A Dinosaur Among Us- The Lake Sturgeon

A Dinosaur Among Us- The Lake Sturgeon

A Dinosaur Among Us- The Lake Sturgeon

 

Like Elvis, dinosaurs are not dead.

Don’t believe me? Well, it’s true…sort of. While they may not be ‘dinosaurs’ per say, they are really really REALLY old.

I’m talking, of course, about Acipenser fulvescens, or the Lake sturgeon as everyone who isn’t trying to sound smart (cough cough) calls it.

A Brief Biology Lesson

As I mentioned, sturgeon are a very old species; fossils have been aged at over 60 million years old. This is evident in that sturgeons do not have calcium-based bones or vertebrae, but rather have a cartilaginous notochord. The only other fish species in the world that still maintains this bone structure are the lamprey.

Lake sturgeons are benthic (bottom) feeders that typically reside over the mud, sand, and gravel of large lakes and rivers. They commonly grow to a length of 3-5 feet and tip the scales anywhere from 20 to 80 pounds. Outside of the Northeastern US, they have been recorded in excess of 7 feet long and weighing more than 300lbs. Lake sturgeon are omnivorous, eating virtually anything that is remotely edible. Prowling the bottom, they use barbels to feel for something tasty. Upon finding something, the fish protrudes its tube-like mouth, sucks the food in, and simply spits out what it doesn’t want.

When sturgeons reproduce in the spring, they put on a show. Groups of adults come together along rocky river banks to perform rituals that include full body rolls, slapping the surface with their tails, and launching themselves completely out of the water. A female can produce 100,000 to 800,000 eggs at a time, which get locked between the rocks as they flow downstream.

Lake sturgeons are one of the longest-living freshwater fish; the oldest on record is 154 years old. This means they are also one of the slowest to reach sexual maturity. It takes nearly 15 years before a female sturgeon can reproduce.

It’s a Hard-Knock Life

Life hasn’t been very kind to the Lake sturgeon. At one time, they were so plentiful in Lake Champlain, they were considered a trash fish. They were a nuisance that fouled up the nets of fisherman trawling for salmon, which were also abundant at the time (notice a theme here?).  Believe it or not, some reports say that in the mid-1800’s, people would catch them to use as fertilizer, or to dry and burn in the winter!

Around 1880, people came to the realization that Lake sturgeon actually tasted pretty good when smoked. Additionally, the discover of isinglass, a gelatinous material found in their swim bladder and used broadly in the culinary world, brought significant fishing pressure on them. By the turn of the century, catch rates had dropped by 80%.

To make matters worse, the sturgeon was dealt a one-two punch of urban and agricultural development. Newly erected dams blocked them from their spawning grounds; toxic PCBs from urban areas caused high death rates; and algae blooms feeding on farm run off sucked the oxygen out of the water.  Catch numbers continued to dwindle until, in 1967, it was closed for good.

Look On The Sunny Side

Lake sturgeons are currently listed as endangered in Lake Champlain, but awareness of this special species is gaining. While no modern stocking program exists for them in Lake Champlain, agencies continue to keep a close eye on them. It is believed that, while slow, the population is rebounding and with proper management of habitat, a stocking program may not be necessary. Genetic sampling has shown that there is a naturally reproducing population that is large enough not to be experiencing any genetic crossover.

 

For more information, please see these links:

http://www.dec.ny.gov/animals/26035.html

http://genome-lab.ucdavis.edu/publications/Welsh_et_al_2008.pdf

http://www.vtfishandwildlife.com/library/Reports_and_Documents/Fish_and_Wildlife/Spawning_Habitat_Suitability_for_Walleye_and_Lake_Sturgeon_in_the_Missisquoi_River.pdf

 

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