Scientists and students starting a census of Georgia Lake sturgeon have found three females with mature eggs – a sign that armored “living fossils” may have reproduced in that state for the first time in half a century.
Martin J., an associate professor at the University of Georgia’s Warnell School of Forestry and Natural Resources. “This is exciting because it is a confirmation that they are maturing and trying to lay eggs,” Hamel said in a recent news release.
According to scientists, fossils indicate that the spade-nosed fish with a vacuum tube down instead of jaws has existed for more than 136 million years.
According to the US Fish and Wildlife Service, one of nine sturgeon species and subspecies found in the US, the lake sturgeon lives in 18 states and five Canadian provinces in the St. Lawrence, Hudson Bay, Great Lakes and Mississippi River watersheds.
Pollution, habitat destruction and harvesting for meat and caviar have reduced their numbers so much that the US Fish and Wildlife Service is considering federal protection for the species.
The bone-plated bodies of sturgeons caused so much damage to fishing nets that commercial fishermen released them into river and lakebeds in large numbers in the 1800s, the Minnesota Department of Natural Resources states on its website.
Dams, which prevent large fish from migrating from the lakes to the rivers where they breed, also reduced their numbers. Now Lake Sturgeon are at less than 1% of historical levels.
State protections, such as fishing limits, and stocking programs, run by some Native American tribes, have helped the sturgeon.
By the 1970s, lake sturgeon had been wiped out from the Kusa River basin in northwestern Georgia—the only place they were found in Georgia.
Hamel said the state’s Department of Natural Resources began reintroducing Lake Sturgeon after the river was cleaned up by the Clean Water Act 20 years ago.
According to the Michigan Sea Grant, it takes 20 to 25 years for females to mature and lay the dark, shiny eggs that men like to eat. So until such eggs arrived this year, with females being implanted with radio telemetry tags to track their movement, no one knew that Georgia’s sturgeon lived long enough to breed. were or not.
“Since lake sturgeons take a long time to mature and then breed intermittently — every two to three years — we really need a strong population of different sizes and age groups,” Hamel said. Told.
The current population assessment is the largest since Georgia first collected eggs from fish in Wisconsin, raised them in a hatchery, and released them to Cusa in 2002. State natural resource workers, working with their Wisconsin counterparts, have been doing this almost every year.
“It’s a big investment because you don’t even know whether the stocked fish are going to survive, let alone grow up and breed,” Hemmel said.
Hemel said in an email to the Associated Press that since 2002, about 330,000 fish, about 6 inches (15 cm) long, have been released.
“While this sounds like a lot of sturgeon, fish released at that size are likely to have a survival rate of between 1-10%,” he wrote.
Students are catching as many lake sturgeon as they can to estimate population size, survival and growth rates. The project started in the spring. It will run this summer and through next spring and summer, ending in winter 2023, Hamel wrote.
Radio telemetry tags will give a better picture of where sturgeons live in the river basin.
“We have implanted 28 fish with telemetry tags so far, and plan to have 12 more in the coming months,” Hamel wrote.
Scientists have applied tiny PIT tags, such as those used to identify pets, to hundreds of fish over the past two decades. Tags let researchers know when and where scientists first caught fish.
Hamel said that about 15% to 20% of the fish being caught have PIT tags, and one is going into every untagged fish.
He said five adults and five juveniles would also get a tag that would record depth and temperature every 10 seconds.
Information from the first three years after recharge suggested that the juveniles were alive.
“There are a lot of questions about longevity, growth rates, and when these fish will become sexually mature – and we are on the verge of determining whether these fish are going to reproduce successfully,” Hamel said. Told.
According to the Fish and Wildlife Service, the oldest lake sturgeon on record was 152 years old. The agency says the fish can reach up to 9 feet (2.7 m) long and 310 pounds (140 kg).
The largest ever caught by the Georgia group was 52 inches (1.3 m) long and weighed 24 pounds (11 kg).
“This is the largest fish anyone has documented on the Kosa River,” Hamel wrote.
McConaughey reported from New Orleans.
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