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

NINA SPECIAL REPORT 34
Annex 3: Genetic and Ecological
Interactions and <strong>the</strong>ir
Management - Session
Chairmen’s Summary
Mary Colligan and Tom Cross
Introduction
The session entitled ‘Genetic and Ecological Interactions
and <strong>the</strong>ir Management’ contained a wide variety <strong>of</strong>
presentations on observed interactions between
aquaculture and wild stocks <strong>of</strong> Atlantic salmon and o<strong>the</strong>r
diadromous fish species. Significant progress has been
made since <strong>the</strong> 1997 symposium in Bath, England, at
which time <strong>the</strong>re was some evidence, but much
speculation, about how wild and aquaculture stocks would
interact in <strong>the</strong> natural environment. Since <strong>the</strong> Bath
symposium <strong>the</strong>re has been more experience with, and
study <strong>of</strong>, interactions between wild and aquaculture
salmon. As <strong>the</strong>se interactions have become more
prevalent, so has experience in methods for managing
<strong>the</strong>se interactions. Presentations at <strong>the</strong> Bergen
symposium provided evidence <strong>of</strong> management
experiences, highlighting both successes and failures.
The Presentations
The first paper was presented by Kjetil Hindar and
entitled ‘Genetic and ecological interactions between wild
and cultured diadromous fish.’ New research since <strong>the</strong>
Bath symposium was highlighted, particularly experiments
in Norway and Ireland. The presentation identified a
number <strong>of</strong> modelled effects farm fish escapees can have
on wild fish. In some cases <strong>the</strong> population eventually
becomes composed entirely <strong>of</strong> hybrids as <strong>the</strong> effects are
cumulative over generations.
Experiences with aquaculture in Chile were presented by
Alejandro Buschmann in a paper entitled ‘Interactions
between salmon farming and marine coastal ecosystems
in <strong>the</strong> south-east Pacific.’ The full environmental effects <strong>of</strong>
aquaculture in Chile are not known. However, <strong>the</strong>
diversity in <strong>the</strong> benthic environment has been
documented to have been reduced in <strong>the</strong> vicinity <strong>of</strong>
aquaculture cages. The abundance <strong>of</strong> predators was also
observed to be higher in areas with aquaculture
installations. It was strongly recommended that <strong>the</strong> effects
on native fish needed to be studied.
A presentation on <strong>the</strong> history <strong>of</strong> genetic research within
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<strong>the</strong> aquaculture industry was presented by Arne Storset,
entitled ‘Past, present, and future <strong>of</strong> genetic improvement
in salmon farming.’ Individual and family selection methods
were reviewed. Molecular methods <strong>of</strong> selection were
identified as likely to increase in importance in <strong>the</strong> future.
It was emphasized that <strong>the</strong> goal within <strong>the</strong> Norwegian
aquaculture industry was domestication.
Aina Valland’s presentation, ‘The causes and scale <strong>of</strong>
escapes from salmon farming,’ identified <strong>the</strong> following
causes: technical failure, predators, floating objects and
boat propellers. The relative contribution <strong>of</strong> each <strong>of</strong> <strong>the</strong>se
causes was found to vary significantly from year to year.
The importance <strong>of</strong> internal control systems and education
and training to ensure staff competence were emphasized.
‘The escape <strong>of</strong> juvenile salmon from hatcheries into
freshwater streams in New Brunswick,’ presented by
Jonathan Carr, illustrated that escapes from freshwater
hatcheries can be a significant cause for concern. Escaped
fish were recorded at <strong>the</strong> majority <strong>of</strong> hatcheries located
near freshwater streams. A call was made for
implementation <strong>of</strong> containment strategies for freshwater
hatcheries.
Information on <strong>the</strong> behavior <strong>of</strong> escaped salmon was
presented by Fred Whoriskey in a paper entitled ‘Sonic
tracking <strong>of</strong> experimentally released farmed Atlantic salmon
in <strong>the</strong> Cobscook Bay region, Maine.’ Escapes were
simulated in <strong>the</strong> winter and spring. Escapees were found
to disperse rapidly beyond 1km from <strong>the</strong> location <strong>of</strong> <strong>the</strong>ir
release. Many <strong>of</strong> <strong>the</strong> escapees were eliminated quickly in
<strong>the</strong> spring, possibly attributable to predation by seals.
Additional information on <strong>the</strong> behavior <strong>of</strong> escaped farmed
salmon was presented by Lars Petter Hansen in <strong>the</strong>
presentation ‘Migration and survival <strong>of</strong> farmed Atlantic
salmon released from two Norwegian fish farms.’ The
escaped fish did not appear to home to <strong>the</strong>ir release site.
The survival and distribution <strong>of</strong> escapees depended on
<strong>the</strong> time <strong>of</strong> year <strong>of</strong> <strong>the</strong> escape and <strong>the</strong> release site. Much
<strong>of</strong> <strong>the</strong> distribution could be explained by currents.
Peder Fiske’s presentation, ‘The incidence <strong>of</strong> escaped
farmed salmon in relation to <strong>the</strong> extent <strong>of</strong> fish farming
activity,’ found a positive correlation between <strong>the</strong> intensity
<strong>of</strong> fish farming and <strong>the</strong> incidence <strong>of</strong> escapes. This study
suggests that <strong>the</strong> number <strong>of</strong> salmon in net pens is a better
indicator <strong>of</strong> farm escapees in rivers than <strong>the</strong> number <strong>of</strong>
reported escapees.
Alan Walker described <strong>the</strong> development <strong>of</strong> programmes
to quantify <strong>the</strong> spatial and temporal distribution <strong>of</strong>