What is a Sturgeon?
A sturgeon is a primitive type of fish from the Acipenseridae family. The term “sturgeon” actually incorporates 25 different species of fish, all identified by the bone plates on their heads and bodies and by the barbels that dangle from around their toothless mouths. The evolution of sturgeons can be traced as far back as the dinosaur era. Species of sturgeons are most commonly found in North America and Russia.
The sturgeon's bony plates, or scutes, serve as protection and replace the scales present on most fish. Their barbels, which look like whiskers, help them find food. The barbels are very sensitive, and sturgeons will drag them along the ocean floor or river bed to locate food sources. The sturgeon's diet consists mostly of small fish and invertebrates.
The term "sturgeon" incorporates more than two dozen species of fish, so their size and weight vary. For example, at its largest, a shortnose sturgeon measures about 4.7 feet (1.4 m) and weighs about 51 pounds (23 kg). The largest freshwater fish in North America, the white sturgeon, can be 20 feet (6 m) long and weigh about 1,500 pounds (680 kg). Still larger, the beluga, found in the Caspian and Black seas, measures about 24.6 feet (7.5 m) and can weigh 2,900 pounds (1,315 kg).
Sturgeons live in temperate waters. Some are restricted to freshwater areas, but many live at sea or near estuaries and enter rivers only to spawn. For many species, the spawning location is determined by the speed of the river. For example, shortnose sturgeons live primarily in areas where the water flow is slow, but they travel to faster-moving rivers to spawn.
Some sturgeons can live more than 300 years, although like their size and weight, their life cycles vary. White sturgeons generally live more than 100 years, reaching maturity between ages 15 to 25 and spawning every four to 11 years. By contrast, shortnose sturgeons have a much shorter life span. Males live only about 30 years, though the females can live as long as 67 years, spawning every three years.
Sturgeons are very useful to humans and have thus been over-fished to the extent that some species, such as the shortnose, have been placed on the endangered species list. To combat this decline, fishing is limited in some areas, and many species are also breed in fisheries. Sturgeon flesh, eggs and swim bladders are all used by humans. The flesh is good to eat, and the eggs are used for caviar. Swim bladders are made into a gelatin called isinglass, which is used in industry.
I saw a couple of shortnose sturgeons while kayaking down a river in Georgia. They scared me, because through the murky water, they resembled alligators. I had just seen a sign at the kayak rental place with a cartoon alligator that said, “Kayak at your own risk,” so they were on my mind.
Those bony scutes that run down the sturgeon’s back remind me of the tough plates on alligators. Also, the shape of their heads are similar. Both have wide set eyes as well, so you can see how I could make that mistake.
Imagine my relief when I saw the rest of the sturgeon’s fishy body. I saw it swim further down under the water, and my adrenaline rush faded.
I recently saw a documentary on the beluga sturgeon. It is the biggest fish in Europe to ever enter fresh water.
It looks like a cartoon character. It has a long, somewhat triangular nose and a wide mouth. Underneath its snout it has four barbels that look like a mustache. They reach nearly all the way to its mouth. It really is quite an ugly fish.
The beluga sturgeon is the world’s most expensive fish, probably because it holds eggs that make the best caviar. One fish can produce around 400 pounds of caviar. Because of this, it is an endangered species.
@OeKc05 - Although predators do eat sturgeon when they are young, most adult ones are too large to be eaten. Sea creatures tend to stay away from fish that are as large or larger than they are out of fear of being consumed.
The same is true for freshwater sturgeon. I work as a wildlife manager at a lake in Minnesota, and the sturgeon is the biggest fish we have.
Most of the time, there aren’t a whole lot of baby sturgeons swimming around to be eaten. The lake sturgeon females only spawn once every few years, and they wait until they are about twenty years old to spawn the first time.
However, once they do spawn, they release up to a million eggs. Only some of these will survive being eaten when young, but the ones who make it to adulthood can live hundreds of years.
Wow! How do sturgeons manage to live that long? Especially if they live in the ocean, how do they avoid falling prey to big fish and sharks?
I have always been under the impression that life cycles of ocean fish are all pretty short. Everything that lives underwater seeks out other creatures for food, so nothing seems like it has much of a chance in that big pool with few hiding places.
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