Report of the 2005 ICES/NASCO Symposium on Interactions ...

NINA SPECIAL REPORT 34
maintenance <strong>of</strong> mutual trust would be assisted by focusing
not just on farm practices but also on habitat
management issues.
Causes for Optimism
O<strong>the</strong>r encouraging items included:
• Øystein Skaala reported on a study <strong>of</strong> genetic impacts
in 7 rivers subject to long-term escapee pressure. His
conclusion was that <strong>the</strong>re were indications <strong>of</strong> genetic
stability in <strong>the</strong> stocks <strong>of</strong> 4 <strong>of</strong> <strong>the</strong>se.
• Harald Lura presented findings which indicated
minimal genetic impact if escapees were maintained
below 10% <strong>of</strong> river stocks. This suggests that we don’t
have to achieve an escape level <strong>of</strong> absolute zero -
which, in any case, is probably impossible.
• Fred Whoriskey studied <strong>the</strong> fate <strong>of</strong> escapees in New
Brunswick and Maine through <strong>the</strong> fascinating use <strong>of</strong>
electronic markers on live fish and found evidence <strong>of</strong>
massive mortality during <strong>the</strong> first few days <strong>of</strong> freedom,
particularly from seal predation.
• Peter Heuch compared two Norwegian fjords in
terms <strong>of</strong> farm contributions to lice loads on wild
salmon smolts. In one <strong>the</strong>re was no perceptible
impact and in <strong>the</strong> o<strong>the</strong>r <strong>the</strong>re was a significant
problem. He concluded that dissimilar hydrographies
in <strong>the</strong> two fjords accounted for <strong>the</strong> difference. This
supports <strong>the</strong> findings <strong>of</strong> o<strong>the</strong>r authors who have
reported that <strong>the</strong> level <strong>of</strong> contribution by a farm to
lice numbers on local wild salmonids is determined by
both <strong>the</strong> size <strong>of</strong> <strong>the</strong> lice population on <strong>the</strong> farm and
<strong>the</strong> hydrography <strong>of</strong> <strong>the</strong> area - thus, farms in more
open locations or near <strong>the</strong> mouths <strong>of</strong> bays/fjords
will be unlikely to have a significant impact.
• Using cautious language, Ron Stagg postulated that
disease epidemics in farms will not necessarily result in
epidemics in wild populations and that <strong>the</strong> risk can be
reduced by good management.
Thus, for me <strong>the</strong>re is more good news than bad but <strong>the</strong>re
is no room for complacency and a lot <strong>of</strong> work remains to
be done. Arising from my participation in this symposium
I would like to suggest <strong>the</strong> basic elements <strong>of</strong> a way
forward.
The Way Forward - Escapes
• We need to get escapes down to as close to zero as
possible. To do this we need to continue
implementing <strong>the</strong> <strong>NASCO</strong> Liaison Group’s Guidelines
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for Containment - improving <strong>the</strong> design <strong>of</strong> fish cages,
matching appropriate technologies to site conditions,
carrying out proper maintenance programmes and
ensuring safe operational.procedures. We need to
ensure all farming staff are trained in <strong>the</strong> essentials <strong>of</strong>
escape prevention and <strong>the</strong>y should all be educated
in <strong>the</strong> potential impacts <strong>of</strong> escapes. I am sure that if
<strong>the</strong> people on <strong>the</strong> ground were made aware <strong>of</strong> what
we have heard here this week it would act as an
incentive to greater effort in escape prevention.
• The Norwegian industry is promoting <strong>the</strong> idea <strong>of</strong> a
national escapes commission to investigate and report
on <strong>the</strong> causes <strong>of</strong> escapes as <strong>the</strong>y occur. I would
suggest that we should consider a similar strategy
internationally, say within <strong>the</strong> Liaison Group.
• R&D has a role to play as well, such as developing less
vulnerable and more operator-friendly cage systems -
Arne Fredheim’s novel net design is a good example
<strong>of</strong> this kind <strong>of</strong> approach. A particular hobby horse <strong>of</strong>
my own is that <strong>the</strong> marine cage farming industry really
needs <strong>the</strong> technologists to develop sonar-based
methods <strong>of</strong> constantly monitoring <strong>the</strong> stock in a fish
cage. As well as simplifying farm management this
would alert <strong>the</strong> farmer to an escape event as
soon as it begins.
• There has been a lot <strong>of</strong> debate here this week about
<strong>the</strong> reduced fitness <strong>of</strong> farm stock and hybrids for
survival in <strong>the</strong> wild. Perhaps we should encourage <strong>the</strong>
breeders to actually select for traits which would make
<strong>the</strong>m totally unfit to survive or breed in <strong>the</strong> wild.
The Way Forward - Lice
In areas where <strong>the</strong>re is a likelihood <strong>of</strong> impacts on wild
salmonids, farms must keep lice levels as close to zero as
reasonably possible. Achieving this requires:
• An area management approach which results in
synchronised treatments and regular fallowing.
• The availability <strong>of</strong> an adequate suite <strong>of</strong> anti-lice
medications and hopefully, in <strong>the</strong> near future,
vaccines. In this regard <strong>the</strong> procedures for <strong>the</strong>
licensing <strong>of</strong> new products needs to be a lot more
streamlined.
• The availability <strong>of</strong> spare farm sites so that fallowing can
be facilitated.
• Fur<strong>the</strong>r work to be carried out on <strong>the</strong> use <strong>of</strong> wrasse
in cages to remove lice from salmon. Ten years ago I
was involved in trials with wrasse which were far from