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Super un-Natural Atlantic Salmon in BC Waters

Authors:
Super un-Natural
Atlantic Salmon in BC Waters
John Volpe, PhD
The David Suzuki Foundation
2211 West Fourth Ave., Suite 219
Vancouver, BC Canada V6K 4S2
E-mail: solutions@davidsuzuki.org
Web: www.davidsuzuki.org
Tel: (604) 732-4228
Fax: (604) 732-0752
John Volpe
John Volpe was born and raised in Toronto,
Ontario, and received a Bachelor of Science
(1991) and Master of Science (1994) from
the University of Guelph (Ontario). He
received his PhD from the University of
Victoria in 2001 and is currently Associate
Professor of fisheries ecology at the
University of Alberta in Edmonton. Dr.
Volpe’s research includes the study of exotic
species introductions and biotic invasions,
the causal mechanisms and rate of physical
and genetic evolution in marine and aquatic
organisms, the conservation of fringe and
insular populations, and relationships
between biodiversity measures and
ecosystem functions.
The Author
David Suzuki Foundation
The David Suzuki Foundation explores
human impacts on the environment, with
an emphasis on finding solutions. The
Foundation was established in 1990 to find
and communicate ways in which we
can achieve a balance between social,
economic and ecological needs.
Sections of this report may be reproduced. Please credit the David
Suzuki Foundation.
ISBN# 0-9689731-0-8
National Library of Canada Cataloguing in Publication Data
Volpe, John Paul 1964-
Super un-Natural
Includes bibliographical references.
1. Atlantic salmon — British Columbia. I. David Suzuki Foundation. II. Title.
QL638.S2V64 2001 597.5'5'09711 C2001-911448-6
Cover and Inside Cover Photos: © Natalie B. Fobes
Maps: Marcel Pepin Mapping and Photography
Design: Metaform Communication Design Inc.
Printing: Western Printers
Paper: Cover — Genesis Text Birch 80#, 100% Post-consumer. Insides — Eureka Bond, 100% Post-consumer and
Process Chlorine Free
Acknowledgements
Earlier drafts of this report benefited greatly from the input of Dr.
Ian Fleming (Hatfield Marine Science Center, Oregon State
University), Dr. Robert Scott (University of Western Ontario), Dr.
Peter Tyedmers (Dalhousie University), Dr. Fred Whoriskey Jr.
(Atlantic Salmon Foundation). I would like to thank Jean
Kavanagh, Ann Rowan, Lynn Hunter, Kim Wright and the staff of
the David Suzuki Foundation for their valued input and support
during this project. J.V.
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Preface
Alien Species
How did we get here?
Introducing Atlantic Salmon
Assumptions and Realities
“Esca pe s ar e very rar e”
“Esca pe s of A tlantic salmo n are in evitable but the y won’t survive”
“Some Atlantic salmon may survive but will not ascend freshwater
spa wning ri vers”
“Some adult Atlantic salmon are likely to be found in freshwater rivers
but can ’t spawn”
Research successful despite DFO
Why not Pacific salmon?
Conclusion
Literature
Table of Contents
List of Photographs
1 Salmon farms 07
2Map of BC salmon farms 08
3 Transfer of salmon smolts 10
4 Atlantic salmon fingerling 12
5Atlantic salmon in net pen 13
6 Map of Atlantic salmon 17
marine capture
7 Searching for Atlantic 18
salmon
8 Map of capture and 19
sightings of Atlantic salmon
in BC streams
9Adult Atlantic salmon 20
10 Spawning channel 21
constructed by John Volpe
11 Tagged Atlantic salmon 24
12 A diver inspects the 26
saltwater net pens
13 Farmer feeding 28
Atlantic salmon
02 Super un-Natural
P r e f a c e Researching the impacts of net-cage
salmon aquaculture in British Columbia is
a major focus of the David Suzuki
Foundation. In 1996, because we were so
concerned about the industry’s expansion
without adequate environmental assessment,
we published Net Loss: The Salmon Netcage
I n d u s t ry in British Columbia, the first
comprehensive public report to examine
the subject. Five years later, our concern
has only deepened as a new provincial
government has indicated it will soon lift
the six-year moratorium on industry
expansion. In addition, the federal
D e p a rtment of Fisheries and Oceans
(DFO) acts more like an advocate than a
regulator, adding to the distress of those
troubled about the effects of what amounts
to having high-density feedlots floating in
our waters.
Dr. John Volpe is the researcher who
confirmed in September 1998 that Atlantic
salmon, having escaped from BC salmon
f a rms, had successfully re p roduced to
several age classes in a Vancouver Island
river. He later discovered more feral
Atlantics in several other streams, and
continues to lead Canadian research on
this issue today. His unprecedented findings,
however, have only been achieved through
relentless effort.
In the fall of 1997, Dr. Volpe (then a
doctoral student) initiated what was to be
a two-year investigation into Atlantic
salmon spawning perf o rmance with funding
f rom the BC govern m e n t ’s Habitat
C o n s e rvation Trust Fund. In order to
simulate natural spawning habitat common
to Vancouver Island, he undertook the
challenging job of re-engineering a
salmon-rearing pond into a river and a
physically contained breeding channel at
D F O ’s Little Qualicum Salmon Enhancement
Facility. Baseline spawning data of farm-
reared Atlantic salmon was to be collected
during year one in order to address the
question, “Will aquaculture-escaped Atlantic
salmon spawn in a [simulated] Vancouver
Island stream? If not, why not and if so, how
do habitat preference, spawning performance,
behaviour etc. compare to published wild
Atlantic salmon data?” In other words, Dr.
Volpe wanted to ascertain to what extent
BC farm Atlantic salmon perform like wild
Atlantic salmon.
In the second year of his research, the
experiment was to be repeated but native
salmon were to be added to the breeding
channel. He proposed that comparing the
performance of the Atlantic salmon with
and without competition would give a good
idea of what might be expected in terms of
spawning perf o rmance in the wild. Dr. Vo l p e
also planned to compare the performance
of the control-group Pacific salmon to the
average performance of wild salmon in the
adjacent Little Qualicum River. This work
would produce baseline data on the effect
of Atlantic salmon on the spawning of
Pacific salmon and vice versa. As there was
literally no data on these phenomena at the
time, Dr. Volpe’s research was a major step
forward in understanding the effects of
Atlantic salmon on native Pacific stocks.
Given DFO’s mandate to enforce the
Fisheries Act, which stipulates the pro t e c t i o n
and conservation of native salmon stocks,
one would assume that DFO officials would
welcome Dr. Volpe’s work. Unfortunately,
this was not the case. Procuring Atlantic
salmon turned out to be a difficult challenge.
There are only two sources of Atlantics in
David Suzuki Foundation 03
BC — industry and DFO. Research staff at
DFO’s Pacific Biological Station (PBS) in
Nanaimo had agreed to provide Dr. Volpe
with Atlantic salmon from their experimental
fish farm. However, just two days before he
was to collect the fish and start his experi-
ments he received a letter from PBS dire c t o r
Dr. Don Noakes informing him of a policy
change not to allow fish to leave the federal
research centre.
Dr. Volpe’s entire research season was
jeopardized by the last-minute DFO policy
change and a later decision to cancel his
permit at the Little Qualicum research site.
E v e n t u a l l y, fish were acquired from a salmon
farm and Dr. Volpe continued his work at a
spawning stream that he engineered at the
University of Victoria. However, he never
received a satisfactory explanation for
DFO’s policy change. One is led to wonder
whether DFO officials were avoiding
questions they didn’t want answered. In
the past year both Canada’s Auditor
General and the Senate Fisheries
Committee have raised serious questions
about how the Department of Fisheries
and Oceans deals with salmon aquaculture.
The department’s treatment of one of the
leading re s e a rchers in the field is more
reason for concern.
To date, industry and DFO have
controlled the aquaculture research agenda
in British Columbia with an almost singular
interest in applied research that will lower
costs or raise productivity — in essence a
public subsidy for industry. Clearly, more
research is needed on the ecological effects
of the salmon aquaculture industry, a point
eloquently made by Dr. Volpe. “ T h i s
knowledge gap permits the all too common
line, ‘There is no evidence to suggest that
Atlantic salmon aquaculture has any negative
effect on native salmonids or their environ-
ment’. This is a worn old gem that i n d u s t ry
advocates trot out at every opport u n i t y. Of
course there is no evidence: How could there
be evidence of an effect if no one has tested
for it? Consider this variation on the theme:
‘Atlantic salmon have not proven capable of
competing with Pacific salmon in the marine
conditions that prevail on the Pacific coast’
(Anne McMullin, Executive Director of the
BC Salmon Farmers Association, Northern
Aquaculture, September 1999). This is quite
true. However, without the necessary research
one is on equal ground by stating: ‘Atlantic
salmon have not proven incapable of competing
with Pacific salmon in the marine conditions
that prevail on the Pacific coast’ ”.
