AMERICAN FRONTIERS program #1306,
airs January 28, 2003, the transcript
will be available January 29, 2003.
Out West - Conquering the Columbia
East - The Extinction Vortex
Rocking the Bluefin Boat
ALAN ALDA These young salmon are some of over
100 million that each year start their journey down
the Columbia River, and out thousands of miles into
the Pacific. But scientists say that America's salmon
are at risk of becoming extinct. On this edition of
Scientific American Frontiers, we're looking at the
future of the ocean's long distance travelers.
ALDA (NARRATION) In the Northeast, can biologists figure
out what makes Atlantic salmon tick, before the last
few rivers lose their wild fish? In the Pacific Northwest,
will elaborate engineering save the Columbia River's
salmon? And in the Atlantic Ocean, scientists are beginning
to understand the giant bluefin tuna -- but will the
rest of us put that knowledge to good use?
ALDA I'm Alan Alda. Join me now as we plunge into a
ALDA Inside this building there's a small food processing
company. There must be thousands like it around the
country. Nothing special about that, right? Well in
fact, what goes on in here is really special, and when
you think about it, really surprising. Because what
they do is prepare meat from wild animals, for shipping
to the shops and markets where we'll all buy it. Let's
take a look. That's right -- fish. Fish are wild animals,
with some exceptions, which we'll get to in a minute.
10,000 years after humans domesticated cattle and sheep
and pigs, and figured out how to cultivate crops, we're
still out there hunting down wild fish to put on the
table. Today, seafood is the main source of animal protein
for about a billion people around the world, and its
importance is growing rapidly. Fish consumption has
gone up fivefold since 1950, and it's still going up.
The results are not hard to imagine -- marine fish stocks
are being overfished, and they're declining fast. What
to do about damaged fisheries is a terrifically complicated
question, that involves many interests -- industry,
fishermen, environmentalists, local economies and livelihoods,
even foreign policy. But this program is going to concentrate
on what all those interests need to know before they
start to argue -- the science. We have to know how fish
behave, where they feed, where they breed, before we
can begin to figure out how best to conserve them. We're
going to concentrate on two kinds of fish we in America
love to eat -- salmon and tuna. Even though salmon farming
is big business, wild Atlantic salmon are now officially
endangered in the US. And even though millions of young
Pacific salmon are raised in hatcheries in the Pacific
Northwest, several species of wild Pacific salmon are
officially endangered, too. We'll look at the work of
biologists on both coasts, who are now trying to determine
how wild salmon can have a future. And we'll look at
the efforts to study the giant bluefin tuna, another
long-distance ocean traveler. Studying bluefin is especially
challenging, because an individual fish may range over
enormous distances -- across the entire Atlantic, for
example. Scientists are just beginning to find out about
the ocean wanderings of the giant bluefin. Even something
as basic as counting fish in the wild hasn't been attempted
until recently. And guess what -- everything we discover
comes as a surprise. OK -- let's dive into a fish's
WEST -- CONQUERING THE COLUMBIA
ALDA (NARRATION) When Lewis and Clark explored the West
200 year ago, they saw sights like this. On the Columbia
River, the salmon were "jumping verry thick," wrote
John Ordway, the expedition's senior sergeant.
ALDA So what are all these slots in here?
ALDA (NARRATION) Today the Columbia is just one part
of a settled and industrialized Pacific Northwest. It's
not impossible to see a wild salmon jumping a waterfall
-- just a lot harder. Dams are the most visible of many
reasons for the decline of the Norwest's salmon. Here
on the Washington-Oregon border, the Army Corps of Engineers'
McNary dam -- opened in 1953 -- reaches for a mile across
the river. It's one of hundreds of large dams distributed
throughout the enormous Columbia-Snake river system,
which stretches across 4 states and up into Canada.
Several of those dams completely blocked fish from going
upstream, knocking out more than a third of the system's
salmon habitat. The dams made life for the remaining
salmon much harder. When young fish head out to the
ocean, for example, they have to contend with this.
McNary's electric generating turbines can kill young
fish, but about 15 years ago the way the dam was run
began to change.
ALDA Is it that the environmental protection laws have
required you to run the plant in a way that's best for
COLEMAN Oh, yes.
ALDA So its not just running the plant, you have to
worry about the fish as part of your job now?
COLEMAN Guaranteed. I mean when I first hired on the
Corps the most important thing in this facility was
the safety of the employees, navigation law, and power.
Since I have been here safety is number one, fish is
ALDA (NARRATION) You can see the result in the control
room. The 14 turbines could together produce 980 megawatts,
but today they're running at less than 860. This is
a salmon smolt, a one-year-old fish that's ready to
move down river to the ocean. It's about to experience
McNary's turbines first hand -- and then report back.
First there's a mild anesthetic, so a radio transmitter
and flotation balloons can be attached. This is one
of millions of smolts raised in hatcheries each year.
At the last instant a foam mixture is added to the balloons,
ALDA Now he goes down through the turbine?
Yes, he's going right through the turbine.
ALDA (NARRATION) Down it goes, 70 feet deep, through
the spinning turbine blades, then out below the power
house. By now the flotation balloons will have inflated,
so the fish will be somewhere downstream, on the surface.
