Deputy Director of the NPAFC presented scientific information
relevant to help enforcement activities regarding 2008 salmon
migration patterns and the areas possible for illegal
activities. J. Irvine of Fisheries and Oceans Canada was also
present to answer any scientific questions.
States asked to what degree sea surface temperature is an
effective proxy for temperatures throughout the water column.
S. Urawa acknowledged that the surface temperature cannot be
relied on particularly during the summer season because there
are indeed areas of cold water inversion under the surface.
However, salmon are typically found between 0 to 50m in depth,
so there is a correlation of sea surface and sub-surface
temperatures in this depth range. Additionally, remote sensing
[satellite imaging] is capable only of revealing surface
temperatures, so this is the best available data for planning
of Canada noted that there can be significant variance between
surface and sub-surface temperatures, and that oceanographers
are working on providing improved sub-surface temperature data.
questioned whether there are depth restrictions for salmon, and
S. Urawa indicated that different species prefer different
depths. Depth varies by species, season and time of day.
States requested further information on water sampling methods
for stock identification of confiscated salmon so that USCG
Kodiak Fisheries Training Center will be able to train and
employ staff for sample collection. S. Urawa responded that
NPAFC Stock ID Working Group may be able to compile a “user’s
manual” of applicable information. If requested, the working
group may be able to discuss at the next RPCM to suggest to
create a manual for collecting samples.
informed the committee that Canadian aircraft occasionally drop
bathymetric temperature devices, which may be employed to
contribute to this data collection effort.