Testing assumptions associated with
farm-escaped Atlantic salmon in British
Columbia
Dr. John Volpe
Biological Sciences
University of Alberta
jvolpe@ualberta.ca
Issues
•
•
•
•
Visual pollution (ecotourism)
Site contamination (organic & pharmacological)
Anti predator methods
Disease transfer to / from wild salmonids
•  Ecological consequences of escapees
1905 5.5 - 13.2 M eggs + alevins released in B.C.
Interspecific agonism (ST) 10 resistance factor
1934
Import of S. salar eggs for aquaculture
1984
1987
First capture of S. salar in B.C. waters
1991
First reported escape of S. salar
1995 SAR initiated
SAR
released
First Atlantic salmon research
on Pacific coast initiated
1997
Phase I research complete 2001
The Explanation Cascade
• Escapes of Atlantic salmon are 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 progeny will not be
competitively viable
And finally, the current position,
• There is no scientific evidence to show that the
presence of feral juvenile Atlantic salmon in some
rivers pose a threat to native populations.
The Explanation Cascade
〈 Escapes of Atlantic salmon are 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 progeny will not be
competitively viable
And finally, the current position,
〈 There is no scientific evidence to show that the
presence of feral juvenile Atlantic salmon in some
rivers pose a threat to native populations.
0%
Revenue
loss
resulting
from
escaped
fish
Retention
of salmon
in net pens
100%
Cost of building / maintaining net pens
According to DFO’s ASWP 396,552 Atlantic salmon
have been reported as escaped 1991-2001
The Explanation Cascade
• Escapes of Atlantic salmon are 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 progeny will not be
competitively viable
And finally, the current position,
• There is no scientific evidence to show that the
presence of feral juvenile Atlantic salmon in some
rivers pose a threat to native populations.
Atlantic salmon are commonly part of commercial
salmon catches from Alaska to Washington
No data are available regarding the source of these fish
(physical or DNA tags) or period since escape and
performance in the interim (otolith microstructure / stable
isotope analyses)
The Explanation Cascade
〈 Escapes of Atlantic salmon are 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 progeny will not be
competitively viable
And finally, the current position,
〈 There is no scientific evidence to show that the
presence of feral juvenile Atlantic salmon in some
rivers pose a threat to native populations.
Atlantic salmon have been
reported in 77 BC streams
and rivers
Atlantic salmon are
now part of the
terrestrial food web
via predation
Th e Explanation Cascade
〈Escapes of Atlantic salmon are rare
〈Escapes of Atlantic salmon are inevitable but
they won't survive in the wild
〈Some Atla ntic salmon may survive but will not
ascend freshwater rivers
〈Some adult Atlantic salmon are likely to be
found in freshwa ter rivers but can't spaw n
〈Spawning is likely to occur but progeny will not be
competitively viable
And finally, the current position,
〈There is no scientific evidence to show that the
presence of feral juvenile Atla ntic salmon in some
rivers pose a threat to native populations.
Tsitika River August 18 1998
• 58 m channel
• Heterogeneous habitat
• 30 females; 20 males
transplanted without
acclimatization
•  1/3 females spawned
•  Spawning initiated
in mid January
Spawning Chronology
Chum
Little Qualicum
Atlantic Salmon
Sockeye
Sept
Oct
Pink
Nov
Steelhead
Dec
Jan
Feb
Mar
Coho
Chinook
Wild Atlantic salmon in native range
Apr
May
0+
•
•
•
•
1+
Natural reproduction
Two year classes present (0+ & 1+)
~50 juveniles identified to date
Sympatric with strong steelhead population
0+ AS
0+ ST
1+ AS
Mean Fork 63.75 ±3.3 55.42 ±5.81 119.25±5.52
Length (mm)
1+ ST
92.59±10.46
Mean Weight
(g)
2.94±0.60
1.91±0.54
19.61±4.01
8.67±2.75
Mean CF
(g x 100)/cm3
1.12
1.16
1.12
1.10
33
8
33
n
4
Feral Atlantic Salmon populations in Vancouver
Island Rivers
Port Hardy
Tsitika R. Eve R.
Amor de Cosmos Cr.