Meanwhile the researchers are sending down a somewhat
less lively instrument package. In the river below the
dam, the recovery crew is on the lookout. Within minutes
they pick up the radio signals from the fish and the
ALDA (NARRATION) Surprisingly enough, the smolt made
it through unharmed. In fact around 90% survive, if
the turbines are run at flow rates which reduce forces
on the fish -- as they are today. Those forces can be
measured with the instrument package, while turbine
speeds are adjusted. Now all the Army Corp's Columbia
turbines are run to minimize fish losses. On a typical
Columbia dam, half the structure is the power house,
the rest is spillway. As with the turbines, spillways
are also now operated with fish in mind.
ALDA That's a great sound. It sounds like Niagara Falls.
COLEMAN It is like that. We spill likeS. today we're
spilling about 100 kcfs.
ALDA That's a spectacular sight. The ability to do a
spill like this on the dam, was that intended originally
as a kind of a pressure valve when there were flood
ALDA It wasn't with the fish in mind at all?
DAVE COLEMAN No way.
ALDA Now you open the spill for the fish as well as
for the flood. DAVE COLEMAN And it's an interesting
story. Originally when you had a spring runoff like
this that's forced spill, it used to cause a lot of
harm for fish because the water used to plunge straight
down, super-saturate the waterSah nitrogen, they'd get
like the bends and it'd cause a lot of mortality. So
all the dams have been retrofit with what they call
flip lips that actually slides the water kinda out instead
of plunging it down.
ALDA (NARRATION) With flip-lips, and if the flow rates
are just right, approaching 100% of young salmon can
make it through a spillway. So it doesn't sound too
hard for a young fish to get past McNary dam. But that's
a small part of the challenges facing the Pacific Northwest's
salmon. Let's take a look at the Columbia system from
a salmon's point of view. In we come from the Pacific
Ocean, through the estuary. We've been using our internal
compass to get here, but now as we head upstream we're
beginning to pick up the distinctive smell that we remember
from the water where we hatched, 4 or 5 year ago. We're
determined to spawn in the exact same river, lake or
stream, and we're prepared to travel 500 miles inland
-- 1,000 or so river miles -- to get here. Now we've
arrived, in central Idaho or eastern Oregon. Once there
were hundreds of different groups of us salmon in the
Columbia system -- distinct stocks that each used the
system in its own unique way. We find the stream, find
the right kind of gravel, find a mate, and make a nest
for the eggs. Next spring the fry hatch, then hang out
and grow for a year before hitching a ride, as smolts,
on the following spring runoff. Down the river we go,
out to sea for a couple of years to eat and grow. Today
more than half the Columbia's original stocks are extinct.
For thousands of years, native Americans were the only
people who exploited the Columbia's salmon, but that
couldn't make a dent in the 10 to 15 million fish that
returned each year. Then as the numbers of settlers
grew in the nineteenth century, salmon came under increasing
pressure. Large scale net fisheries were established
in the Columbia estuary. Canneries were set up. By the
1930s returning fish numbers were down by half. At the
same time another bonanza was under way in the forests
through which many salmon rivers and streams flowed.
FILM SOUNDTRACK Timber. Shoot them off the hillside.
Snake them down the creek. Raft them down the river.
Out to the Pacific, to Africa and Australia and Ireland.
Feeder logs for the plywood mills of Japan, ties for
the Trans Siberian Railway, timbers for North China
ALDA (NARRATION) Logging was devastating for the salmon.
It turned clear, cool streams into muddy, warm pools
that no longer support spawning. Some attempts are made
to protect streams today, but it's still a serious problem.
And then on top of the fishing pressure and the logging...
SOUNDTRACK At Bonneville, Oregon, Man takes up the struggle
against the frontier. Cascade rapids, since pioneer
days the graveyard of ill fated ships, in 1933 make
way for Bonneville dam. America's conquest of the Columbia
has begun Just as the Nile is the lifeblood of the historic
land it drains, so this river of the west is the key
to the future of the Oregon country. An unshackled giant
becomes a seaway to an empire. The promise of power
for every corner of the Northwest. Power to make a million
and a quarter acres bloom again. Power to push the city
to the farthest county line. To bring better crops and
better living to the farmers of the region. Power for
the home, good light for Billy's eyes, electric cooking
for mother, the comfort of electric heat and electric
cold. Leisure to replace the burdens of an outworn era.
Power to make the American dream come true.
ALDA (NARRATION) As far back as the 1870s it was thought
that we could have the America dream, and salmon too,
by building these. It's a hatchery where young salmon
are raised for a year until they're ready to go to sea
as smolts. There are about a hundred hatcheries in the
Columbia system, producing about 200 million smolts
a year. All hatchery smolts are marked by clipping a
fin that's not used for swimming -- an evolutionary
leftover. This mark persists with the adult fish, so
it's been possible to track how well hatchery fish do,
compared to their wild companions. Only about 10% of
the smolts in the Columbia system are wild -- spawned,
hatched and raised naturally, without human intervention.
