Sturgeon are the oldest living bony fish on Earth, with the longevity of their existence estimated at between 208 and 245 million years. These dinosaur fish are extensively (mostly unlawfully) fished for their yield of roe, from which the only true caviar is produced.

There are about 25 classified species of Sturgeon, some of which might be extinct. They mostly inhabit cold river deltas and estuaries worldwide, venturing upstream for spawning purposes, with some species adapted exclusively to fresh water conditions and others to coastal and open oceanic waters.

Plagued with slow growth and hindered reproduction due to roe harvest, about 85% of species of Sturgeon are critically endangered, making this family the most extinction-prone out of all fish.

Sturgeon are true aquatic giants, with several species growing to between 7 and 12ft and anywhere from 180 to 800lbs on average, depending on the species. The largest Lake Sturgeon was caught over 7.3ft and 240lbs, the largest White Sturgeon was 1,799lbs and 20ft, while the largest ever fish caught (in the world) was a Beluga Sturgeon - a mythical 3,463lbs heavy and 24ft long. A good tool that can give you an idea of the length/weight ratio can be found here.

These fish can live over a century and take 15 to 20 years to mature.

Different species of Sturgeon can be found worldwide in subtropical and subpolar rivers, lakes and coastlines.

In North America, Sturgeon can be found along the Pacific coast from California to Alaska (White - Acipenser transmontanus), in the Mississippi River and the Great Lakes (Lake - Acipenser fulvescens), and along the Atlantic coast from the Gulf of Mexico to Newfoundland (Atlantic - Acipenser oxyrinchus).

The European Sea Sturgeon (Acipenser sturio) can be found along the Atlantic coast of Europe, in the Mediterranean basin, particularly in the Adriatic Sea and northern Italian rivers, and Beluga (Huso huso) inhabits rivers going into the Black, Azov, and Caspian Seas, the Arctic Ocean, central Asian rivers and Lake Baikal.

Warmer weather marks the spawning season, so July through August are usually the most productive. During low tides, Sturgeon will be in deeper water and high tides may bring them close enough to shore to be caught in 4 to 6ft of depth.

Winning a Sturgeon battle may require the effort of several people. This battle won by Fraser River Sturgeon Unlimited in Harrison Mills, BC

Not much to say about the fishing technique needed to catch Sturgeon, except - bring your heaviest artillery, as the pull of these fish has been compared to a cross between Marlin and a freight train.

6-9ft single piece rod, 250yds of at least 80lbs test line, 5/0 to 9/0 barbless hook baited with crawfish, clams, salmon eggs, shad or other small fish. If fresh bait isn't available, you can use any fish oil to add scent to your bait for better results.

Mostly valued for the roe yield (Beluga caviar is a luxurious eating item appreciated worldwide), but the meat is delicious as well. Jewish laws forbid the consumption of Sturgeon and in England and Wales the fish is considered royal and, therefore, the property of the Crown.

• Season - always open;
• Size limit - 40 to 60'';
• Bag limit (per angler per day) - 1 (maximum 3 per year);