As the government of British Columbia
prepares to lift the moratorium on new
salmon farms and the federal government
continues its unabashed advocacy of the
industry, the David Suzuki Foundation
believes that British Columbians and
Canadians must heed the advice of scientists
like Dr. Volpe and tell our political leaders
that the mandate of government research
into salmon farming must be expanded to
include the potential impacts on native
species and entire coastal ecosystems.
Jim Fulton
Executive Director
October 2001
Increased global activity, with a remarkable
volume of both people and goods being
transported at any given time, creates the
potential for mass transfer of organisms.
Simultaneously, with industrial activity and
growing urbanization, we have affected
dramatic — even violent — changes on the
world’s environment, undermining natural
barriers to invasion on which both local
and global ecological functions depend.
The transfer of organisms among de-
stabilized environments is rapidly eroding
One of the least understood of the world’s major environmental issues is
the movement and eventual establishment of species beyond their
native range. In contrast to other significant environmental problems
such as urbanization and pollution, ‘biotic invasions’ mean that living
organisms are the threat. Invading species independently reproduce,
grow and spread, all the while evolving to help them adapt to their new
environment. The United Nations recently declared the introduction of
exotic species the greatest threat to global biodiversity after habitat loss.
This second-place ranking is misleading when we consider habitat loss is
itself a major effect of invasive species. For instance, in the United States,
1,800 hectares of forest, park, crop and range land are lost every year to
invasive plant species.
04 Super un-Natural
Alien Species
an urgent environmental issue
worldwide biodiversity and reshaping
Earth’s natural systems in our own lifetime.
While the rest of the world scrambles
to address the challenges represented by
exotic species, Canada — a country with
more to lose than most — has remained
silent. The quality of life in Canada is the
envy of most of the world. Ironically, how-
ever, our natural resources, which form the
foundation of our prosperous lifestyle,
remain exposed to this most dangerous and
underestimated threat.
Davi d Suzuki Foundation 05
Lessons from Australia
One of the earliest intentional introductions remains among the most instructive in demonstrating the
perils of alien species: the introduction of the rabbit (Oryctolagus cuniculus) to Australia. Intro d u c t i o n s
began in 1788 for sport hunting purposes, and populations remained only moderately abundant and
patchily distributed for years to come. To bolster establishment, feral rabbits were accorded federal
p rotection for four months of the year by the Games Act of 1864. A decade later, the situation had
changed dramatically. Rabbit abundance suddenly exploded and what was to become known as the
‘plague of rabbits’ spread at 130 kilometers per year (a rate maintained until 1910 when all suitable
habitats were occupied). The rabbits’ intense grazing transformed productive farm land to earthen
barrens. Then in a radical about-face, the federal government passed the South Australian Rabbit
D e s t ruction Act in 1875. Costly and large-scale attempts to control the rampage failed and farms were
abandoned because of rabbit damage as early as 1881 (Stodart and Parer 1988). To d a y, rabbits
remain common across the same range they occupied in 1910 despite poisoning, fumigation, destru c t i o n
of warrens and the erection of vast exclusion fences. Curre n t l y, agricultural losses attributed to rabbits
a re estimated at AUS$20 million annually (Environment Australia, unpublished data). The full loss in
ecosystem-wide pro d u c t i v i t y, however, remains to be calculated. Issues first observed during the rabbit
plague of Australia re c u rred in other invasions and typify the introduction of alien species worldwide.
F a i l u re precedes success: More than 30 attempts to introduce the rabbit are on re c o rd in
Australia, but the plague is traced to a single introduction of 12 pairs in 1859.
A lag period of low density often will precede explosive population growth: In the latter 1800s,
after decades of seemingly neutral population growth, rabbits in Australia began a rapid, decades-
long expansion of 130 km/year.
Behaviour is inconsistent from one introduction to the next: while the rabbit was devastating
Australia, England, New Zealand and many other locales, widespread introductions to Spain and
Italy failed to develop beyond localized populations.
Alien populations evolve novel characteristics not seen in ancestral populations.
The myxoma poxvirus was known to be lethal in some rabbit species and was introduced on numero u s
occasions in Australia in the hopes of acting as a biological control. After initial failures and a lag
period, a viral epidemic erupted across Australia. Infected populations showed a death rate of 99
p e rc e n t and early forecasts predicted the end of rabbits in Australia. However, within 18 years both the
v i rus and the rabbits had evolved, resulting in an equilibrium rabbit survival rate of 30 to 50 perc e n t
( reviewed in Williamson, 1996).
I n t roduced species in the United States,
United Kingdom, Australia, South Africa,
India and Brazil cause an estimated US$314
billion per year in economic damages
(Pimentel et al. 2001). For scientists, alien
species are often puzzling, defying our best
efforts to predict their appearance and
characterize their spread and performance
in new habitats — a testimony to the
complexity of natural systems.
The rabbit (see inset) is but one of
thousands of introduced species reshaping
Earth’s ecological systems. The effects of
introduced species in Canada is being
increasingly documented in the popular
press. Asian long-horned beetle, West Nile
virus, European carp, Eurasian milfoil,
knapweed and zebra mussel are just some
of the species that are currently making
headlines. One thing biologists have
learned from these diverse introductions is
that it is much easier, and less costly, to
prevent introduction of a species than to
remove it after it has established.
Currently in coastal British Columbia,
the most contentious alien species is
Atlantic salmon (Salmo salar). The Atlantic
salmon, as the name suggests, is a native of
Canada’s east coast but in 1984 was intro-
duced to the west coast. Deemed easier and
more successful to farm than Pacific
species, multinational companies are
capitalizing on a worldwide demand for
salmon by growing Atlantics in open net
cages along the coastal fringe of BC. Young
salmon are reared in freshwater hatcheries
and then moved to sea cages to be grown
to market size. A typical farm is comprised
of 10 to 30 cages, each 12 or 15 metres
square and containing on average 20,000
fish (Alverson and Ruggerone, 1997).
06 Super un-Natural
Having net ‘walls’, sea cages are prone to
tearing from storms, human erro r, pre d a t o r s
or other causes, resulting in the mass
escape of fish annually. The sea cages or
net pens also allow virtually complete
interaction between the farm and the
s u rro u n d i n g environment. Therefore,
clean, oxygenated water is free to pass into
the net pen while uneaten food pellets,
feces, antibiotics and toxic anti-foulants
flow out. The exchange of clean water into
the farm and dispersal of industrial wastes
away from the farm means that the industry
benefits from a subsidy from nature.
Economists employed by industry are
quick to note that placing salmon farms on
land, which would reduce or eliminate
most environmental problems, including
escapes, would be economically unfeasible.
This is largely because while the cages
remain in the sea, nature absorbs the cost
of maintaining a healthy environment for
the farm stock. Unfortunately, however, not
enough is known about the buffering
capacity of the natural environment and
how close we may be to saturation on this
One thing biologists have
learned from these diverse
introductions is that it is
much easier, and less costly,
to prevent introduction of
a species than to remove it
after it has established.
David Suzuki Foundation 07
coast. At present, we are unaware of what
mitigative capacity the coastal environment
has for organic wastes, diseases, parasites,
toxic anti-foulants, antibiotic therapeutants
or escaped alien salmon. Industry and
government have assured us many times
that we need not worry about these issues
nor about the presence of salmon farms in
British Columbia. For the most part, the
public assumes that these concerns have
been scientifically addressed and found to
be within accepted limits of risk.
Unfortunately this is not the case.
Below I chronicle my studies on the
p o t e n t i a l ecological effects of escaped
Atlantic salmon in coastal BC. Contrary to
the opinions of government and the
i n d u s t ry, I conclude that there is no scientific
evidence that salmon aquaculture on the
scale presently practiced in British
Columbia will not unduly affect wild
stocks or their natural enviro n m e n t .