Campbell R.
<1% potential spawning
and rearing habitat has
been surveyed on
Vancouver
Island. Coastal
mainland systems
remain entirely
uninvestigated.......?
Port
Alberni
N
100 km
Nanaimo
Tofino
Victoria
The Explanation Cascade
〈 Escapes of Atlantic salmon are rare
〈 Escapes of Atlantic salmon are inevitable but
they won't su rviv e in the wild
〈 Some A tlantic sa lmon may survive but will not
ascend fresh water rivers
〈 Som e adult Atlantic salmon are likely to be
found in freshwa ter rivers but can't spawn
〈 Spawning is likely to o ccur but progeny will not
be comp etitively viable
An d finally, the current position,
〈 There is no scientific evidence to show that the
presence of feral juvenile Atlantic salmon in some
rive rs pose a threat to native populations.
Wetted area:
2.2m x 0.6m x 0.9 m
Coarse river cobble
(19.4 ± 5.6cm)
~ 10% replacement per
hour
Flow 0.85 ms-s
(4542.5 L min-1)
10 hp centrifugal pump
Water temp maintained
by a 240V, 60amp chiller
Clear Lexan viewing
windows
Natural prey provided by
a unique “upweller”
feeding system
Treatments
High Forage
4 AS
4 AS
4 ST
4 AS
4 AS
4 ST
•  High / low forage
4 ST
4 AS
4 ST
4 ST
Response Variables
αAA αSA assembly
•  Growth
Low Forage
4 AS
4 AS
4 ST
4 AS
4 AS
4 ST
4 ST
•  Density
•  Intra- / interspecies comp.
•  Assembly of “community”
4 AS
•  Foraging
•  Agonism (action + result)
•  Territory size
α = comp. coefficient (Δ g)
A = Atlantic salmon
αSS αAS S = Native Steelhead
4 ST
4 ST
ST on average engage in agonism 5:1
over AS
ST show agonistic bias towards other
steelhead 2 : 1
AS show bias towards steelhead
2.2 : 1
Therefore, steelhead are agonism
targets, Atlantic salmon are not
Of all treatment combinations the only
consistent and significant predictor of
performance is assembly order
Residents with 3 days prior residency
performed better than challengers under
all conditions - regardless of all other
parameters
Atlantic salmon
- residency
+ residency
Perform well
relative to steelhead
Perform poorly
relative to steelhead
1905-1934: Very low likelihood of establishing prior
residency in Vancouver Island rivers
Today: Vancouver Island steelhead populations are at
~ 10 - 20% of historical abundance
∴
Potential for successful colonization is likely much
higher today than during historical intentional introductions
Are production fish capable of spawning?
YES
Are juvenile Atlantic salmon competitively viable?
YES (qualified)
Are such conditions present in coastal B.C.?
At present YES
Historically NO
Sufficient spawner densities for natural reproduction?
YES
Presence of feral populations?
YES (3)
Feral individuals perform as predicted?
YES
Prognosis?
Pink salmon smolts
June 2001
Sea lice are native however the density of farms may act
as bio-magnifiers of parasites and disease such that the
migratory habitat becomes saturated ie. pink smolt run
The Explanation Cascade
〈 Escapes of Atlantic salm on are rare
〈 Escapes of Atlantic salmon are in evitable 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 progeny will not
be compet itively viable
And finally, the current position,
〈 There is no scientific evidence to show that the
presence of feral juvenile Atlantic salmon in
some rivers pose a threat to native populations.
There is no scientific evidence to show that the
presence of feral juvenile Atlantic salmon in
some rivers pose a threat to native populations.
There is no evidence that salmon aquaculture as currently
practiced in BC will not result in serious harm to native
salmon populations or their environment.
Principle 15 of the 1992 Rio Declaration on Environment and Development (to
which Canada is a signatory) explains the precautionary principle as, "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 measures to prevent
environmental degradation."
1) all reasonable actions must be taken to protect the
environment
2) inherent to this statement is the understanding of
“reverse onus” - the burden of proof lies with industry
to satisfactorily demonstrate their activity is not detrimental
to the environment. The burden is not on the public to
demonstrate the opposite