But up to 30% of the adults that make it back from the
ocean were wild smolts. Wild fish do much better, in
the ocean and the river. Biologists think they're more
aggressive, know how to avoid predators -- just smarter
and tougher. Dams have made the river more difficult
for all smolts, wild and hatchery. For example, there's
not enough flow in the reservoirs behind the dams to
carry young fish downstream, so they have to use precious
energy to swim. Since the 1970s, a lot of effort, and
hundreds of millions of dollars, have been put into
helping smolts down the river. The most important dams
have been fitted with elaborate screen systems to catch
the smolts and divert them around the turbines and spillways.
This is just one part of one of the 42 fish screens
at McNary dam. The system works by directing the young
fish up and away from the turbine intakes, and into
a separate channel inside the dam. The channel leads
to a special fish processing facility. At the heart
of the system are stainless steel screens that create
a cushion of water to guide the fish. This is sophisticated
-- and expensive -- engineering. McNary's screens alone
cost 17 million dollars.
ALDA The water's hitting that screen.
ALDA And its backing up a little bit.
DAVE COLEMAN Yes, and the fish are actually tumbling
kinda back with their tail to the stream.
ALDA Why are the fish going backwards?
COLEMAN They are not really swimming to the ocean, they're
just flowing with the current heading to the sea.
ALDA Ah, is that how they ordinarily go down?
COLEMAN Yeah...and the big spring run off, just mother
nature takes care of them and flushes them.
ALDA You know, you could have asked me a million times
I would have never have said they go backwards to the
ocean. I mean that just...
ALDA What's happening here?
COLEMAN We're closing down the shop. They've got work
to do. You're OK. If you don't move you're OK. You're
OK if you don't move.
ALDA (NARRATION) Dave Coleman took me down inside the
dam to see the channel where the separated fish end
COLEMAN We're entering the juvenile collection channel...
ALDA (NARRATION) We're here at the height of spring
runoff, when they're collecting 350,000 smolts a day.
The screens are not perfect -- they catch 75% of some
species, but only 30% of others.
ALDA Don't they get shaken up a lot? That's really going
very fast, isn't it?
COLEMAN That's engineering by the greatest fish design
engineers in the world and that's perfectly acceptable.
ALDA (NARRATION) The quarter-mile-long channel is just
the beginning of a peculiar journey for the young fish.
I saw my chance to check if they really were going backwards.
COLEMAN You can start seeing some of the fish right
here. There's one, there's one, there's one.
ALDA Oh yeah, now I can see them.
ALDA (NARRATION) Dave was right. They do go backwards.
ALDA You know what it is? When you go some place in
the car, you can't find your way back because the scenery
looks different in the other direction. They go backwards,
so they see what it looks like coming the other way,
so they know where to go.
ALDA (NARRATION) Actually they head into the flow because
that gives them maximum control. The diverted fish emerge
from the dam in this pipe, which loops down into the
fish facility. A sample is anesthetized so they can
be identified and counted. The Columbia has 5 salmon
species, and 2 closely related steelhead. Hatchery and
wild fish are counted. And now the smolts' journey is
about to get more peculiar. For 15 years, about half
the smolts in the Columbia system have been given a
ride downstream, courtesy of the Army Corps of Engineers.
They're loaded into specially built barges, a quarter
of a million fish at a time, and driven down river in
luxury -- safe from turbines, spillways, predatory fish
and hungry birds. It takes a couple of days for smolts
to get down below the Bonneville dam, the last on the
river. Almost all survive the barge trip, and a higher
proportion of barged fish return as adults, compared
to those that came down the river on their own. But
the return rate for both groups is very low, only a
percent or two -- much less, it's believed, than made
it back historically. There's a net system used to count
smolts as they leave the river. One theory is that both
groups are in poor shape as they go out to sea -- the
barged fish because they have to cope with salt water
before they're ready, and the others because their river
journey has been so stressful. Many smolts heading out
to sea -- still backwards -- have electronic tags that
the net system detects. They're called PIT tags -- microchips,
containing unique ID numbers. Once implanted, the tags
stay with the fish for life. In the last decade more
than 5 million have been used on the Columbia, and they've
revolutionized research. PIT tags have told us about
the effects of barging -- these fish are part of the
continuing barging study. They've told us about the
effects of turbines and spillways. They're a sophisticated
tool to match the technology that -- to the dismay of
environmentalists -- is now an integral part of the
life of Columbia river salmon.
SCHIEWE These are fish that have been collected up on
the base of the dam, and through a series of pipes...
ALDA (NARRATION) I'm at the McNary fish facility with
Mike Schiewe, the biologist who runs much of the research
on the effects of technology on fish.
SCHIEWE This is the juvenile fish separator, and this
is where the different size juveniles are sorted.
ALDA (NARRATION) The facility is a maze of pipes and
channels, equipped to detect PIT tags and automatically
divert a fish that's part of a study, for example.
SCHIEWE If it were to detect a fish, what would happen
ALDA Ha, ha, ha...
SCHIEWE Then the fish just drops down below.
ALDA It's like an amusement park.