Salmon Farms. The newer round pens help the salmon school together, limiting the damage they do to each other
in the close confines of the net pen.
08 Super un-Natural
Since 1972, no less than four federal
government departments and six
provincial ministries have been
involved in regulating and guiding
the development of British Columbia’s
aquaculture industry. Despite seemingly
obsessive government attention, the
bureaucratic environment in which the
industry has and continues to exist
remains a jury-rigged collection of
modified capture fishery and terrestrial
agricultural policies. The result has
been largely ineffective, leaving farmers
to learn by their mistakes.
In spite of some rather spectacular failures,
aquaculture grew rapidly in BC from 1972
to 1985, with salmon farming expanding
from zero to 100 companies operating 185
coastal farm sites (Keller and Leslie 1996).
At first, the typical farm was a small family
business, which was undercapitalized and
lacking adequate government technical
support.
Norwegians pioneered salmon aqua-
culture and remain the world’s leading
salmon-farming nation. A near collapse in
the early 1970s, due to disease and a satu-
rated world salmon market, prompted the
N o rwegian government to overhaul its
re g u l a t o rypolicies and institute an agenda
designed “to lead and control the industry”
(Keller and Leslie 1996). Implementation
How did we get here?
Map of BC salmon farms
David Suzuki Foundation 9
of rigorous controls on production levels
and expansion limits were instituted.
In Canada, the 1984 election of the
Progressive Conservative government led
to the replacement of the F o reign Investment
Review Act with the Investment Canada Act,
which further encouraged foreign invest-
ment. This legislation set the stage for a
new era of aquaculture in British Columbia.
While producers had demonstrated the
potential of salmon farming, Canadian
banks remained skeptical. If the BC industry
was to realize its perceived potential,
financial and technological backing would
have to be imported. Norwegian companies,
eager to expand but restricted by the new
regulatory climate at home, quickly took
advantage of the new-found political support
for their industry in western Canada. A
Norwegian parliamentarian explained why
to the Canadian Parliamentary Committee
on the Environment: “We are very strict
about the quality and the enviro n m e n t a l
q u e s t i o n s [in Norway]. Therefore, some of
the fish farmers went to Canada. They said,
‘We want bigger fish farms; we can do any-
thing; we can do as we like.’” (transcript,
House of Commons Standing Committee
on the Environment, Sept. 12 1990).
Vigorous Norwegian-financed expansion
and consolidation then exploded in
Canada. In 1985, the BC industry was
made up of one hundred small businesses;
today, the BC Salmon Farmers Association
represents 15 producers, dominated by
Norwegian-based multinationals.
The focus of this report is the most
significant industry change that occurred
during this transition period. Before the
Norwegian-sponsored restructuring, BC
salmon farmers were in the business of
raising and selling Pacific stocks, specifically
chinook and coho. Thanks to technological
innovation and market domination —
often through novel but relentless product
marketing — Norway became the world
leader in farm salmon production (using
Atlantic salmon), and often created markets
that did not previously exist. Today,
Atlantic salmon is the favoured species for
culture in BC for a number of reasons.
The Norwegian-dominated industry
had decades of experience culturing
Atlantic salmon but were unacquainted
with the culture of Pacific salmon
species.
Norwegian companies had invested
heavily in developing international
markets for Atlantic salmon, and
chinook and coho products could not
easily fit in to this marketing strategy.
On average, Atlantic salmon convert
feed to meat more efficiently and are
less aggressive (leading to greater
growth and lower mortality) under
culture conditions than chinook or
coho salmon.
Thus from both a production and marketing
perspective, it became clear that Atlantic
salmon would be a more profitable product
than native chinook or coho.
10 Super un-Natural
Introducing Atlantic Salmon
Transferring salmon smolts from freshwater to saltwater grow-out site by helicopter.
Photo: Natalie B. Fobes
David Suzuki Foundation 1 1
In 1999, nearly three times the amount of
farm salmon was brought to market than
wild salmon. Note that a tonne of landed
wild salmon is worth only one quarter of
what the same amount of salmon sells for
at the farm gate. However, the relationship
is reversed at the wholesale level, with wild
salmon worth 1.5 that of farm salmon.
Product demand, supply consistency and
value-added processing drive much of the
price differences. One of the most signifi-
cant points to be taken from these data is
that farms earn 89 percent of the wholesale
value of their product while fishers only
realize 15 percent.
Table 1 1999 BC salmon aquaculture and commercial salmon capture fishery
statistics (most recent figures available).
na = not available.
Farm Atlantic
Farm Chinook
Farm Coho
Aquaculture Total
Salmon capture fishery
(all species)
Source: Source BC Ministry of Fisheries.
3 7 , 6 7 3
7 , 5 1 0
1 , 5 5 5
4 9 , 1 0 0
1 6 , 9 0 0
8 1
1 6
3
1 0 0
1 0 0
n a
n a
n a
$ 5 , 9 5 1a
$ 1 , 5 0 3b
n a
n a
n a
$ 6 , 7 0 0
$ 1 0 , 0 0 0
Production
( t o n n e s )
% Total
P r o d u c t i o n
Farm Gatea/
L a n d e dbValue
per tonne
Wholesale Value
per tonne
Atlantic salmon were introduced to BC in 1984, foreshadowing the industry’s
Norwegian-influenced restructuring that was soon to come. Today, Atlantic
salmon dominate the BC aquaculture industry (Table 1), whose returns are three
times greater than that of the Pacific salmon capture fishery, as well as being BC’s
most valued ‘legal’ agricultural export crop.
Farm salmon mainly feeds the export
market, while most wild salmon is consumed
domestically. Over 77 percent of all aqua-
culture production is exported, bringing
new money into provincial and federal
c o ff e r s , while domestically consumed
salmon simply redistributes revenue and
thus does not deliver the same economic
benefits. There f o r e, the aquaculture industry
is now a powerful agribusiness with formi-
dable lobbying power, commanding a
significant presence in government policy
development.
While the economic benefits of aqua-
culture are obvious, the industry’s hidden
costs are rarely discussed. These costs
include but are not limited to: the potential
for disease transfer to and from wild
salmon stocks, development of antibiotic-
resistant pathogens, organic pollution from
uneaten food and feces (which can lead to
diminished ecosystem functioning), and
questionable methods of predator (marine
mammals and birds) deterrence. These and
other issues are all worthy of vigorous
s c ru t i n y. I will focus, however, on one
particular issue: the ecological and genetic
implications of escaped Atlantic salmon in
British Columbia waters.
Atlantic Salmon in BC: Ecological
Assumptions and Realities
Government efforts to allay public concern
about the presence of Atlantic salmon in
Pacific waters have on occasion been hope-
lessly naive and clearly contrary to accepted
scientific opinion. Consider the following
excerpt from Fish Farming: BC’s New Ve n t u re
on the Coast distributed in 1987 by the BC
Ministry of Agriculture and Fisheries,
Aquaculture and Commercial Fisheries
Branch.
“[Atlantic] salmon have no home stream to
return to in order to spawn. Instead, they would
return (if they survived that long) to their home
fish farm. Without a freshwater spawning
ground they would be unable to reproduce.”
12 Super un-Natural
This statement was as ridiculous then as it
is now. It was common knowledge in 1987
that salmon reared in captivity and released
(more often escaped) at sea would display
a homing capacity consistent with that of
their natural counterparts. The major
difference is that salmon released at sea
will choose a spawning river based on as
yet undefined criteria. Certainly no biologist
worth their salt would suggest that they
would simply return to the net pens and
conveniently perish.
To date, the politically palatable
responses of government and industry to
queries regarding the fate and potential
impact of escaped Atlantic farm salmon
have repeatedly proven to be false.
Beginning in the mid-1980s, those with
concerns about salmon farming in BC have
been told in chronological order:
escapes are very rare
escapes of Atlantic salmon are inevitable
but they won’t survive in the wild
some Atlantic salmon may survive but
will not ascend freshwater rivers
some adult Atlantic salmon are likely
to be found in freshwater rivers but
can’t spawn
spawning is likely to occur but pro g e n y
will not be competitively viable; and
finally the current position,
multiple-year-classes of juvenile
Atlantic salmon in some rivers do not
pose a threat to native populations.
At every stage the politically expedient
response has fallen when empirically tested,
which I will now demonstrate.
