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~ sturgeon ~
Featuring:
Sturgeon characteristics
All 29 Species
~ characteristics ~
Sturgeon are prehistoric fish that have lived for around 200 million years. The earliest fossils are from the Jurassic period, found in China, and dated to be 125-150 million years old.
The present form of sturgeon is very similar, basically unchanged, from sturgeon dating back 65 million years to the Cretaceous period and the time when dinosaurs became extinct.
There are 29 sturgeon species worldwide (as recognized by the World Sturgeon Conservation Society) and they only live in the Northern Hemisphere from the South Arctic Ocean to around the Tropic of Cancer. In North America there are nine species: Alabama, Atlantic, Green, Gulf, Lake, Pallid, Shortnose, Shovelnose, and White.
Sturgeon are a bizarre fish, with many characteristics uniquely their own. First of all being their scutes; All sturgeon have 5 rows of bony plates called scutes.
The picture on the next page shows all 5 rows. Starting at the top; Ventral/Belly - Lateral/Side - Dorsal/Top - Lateral/Side - Ventral/Belly.
Scutes, or Scutum, are hard bony, chitinous, and/or horny plates or scales that are similar to scales but unlike scales they are derived from the epidermis and have the feel and appearance of bone. There can also be a razor sharp barb, or spur, on all scutes in every row, that curves toward the tail (usually in younger fish, in older fish the scutes are usually almost flat)
Some sturgeon even have anal, or post-vent scutes. Sometimes in a row and sometimes 2 rows.
The scutes are the main defense sturgeon have against predators because they possess a skeleton that is mostly cartilege. They do have a skull, that is made up of many plates, but is external for the most part with a very thin skin like membrane connecting the plates.
Another unique characteristic is their mouth.
Sturgeon have a protractile, extendable mouth. Their mouth is a tube which is on the underside of their head and stays up inside until they find food. It then extends out and like a vacuum sucks up the food. Any silt, gravel, or unedibles are expelled through the gills or back out the mouth. At times they even extend their mouth while not feeding, perhaps just just for a stretch.
They also have 4 Barbels, or Whiskers, (as seen in the picture above) which are soft, tactile organs near the mouth. They house the taste buds and are used to search for and locate food, especially in murky water. All sturgeon have 4 Barbels located on the underside of the head. In most species they are just about halfway between the end of the snout and the eyes.
Most species of sturgeon have Whiskers that are evenly spaced apart, smooth, and all the same length. But some have 2 pairs of Barbels, and with others the inner two are shorter/much shorter than the outer two. Some are even fringed while others have small buds.
The tail of the sturgeon is also unique among fish. They have a heterocercal tail in which the upper half/lobe is longer than the lower half, and the spinal column actually extends into the upper half, which makes their tail much stronger than other fish. The heterocercal tail is exactly like the tail of the Shark and in fact many tail variations among different species of sturgeon closely resemble those in different species of Shark.
The fin placement in sturgeon is common for the most part but they do not have a fin in the middle/top of their back. Most fish have a dorsal fin located in the middle/top of the back and a much smaller, fatty, adipose fin located just before the tail. In sturgeon the dorsal fin is located where the adipose fin would be just before the tail, is large, and consist of rays/spines like the other fins.
Sturgeon vary greatly in size from the tiny dwarf sturgeon of Central Asia which rarely exeeds 1 foot in lenth to the massive "caviar" beluga sturgeon of Eurasia which can grow to almost 30 feet in total length.
Sturgeon also vary greatly in shape, and even color, and though all the characteristics mentioned here comprise every sturgeon species they all have their own unique variations.
If you encounter a sturgeon in the wild, or fish for sturgeon, please be respectful of them. Though they are very old, and many species can live over 100 years, they are very succeptible to changes in the environment and their habitats. And though they do recover from harm, injury, or misfortune, they posses a medium-very low resilience (the ability to recover). Therefore, it takes them a long time to heal, and if they undergo constant harm, or stress, they will most likely die.
IF YOU FIND DEAD STURGEON OR STURGEON PARTS (like Scutes) - PLEASE CONTACT ME - I AM VERY INTERESTED IN AQUIRING ALL OR SOME - (especially any species other than White)
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