SACRAMENTO, Calif. - The Puyallup tribe is
trying to unravel the mystery behind a
federally listed threatened species. In the
coming months the tribe will take a high-tech
approach to learn more about the elusive bull
trout.
The fish will be tagged with devices that emit
a low frequency signal that will be relayed to
Puyallup tribal staff, who will monitor
several patterns of the bull trout. The
devices are estimated to emit signals for up
to a year and will be monitored throughout
that entire period.
''One of the main questions we have is where
are they [bull trout] going,'' asked Puyallup
Resource Protection Manager Russ Ladley.
Since bull trout do not migrate in
nearly-solid schools as do other fish such as
salmon, the amount of information on the
species is somewhat limited. Like salmon, bull
trout are anadromous, meaning they migrate
from salt water to fresh water. However,
Ladley said it is apparent that some bull
trout stay within river systems and do not
migrate out to sea.
It is these differences with other species in
the salmon family, to which bull trout belong,
that led to the radio tracking system. Since
most of the information on bull trout is
fragmentary, the tribe is hoping that more
detailed information can lead to their
ultimate restoration.
Though the fish are found in a large portion
of the Puget Sound region, populations of bull
trout are found as far south as the Columbia
River and as far north as Alaska. Another
population also exists in the mountains of
western Montana. However, the study will
concentrate mainly on bull trout in the White
River, one of the tributaries of the larger
Puyallup River.
Tribal data on the fish already shows that a
main population of bull trout stays close to
the glacial source of the White River in the
western Cascade Mountain Range. Bull trout
seem to need very cold water in which to
spawn. However, another population migrates
downstream to the lower part of the Puyallup
system.
From this a much smaller group then migrates
out to the Puget Sound, a saltwater inlet of
the Pacific Ocean, and stays out for up to
four years before returning to the river's icy
upper reaches to spawn. Ladley said that fish
going into the Puget Sound will not be the
focus of this study.
Ladley said there is no population estimate on
the total number of bull trout. However, at
one fish trap only 40 bull trout were caught.
This pales in comparison to the tens of
thousands of salmon that routinely traverse
the same river path.
Bull trout are not commercially harvested
anywhere and are considered a ''sport'' fish
to be taken in only by individual anglers.
The bull trout used in the study will be
caught in one of the oldest fish traps in the
Puget Sound, dating to 1941, and operated by
the Army Corps of Engineers.
Ladley said the effort is important since the
bull trout are one of many species important
to the Puyallup river system.
''Bull trout, chinook, coho and all of the
other fish in the river don't live in
isolation of each other. The more we
understand about how one fish species lives,
the better we understand all species.'' |