Atlantic salmon fingerling Photo: John Volpe
David Suzuki Foundation 1 3
“Escapes are very r are
Public inquiries regarding the potential
negative effects associated with
importing Atlantic salmon were met
with assertions that escapes were
unlikely, even though this was contrary
to what was known to be happening
on existing farms producing Pacific
species. One can only assume that the
prevailing logic was that the small
ratio of escaped Atlantic salmon to
wild Pacific salmon would dilute any
negative effects beyond observation.
It would be a truthful, but s o o n - t o - b e -
unemployed, bureaucrat or industry
spokesperson who stood up in public
and explained that escapes are going
to happen because it is not in the
companies’ financial interest to operate
farms with zero percent escape rates.
A s s u m p t i o n s
and Realities
Atlantic salmon swim in net pen. Photo: Natalie B. Fobes
The costs of building such stru c t u res (either
in the ocean or on land) are high, a l t h o u g h
technically possible. Unfortunately, the
money saved by building “leaky farms” is
considerably more than the value of the
fish that escape. It is the same maximum-
minimum type problem that is taught to
grade nine math students. At what level of
expenditure are both the cost of net pens
and the financial costs of escapees mini-
mized? As can be seen in Figure 1, escapes
are integral to maximizing profitability.
Reducing escapes beyond the star on the
curve is costlier than the amount realized
by harvesting the additional fish.
It is worth noting here that the exact
number of farm escapes is not known, and
therefore defining relationships between
14 Super un-Natural
capital investment and escapes are limited
to qualitative representations such as
F i g u re 1. Unaccounted-for losses are
common to all net-pen operations. Over a
214- to 260-day test period, losses in a
Puget Sound chinook farm ranged from 8.4
p e rcent to 37.9 percent of the net-pen
p o p u l a t i o n, averaging approximately 22
percent (Moring 1989). These losses
occurred even though daily dives found no
tears in the nets. In addition to live escapes
(known as leakage), unaccounted losses
could also occur because of death (followed
by sufficient rotting to allow the carcass to
pass through the net and not be recovered
during typical twice-weekly “mort dives”),
and predators (marine mammals and
birds). Under current operation protocols,
Figure 1 Schematic diagram representing diminishing returns on investment in “escape
proofing” salmon grow-out operations. The area to the right of the mark on this hypothetical
curve is where investment in overhead will exceed profit gained. The shape of the curve will
change with different technologies, but at present, all marine-based technologies have an
inflection point (star) below 100 percent containment.
Revenue loss
resulting from
escaped fish
Cost of building / maintaining net pens
Retention of
salmon in
net pens
0 %
1 0 0 %
Davi d Suzuki Foundation 1 5
the contribution of each of these thre e
factors to the total number of unaccounted
losses cannot be determined. Educated
guesses of leakage, without conducting
f o rm a l evaluation, suggest that between 0.5
- 1.0 percent per year of the net pen popu-
lation is “leaked” annually (B. Ludwig,
cited in Lough and Law 1995; J. Forster,
cited in Alverson and Ruggerone 1997).
Using 1999 production figures, and
a s s u m i n g a mean harvest weight of 3.5kg,
55,400-110,800 Atlantic salmon, 12,650-
25,300 chinook and 2,950-5,900 coho
were “leaked” in 1999 on top of reported
escapes. The leakage estimates of 0.5 - 1.0
percent per year, however, are only guesses,
and until the issue is rigorously examined
we will not know to what extent these
e s t i m a t e s reflect reality.
Adding further confusion to the estimates
of the number of salmon released is the
fact that farm managers themselves often
don’t know how many fish are in their nets
at a given time. A particular net pen is
designed to hold a certain number of kilo-
grams of fish. When smolts arrive from the
h a t c h e ry a re p resentative number are
weighed to determine an average weight
per fish. This calculation allows the
approximate number of fish in the ship-
ment to be determined. For instance, if
1000 kilograms of smolts are delivered and
the mean individual weight is 50 grams per
fish, there are approximately 20,000 individual
fish. There f o re, farm managers have a
relatively good idea of the total biomass
(weight) that should be present in each net
pen but can only estimate how many fish
this represents. Inaccurate estimates are
particularly common during the transfer
from freshwater rearing farms to marine
grow-out operations since individual
weights vary widely at this stage (Alverson
and Ruggerone 1997). From a business
perspective, this problem is seen as “poor
inventory control”, and has been cited by
Canadian financial institutions for their
past reluctance to be involved with salmon
aquaculture (Keller and Leslie 1996).
The number of salmon residing in a
net pen can only be loosely estimated
because of:
i) unaccounted losses due to mortality or
predation
ii) leakage
iii) inaccurate estimation of the original
population size.
T h e re f o re, the only conclusion one can draw
is that the annual number of escaped f a rm
salmon cannot be accurately estimated. This
means that yearly published numbers of
escapes are underestimates and should be
treated with skepticism, and that the actual
number of Atlantic salmon presently free-
ranging in BC waters remains unquantifiable.
Unfortunately, the money
saved by building leaky
farms” is considerably
more than the value of the
fish that escape.
“Escapes of Atlantic salmon are
inevitable but they won't survive”
When tangible proof of escapes began
to appear in the form of Atlantic
salmon turning up in the catches of
Pacific salmon gillnetters, seiners and
even trollers (which suggests that at
least some escapees were likely to be
successful predators), it became clear
that escapes were hardly rare events.
The public was then told that escapes
are inevitable, but the number of
survivors negligible. Prior to the switch
on the west coast to the predominant
use of Atlantic salmon, farm escapes
were difficult to assess because the
free-ranging escapees were the same
species as the naturally occurring wild
fish, and thus, very difficult to distin-
guish. Interestingly, Atlantic salmon
began showing up in commercial
catches in 1987 — four years before the
first reported farm escape (Alverson
and Ruggerone 1997).
Although the reporting of escapes is
required by a farm’s license, the federal
Department of Fisheries and Oceans
(DFO) acknowledges that the level of
c o m p l i a n c e remains unknown. At present
there is no way to trace an escapee back to
its farm of origin as fish carry no clips,
marks or tags so farmers have little moti-
vation to re p o rt the mishap unless an
insurance claim is made, in which case it
16 Super un-Natural
becomes public knowledge. And even if an
escape is reported and found to be the
result of gross misconduct by farm staff, no
significant legal sanctions are available to
encourage the farm to be accountable for
its actions. At times, farm staff are not even
aware that major escapes occur. In the
summer of 2000, approximately 35,000
Atlantic salmon escaped from a farm in
Johnstone Strait, off the northern tip of
Vancouver Island. The escape happened to
occur concurrently with one of the few
commercial fishery openings in the area.
Radio traffic among skippers was constant
and no one could believe how many
Atlantic salmon were being caught.
Suspecting the worst, the farm manager,
who would ultimately take responsibility for
the escape, sent workers off to inspect the
net pens. To their surprise they discovered
where the sudden pulse of Atlantic salmon
in Johnstone Straight was coming from.
The radio traffic also caught the
a t t e n t i o n of a local researcher who took it
upon herself to survey as many fishing
boats as possible, either by radio or in
p e r s o n , in the hope that informative data
could be gathered. Skippers reported
10,233 Atlantic salmon had been caught,
of which biological data were collected on
796 specimens (A. Morton, Raincoast
Research, unpublished data). Interestingly,
DFO’s Atlantic Salmon Watch Program
(ASWP) annual report for 2000 lists only
7,833 marine captures of Atlantic salmon
across BC, in addition to the 126 adults
and 12 juvenile Atlantics reported in fresh-
water rivers (http://www-sci.pac.dfo-
mpo.gc.ca/AQUA/PAGES/ATLSALM.HTM).
The bulk of ASWP figures result from com-
mercial fishers reporting marine captures,
David Suzuki Foundation 1 7
but various problems exist with these data.
Foremost, the data are opportunistic and
collected in the absence of any experimental
design or controls. For instance, it is
unknown how many captured Atlantic
salmon are re p o rted, 10 percent, 50 perc e n t ,
80 percent? Many fishers do not report
catching Atlantic salmon and instead freeze
the carcasses to be used as bait during the
commercial halibut season (pers. obs., J.
Volpe). Given that we don’t know how
many Atlantics escape in the first place, it
is impossible to use ASWP figures as any-
thing more than extremely conservative
“minimum estimates” of captures.
