1st time in 50 years
By JANET McCONNAUGHEY, Associated Press
Scientists and students embarking on a survey of Georgia’s lake sturgeon have found three females with mature eggs – an indication that armored “living fossils” may be breeding in this state for the first time in half a year. century.
“It’s exciting because it’s confirmation that they’re becoming mature and trying to reproduce,” said Martin J. Hamel, an associate professor at the University of Georgia’s Warnell School of Forestry and Natural Resources, in a recent press release.
Fossils indicate that the spade-nosed fish with a bottom-mounted suction pipe instead of jaws has been around for more than 136 million years, scientists say.
According to the US Fish and Wildlife Service, the lake sturgeon lives in 18 states and five Canadian provinces in the watersheds of the St. Lawrence, Hudson’s Bay, Great Lakes and Mississippi.
Pollution, habitat destruction, and the harvesting of meat and caviar have diminished their numbers so much that the U.S. Fish and Wildlife Service is considering federal protection for the species.
The bone-clad bodies of sturgeons damaged fishing nets so badly that commercial fishermen hauled away large numbers in the 1800s and left them on the banks of rivers and lakes, says the Minnesota Department of Natural Resources. on its website.
Dams, which prevent large fish from migrating from lakes to rivers where they spawn, have also reduced their numbers. Lake sturgeon are now less than 1% of historical levels.
State protections, such as fishing limits and stocking programs, some run by Native American tribes, have helped the sturgeon.
In the 1970s, the lake sturgeon was wiped out from the Coosa River basin in northwest Georgia, the only place it was found in Georgia.
The state Department of Natural Resources began reintroducing lake sturgeon 20 years ago after the Clean Water Act cleaned up the river, Hamel said.
Females take 20 to 25 years to mature and produce the shiny black eggs people love to eat, according to Michigan Sea Grant. So until such eggs appeared this year in females implanted with radio-telemetry tags to track their movements, no one knew if Georgia sturgeon survived long enough to reproduce.
“Because lake sturgeon take a long time to mature and reproduce intermittently – every two or three years – we really need a robust population of different size and age classes,” Hamel said. .
The current population assessment is the largest since Georgia first collected fish eggs in Wisconsin, raised them in a hatchery, and released them into the Coosa in 2002. Natural Resources staff of the state, in conjunction with their counterparts in Wisconsin, have done so almost every year since.
“It’s a big investment because you don’t even know if the stocked fish will survive, let alone grow and reproduce,” Hamel said.
About 330,000 fish, most about six inches long, have been released since 2002, Hamel said in an email to The Associated Press.
“Although that seems like a lot of sturgeon, the survival rate of fish that are released at this size is probably between 1 and 10 percent,” he wrote.
Students catch as many lake sturgeon as possible to estimate population size, survival and growth rates. The project started in the spring. It will run this summer and next spring and summer, ending in the winter of 2023, Hamel wrote.
Radio telemetry beacons will give a better picture of where sturgeons tend to live in the river basin.
“We have implanted 28 fish with telemetry tags so far, and plan to implant 12 more in the coming months,” Hamel wrote.
Scientists have implanted tiny PIT tags, like those used to identify pets, into hundreds of fish over the past two decades. The tags let researchers know when and where scientists have captured the fish before.
Hamel said about 15-20% of the fish caught had PIT tags, and there was one in every untagged fish.
Five adults and five juveniles will also be given a tag that records depth and temperature every 10 seconds, he said.
Information from the first three years of restocking suggests that the juveniles are surviving.
“There have been a lot of questions about long-term survival, growth rates and when these fish would become sexually mature – and we are in the process of determining whether these fish will be successful in reproducing,” Hamel said. .
The oldest recorded lake sturgeon was 152 years old, according to the Fish and Wildlife Service. The agency says the fish can grow up to 9 feet (2.7 meters) long and 310 pounds (140 kilograms).
The largest captured so far by the Georgia group was 52 inches (1.3 meters) long and weighed 24 pounds (11 kilograms).
“This is the largest fish anyone has documented on the Coosa River,” Hamel wrote.
McConnaughey reported from New Orleans.
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