Demersal fish, either on the continental shelves,
slopes or sea mounts, support major fisheries in both the eastern
and western Pacific. These include such fish as the rockfishes (genus
Sebastes), thornyheads (genus Sebastolobus) and many flounders (family
Pleuronectidae). These species are known to exhibit periodic shifts
in their distribution either latitudinally (moving north-south)
or longitudinally (moving east-west). While these shifts can at
times be attributed to such things as life history characteristics,
often they are due to changes in the fish’s environment. Changes
in the fish’s environment can be the result of short-term
phenomena, such as seasonal depletions in oxygen levels, or long-term
phenomena, such as decadal climate shifts. Shifts in the spatial
distribution of these species due to changes in the fish’s
environment can cause these populations to move into and out of
the areas traditionally covered by the fisheries they support, as
well as the surveys that seek to assess their abundance. Consequently,
resource surveys designed to develop annual indices of abundance
for these species can produce erroneous trends, and as a result,
the stock assessments that depend on these surveys will be inaccurate.
If the causes of these distributional changes were known, indices
of abundance could be modeled so as to account for these changes
in ways other than changes in overall stock abundance. This session
invites papers that describe the changes in demersal fishes distributions
with specific emphasis on those changes due to changes in climate,
either short- or long-term. The goal of the session will be to provide
sound evidence for ecosystem-based distributional shifts that can
be used to account for some of the year-to-year variability in survey
trends of demersal fish, that may currently be attributed to changes
in overall abundance.
Publications
marked PDF can be viewed and or printed using the Adobe
Acrobat Reader®