SCHIEWE Oh it is yeah. It's quite amazing. Let me do
ALDA So what, the fish goes through here?
ALDA And the tag is read by the computer, and that gate
opens that fast, so by the time the fish gets there
the gate's open.
SCHIEWE That's correct. It's an amazing system. It's
what the computer age has brought to fisheries.
ALDA (NARRATION) The computer age arrived on the Columbia
just in time to help study a crisis. In the O60s and
O70s, four new dams were built on the Snake river. Now
Snake river fish had twice as many dams to pass to reach
the ocean. Four salmon stocks began to collapse. They
and eight more stocks elsewhere in the system were declared
endangered. For West Coast salmon today, the count is
26 endangered stocks -- half those that are left. The
response at the eight Snake and Columbia dams was the
measures we've seen -- fish screens, spilling water
and adjusting the turbines. Even so about 10% of smolts
are lost at each dam. Bypassing with barges helps make
up some of the losses.
ALDA Does the fact that 10% die lead you to think that
maybe the dams are stressing the fish, and that's why
a lot of that 10% may be perishing?
SCHIEWE Well, I don't think there's a question that
fish would survive at a higher rate without the dams.
We've made major improvements, I think, in the system
and how it operates in the last twenty years. The survival
now for the yearling fish is roughly fifty to sixty
percent through the whole system. The eight dams coming
down from the Snake River to below the Bonneville dam
at the Pacific Ocean. This compares with what the survival
was about twenty to thirty years ago when there were
only four dams in place. But we hit a real low point
in the 70s when more dams were coming on line, when
the operations were not as safe for fish. So we're making
progress in that regard.
ALDA (NARRATION) We're heading back to where we picked
up the smolt that came through the turbine. It's a measure
of how unnatural things are that there is a program
to reduce the number of predators that hunt salmon smolts.
Smolts make easy prey in the reservoirs where there's
no shelter, and also as they emerge, disoriented, from
the turbines and the spillways.
FRIESEN Be careful not to touch the water when the generator
FRIESEN It might give you a little buzz.
ALDA Don't touch the water while the generator's on.
Liable to get electrocuted.
ALDA (NARRATION) The electric shock stuns all the fish
around the boat for a few seconds.
FRIESEN These are American shad. They're a game fish
introduced from the East Coast.
ALDA (NARRATION) We're going to pick out the three important
FRIESEN Those are all large scale suckers. That's what
we're looking for. Got a keeper. This is a walleye.
ALDA Now, that's a predator?
FRIESEN That is a predator.
ALDA (NARRATION) Back at the dock, the unfortunate walleye
showed us where about 12 million smolts a year end up
-- 6 percent of the smolts in the system.
TOM FRIESEN That is a fish that just popped out of his
ALDA (NARRATION) Then Tom Friesen did a surprising thing.
FRIESEN Back in the water.
ALDA Now if he's a predator why do you release him?
Because he's going to be able to get more salmon right?
TOM FRIESEN Right, walleye are pretty highly regarded
game fish so if we just removed all we could, there
would be people upset that they couldn't fish for walleye
anymore. And smallmouth bass are the same way.
ALDA (NARRATION) So our smallmouth bass was also released.
But not so the third fish. There's a million or more
of them, they're not game fish, and fishermen are paid
to catch them.
FRIESEN Northern pikeminnow...
ALDA (NARRATION) It's hard to know how much effect this
all has on how many adult salmon eventually make it
back from the ocean -- and that's the case with virtually
everything we're doing on the river. This is the fish
ladder at McNary, and right now it's full of returning
adults. Last year was pretty good too, with a million
returns. That's good news, but it's confusing. They
got down to only a quarter of a million returns in the
1990s, just when all the efforts to help juvenile fish
survive the downstream trip should have been paying
off. So there are still big unknowns out at sea.
ALDA These are big guys aren't they?
SCHIEWE Ah they're beautiful fish. These are summer
chinook. They've been down through the system as juveniles
and been out to sea for 2, 3, 4 years and now they're
ALDA Do you count every single fish that comes through?
SCHIEWE Every fish that comes through the ladder comes
by this window.
ALDA So this is where they come in?
SCHIEWE Yes, it is.
ALDA So you see, what... you narrow it down so that
you only get one at a time?
SCHIEWE Exactly. Now that's a shad, big chinook, another
ALDA That ladder looked like a pretty long structure.
Is...does that put them through more work than they
would ordinarily have to go through to get up the river
if there weren't a dam they had to climb up?
SCHIEWE Well, before the dams they definitely climbed
the falls and so they went through those kinds of structures.
Sometimes they have a little trouble finding the entrance
to the fish ladder but once they do, they move through
it fairly quickly. Fish ladders are one of the real
success stories of salmon migration.
ALDA (NARRATION) As the observers do the count, they
distinguish between wild and hatchery fish. Here's a
wild chinook, with its rear fin intact And here's a
hatchery fish, with the fin missing. Overall about two
thirds of adults are from hatcheries. Hatchery fish
saved the salmon fishing industry in the Northwest,
but one concern is that hatchery and wild fish may interbreed.
