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Over
Fishing
photo M.
Noonan
As the human population continues
to explode, the demand for food grows with it.
Over-fishing by humans is a consequent huge threat to
all species in the ocean and has led to widespread
migrations by marine mammals in search of remaining
fish. It is not that we are saying that all use of fish
is wrong. But when humans take too much, the entire
ecosystem in each area of the ocean can be seriously
disrupted and too little is left for predators like
killer whales which also depend on the fish.
Salmon is one extremely popular
fish species among commercial and sport fishermen. Every
year, the salmon of the Pacific Ocean make "runs" to
their freshwater spawning grounds in the Pacific
Northwest of North America. Fishermen know the peak
times during the year to catch these fish and they have
the ability to net huge areas. When this happens, orcas,
seals, and sea lions that come to the same areas for the
same fish have too little to feed upon.
What Is Being Done
photo M.
Noonan
Many fishery enhancement programs
have been developed by governments around the world. We
ourselves, studied the Canadian program at the Big
Qualicum fish hatchery on Vancouver Island. There, and
at many other locations, professional aquarists catch
adult salmon as they make their way upstream to spawn.
They artificially harvest their eggs and sperm and
provide artificial habitat fertilization of millions of
new fish. The resultant salmon fry are fed and closely
monitored for health concerns. Hundreds of millions of
baby fish are cared for in this way for years until they
are ready to be released back into the streams where
they will swim out into the ocean to become adults. They
serve to support commercial and sport fisheries. But
they also support the salmon-dependant wildlife like
killer whales. And some of the fish artificially bred in
this way survive the fishing nets and natural predators
so that they can return to fresh water streams on their
own to spawn a new generation of salmon for the future.
photo M.
Noonan
A fairly new
alternative is the salmon farm. In this case, salmon are
raised to adulthood in enclosures in inland salt-water
areas. We inspected salmon farms of this type in a
number of locations in British Columbia.
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photo M.
Noonan |
These farms are
growing in popularity, but a number of
questions remain about their impact on the
environment. For one thing, most farms
utilize Atlantic Salmon even though they are
located in the Pacific Ocean. When these
fish escape (as some inevitably do), the
impact they have on the local populations of
wild fish is unknown.
For another, there is evidence
that certain fish diseases tend to break out in fish
farms due to the unusual crowding that necessarily
occurs. There is concern that such diseases could spread
to wild populations and there is also concern about
residual antibiotics (used by farmers to treat their
fish) working their way into the human food products.
Lastly, the sea bottoms in the areas around these farms
often become densely packed with a thick, muddy waste
that stems from the concentrated number of Atlantic
Salmon enclosed in the farm nets. The concentrated waste
often kills bottom-dwelling fish, clams, crabs, and
kelp. |
What You Can Do
We don’t argue that everyone has
to stop eating fish in order to avoid over-fishing
problems. However, by recognizing where our food comes
from, and the potential environmental effects that
different food production practices can have, we can do
our best to favor food products that have the least
detrimental effects on the environment.
We can also work to support
legislation that regulates the amount of fish being
taken from our oceans. We need to leave enough fish in
our oceans for the animals that live there and depend
upon them.
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