VANCOUVER -- The Pacific
Ocean off British Columbia's coast was warmer
and drier than normal last year, leading to an
increased number of exotic species such as
tropical squid, and a reduced growth rate in
salmon, according to a new federal study.
The seventh annual State of the Pacific Ocean
report, which was compiled by more than 30
scientists from the Department of Fisheries
and Oceans, predicts poor salmon runs this
summer and fall because of poor ocean
conditions dating back three years.
The document holds out a glimmer of hope that
the warm-water cycle -- which is bad for
salmon and herring -- might be ending,
although it is too early to tell.
"Warm oceanic waters appeared to be cooling to
normal temperatures at the end of 2005, but it
is unclear if this represents a break in the
warm conditions that have persisted since 2003
or a temporary event," the document states.
Among the key findings are that the warm ocean
temperatures led to a reduced upwelling of
cold water that normally carries a rich supply
of microscopic plants (phytoplankton) to the
surface, where juvenile salmon feed.
There was also a delay in the spring bloom of
plankton, which in cold-water years comes just
as young salmon are emerging from spawning
rivers, to start their juvenile period of
growth in salt water. The result: salmon
growth and survival rates were down.
"The biomass of zooplankton (food for many
marine fishes) was below normal, and there
were unusually high abundances of zooplankton
species that normally occur off California;
the typical cold-water copepods and
euphausiids (krill) in B.C. were
proportionally less abundant. . . . The growth
of juvenile coho salmon on the west coast of
Vancouver Island during spring to fall was the
lowest that has been measured since these
observations began in 1998. Survival can be
low in years of poor ocean growth," the report
states.
The growth of juvenile coho in southeast
Alaskan waters, by contrast, was twice the
rate exhibited by salmon off the west coast of
Vancouver Island.
While cold-water fish such as salmon had
difficulties with the warm conditions, other
species were moving in from the south.