Dr. John Volpe Biological Sciences University of Alberta jvolpe@ualberta

Dr. John VolpeBiological Sciences

University of [email protected]

Testing assumptions associated with farm-escaped Atlantic salmon in British

Columbia

Issues

• Visual pollution (ecotourism)• Site contamination (organic & pharmacological)• Anti predator methods• Disease transfer to / from wild salmonids

• Ecological consequences of escapees

2001

1984 Import of S. salar eggs for aquaculture

1905

1934

5.5 - 13.2 M eggs + alevins released in B.C. Interspecific agonism (ST) 10 resistance factor

1987 First capture of S. salar in B.C. waters

1991 First reported escape of S. salar

1997First Atlantic salmon research on Pacific coast initiated

Phase I research complete

1995 SAR initiated

SAR released

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.

The Explanation Cascade

Revenueloss

resulting from

escapedfish

Retention of salmonin net pens

Cost of building / maintaining net pens

0%

100%

According to DFO’s ASWP 396,552 Atlantic salmon have been reported as escaped 1991-2001

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

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 / stableisotope analyses)

⟨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

Atlantic salmon have been reported in 77 BC streams and rivers

Atlantic salmon are now part of the terrestrial food webvia predation

⟨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

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

Sept Oct Nov Dec Jan Feb Mar Apr May

Pink

Sockeye

Chinook

Chum

Coho

Steelhead

Little Qualicum Atlantic Salmon

Wild Atlantic salmon in native range

• Natural reproduction• Two year classes present (0+ & 1+)• ~50 juveniles identified to date• Sympatric with strong steelhead population

0+ 1+

0+ AS 0+ ST 1+ AS 1+ ST

Mean ForkLength (mm)

Mean CF(g x 100)/cm3

n

63.75 ±3.3 55.42 ±5.81 119.25±5.52 92.59±10.46

2.94±0.60 1.91±0.54 19.61±4.01 8.67±2.75

1.12 1.16 1.12 1.10

4 33 8 33

Mean Weight (g)

Port Hardy

Campbell R.

Nanaimo

Victoria

Tofino

Port Alberni

Feral Atlantic Salmon populations in Vancouver Island Rivers

Eve R.N

100 km

Amor de Cosmos Cr.Tsitika R.

<1% potential spawning and rearing habitat has been surveyed on Vancouver Island. Coastal mainland systems remain entirely uninvestigated.......?

⟨Escapes of Atlantic salmon are rare

⟨Escapes of Atlantic salmon are inevitable but they won't survive in the wild

⟨Some A tlantic sa lmon 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 o ccur 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

Wetted area:2.2m x 0.6m x 0.9 m

Coarse river cobble (19.4 5.6cm)

~ 10% replacement perhour

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

4 AS 4 AS

4 AS

4 AS

4 ST4 ST

4 ST4 ST4 ST

4 AS

High Forage

AA SA assembly

4 AS 4 AS

4 AS

4 AS

4 ST4 ST

4 ST4 ST4 ST

4 AS

Low Forage

SS AS

Treatments• High / low forage• Density• Intra- / interspecies comp.• Assembly of “community”

Response Variables• Growth• Foraging• Agonism (action + result) • Territory size

comp. coefficient (Δ g)A = Atlantic salmonS = Native Steelhead

ST on average engage in agonism 5:1 over AS ST show agonistic bias towards other steelhead 2 : 1

AS show bias towards steelhead2.2 : 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

Perform wellrelative to steelhead

Perform poorly relative to steelhead

+ residency - residency

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?

Sufficient spawner densities for natural reproduction?

YES (3)

YES

Are juvenile Atlantic salmon competitively viable?

YES

YES (qualified)

Are such conditions present in coastal B.C.?

Presence of feral populations?

Feral individuals perform as predicted?YES

At present YESHistorically NO

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

⟨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 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.

The Explanation Cascade

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 (towhich Canada is a signatory) explains the precautionary principle as, "Wherethere are threats of serious or irreversible damage, lack of full scientific certaintyshall not be used as a reason for postponing cost-effective measures to preventenvironmental 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