What happened to the biggest and oldest Great Lakes fish?

A little more than 100 hundred years ago, the lake sturgeon was the biggest predator in the Great Lakes.

The filter-feeding fish can grow up to eight feet long, 300 pounds and can live from 55 to 150 years, according to Michigan Sea Grant. Lake sturgeons are the oldest and largest fish in the Great Lakes.

European settlers who came to the Great Lakes region recorded such a large sturgeon population that the fish were known to capsize fishing boats.

By the mid-1800s, sturgeons were discovered to be highly profitable as their meat and eggs could be processed into a delicacy and sturgeon swim bladders could be turned into isinglass, a gelatin used in making beer and wine.

However, due to this high demand, the population dwindled, and by 1928, the total Great Lakes sturgeon harvest hit only about 2,000 pounds.

The lake sturgeon has been decimated due to over-fishing and habitat intervention. The fish is currently listed as threatened, and methods are being created to help save the disappearing lake sturgeon.

Michigan prohibits lake sturgeon fishing and closely regulates sturgeon sport fishing. Restoration efforts to improve sturgeon habitats are underway by volunteers in the Michigan area.

On Oct. 6, the Toledo Zoo and and several partnering organizations released 3,000 young lake sturgeons into the Maumee River to help flare the population numbers back up, according to a Toledo Zoo press release. Additional fish released from the USFWS National Fish Hatchery in Genoa, Wisconsin, contributed to the 3,000 released sturgeons.

The Great Lakes Fish and Wildlife Restoration Act Grants Program and the U.S. Fish and Wildlife Services provided the Toledo Zoo with grants to “construct a modular facility on Zoo-owned property near the Maumee River to hatch and rear the fish.”

Lake sturgeons reach adulthood after about 15 years, and the zoo hopes that with its aid, the released sturgeons can revive the small and scattered population.

Maintaining the population isn’t as easy as it sounds.

The current lampricide being pumped into rivers to kill sea lamprey larvae actually targets juvenile lake sturgeons as well, said Michael Wagner, an aquatic ecologist and associate professor at Michigan State University. 

To give the lake sturgeon a fighting chance, lampricide methods need to be changed to either more natural methods using sea lamprey odor manipulation or a different chemical compound used to kill larvae.



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