Lake Sturgeon (Acipenser fulvescens)

Description

The sturgeon is one of the largest and most ancient of freshwater fish in North America. These fish seem to have survived from the Cretaceous period that ended around sixty-four million years ago -- around the time of the extinction of the dinosaurs. Saskatchewan has only one species of this incredible fish. The lake sturgeon, can attain a size of 2.5 metres in length and weigh over 140 kilograms. It has been known to live for more than 150 years. Once numerous in our lakes and rivers, the lake sturgeon is struggling to survive today because of over-fishing and habitat loss.

The two most distinguishing features of the sturgeon are

• its long, almost scaleless body supported by a partially cartilaginous skeleton and
• the five rows of prominent, bony plates or scutes which partially cover the thick, tough skin of the back and sides.

Other noticeable features include a heterocercal tail (shark-like tail with large upper lobe) and a shovel-like snout with four barbels which serve as sensory organs for locating food. The mouth is toothless and they are primarily bottom feeders feeding on insect larvae, mollusks, worms, small crustaceans and a variety of aquatic vegetation. A single dorsal fin is located far back on the body.

The appearance of the fish changes as the fish ages. Young sturgeon have sharp snouts, and the body is reddish in color with dark grey or black blotches on the back and sides. Adult sturgeons are olive brown to grey on the back and sides, and white on the ventral surface of the head and body.

Reproduction

They are a very slow maturing fish. It takes about 25 years for the fish to weigh 14 kilograms and a length of 1 metre. Lake sturgeons reach sexual maturity at the age of 15 to 30 years, males maturing before females. Late, springtime spawning occurs every two or three years for males and every four to six years for females. This limits the growth of the sturgeon population and, along with its very slow growth rate, decreasing habitat and overharvesting contributes to the decline in numbers of the species.

Spawning occurs in the rocky shorelines of rivers near strong currents where the water is 0.6 to 5 metres deep and the temperature range is 13 to 18 degrees Celsius. A single female arrives at the spawning grounds and is met by several males. The spawning of sturgeon is characterized by lots of rolling near the bottom and leaping out of the water by the males. No nest is made and a single female releases hundreds of thousands of dark-colored eggs. These measure about 3 millimetres in diameter and stick to the rocks and logs on the bottom. Strong currents are needed to disperse the eggs and keep them from clumping, which decreases the hatch rate. The current also supplies and removes sediment and metabolic waste that could destroy the eggs. The eggs hatch in about a week.

Habitat

In Saskatchewan, sturgeon can be found in Cumberland Lake, the Churchill River and the Saskatchewan River. You would need a special licence to angle for this species in Saskatchewan.

Interesting Tidbits About Lake Sturgeon

• The fish has been known to 'jump' out of the water; sometimes into the boat of the unsuspecting fisherman!
• Once the market value was so low for this species, that it was used as firewood, fertilizer and animal food.
• A sturgeon, weighing over 140 kilograms (that's 310 pounds) and over seven feet in length, was caught in one of the Great Lakes of Canada in the 1950's. The age of the fish was over 150 years!
• A monster sturgeon was taken from Roseau River (in Manitoba) at the turn of the century. It weighed over 180 kilograms. That's big!
• The age of a sturgeon can be determined by counting the number of rings on the pectoral fins; the fish continues to grow as it ages.
• The swim bladder contains a gelatin substance which was used in making beer and wine as well as jams and jellies. The hide was used as leather.
• The roe was considered a delicacy; caviar for kings. In fact, in England, King Edward II declared the sturgeon to be a 'royal fish'. Needless to say, the value of the fish increased dramatically.
• The native peoples considered sturgeon to be 'buffalo of the water'. All parts of the sturgeon were used; the flesh from a large sturgeon made several portions for meals, the tailbones provided arrowheads, cartilaginous skeletons were used to make soup.