The remaining wild stocks could begin to lose their
unique adaptations. Some wild stocks are now down to
a few thousand returning adults. With some, only half
of one percent of the smolts that went to sea make it
back. So there may be a million salmon in the Columbia,
but some may still be headed for extinction. It's vital,
says Mike Schiewe, to preserve the variety of salmon
stocks that we still have left.
ALDA Its not just saving some salmon, its trying to
save as many kinds of salmon as you can. Otherwise,
you're just leaving them open to the elements and they
could get wiped out anytime. We couldn't predict when,
SCHIEWE No, that's exactly right. You're buying insurance
against variations that are bound to occur. Populations
of fish rise and fall over the years. And this diversity
of different life forms utilizing the habitats and the
food resources in different ways allow the salmon to
persist at the levels that they do. So saving the diversity
of salmon is every bit as important as just talking
EAST -- THE EXTINCTION VORTEX
ALDA (NARRATION) We're heading up the Narraguagus River
in Downeast Maine. For the biologists we're with, this
rugged and beautiful country is in the grips of a catastrophe.
This river, along with seven others nearby, is losing
its last few wild Atlantic salmon and they don't know
why. It's spring runoff, and the traps in the river
have been set to sample the two-year-old salmon smolts
heading downstream to the Atlantic ocean. Every year
the numbers go down -- just 2,000 this year, one tenth
of the numbers in the past.
KOCIK One American eel.
ALDA (NARRATION) The traps catch everything. The smolts
they are looking for are wild descended from wild
parents that know only this river.
KOCIK One salmon smolt. OK we've got two smolts.
ALDA (NARRATION) As in the Pacific Northwest, hatchery
fish that are not adapted to a particular place are
not counted as wild. RESEARCHER Dorsal score?
ALDA (NARRATION) The last wild Atlantic salmon in the
US are confined to 8 Maine rivers, and all 8 stocks
are officially endangered. RESEARCHER Weight?
ALDA (NARRATION) The numbers are incredibly low. In
2001, less than 150 wild adult fish returned to all
8 rivers combined. The numbers of smolts heading out
are correspondingly low for example, in the nearby
KOCIK Our crew here is...I think they're really feeling
the numbers going down. It's not just looking at them
on paper. Having been here last year, handled 60, 70
smolts a day, this year we haven't even broke twenty
smolts a day.
ALDA (NARRATION) Things got this way in the Northeast
for the same reasons the Columbia salmon declined. Atlantic
salmon were once abundant everywhere north of the Hudson
River. But change came with colonization. There was
large-scale fishing. Thousands of dams were built to
power mills and factories. The Connecticut River, a
major salmon habitat, was completely blocked. Logging,
agriculture and water pollution all took their toll.
Throughout the Atlantic salmon's range, from Canada
to Russia, the same processes were underway. It's now
extinct in half the 50 or so major river systems it
once inhabited. Healthy populations remain in parts
of just four countries. The big concern is that numbers
have continued to plummet, even after heavy fishing
in the salmons' ocean feeding grounds off Greenland
was stopped 15 years ago. In Maine, research is going
on to try to understand the causes. They're going to
implant an acoustic transmitter in a smolt, and then
follow it down the river and out into the Gulf of Maine.
At the start of the research, they tested the effects
of the implant and, surprisingly enough, neither the
fish's behavior nor its health seem to be affected.
BELAND The body cavity starts healing almost immediately
post surgery. Within a very short period of time, everything
will be back to normal and the fish'll be on their way
into the river and then out to sea.
ALDA (NARRATION) Once the smolt has recovered from the
anesthetic, it's released.
KOCIK OK, we got a good signal on him.
ALDA (NARRATION) They follow the fish for a few hours
to make sure it's healthy and the system's working.
BELAND The signal's really strong. The fish is quite
close to us, probably within forty or fifty feet, right
up against the river bank.
ALDA (NARRATION) Right now we know surprisingly little
about the life of an Atlantic salmon smolt.
BELAND What we're hoping is, by understanding where
mortality may or may not be occurring, is there a single
smoking gun? Are there a number of factors each of which
contributes a little bit? And in total, we're really
sort of writing a missing chapter in the life history
ALDA (NARRATION) An array of 20 remote receivers is
set out in the river and the ocean just offshore. They'll
record the signal if the fish passes. So far they've
tracked 400 smolts, and only half have made it out to
sea. That's as bad as the smolts that have to get through
8 Columbia River dams, and it's a surprise. But there
is a pattern emerging.
BELAND It's a little suspicious that we're having more
mortality than expected and it seems to be occurring
disproportionately in or about the area where they first
hit salt water.
ALDA (NARRATION) Research in Norway suggests that young
salmon from acidified rivers have trouble regulating
salt. So New England's notorious acid rain may be, if
not the smoking gun, at least one of them. In the 1980s
the Pleasant River had a couple of dozen adult returns
a year. It's just a few now, in some years none. It's
called an extinction vortex not enough breeding adults
to stay ahead of the losses. As a last desperate measure,
biologists are trapping and removing smolts, to be raised
in captivity. This is the strategy being tried with
the California condor, for example.