In 1990, Atlantics demonstrated how
far they could expand their range when
they first were documented in Alaskan
waters (Wing et al. 1992). This indicated
not only their capacity for long-distance
dispersal (the most northerly possible
release site was northern Vancouver
Island), but also suggested that any future
problems due to the presence of Atlantic
I n t e r e s t i n g l y ,
Atlantic salmon
began showing up
in commercial
catches in 1987 —
four years before
the first reported
farm escape.
salmon may well become international as
Alaska has invoked a constitutional
amendment banning net-pen aquaculture
because of fears it will negatively affect
native stocks. In 2000, 81 Atlantic salmon
were reported caught in Alaskan marine
waters, and one was caught ascending the
state’s Doame River (ASWP data).
“Some Atlantic salmon may survive but
wil l not ascend freshwater spa wning
r i v e r s ”
Anecdotal reports of sport fishers landing
Atlantic salmon in coastal rivers occurred
with increasing frequency through the late
1980s and early 1990s. In 1994, a fre s h-
w a t e r survey program for Atlantic salmon
was initiated by the provincial Ministry of
Environment (Lough and Law 1995; Lough
et al. 1997; Volpe 1998; 1999; 2000) and
funded through the BC Habitat
Conservation Trust Fund (HCTF – the
conservation surcharge on provincial fish-
ing, hunting and trapping licenses). The
primary objective of the program was to
s u rvey selected coastal streams for evidence
of natural reproduction of Atlantic salmon
and to collect distribution and abundance
data on ascending adult Atlantic salmon.
The primary method of survey was snorkeling
pre-selected reaches (1 - 9 km) of rivers
with previous reports of Atlantic salmon
activity or those deemed highly likely to
have Atlantics. The freshwater surv e y
p ro g r a m suffers from similar limitations as
the ASWP — most notably, data are collected
in the absence of controls which would
allow calibration or error estimates to be
generated. For instance, during a survey in
a river where juvenile Atlantic salmon are
present, what are the chances of missing
18 Super un-Natural
half the population? How much more likely
would a surveyor see an adult than a juve-
nile or a fry? Juvenile Atlantic salmon diff e r
considerably from native Pacific salmonid
species in behaviour and habitat pre f e re n c e s ,
making them less likely to be observed by
survey crews used to dealing exclusively
with native species (Volpe 2000; Volpe et
al. 2001a). To date, conclusive evidence
shows that three Pacific salmon-bearing
systems (Amor de Cosmos Creek, Adam
and Eve River and Tsitika River) currently
support presumably wild-spawned juvenile
Atlantic salmon (Volpe 1999; 2000; Volpe
et al. 2000). Juvenile Atlantic salmon have
also been found in four additional rivers,
but analyses suggest these fish escaped
from fresh water hatcheries on the same
river system in which they were found.
While only seven rivers have been identi-
fied as holding juvenile Atlantic salmon, it
must be noted that less than one percent of
potential rearing habitat on Vancouver
Island alone has been surveyed. And
despite the obvious limitations of the tech-
nique used, adult Atlantic salmon have
John Volpe and his research team ascend a freshwater
river in search of Atlantic salmon. Photo: John Volpe
David Suzuki Foundation 1 9
been observed ascending every major
drainage on Vancouver Island. How many
rivers may be found to be colonized if 100
percent survey coverage was applied?
Whatever the figure, we can be certain it
will be greater than what has been docu-
mented to date.
“Some adult Atlantic salmon are likely
to be found in freshwater rivers but
can’t spawn”
Spawning success of escaped farm Atlantic
salmon has been shown to be inferior
relative to their wild counterpart s
(Fleming et al. 1996; 2000; Volpe et al.
2001b). Upon escape, farm fish are suddenly
faced with a completely novel set of
c h a llenges, and generally, do not perform
well. As the product of artificial selection,
farm fish have been bred to thrive under
Anecdotal reports
of sport fishers
landing Atlantic
salmon in coastal
rivers occurred
with increasing
frequency through
the late 1980s and
early 1990s.
conditions on the farm. Wild salmon, how-
ever, return to their natal river to spawn
and each generation is repeatedly tailored
by natural selection to the conditions of
the river. Each river system ‘selects’ only
those individuals possessing traits that a re
most suited to survive in the local environ-
ment. Thus, each adult wild salmon
returning to spawn is an organic extension
of not only its parents, but also of the river
that produced it. An optimally adapted
individual is the result of 10,000 years of
evolution — a process of trial and error
that matches salmon and river. Successful
salmon survive to spawn, and the secret to
their success is encoded in DNA and
passed on to their progeny in egg and
sperm. Significant input of genetic material
from outside the population, such as
hybridization with hatchery salmon or
aquaculture escapees, erodes the unique
genetic character of the population and is
likely to negatively affect the population’s
viability. It is not surprising, therefore, that
farm escapees, likely three generations
removed from any natural selection, do not
perform as well as wild fish when put into
a competitive, natural environment.
Some comparison of spawning perf o rm-
ance between farm and wild Atlantic
salmon has been investigated. In a study of
Norwegian Atlantic salmon, farm females
retained more eggs, had greater egg mort a l i t y,
20 Super un-Natural
and overall, were only 20 to 40 percent as
successful as wild females (Fleming et al.
1996). The same study showed that
restrained and inappropriate behaviours of
farm males resulted in less than 3 percent
of the success of wild males. Evidence of
poor spawning performance, coupled with
the presumption of poor competitive ability
with any wild-re a red Atlantic salmon
p ro g e n y have led to suggestions that aqua-
culture escapees pose a minimal threat to
native species in coastal British Columbia
(Needham 1995; Alverson and Ruggerone
1997).
There is little doubt that farm Atlantic
salmon do not perform as well as wild fish
within their native range of the north
Atlantic Ocean. However, Atlantic salmon
spawning perf o rmance has never been
evaluated in coastal British Columbia
rivers. Physical and biological parameters
in BC may differ substantially fro m
Maritime and nort h e rn European rivers,
but the interactions of farm escaped
Atlantic salmon with native Pacific
salmonids has never been evaluated. In
short, despite being present in the province
for over a decade, by 1997 no one had yet
thought it necessary to conduct an enviro n-
m e n t a l assessment to evaluate the potential
spawning performance of aquaculture-
reared Atlantic salmon versus native Pacific
salmon. Escaped Atlantic salmon were seen
as equivalent to domestic cows, “They’re
domesticated, vaccinated, dopey fish that
grow. They are like the cows of the sea.’”
(Terry Nielsen, Tofino fish farmer, The
Juneau Empire, May 3 1999). The silence of
the provincial and federal governments has
been deafening, implying tacit agreement
on this point.
Adult atlantic salmon Photo: John Volpe
David Suzuki Foundation 2 1
In 1997, I began research to help fill
this significant gap in scientific
understanding. Specifically, I devel-
oped an experimental program to test
the spawning capabilities of farm
Atlantic salmon in a typical Pacific
river system. At the outset of my
research project I naively assumed
everyone at DFO would be interested
and supportive of this work. I enjoyed
tremendous support from those within
DFO who were “on the ground”, but at
the bureaucratic level and beyond,
reaction to my plans ranged from
indifference to agitation.
The difficulties I had with DFO over my
research are outlined in the preface of this
re p o rt. What became very apparent was that
DFO, in this instance, was not eager to ask
questions they didn’t want the answers to.
The spawning channel I constructed
was surrounded by a chain-link fence, but
the activity in the channel was visible to
anyone that happened by. The immediate
a rea is a popular walking route for the
p e o p l e of Qualicum Beach, and before long
an extensive group of regulars were fre q u e n t
visitors to the channel. So it wasn’t surprising
that as soon as the experimental Atlantics
Research successful
despite DFO
Spawning channel constructed by John Volpe at
the University of Victoria. Photo: John Volpe
began to spawn, news of the event quickly
appeared in press reports. This event, in
and of itself, was not surprising: no one in
the scientific community really doubted
the ability of farm Atlantic salmon to
spawn if given the opportunity. What was
of scientific interest was, what proportion
of fish would spawn? Would they utilize
similar habitats and display the same
behaviours as we would expect from wild
Atlantic salmon? This information would
be a major step towards understanding
w h e re Atlantic salmon were likely to spawn
in BC rivers, as well as how successfully,
and to what degree, Atlantic and Pacific
salmon may affect each other.
Details of year one of the study have
been published (Volpe 2001b). In summary,
my findings indicate that commercially
reared Atlantic salmon will sexually mature
and successfully spawn to produce viable
p rogeny in a simulated natural enviro n m e n t .
