe symptoms, this is not uncommon in a pandemic situation where the less sick patients may stay home and not present for medical care for fear of being exposed to the virus. This, plus the limited COVID-19 testing capability across the U.S., may skew our current detection of Guillain-Barre Syndrome cases toward the sicker patients who have to go to a hospital. In general, the majority of Guillain-Barre Syndrome patients do recover, given enough time. We do not yet know whether this is true for COVID-19-related cases at this stage of the pandemic. We and colleagues around the world are working around the clock to find answers to these critical questions.

Sherry H-Y. Chou is an Associate Professor of Critical Care Medicine, Neurology, and Neurosurgery, University of Pittsburgh.

Aarti Sarwal is an Associate Professor, Neurology, Wake Forest University.

Neha S. Dangayach is an Assistant Professor of Neurology and Neurosurgery, Icahn School of Medicine at Mount Sinai.

Disclosure statement: Sherry H-Y. Chou receives funding from The University of Pittsburgh Clinical Translational Science Institute (CTSI), the National Institute of Health, and the University of Pittsburgh School of Medicine Dean's Faculty Advancement Award. Sherry H-Y. Chou is a member of Board of Directors for the Neurocritical Care Society. Neha S. Dangayach receives funding from the Bee Foundation, the Friedman Brain Institute, the Neurocritical Care Society, InCHIP-UConn Center for mHealth and Social Media Seed Grant. She is faculty for emcrit.org and for AiSinai. Aarti Sarwal does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

Reposted with permission from The Conversation.