Climate Change - Cohen Commission

ix) Carry-over and intergenerational effects
Research is needed that examines cumulative impacts across life history stages (i.e. carryover
effects) and/or generations (i.e. intergenerational effects). Specifically, this could
include examining: how the effects of environmental conditions on one life stage are
carried over to a subsequent life stage (e.g. how poor growth during warm oceanic
conditions affect survival during the return migration and spawning and the construction
of nest at appropriate depths to prevent scouring); and how the quality and quantity of
eggs successfully deposited by females is affected by the river conditions (e.g.
temperature and flow) encountered during migration and the links to subsequent offspring
survival (i.e. intergenerational effects).
x) Climate change modelling
Managers and policy makers need to plan now for how to deal with continued trends in
climate warming and declining abundances. Projections of future summer temperature
and flow for the Fraser River already exist (Ferrari et al. 2007; Foreman et al. 2001;
Morrison et al. 2002;), but similar information is also needed for other seasons since air
temperature and precipitation as rainfall are expected to increase the most during winter
and spring (Rodenhuis et al. 2009). Also needed is a better understanding of how future
climate change will affect temperature and flows of spawning streams and rearing lakes,
physical conditions of marine habitats and the interaction of sockeye salmon with their
prey and predators.
Recent research has shown that some stocks appear to be more resilient to river warming,
whereas others cannot cope with increasing temperatures (Farrell et al. 2008; Hague et al.
2011; Martins et al. 2011). More stock-specific information on the susceptibility to
climate change is needed for productivity and escapement planning. In addition, needed is
the development of life-stage models in order to quantify the impact of en route and prespawn
mortality, as well as mortality in other life history stages, on future trends in
salmon productivity and abundance (i.e. population viability analysis). Research aimed at
understanding how sockeye salmon would adapt to climate change through genetic and
non-genetic mechanisms continues to be needed.
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