However, per capita, reproductive success
is low: most females sexually matured but
did not spawn, and those females that did
spawn exhibited considerable egg re t e n t i o n ,
poor nest construction and limited egg
v i a b i l i t y. Nearly all males matured, but
showed subdued breeding behaviour re l a t i v e
to what would be expected of wild Atlantic
salmon (Gibson 1993; Fleming 1996).
These results correspond with other studies
that have shown farm escapees to be less
productive than their wild counterparts
(Fleming et al. 1996; 2000). However, it is
important to note that both Fleming and I
a re in agreement that our data paint a
c o n s e rvative picture of the spawning
potential of escapees. Our studies used fish
that were re a red to maturity in a domestic
e n v i ronment, and we suspect a larg e
22 Super un-Natural
p ro p o rtion of the observed inferior
spawning perf o rmance is likely due to
e n v i ronmental effects of the domestic
e n v i ronment. Thus, a critical hypothesis
awaits testing: An individual’s p e rf o rm-
ance in the wild is inversely associated
with the age at which the fish escaped;
the younger the fish at escape the better
the performance as an adult. It is intuitive
that an adult that has experienced life in
the wild over the previous year is likely to
outperform a sibling that escaped captivity
the previous week. I extend this to suggest
the perf o rmance of wild-spawned individuals
will be demonstrably superior by virtue of
not having spent any time in captivity. If
this hypothesis is correct, the likelihood of
w i d e s p read colonization increases with
each natural spawning event that occurs.
This scenario concurs with the often
observed lag period of relatively low abun-
dance soon after introduction of an exotic
species and prior to population growth.
The fish in my BC study did not initiate
spawning behaviour until early winter
1998, which is considered quite late by BC
standards but within the observed range of
wild Atlantic salmon populations (Mills
1989; Fleming 1996). If these Atlantic
salmon were in a BC river in late January,
coho salmon would have largely completed
spawning (Sandercock 1991) and steelhead
would not likely have begun. Thus, they
would face limited competitive interference
from native salmonids and in fact might
superimpose their eggs on top of those of
the native fish. Superimposition has been
demonstrated to be a significant factor in
determining spawning success in space-
limited systems (Hayes 1987). Nest
destruction and superimposition by later-
David Suzuki Foundation 2 3
spawning steelhead may act to reduce this
advantage, but the magnitude of the effect
would be density dependent and steelhead
are currently at all-time recorded lows in
British Columbia (Slaney et al. 1996). For
instance, the 1998 smolt production of
Keogh River steelhead, one of the few
populations with reliable long-term data in
BC, was only 16 percent of the average
since 1977 (Ward and McCubbing 1998).
These results set the stage for the second
half of my experiment: evaluation of
spawning performance in the presence of
native salmon. Due to political sensibilities,
the climate surrounding my re s e a rc h
program was heating up. With, for the first
time, empirical evidence that Atlantic
salmon colonization in BC waters may be a
possibility, the time and energy required to
defend the program against those who
would have it shut down became too great
and it was decided that year-two experi-
ments would not be possible and that the
young salmon being reared in the channel
would be transferred to the University of
Victoria for observation. The impact of
l o s i n g the second year of data — Atlantic
salmon spawning perf o rmance in the
company of Pacific salmonids — was
essentially re n d e red moot, however, the
following summer with the discovery of
the first population of wild-reared juvenile
Atlantic salmon in the Tsitika River on
Vancouver Island (Volpe et al. 2000). This
discovery provided definitive proof that
adult Atlantic salmon were capable of
successful re p roduction in BC.
“S pa wning likely but progen y no t
co mpetitively viab le
Armed now with both experimental and
field evidence that escaped farm Atlantic
salmon were capable of successfully
spawning, my research focus shifted to
beginning the evaluation of the potential
effects associated with the presence of feral
juvenile Atlantics in BC streams. Since
Atlantic and Pacific salmon have only on
very rare occasion come into contact, there
is a dearth of information regarding their
interactions. It has been assumed that the
aggressive nature of juvenile Pacific
salmonids would generate sufficient biotic
resistance to Atlantic salmon to prevent
colonization. Habitat pre f e rences of juvenile
steelhead / rainbow trout (Oncorhynchus
mykiss) are the most similar to juvenile
Atlantic salmon of any of the Pacific
salmonids. Therefore, if resources (food
and space) become scarce, the two species
a re likely to come into vigorous competition
(Gibson 1981; Hearn and Kynard 1986)
and the more aggressive steelhead would
displace the juvenile Atlantic salmon. I
assumed that if the presence of Atlantic
salmon were to affect native salmonids, the
impact would be first and perhaps most
v i g o rously manifested in, though not
necessarily restricted to, steelhead tro u t .
Thus the re s e a rch objectives could be
s u m m a r i z e d as: to quantify the strength of
intraspecific and interspecific competition
among juvenile Atlantic salmon and steel-
head under a range of conditions (high/low
density, high/low prey availability, different
species compositions, steelhead invading
Atlantic salmon as well as vice versa). A
detailed account of these experiments and
results can be found in Volpe et al.
(2001a). The following are some of the
more informative points that arose.
Steelhead were much more active
(4.5x) and aggressive (5x) than
Atlantic salmon. However, steelhead
were 2.1 times more likely to be
aggressive towards another steelhead
than an Atlantic salmon.
In contrast, Atlantic salmon were 2.2
times more likely to attack a steelhead
than another Atlantic salmon.
Overall, steelhead were considerably
more aggressive than Atlantic salmon
but steelhead aggression is much more
focused on other steelhead with
Atlantic salmon being largely ignored.
24 Super un-Natural
Therefore, the assumption that steelhead
a g g ression is likely to form significant biotic
resistance to Atlantic salmon colonization
was not supported. When the data were
analyzed to see what factors were most
responsible for differences in performance,
the magnitude of one factor greatly over-
shadowed the contribution of all others:
residency. Residents that have as little as
three days prior residency in the habitat
before being challenged by “invaders” are
competitively dominant. It makes no
difference which species is the resident and
which is the challenger — residents domi-
nate to the extent of rendering all other
factors (forage level, density etc.) moot.
In my research, resident/invader status
had a pre-eminent effect on pre d i c t i n g
p e rf o rmance. In simplest terms, and
g e n e r a l l y for both species, residents gained
weight and challengers lost weight. This
pattern was consistent no matter which
species was resident or invader. The so-
called “resident advantage” is a common
phenomenon, particularly well documented
in territorial mammal and bird species. The
premise is that a resident is aware of the
relative value of its territory and will
defend it accordingly, leading to vigorous
defence of profitable areas. The invader is
naïve to the value of the territory it finds
itself in, and therefore, is more likely to
concede to the resident. My work shows
that it made no difference which species
w e re the residents or the challengers,
residents always dominated — including
Atlantic salmon residents dominating steel-
head challengers. In my controlled research
setting, when Atlantic salmon were not
permitted prior residency before being
challenged by steelhead, their performance
Since Atlantic and Pacific
salmon have only on very
rare occasion come into
contact, there is a dearth
of information regarding
their interactions.
Tagged Atlantic salmon Photo: John Volpe
David Suzuki Foundation 2 5
was very poor under all conditions (Volpe
2001a). Therefore I conclude that prior
residency is a key factor in predicting the
relative performances of Atlantic salmon
and steelhead in competition.
This insight may especially help
explain why Atlantic salmon are apparently
colonizing BC today but failed to do so
during previous intentional introductions
from 1905-1933 (Carl and Guiguet 1958).
At that time, BC’s coastal river systems
were likely at or near saturation with
native resident salmonids, therefore it
would be highly unlikely that introduced
Atlantic salmon would have undisturbed
access to habitat. The present data uphold
that Atlantic salmon do not perform well
under such conditions. This point, however,
is moot today as these conditions no
longer exist. Steelhead populations in 12 of
the 19 major river systems on Vancouver
Island’s east coast (adjacent to the majority
of aquaculture activity) have been classified
as “high risk”, with population estimates
over the past decade at less than 20 percent
of their long-term means (Bruce Ward, BC
Ministry of Fisheries, pers. comm.). This
situation is replicated across coastal BC.
Unlike at the beginning of the 20th
Century, access to suitable rearing habitat
is no longer limited. If this is as critical a
factor as my data suggest, the decline of BC
steelhead populations significantly incre a s e s
the likelihood of successful Atlantic
salmon establishment.