ALDA (NARRATION) The young fish has the special adaptations
that suit it to just this river. As in the Columbia,
the only way to keep wild fish in the river is to preserve
each unique stock.
KOCIK There are differences between this river and the
Narraguagus River right down the road. Differences in
rearing habitat that we think, over time, have led to
local adaptations. So it's important to put fish back
into the river their parents came from.
ALDA (NARRATION) Young fish from 6 of the 8 Maine rivers
have now been removed for captive breeding. Genetic
tests have confirmed that each river's fish are distinct.
They're kept separately, and they're only bred within
their own group. This is exactly what salmon hatcheries
in both the Northeast and Northwest have not done, which
is one reason hatchery fish have low survival rates.
Their genetic adaptations have been mixed up, so they
don't know how to use particular places. A puff of air
helps this Machias river female release her eggs. She
was brought here as a 6-inch-long smolt, 3 years ago,
so now she's ready to breed. Her mate has the same impeccable
credentials. The eggs hatch in spring, as they would
in the river, and in about a month they're one-inch-long
fry. These are what will go back into the wild, to the
specific river their parents came from. We're on the
Machias river for spring fry stocking. This river also
gets very low or zero adult returns.
Run her all the way through, Dan.
ALDA (NARRATION) River-specific breeding and fry stocking
have been in operation in 6 Maine rivers since the mid-1990s,
with over a million fry a year distributed.
Why don't we swing close to these little rocks over
here and I'll put out a few.
ALDA (NARRATION) It's no exaggeration to say that whether
or not wild Atlantic salmon have a future in the United
States depends on the river-specific program. If it
doesn't work, there's very little chance that the species
can recover on its own. The fry hang out in the river
for two years, until they're ready to go to sea as smolts.
Then they catch a ride on the spring runoff, like the
Pacific salmon, and head out to Greenland to feed and
grow. Two years later the survivors should be back in
the same river to mate, and the cycle begins again.
We're back on the Machias river, in the fall of 2000
five years since the river-specific program geared
up on this river. It's the first year we could see a
boost in the number of returning adults.
BOISVERT Do you know how many there were here last year
or the year before?
ATKINSON The year before I counted ten or eleven in
ALDA (NARRATION) We're looking for salmon nests, or
redds, in the gravel.
ATKINSON There's no redds, it's kind of surprising.
This is a really nice spot here, you have the ideal,
or the classic type spawning gravel here.
BOISVERT Here's one here.
ATKINSON There's a redd?
ALDA (NARRATION) The patch of disturbed gravel is easy
to spot. Each female typically builds two redds during
the fall spawning season, so it's not hard to estimate
adult numbers by counting redds. This disturbance in
the gravel is where the female flapped her tail to create
a pile of stones to cover the eggs just downstream.
BOISVERT Zero, five, eight, nine...
ALDA (NARRATION) They note the GPS coordinates of the
redd, so they can come back to check how it does. The
Machias had 23 redds in the year 2000, representing
2 dozen adult fish not bad, but not a clear improvement.
Numbers are unchanged or still declining in the other
Maine rivers. So we don't yet know if the river-specific
program is going to work. Wild salmon are in trouble
everywhere, but there's no shortage of salmon. In the
last 20 years, salmon farming has become a major industry,
with more than 600,000 tons of fish produced a year.
80 percent is raised in Norway and Scotland, while Maine
has a small industry. Small is relative, though. There's
a hundred tons of Maine farmed salmon to each individual
wild Maine fish. Everywhere, salmon cages are usually
very close to salmon rivers. Biologists say the cages
that give us cheap salmon are nothing but trouble for
the wild fish. One problem is disease. In Norway, for
example, they found that young wild salmon can pick
up a lethal dose of parasites as they pass near farm
cages, on their way to the ocean. Salmon farmers check
and treat their fish, but you can never be perfect.
Another problem is escaped fish. Fish escape everywhere.
Here in Norway an astonishing 1 million fish a year
get out. Many run up the rivers and compete with wild
fish for food and spawning sites. But Norwegian research
shows the offspring are much less successful than their
wild neighbors. On this river, scientists have developed
an experimental system to remotely detect escaped farmed
salmon. It's based simply on how the fish look.
EIDE What we have built here is the monitoring unit,
with a transparent channel that the salmon has to swim
through. And we're using five mirrors and a video camera
to create an image with both a side view and a top view
of the fish.
ALDA (NARRATION) The video pictures are monitored a
hundred yards from the fish ladder. A returning adult
is about to get its picture taken.
LEKANG [In Norwegian] Here it comes.
ALDA (NARRATION) The system takes a frame of the top
and side views of the fish, then makes a simple outline.
The basic idea is that wild fish like this one are
literally in better shape. They're slimmer, and their
fins are sharper and less worn.
EIDE If you look at the left image of the wild salmon,
you can see that the fins are very nice. The dorsal
fin is more pointed than the farmed one, which shows
signs of wear on the fins.
