Coming up next on Jonathan Bird's Blue World,
Jonathan joins a team of biologists working to save the sturgeon!
Hi, I'm Jonathan Bird and Welcome to my world!
Caviar is one of the most well-known delicacies in the world, an epicurean tradition dating
back to the ancient Greeks and beyond.
The Romans loved their caviar, and today a thousand years later, some people still go
crazy for these expensive, salty fish eggs.
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.
In fact, during the time of the dinosaurs, there were Sturgeon swimming around in oceans,
rivers and lakes.
Today, there are 27 species of Sturgeon remaining, and every one of them is endangered!
In North America, Sturgeon used to be so plentiful that they were considered a nuisance to fishermen.
But in the mid 1800s, the Caviar industry discovered the North American sturgeon. Within
20 years, they were nearly gone.
Now, more than a hundred years later, Sturgeon stocks are only just beginning to rebound.
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.
I tag along with Jen and David, as we explore the river where Jen grew up.
We pass a huge hydro-electric dam. It generates clean, renewable power for the area. But it
does have an environmental side effect.
Hydro-electric dams are usually built in the parts of a river with the most vertical drop.
This creates more elevation of water behind the dam to run the turbines.
But the places with the most vertical drop are usually rapids, with fast moving water.
And that’s exactly where sturgeon like to spawn.
The rest of the river has slow water and a muddy bottom. The eggs sink into the mud and
vanish. What few rocks there are get a coating of algae and plants. Not good for spawning.
With no rapids, the sturgeon have no place to lay their eggs, and that has made it tough
for this fish to reproduce.
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
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.
The end of the net is marked with a red flag.
The nets catch fish as they swim along the bottom, but they do not harm the fish.
Gently, each fish comes aboard the boat and goes into a holding tank.
They keep plenty of fresh, oxygenated water in the tank to keep the fish alive.
When they have 3 or 4 fish in the tank, they head back to the dock.
The fish are measured, weighed and tagged. The biologists are building a database to
keep track of individual fish. If they catch them in subsequent years they can compare
notes from the previous years to learn how quickly they grow.
The smaller sturgeon go back into the river, where they take a few minutes to catch their
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.
They swim away, slowly at first, none the worse for wear.
The larger fish, especially females that have a lot of eggs, go up the hill to a larger
holding tank with a pump recirculating fresh water.
A few mature males go into another tank.
Once they have enough fish in their holding tanks, it’s time to make some baby sturgeon!
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
My job is to hold the egg collection bowl as a female sturgeon comes out of the tank
and her eggs are massaged from her belly. This does not harm the fish at all and immediately
after this process she is set free in the river.
Talk about a science project! Now the eggs are fertilized with the sperm from the male
and the biologists will attempt to create the perfect conditions to produce thousands
of healthy sturgeon babies.
All of these eggs are going to be baby sturgeon, and that’s a lot of sturgeon to put back
into the population. I’m using a feather to stir these eggs. We have added an agent
in there that is sort of made of clay and we stir it around. This clay substance helps
the eggs to lose their stickiness. The problem is that we don’t want sticky eggs. In the
wild, sticky eggs are good because they stick to the bottom of the river but in a hatchery,
sticky eggs are not good.
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.
Once the baby sturgeon get to be about, oh about that big, they release them here.
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.
The location of the bed is a secret, but Ben told us how to find it.
It’s quite far from a dock, and we have a lot of gear, so while Jen and David bring
the boat, the Blue World team drives out into a remote area near the river to set up base
Soon Jen and David arrive and we load the boat for a dive on the spawning beds.
Cameraman Todd is along to film the underwater action with me.
Jen’s nephew Troy is captaining the boat so Jen and I can dive down to the spawning
There's a lot of species on the beds right now. There's Red Horse, that lay their eggs
just ahead of the Sturgeon. And things that come on the beds to eat all the eggs—it's
like a fiesta, like a big buffet of eggs, when the Sturgeon spawn and the Red Horse
spawn, you'll have eels, there's walleye, there's carp galore…
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.
Underwater, the visibility actually isn’t bad for a river: 15-20 feet of greenish water.
But the current is ripping! There is no way I can swim against it, but instead tumble
along the river bottom. All I can do is follow Jen downstream. And even though the spawning
bed is a third the size of a football field, we completely miss it. We surface without
seeing any sturgeon.
Well, we went down okay. The current was ripping! We went flying by all these rocks and stuff,
getting smashed into them, bubbles everywhere, and I think we missed the sturgeon. We'll
Troy positions the boat a little closer to shore, a tricky proposition in this much current.
We got to get a little bit closer!
On the second try, we hit it just right and the current carries us out into an area that
doesn’t quite look like a natural river bottom. That’s because it’s not. 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
Many of the sturgeon have lampreys on them. These primitive fish are like vampires, attaching
themselves to a sturgeon and living off its blood.
I grab onto a larger rock and cling desperately in the current, flapping like a flag in the
breeze. This is definitely not an easy way to film anything. I only have one hand available
for my camera and I can barely hold it in place in the water.
But sturgeon are all around me. A gathering of this many fish would seem to indicate spawning,
but so far there is no sign of it.
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, holding onto the rocks to pull myself against the current.
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! And not only
am I the first person to ever see these fish spawning on the artificial spawning beds,
but I have managed to somehow film it in all this current!
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!
After a while, the current pushes Cameraman Todd and I off the edge of the spawning bed,
so we call it a dive and head to the surface. Jen surfaced just before us. She and David
greet us with a victory dance.
We can cover a lot of river just getting our gear off and climbing onto the boat!
Woo! That’s just amazing! Hundreds and hundred of sturgeon, all sort of getting together
to spawn, for as far as the eye can see in every direction, which is actually only about
20 feet, there’s sturgeon looking at you! Very cool!
So, at the end of a long day of battling the current to film a secret sturgeon spawning
bed, we bring the boat ashore at our remote riverside camp to warm up and celebrate having
proved that the sturgeon are in fact spawning on these beds.
Over their millions of years on Earth, sturgeon have encountered many obstacles to survival,
but humans are the greatest obstacle. From overfishing to loss of spawning grounds, the
sturgeon nearly didn’t survive. But now, with efforts to propagate the species and
rebuild their spawning grounds, sturgeon are making a fantastic comeback. It just goes
to prove that when people put their minds to it, they can repair damage they have done
to nature. It just takes a little creative thinking, and the determination to do what’s