Abstract
The historical, political and scientific
aspects of salmon hatchery programmes designed
to enhance fishery production, or to recover
endangered populations, are reviewed. We start
by pointing out that the establishment of
hatcheries has been a political response to
societal demands for harvest and conservation;
given this social context, we then critically
examined the levels of activity, the biological
risks, and the economic analysis associated with
salmon hatchery programmes. A rigorous analysis
of the impacts of hatchery programmes was
hindered by the lack of standardized data on
release sizes and survival rates at all
ecological scales, and since hatchery programme
objectives are rarely defined, it was also
difficult to measure their effectiveness at
meeting release objectives. Debates on the
genetic effects of hatchery programmes on wild
fish have been dominated by whether correct
management practices can reduce negative
outcomes, but we noted that there has been an
absence of programmatic research approaches
addressing this important issue. Competitive
interactions between hatchery and wild fish were
observed to be complex, but studies researching
approaches to reduce these interactions at all
ecological scales during the entire salmon life
history have been rare, and thus are not
typically considered in hatchery management.
Harvesting of salmon released from fishery
enhancement hatcheries likely impacts vulnerable
wild populations; managers have responded to
this problem by mass marking hatchery fish, so
that fishing effort can be directed towards
hatchery populations. However, we noted that the
effectiveness of this approach is dependant on
accurate marking and production of hatchery fish
with high survival rates, and it is not yet
clear whether selective fishing will prevent
overharvest of wild populations. Finally,
research demonstrating disease transmission from
hatchery fish to wild populations was observed
to be equivocal; evidence in this area has been
constrained by the lack of effective approaches
to studying the fate of pathogens in the wild.
We then reviewed several approaches to studying
the economic consequences of hatchery activities
intended to inform the social decisions
surrounding programmes, but recognized that
placing monetary value on conservation efforts
or on hatcheries that mitigate cultural groups'
loss of historical harvest opportunities may
complicate these analyses. We noted that
economic issues have rarely been included in
decision making on hatchery programmes. We end
by identifying existing major knowledge gaps,
which, if filled, could contribute towards a
fuller understanding of the role that hatchery
programmes could play in meeting divergent
goals. However, we also recognized that many
management recommendations arising from such
research may involve trade-offs between
different risks, and that decisions about these
trade-offs must occur within a social context.
Hatcheries have played an important role in
sustaining some highly endangered populations,
and it is possible that reform of practices will
lead to an increase in the number of successful
programmes. However, a serious appraisal of the
role of hatcheries in meeting broader needs is
urgently warranted and should take place at the
scientific, but more effectively, at the
societal level.