ALDA (NARRATION) It's the same with the tail. Wild fish
on the leftS farmed on the right. Farmed fish get bitten
and knocked around in the crowded cages. They also don't
get much exercise, so they're fatter. The system's software
makes a series of measurements on each fish's profile,
then compares the results to typical values. It's right
more than 98 percent of the time. On this river one
of the healthiest in the world only about 2 percent
of its 5,000 returning adults are farm escapees. It
has no nearby farms, but other Norwegian rivers get
up to 90 percent farmed fish. The danger is that interbreeding
will steadily dilute the special local adaptations of
native salmon, until there are no fish left that know
how to use a particular river. That is a real risk here
in Maine. There have already been large farm escapes,
and at some point the tiny remaining number of wild
fish could simply get swamped. The challenge for scientists
is to fully understand why Maine's salmon are still
declining. That applies equally to many rivers in Canada,
Scotland and Norway, which until recently were regarded
as healthy. If the challenge is not met, then the future
of wild Atlantic salmon is not bright.
THE BLUEFIN BOAT
ALDA How long have you been coming out here with the
LUTCAVAGE I started on tuna in 1993.
ALDA (NARRATION) It's early on a summer morning, and
I'm going fishing with Molly Lutcavage, a marine biologist.
We're licensed to catch giant bluefin tuna, but we're
also licensed to attach satellite trackers to them
and there aren't many charter boats that can say that.
Fishermen have been leaving this harbor for over 300
years, but it's only in the last 30 that anyone's gone
after giant bluefin.
ALDA How do you know when you're near a place where
you're liable to catch a fish?
MURRAY Sometimes you see the fish jumping or see them
on the surface. Sometimes there's a lot of bait or birds,
ALDA (NARRATION) We're heading out to the giant bluefin's
summer feeding grounds. In the 1970s a gold rush developed
for bluefin, which are in demand for sushi. They can
weigh up to 1500 pounds, so a single fish may be worth
thousands of dollars. The record is 173,000 dollars
for a fish caught near Japan. Fifty miles out, we begin
to see dolphins and whales. It means we're in the right
LUTCAVAGE We often actually track tuna that are following
whales. They sometimes accompany fin whales or humpback
whales. So most fisherman are very pleased to see the
fins of the whales, because that's a sign that the tuna
may be there as well.
ALDA (NARRATION) Bluefin are ocean travelers. We know
they feed here in summer, and spawn in the Gulf of Mexico
in spring. Across the Atlantic we know they feed off
the coast of Africa, and spawn in the Mediterranean.
We're on the Italian island of Sardinia. This is the
village of Carloforte. Everyone's shown up for a celebration
of spring. The 500 pound giant bluefin showed up to
spawn, but the fishermen's nets were waiting as they
have been every spring for maybe 2000 years. The traditional
"mattanza" it simply means the killing is celebrated
in many Italian fishing villages. Many Mediterranean
countries have traditionally fished for tuna, but with
the coming of industrial-scale fishing in the 1960s,
traditional gave way to modern. Catches shot up, and
quotas were imposed -- on both sides of the Atlantic.
Back in the Gulf of Maine, we've had a strike on one
of our lines. The quotas were based less on bluefin
biology than on how many had been caught in the past.
Now biologists like Molly are trying to build up a scientific
understanding of bluefin. High tech tags like this one
are one of the key tools. Our bluefin's putting up quite
LUTCAVAGE It's about 150 pounds. So it's a small one.
ALDA (NARRATION) Our 150 pound fish is four years old
and half the legal size for sale. It won't spawn until
it's reached 8 years. The official estimate is that
there are up to 20,000 tuna over spawning age in the
western Atlantic. The tag has to be anchored into the
strong tendons around the dorsal fin.
LUTCAVAGE Wait for the shot. Nice one.
ALDA (NARRATION) The tag was placed perfectly. But then
we decided the fish was likely to be in poor shape after
the long struggle. So the catch was brought in to end
up on the table. One non-commercial keeper per trip
is permitted. Over the last 5 years, the boat has tagged
about 50 fish for Molly. The tags are designed to record
where the fish go, then at a pre-set date automatically
release from the fish, float to the surface and upload
their data to a satellite. They're called pop-up tags.
Pop-ups have revolutionized research on ocean travelers
like bluefin. We no longer have to make guesses about
their habits, based on where they happen to get caught.
But you still have to catch a fish before you can tag
it, and for that scientists like Molly depend on fishermen.
These guys don't have to take Molly out for free, or
stay out after they've reached their 2-fish-a-day bag
limit. They see the value of good information. They
know in the long run, it's the only thing that will
preserve bluefin -- and jobs. Soon after we caught our
fish, we almost literally ran into another boat that
Molly works closely with.
LUTCAVAGE Hey. We got it. We got one.
ALDA (NARRATION) Actually they were just dropping off
some fresh bread. This is a commercial tuna boat, that
uses nets. They're interested in good science too.
LUTCAVAGE Thanks for the bread. Good luck. See you guys!
It's a vital part of our research program is the fisherman
partnership. And not just recreational fisherman but
you can clearly see that the commercial fisherman here
have been the backbone of our studies for years. And
they've really given us our primary fishing and tagging
platforms. They've done it, for the most part, on a
strictly voluntary basis. And they've brought all their
expertise to the table. And we didn't have those skills
and we couldn't have done this work without their input.