Implications for Hatchery Fish
An interesting side note arises here. This work may have implications for enhancement and other
management initiatives using stocked fish. Hatchery - re a red fish introduced as part of wild stock
augmentation programs have been shown to be deficient in numerous characters important for
s u rv i v a l and fitness (Olla et al. 1998; Utter 1998). However, I am not aware of any such studies that
have explicitly tested the role of residency in calibrating the perf o rmance of wild and intro d u c e d
c u l t u re d stocks. The observed reduction in performance of hatchery-reared fish may be partly
explained by simply being challengers. Only a three-day acclimatization period was necessary to
p roduce significant perf o rmance diff e rences in both species during intra- as well as interspecific
t r i a l s . In other words, challenger steelhead did not fare well against resident steelhead. The apparent
poor performance of hatchery-reared fish upon release may not be due entirely to the fact they are
“hatchery fish” but maybe also linked to some extent to resident-challenger competitive dynamics.
26 Super un-Natural
Many people believe that an escaped
Atlantic salmon represents a greater
ecological threat than an escaped
native farm fish (chinook or coho). The
corollary is that much of the potential
ecological harm due to escapes could
be remedied if industry were forced
back to its roots to culture only native
salmon species. As is the case with
most aquaculture issues, the answer is
not that simple.
Those who support the ‘natives only’
a p p roach make the assumption that a
c h i n o o k is a chinook and, therefore, it
makes little difference if it’s a product of
natural spawning or artificial selection
(commercial aquaculture hatchery).
H o w e v e r, there is a growing body of evidence
that suggests these two scenarios do make
a significant difference. Recall the intimate
relationship between a salmon population
and its natal river discussed earlier, showing
that the salmon-river relationship is a
product of 10,000 years of evolution main-
tained by reproductive isolation among
populations. That relationship breaks
down when foreign genetic material is
introduced into the population.
If there is a silver lining on the cloud
that hangs over BC aquaculture, it is that it
appears Atlantic salmon-Pacific salmon
hybridization is unlikely (this point,
h o w e v e r, awaits a rigorous test). This
Why not Pacific salmon?
A diver inspects the saltwater net pens.
Photo: Natalie B. Fobes
David Suzuki Foundation 2 7
means that the genetic integrity of Pacific
salmon populations is unlikely to be dire c t l y
affected by hybridization with escaped
Atlantic salmon. Approximately 20 percent
of BC salmon farming uses native Pacific
stocks, and if we were to replace Atlantic
salmon with chinook or coho we would
need to look to Maritime Canada and
n o rt h e rn Europe for what is likely to happen.
In these regions, Atlantic salmon aqua-
culture operations share the waters with
wild Atlantic salmon stocks. Given that the
same species is on either side of the nets,
when there are escapes the risk of
hybridization is extreme and wild and farm
genetic material become irreversibly mixed
— known as ‘genetic introgression’. The
salmon-river relationship is then lost fore v e r.
If enough farm fish escape, the natural
variation among wild populations is
homogenized. Wild populations 10,000
years in the making can conceivably be
replaced by ill-adapted hybrids in a single
generation. Some salmon populations in
Norway are now made up of greater than
80 percent farm fish. The long-term viability
of these populations is unknown, but the
disruption of the gene pool leading to the
degradation of adaptive capacity is yet
another difficulty to contend with. I there-
fore postulate that there is no reason to
believe the commercial culture of chinook
or coho in BC would result in anything but
negative impacts for our already degraded
wild stocks.
There are yet even more considerations
to be weighed in the Atlantic versus Pacific
salmon debate. When an Atlantic salmon is
observed or caught in the wild, it is clear if
the fish (or its descendants) originated
from a farm, which is not possible with
coho or chinook. Therefore, unambiguous
range and abundance data can be collected
provided the funding and political will
exists to see such work undertaken. Also,
when farm and wild fish are the same
species they are likely to come into more
intimate contact because the life history or
behavioural differences that act to separate
members of different species are absent.
The potential for increased competition for
limited resources therefore increases as
does the shared susceptibility to pathogens.
Additionally, the greater level of contact
will likely aid maximum rate of transfer of
pathogens and parasites from farm to wild
individuals or vice versa.
T h e re are legitimate concerns associated
with the introduction of Atlantic salmon as
an exotic species, however, there are another
set of equally compelling reasons not to
adopt anative-only aquaculture policy.
No matter what type of aquaculture is
practiced, the key is to eliminate all escapes.
“Multiple-year-classes of juvenile
Atlantic salmon in some rivers do not
pose a threat to native populations”
I once made an off-the-cuff remark to a
colleague that “anyone who says they
know what’s going to happen [with regard
to the fate of Atlantic salmon in BC] is
lying or stupid” in response to a particular-
ly naïve statement in the morning paper.
Unaware that a reporter was within
earshot, my statement soon after appeared
in a variety of publications. Flippancy
aside, the statement rings as true today as
28 Super un-Natural
it did then. If anything is taken from this
report it should be that the correct
response to any question regarding the
potential ecological effects of the BC
salmon farming industry is, “We don’t
know”. It has been my experience that
there is great trepidation on the part of
some to utter these three simple words. But
how could any other answer be truthfully
offered in the midst of such a knowledge
vacuum? There remains a staggering level
of uncertainty re g a rding the potential
e n v i ro n m e n t a l impacts of net-cage aqua-
culture. This uncertainty, however, cannot
C o n c l u s i o n
Farmer feeding Atlantic salmon. Photo: Natalie B. Fobes
David Suzuki Foundation 2 9
be used as license to continue curre n t
practices given the potential for serious
ecological harm. In fact, Principle 15 of the
1992 Rio Declaration on Environment and
D e v e l o p m e n t, to which Canada is a signatory,
recommends caution. It states: “Where there
are threats of serious or irreversible damage,
lack of full scientific certainty shall not be used
as a reason for postponing cost-effective measure s
to prevent environmental degradation.” This
principle has two implications for the BC
aquaculture industry. First, industry should
be compelled to take all reasonable pre-
cautions to protect the environment. Second,
inherent in Principle 15 (and 16) is the
understanding of ‘reverse onus’, i.e. the
burden of proof for safety falls to the aqua-
culture industry, not to the general public.
International agreements hold that it is
industry’s obligation to prove their a c t i v i t y
falls within acceptable enviro n m e n t a l policy
and not the public’s to prove otherwise.
My own modest contribution to the
current science on this topic has actually
increased rather than reduced uncertainty.
After nearly five years of work pursuing
my doctorate, my conclusion is that the
assumptions that accompanied Atlantic
salmon to BC were false. In no way do my
data allow me, or anyone else, to adopt a
p redictive stance. There f o re, all potentialities
in terms of type and magnitude of effect
remain possible until explicitly tested and
shown to be within the limits of acceptable
risk. Unfortunately, this knowledge gap
permits the all too common line, “There is
no evidence to suggest that Atlantic salmon
aquaculture has any negative effect on native
salmonids or their environment”. This is a
worn old gem that industry advocates trot
out at every opportunity. Of course there is
no evidence: how could there be evidence
of an effect if no one has tested for it?
Consider this variation on the theme:
“Atlantic salmon have not proven capable of
competing with Pacific salmon in the marine
conditions that prevail on the Pacific coast”.
(Anne McMullin, Executive Director of the
BCSFA, Northern Aquaculture, September
1999). This is quite true. However, without
the necessary research one is on equal
ground by stating: “Atlantic salmon have
not proven incapable of competing with
Pacific salmon in the marine conditions that
p revail on the Pacific coast”. Absence of
e v i d e n c e is not evidence of absence. Today,
two years after Ms. McMullin’s statement,
there is evidence to suggest that Atlantic
salmon are viable competitors to Pacific
salmonids. Further, we only have to look
to the European experience for ample
e v idence that the culture of Atlantic
salmon has indeed had negative effects on
native salmonids (eg. McGinnity et al.
1997; Fleming et al. 2000).
