Saving the Sturgeon (And we filmed them SPAWNING!) скачать в хорошем качестве

Saving the Sturgeon (And we filmed them SPAWNING!)

Jonathan travels to upstate New York to learn how biologists are working to save the sturgeon in the St. Lawrence river. During a dive he films an amazing spectacle that has never been recorded before--Lake Sturgeon spawning! ********************************************************************** If you like Jonathan Bird's Blue World, don't forget to subscribe! You can join us on Facebook!   / blueworldtv   Twitter   / blueworld_tv   Instagram @blueworldtv Web: http://www.blueworldTV.com ********************************************************************** Caviar is one of the most well-known delicacies in the world, an epicurean tradition dating back to the ancient Greeks and beyond. Caviar comes from an ancient fish called a sturgeon. Sturgeon are one of the oldest families of bony fish in existence—they have been around for hundreds of millions of years. Today, there are 27 species of Sturgeon remaining, and every one of them is endangered! In the mid 1800s, the Caviar industry discovered the North American sturgeon. Within 20 years, they were nearly gone. To learn more about the Sturgeon, I have teamed up with Jen Hayes, a biologist who did her PhD work with the Lake Sturgeon in the St. Lawrence river. These days, Jen and her husband David Doubilet are underwater photographers, working on a story about the St. Lawrence for National Geographic Magazine. New York State’s Department of Environmental Conservation has undertaken an ambitious project to help increase the number of sturgeon in the river. I meet Rodger Klindt, an Aquatic Biologist with the state who is out this morning with his team. The team’s job is part research, and part midwife. They are collecting eggs from healthy sturgeon to raise them partly in captivity. Certain areas of the river have sturgeon present. Rodger and his team have set nets to capture both male and female mature sturgeon. Sturgeon can live to be over 100 years old and weigh more than 200 pounds. While these might look like big fish, they get a lot bigger. But big ones these days are rare. Since sturgeon are not mature enough to produce eggs until they are around 20 years old, most of these fish are immature and have to go back into the river. First, a male sturgeon is taken from his tank where the team extracts sperm using a syringe. Then fish is set free. Once they have samples of sperm from several fish, it’s time to harvest some eggs from the females. Next the fertilized eggs go into bags to be transported in coolers to the hatchery. They will be raised there until they are about the size of your hand. Raising fish in a hatchery helps the dwindling stocks of sturgeon in the river, but it doesn’t do anything to address their loss of spawning habitat. Fortunately, someone is working on that problem as well. I meet Ben Lenz, an environmental scientist with the New York Power Authority. He is part of a team that installed an experimental spawning bed for sturgeon, paid for by the power authority. We’re diving close to a dam, in extremely fast moving water. This dive can be quite tricky as the current is too strong to swim against. We’ll have to jump into the water upstream from the spawning bed and drift down until we get to it. We’ll need to get lucky to hit the spawning bed. The New York Power Authority created this spawning bed by dumping tons and tons of crushed rocks onto a fast-moving section of water to simulate the conditions of rapids. They hoped it would encourage the sturgeon to spawn. As we approach the beds, I start to see sturgeon everywhere. Using remote cameras towed by boats, scientists learned that sturgeon come to the beds at certain times of the year, but nobody has ever seen them actually spawning. This sturgeon is eating the algae from the rocks. Many of the sturgeon have lampreys on them. These primitive fish are like vampires, attaching themselves to a sturgeon and living off its blood. A glance between the rocks shows definitely evidence of spawning: sturgeon eggs! This is why they are sticky, to cling between the rocks in the current. I can hear a strange sound. It sounds like clunking or vibrating. I suspect it’s coming from the fish, but I can’t see it. Are the fish fighting? I fight my way upstream. Then just ahead of me, it happens! The male vibrates his body against the female. Then he releases his sperm just as the female releases her eggs! The fish are spawning! Sperm clouds the water, fertilizing the eggs. And the eggs sink to the bottom and stick. The sound comes from the male hitting the rocks on the bottom as his body shakes! So every time I hear that sound, I know that somewhere nearby, a pair is spawning. And I hear it a lot! The spawning grounds definitely work!