Transcript:

Today on Animal Fact Files we’re discussing sturgeons. These large fish look like something straight out of the prehistoric times, and they kind of are - they’ve been around for hundreds of millions of years and remain largely unchanged from their fossil forms. Today there are around 30 living sturgeon species and they’re all natively found in the northern hemisphere. Some sturgeon farms are located in the southern hemisphere and so there may be stock sturgeon living in the southern hemisphere, but they’re specifically known from North American and Eurasian water systems. Some sturgeons swim in marine waters, typically sticking to coasts and saltwater estuaries, but many also live in freshwater lakes, streams, and rivers. Sturgeons are anadromous meaning they live in brackish and saltwater areas for their adult lives, but travel to freshwater to spawn - not unlike the well documented salmon migrations that occur each year in North America. This travel plays a part in why sturgeons are declining in population - but we’ll get back to this.

Sturgeons can be some big freshwater fish - they have a mostly cartilaginous skeleton like a shark, but they’re still considered bony fish. In size, they can reach more than 13 feet (4m) in length and there are observations of individuals reaching double this, however these are few and far between and these days they’re basically non-existent. These large fish don’t have teeth and survive by sucking their prey up in a vacuum-like mouth. Sturgeon live towards the bottom of the water column. They have four barbels on their mouths which they use to sense the substrate. Once discovered, a sturgeon will suck up all sorts of food items including other fish, crustaceans, and mollusks.

Sturgeons themselves are well protected against predators. They have rows of bony plates, called scutes, that give them a tough defense, unfortunately, they still fall to human related threats. Much like the paddlefish, to whom sturgeons are related, hydroelectric dams are a threat to sturgeon populations as many are constructed without throughways for the fish to swim through in order to reach spawning grounds. These fish also suffer from pollution and overfishing - sturgeons were once caught in the droves for their flesh and eggs, though now their numbers are so few that most species aren’t commercially viable. More than half the living sturgeon species are listed as endangered or critically endangered to extinction. These slow growing, long lived fish struggle to bounce back from dips in their populations. It may take upwards of 18 years for sturgeons living in northern regions to reach reproductive maturity. When they are ready to mate, males may do so only once every one to two years while females may mate only mate every three to five years! When they do spawn, females can release hundreds of thousands of eggs depending on size and species. On average sturgeons live 30 years but some have been known to double that in the wild and there are further reports of them potentially living past 100 years of age!

For more facts on sturgeons, check out the links in the description. Thank you to Jason for today’s request! Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files!