ALDA (NARRATION) Molly first began working with tuna
fishermen in 1993. They were convinced, based on what
their spotter planes saw, that there were more fish
out here than the official estimates. Of course fishermen
always make claims like that, but here was a chance
to really check out their story. Molly and her colleagues
decided to simply count the tuna, using aerial photographs
and a mapping system that they set the spotter pilots
up with. Every summer for 5 years the pilots handed
in their pictures, and Molly's team laboriously counted
every fish they could see. The result surprised even
the fishermen. There were huge numbers. On one single
day, 17,000 fish were counted just in the Gulf of Maine
about the same as the official estimate for the entire
western Atlantic at the time. But could they have counted
the same fish in different places? And also how many
fish might have been out of sight, below the surface?
So next they marked fish with acoustic tags and followed
them. The aim was to measure tuna swimming speeds --
to eliminate double counting -- and also to assess typical
LUTCAVAGE We found out that they travel anywhere from
24 miles to say 30 miles in a single day. And that they
spent less than ten percent of their time in a single
day at the surface where we can see them.
ALDA They spend less than ten percent of the time at
the surface? So does that mean, on the day that you
photographed seventeen thousand fish in one area--in
one part of the Atlantic, that that might have only,
the chances were pretty good that that was only ten
percent of the fish in that area?
LUTCAVAGE We don't exactly know what percentage...
ALDA Or do they all go down at the same time?
LUTCAVAGE You're absolutely right. It showed us that
that represents only a small portion of the population
that's going to be in the area. Because we know that
we're only seeing a tiny slice of the water column at
ALDA (NARRATION) We're out on the commercial tuna boat
we saw earlier. Molly's team now estimates that there
are up to 65,000 giant bluefin just in the Gulf of Maine.
The research headed off a move to get the western Atlantic
quota cut in half. She was popular with fishermen, but
environmentalists said she was irresponsible. The western
Atlantic quota is about 10,000 large fish a year, which
it's believed is sustainable. This boat's quota is 50
tons about 200 large fish. The fishermen are happy
to help Molly with her pop-up tag research, even though
letting some fish go means it takes longer to fill their
quota. In the last 5 years this boat has tagged nearly
100 fish more than half the tags put out by all of
Molly's collaborating boats. The last few fish in the
net find they're not going to end up as sushi. It's
probably fair to say that western Atlantic bluefin fishing
is under control. It's well regulated and catches are
reasonable. Things are different on the other side of
the ocean. We're back in Sardinia, where Italian scientists
are preparing to take advantage of the mattanza to tag
some bluefin with pop-ups. The bluefin quota in the
Mediterranean and eastern Atlantic is enormous and probably
unsustainable 20 times the west's. That's because
of history and politics, not science. For years catch
quotas were based on the assumption that eastern and
western bluefin are separate stocks. But scientists
from both sides are now telling regulators they have
to think again. So far on this side they've got results
from 23 pop-ups. Here are all the results to date
Molly's, the Italian group's, and also those from a
Stanford University group that tagged fish off North
Carolina. The clear evidence of the pop-ups is that
tuna go all over the place sometimes right across
the ocean, and across the theoretical dividing line
that's used to separate eastern fish from western.
ALDA Has this radically changed what we know about tuna?
LUTCAVAGE It's absolutely radically overturned what
was thought about what bluefin did.
ALDA Oh, in what way? To what extent?
LUTCAVAGE Well, I suppose the biggest point is that
the fish are mixing at a much higher rate than was ever
believed. So we immediately learned that these fish
are not following the rules that everyone laid out for
them. And that there's no line down the middle of the
ocean and that they hit and they turn around. So that
was an eye opener to, I think, fisheries biologists
and managers, because they realized that what happens
on one side of the ocean, effects what happens to the
fish and the population on the other side.
ALDA (NARRATION) So it could be that large catches in
the east are being fed by good conservation in the west.
If that's so there'll be political problems down the
road. The pop-up results offered another eye-opener.
Many fish ended up, in the spring, in the wrong place.
LUTCAVAGE The giant fish that we assume were going to
spawn, after they got nice and fat and ready to go,
they should have been in the known spawning areas during
the spawning period. And that would be the Gulf of Mexico
or the Med. And for the first three years in a row,
none of the giant bluefin that we tagged here were in
either known spawning area during the presumed spawning
ALDA So that suggests that there's some area that you
haven't identified yet.
LUTCAVAGE It raised the question, Is it possible that
bluefin are spawning elsewhere?
ALDA Or do they just take a break?
LUTCAVAGE Or do they take a break?
ALDA It's amazing how much there is to learn about these.
You've been studying them carefully for years.
LUTCAVAGE Absolutely. I think that our independent tagging
studies have only raised more questions about what bluefin
do for a living.
ALDA (NARRATION) You can be sure that Molly and her
fellow scientists are going to be raising questions
about bluefin -- and about salmon -- for a while. Regulators
are going to be uncomfortable with the process, and
fishermen may or may not welcome the results -- but
the bluefin and the salmon could at least come out of
it with a future.