host: There has been a growing
appetite for fish around the
world of the demand is raising
questions and concerns about
sustainability and impact.
Our signs correspondent has a
first of a two-part look at what
is known as aquaculture.
Reporter: It was a perfect
summer day when we steamed out
of southwest harbor, Maine on a
different kind of fishing
vehicle.
Is this a good place to raise
salmon?
>> Certain places are great.
Reporter: Our guide was with
cook aquaculture.
>> This is where fish have been
living for thousands of years.
Reporter: And yet pollution,
dams and fishing rendered
atlantic salmon and endangered
species in the U.S.
Cook firms them at 120 leases
here and in Canada.
The company raises all sorts of
fish all over the planet, 18
countries in all and business is
booming.
The global appetite for seafood
as rapidly increasing.
Aquaculture is the
fastest-growing form of food
production in the world.
>> There is no question there is
a strong demand for our product.
Reporter: Off of swan island we
boarded the ship where they
monitor and feed their crop of
nearly half a million salmon.
They are kept in 16 flexible
floating net made with stainless
steel fiber to guard against
escapes.
We watched as they fed some of
the fish using a network of
submerged cameras.
>> There is no feed coming down
through the water column.
Reporter: The trick is releasing
the feed at the right rate.
Too fast and it falls to the
bottom of the sea impacting the
bottom line.
But it also can cause an
environmental problem as the
feed decomposes and generates
nitrogen as does the fish poop.
High nitrogen levels are a
persistent problem for part
salmon problems -- for salmon
problems.
>> One way to deal with it is
proper density and proper site
location.
We get a 12 foot rise and fall
of water so a lot of freshwater
going through here.
Reporter: Even at the perfect
location, fish farmers have to
closely monitor a myriad of
factors to keep their crops
healthy.
Firmed salmon are frequently
best that with serious
infestation of sea lice.
He deploys custom-designed boats
with warm freshwater showers to
clean the fish.
It is an expensive solution that
may have an unlikely
replacement.
A marine biologist is director
of the center for cooperative
aquaculture resource at the
university of Maine.
>> These are used as a cleaner
fish to remove sea lice off of
farmed salmon, form of
biological control.
Reporter: Norwegian salmon
farmers developed the technique.
Researchers here believe one or
two long fish -- lungfish should
be enough.
>> As the salmon swim by and the
lice become a problem, they dart
out and plucked it off the
salmon's back and needs edge.
Reporter: Cook makes his own
feed.
It is a mixture.
The company claims each pound of
salmon sold that market requires
6/10 of a pound of fish meal and
fish oil.
In the early days of the
industry, 30 years ago, it
required almost seven times as
much.
>> These fish are six-month-old
atlantic salmon.
Reporter: A microbiologist is
the director of the university
of Maine's aquaculture research
institute.
She and her team are looking at
alternatives to make salmon
aquaculture more sustainable
including insects.
>> Fish meal is more complicated
and just the protein you are
putting in it.
As long as they are getting the
omega threes and the other fish
oil and the other oils they need
and we have come a long way and
still having them taste really
good I can atlantic salmon.
Reporter: It takes about three
years for a salmon to grow from
big to market.
Ash from -- from egg to market.
It's sustainability favors --
its sustainability positively
is compared to land agriculture.
>> You can understand them being
excited about that momentum but
if you stop drinking the
kool-aid for a moment and look
at the other options on the
table, like things that are
already efficient, you stay,
let's put this in perspective.
Reporter: The other options,
aquatic farms that produce crops
further down the food chain.
And in fact muscle and oyster
farms in Maine are also doing
well.
These crops require no imports
and filter the water.
Sustainable sources of protein.
>> I think the oceans have an
important role of feeding the
present and future of humanity.
Reporter: 70%-80% of the seafood
that Americans eat is imported.
With its long sparsely populated
coastline, Maine may be an ideal
place for aquaculture to grow
but a coalition of lobster
fissures and summer residents
are opposed.
Jerry bowers is a ninth
generation Mainer who lives near
frenchman's bay where a company
seeks to build a 120 acre salmon
farm and hatchery.
>> To see this proposal in the
heart of acadia national park
rang alarm bells for us.
Reporter: The project is mired
in opposition.
She says the state is too eager
to approve aquaculture leases.
>> It is the equivalent of
setting up a farm on the town
green.
These are public waters.
While I am supportive of making
a living on the water, I want it
done in a balanced way.
Reporter: Jerry bowers believes
land-based aquaculture is a
better idea.
The seeming contradiction in
terms is gaining momentum as
consumers' demand, technology
permits and the oceans reached
their limits.
We will visit a fish farm in the
middle of some cornfields in
Indiana in our next installment.
The pbs newshour, I am miles
o'brien in Maine.