In British Columbia, each assumption
re g a r ding Atlantic salmon escapes has fallen
when tested. We’ve heard: “They can’t
I once made an off-the-
cuff remark to a colleague
that “anyone who says
they know what’s going to
happen [with regard to the
fate of Atlantic salmon in
BC] is lying or stupid”
escape; they’ll escape but not survive; they’ll
survive but not spawn; they’ll spawn but the
progeny won’t compete successfully,” and
now: “Feral progeny may be able to compete
but not complete their life cycle.” And so, we
have reached the very last assumed barrier
to Atlantic salmon establishment: there is
no evidence that wild-spawned juveniles
are capable of going to sea and returning as
adults to complete the life-cycle. Of course
there is also no evidence to suggest they
won’t, and completing the life-cycle is a
p re requisite to establishment. Since govern-
ment and industry scientists assume the
likelihood of feral juveniles completing
their life-cycle is so low, they tell us there
is little reason to worry at all. In the aqua-
culture world, however, the ‘life-cycle’ is
completed when farms act as the re p ro d u c t i v e
stage, annually spilling forth tens- to
h u n d reds-of-thousands of adults that, in
effect, constitute the next generation.
Therefore, it doesn’t matter if juveniles can
successfully go to sea and return to spawn
because the population is re p l e n i s h e d
annually by escapees. This last stage,
reaching the sea and returning to spawn, is
the only one yet to be explicitly demonstrated.
Therefore, I argue that Atlantic salmon are
in fact established in BC already and any
negative effects associated with establish-
ment are to some extent already under way.
Unfortunately, we are no closer to
knowing the effects of Atlantic salmon on
native Pacific salmon today than when
Atlantics were first imported to BC nearly
two decades ago. We do know, however,
that the assumptions that accompanied
Atlantic salmon were false and we must
critically re-evaluate Atlantic salmon aqua-
culture in BC in this light. Both federal and
30 Super un-Natural
provincial policy makers are fully aware of
the economic benefits represented by the
a q u a c u l t u re industry. However, to date, these
agencies have been unable or unwilling to
acknowledge that their calculations do not
include much of the ‘costs’ of aquaculture.
In particular are those costs that are exter-
nalized to the natural environment and
therefore passed on to all of us: clean water
and inshore habitats are common resources
consumed by industry practically free of
charge. In return, we get Atlantic salmon
escapes, massive nutrient (nitrogen and
phosphorus) inputs, antibacterial residues,
potential pathogen introduction and/or
amplification, toxic heavy metal anti-
foulants, and other harmful effects. While I
am not opposed to salmon aquaculture in
principle, I foresee problems in the way it
is practiced at present in British Columbia.
Initial public concern has rapidly turned to
criticism as provincial and federal agencies
continue to ignore their mandate to safe-
guard our common resources. The first
step in fulfilling this mandate is a rational
evaluation of the industry with a full
accounting of not only the benefits, but also
of the risks. Only after this is accomplished,
can salmon aquaculture in British Columbia
be carried out in both a profitable and
ecologically sustainable manner.
David Suzuki Foundation 3 1
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John Volpe
John Volpe was born and raised in Toronto,
Ontario, and received a Bachelor of Science
(1991) and Master of Science (1994) from
the University of Guelph (Ontario). He
received his PhD from the University of
Victoria in 2001 and is currently Associate
Professor of fisheries ecology at the
University of Alberta in Edmonton. Dr.
Volpe’s research includes the study of exotic
species introductions and biotic invasions,
the causal mechanisms and rate of physical
and genetic evolution in marine and aquatic
organisms, the conservation of fringe and
insular populations, and relationships
between biodiversity measures and
ecosystem functions.
The Author
David Suzuki Foundation
The David Suzuki Foundation explores
human impacts on the environment, with
an emphasis on finding solutions. The
Foundation was established in 1990 to find
and communicate ways in which we
can achieve a balance between social,
economic and ecological needs.
Sections of this report may be reproduced. Please credit the David
Suzuki Foundation.
ISBN# 0-9689731-0-8
National Library of Canada Cataloguing in Publication Data
Volpe, John Paul 1964-
Super un-Natural
Includes bibliographical references.
1. Atlantic salmon — British Columbia. I. David Suzuki Foundation. II. Title.
QL638.S2V64 2001 597.5'5'09711 C2001-911448-6
Cover and Inside Cover Photos: © Natalie B. Fobes
Maps: Marcel Pepin Mapping and Photography
Design: Metaform Communication Design Inc.
Printing: Western Printers
Paper: Cover — Genesis Text Birch 80#, 100% Post-consumer. Insides — Eureka Bond, 100% Post-consumer and
Process Chlorine Free
Acknowledgements
Earlier drafts of this report benefited greatly from the input of Dr.
Ian Fleming (Hatfield Marine Science Center, Oregon State
University), Dr. Robert Scott (University of Western Ontario), Dr.
Peter Tyedmers (Dalhousie University), Dr. Fred Whoriskey Jr.
(Atlantic Salmon Foundation). I would like to thank Jean
Kavanagh, Ann Rowan, Lynn Hunter, Kim Wright and the staff of
the David Suzuki Foundation for their valued input and support
during this project. J.V.
Super un-Natural
Atlantic Salmon in BC Waters
John Volpe, PhD
The David Suzuki Foundation
2211 West Fourth Ave., Suite 219
Vancouver, BC Canada V6K 4S2
E-mail: solutions@davidsuzuki.org
Web: www.davidsuzuki.org
Tel: (604) 732-4228
Fax: (604) 732-0752
... Atlantic salmon are anadromous and their introduction may impact both freshwater and marine ecosystems on the west coast of North America. Atlantic salmon may compete with native salmon for limited spawning sites, thereby adversely affecting native stocks (Volpe, 2001). Several native salmon stocks have been listed as threatened or endangered under the Endangered Species Act 2 and even minor adverse effects could have large consequences. ...
... However, should cultured fish escape, wild populations may be effected. Such issues have developed in salmon culture on both the east and west coasts of North America (Waples, 1991;Volpe, 2001). Further, the culture of marine fish with pelagic eggs and larvae is more difficult than the culture of freshwater fish with demersal eggs and well-developed larvae. ...
... Similarly, aquaculture facilities need to protect against releases. Atlantic salmon now inhabit the Pacific coast, which is a direct result of releases from aquaculture operations (Volpe, 2001). ...
... In the Pacific region, Atlantic salmon are an exotic species, and critics fear that escaped fish may be colonizing Pacific waterways (e.g. Volpe 2001). ...
... In 2000 and 2001, Volpe and colleagues began publishing findings from fieldwork and experimental research in scholarly journals regarding the capacities of escaped salmon to spawn in the wild (Volpe et al. 2000;. For the industry, however, the more significant blow came from the publication of the report Super-Unnatural: Atlantic Salmon in BC Waters, produced by The David Suzuki Foundation, in October 2001 (Volpe 2001). Like Ellis's Net Loss, Super-Unnatural uses a weight-of-evidence approach of listing facts and examples of foreign species colonization from around the world. ...
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In the past few years, salmon aquaculture has become one of Canada’s most controversial industries. Environmentalist and other oppositional groups have mounted aggressive communications campaigns on issues such as the environmental and health impacts of the industry. In coastal regions, local opinion is divided, with some stakeholders and First Nations (indigenous) groups vehemently opposing the industry, while others see it as an important contributor to stressed coastal economies. In this article, we analyse industry responses to both organized and local opposition. Existing research on risk communication and ‘risk issue management’ tells us that important strategies for addressing controversy include building public trust, acknowledging the legitimacy of critics and their concerns, engaging in transparent and pro‐active risk communication, establishing meaningful partnerships with stakeholders, and ultimately reforming controversial practices. Drawing on an analysis of advocacy materials and transcripts from public hearings into aquaculture, we conclude that the salmon aquaculture industry has been largely unsuccessful in its attempts to blunt criticism from organized oppositional groups, but has taken some important (if tentative) actions to enhance its legitimacy at the local level.
... Since 1972, the BC aquaculture industry has been regulated and guided by four federal departments and six provincial ministries (Volpe, 2001). There has been some research, development and testing into ocean-based closed containment systems and land-based farms however, the costs are simply too high for the industry. ...
... While little empirical research has been done on the effects of escapees on wild cod populations and their ecosystems, past experiences with the introduction of exotic Atlantic salmon in the Pacific ocean in British Columbia provide grounds for prudence and precaution (Leggatt 2001, Volpe 2001. Selection in natural and cultured environments is radically different. ...
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... Although development of more secure containment systems would reduce escapement, the current costs of fail-safe retention systems are not economically viable for salmon farming (Volpe, 2001). Furthermore, many escape events are associated with handling mishaps, e.g., transferring fish from net to net, that system design cannot readily prevent. ...
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