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Today on Animal Fact Files we’re talking about paddlefish. Don’t paddle out of here without subscribing! There are two species of living paddlefish; one species is native to America and one species is native to China. I’m sure you can guess their common names based on that information. The Chinese species of paddlefish may be extinct as this species hasn’t been seen in the wild in more than two decades. Even if it is still alive, there’s concern that the population may have, at this point, hybridized with the American species because the American species has been introduced to Chinese water systems. The American species has also been introduced in Russia, Europe, the Middle East, and many Asian countries. This was done purposefully by humans because paddlefish have prized flesh and roe. Paddlefish are almost completely lacking in scales with the exception of a small patch or two around their tails. Their meat is easily cured and consumed by humans. Their roe, which is the name for fish eggs, is used as caviar. When they’re not being hunted by humans, adult paddlefish are usually left alone, though juveniles and smaller individuals may be taken by herons, osprey, and other predators.

Paddlefish are related to sturgeons and when first discovered they were thought to be sharks. Maybe you can see the resemblance? Paddlefish do have cartilaginous skeletons like sharks, and, like some sharks, they have to keep swimming to survive - but remember, like we talked about in the wobbegong episode, this isn’t the case for all sharks as the myth might suggest! Paddlefish are ram ventilators which means they are not able to pump water over their gills. Paddlefish depend on their movement in the water to obtain oxygen. This works out for them, though, because paddlefish are filter feeders. If you’ve ever seen a basking shark you might think paddlefish resemble these gentle giants, though paddlefish are much smaller. American paddlefish don’t typically grow more than five feet (1.5 meters) in length, though there are reports that the Chinese species may reach more than twenty feet (6 meters) in length. Do you believe these fisherman’s tales?

In most areas paddlefish are found, they’re protected and must be released back into the water if caught. Their populations are declining, and it’s mostly the fault of humans. To breed paddlefish travel into tributaries and look for sections where gravel sediment has collected. This is where they lay their eggs. Once the eggs are laid, they are fertilized by many males in spawning events. Females may only lay eggs every couple of years and can be picky about conditions. For example, one observation suggests females may require a rise in the water level before they will lay. Paddlefish parents don’t protect their eggs, so paddlefish eggs are left to hatch on their own and young fish float down river to standing pools of water. When they've grown a bit, juveniles may join adults in the main river system. Paddlefish tend to live in slow moving, large, deep rivers. They may also live in lakes connected to these rivers, however, human construction has caused fragmentation of their populations. Construction of dams has prevented paddlefish from migrating to breeding grounds, so some areas have conservation efforts that restock certain water systems with paddlefish. If these efforts weren’t made, the paddlefish populations would likely die off due to their inability to effectively breed. So while people may eat them, there are also people trying to help them survive!

Paddlefish look somewhat like sawfish who lost all their teeth, though the two aren’t related! American paddlefish have more spoon shaped noses while Chinese paddlefish have a nose that comes in a sword shape. A paddlefish’s nose, or rostrum, is used to detect electrical pulses in the water and is especially helpful to young fish seeking out prey. Generally paddlefsh eat zooplankton which is caught in their gaping mouth while swimming. Considering paddlefish can live for decades, I wonder if their mouths ever get tired..?!

For more facts on paddlefish, check out the links in the description. Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files.