Excerpt from The Dynamic Great Lakes
"The largest and most primitive fish in the Great Lakes is the
Sturgeon. Cruising along on bottoms of the lakes, they remind us of
dinosaurs that roamed planet Earth in earlier epochs. Their huge
bodies are supported by cartilage as well as bone. They can weigh up
to 300 pounds, and like some dinosaurs, they have rows of plates
along their heads and bodies to protect them. When all of the lakes
and their tributary rivers were cleaner than they are now, and when
there were no dams to block their way, these great fish would spawn
by running up rivers. In Lake Superior, they still run up the Sturgeon
River in Michigan’s Upper Peninsula to spawn and may be seen
surfacing like submarines, sticking their snouts above the water in
pools below waterfalls. The Sturgeon has been living in the Great
Lakes ever since the last glaciers retreated and fish entered the lakes
through crystal clear tributary streams. Sturgeon’s eggs (roe) are a
delicacy known as caviar when processed for human food.
In 1974 the Sturgeon was included on a list of threatened species.
These ancient fish cruise the lake bottom feeding upon crayfish,
insect larvae, clams and bottom plants. This is their ecological niche
where they use their long shovel shaped snout with a sucker-like
mouth underneath to feed. Two whisker-like barbels near their
mouths help them to feel their way along the bottom. The Sturgeon
is slow to mature; it may not spawn until it is 14 to 22 years old."