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<DIV><FONT face=Arial size=2><BR><FONT face="Times New Roman" size=3>Contact:
Tim Stephens<BR></FONT><A href=""><FONT face="Times New Roman"
size=3>stephens@ucsc.edu</FONT></A><BR><FONT face="Times New Roman"
size=3>831-459-2495<BR>University of California - Santa Cruz<BR><BR>Hatchery
fish greatly outnumber wild Chinook salmon in troubled fall run<BR><BR>SANTA
CRUZ, CA--A recent study indicates that wild salmon may account<BR>for just 10
percent of California's fall-run chinook salmon population,<BR>while the vast
majority of the fish come from hatcheries. The findings<BR>are especially
troubling in light of the disastrous decline in the<BR>population this year,
which will probably force the closure of the 2008<BR>season for commercial and
recreational salmon fishing.<BR><BR>The role of hatcheries in the management of
salmon populations has been<BR>a contentious issue for many years. The new
findings appear to support<BR>the idea that including artificially propagated
fish in population<BR>estimates can mask declines in natural populations caused
by a lack of<BR>suitable habitat.<BR><BR>"Our finding that 90 percent of the
fish are from hatcheries surprised<BR>a lot of people," said Rachel
Barnett-Johnson, a fisheries biologist<BR>with the Institute of Marine Sciences
at the University of California,<BR>Santa Cruz.<BR><BR>Barnett-Johnson and her
coworkers published their results in the<BR>December 2007 issue of the Canadian
Journal of Fisheries and Aquatic<BR>Sciences. The main focus of the paper is the
development of a new<BR>technique for distinguishing between wild and
hatchery-raised salmon.<BR>The researchers validated the technique and used it
to estimate the<BR>percentage of wild fish among the fall-run chinook salmon
caught by<BR>commercial fishing boats along the central California coast in
2002.<BR><BR>"It's a one-time estimate for that year, and these things do
change<BR>over time. But it's the most recent and perhaps best estimate we
have,"<BR>said Churchill Grimes, director of the National Marine Fisheries
Service<BR>Santa Cruz Laboratory and a coauthor of the paper.<BR><BR>In 2002,
the fall run of chinook salmon in the Sacramento River was<BR>estimated at
775,000 adults returning to spawn, according to the Pacific<BR>Fisheries
Management Council. Fewer than 60,000 are expected this year,<BR>even with no
ocean fishing allowed. If the percentage of wild fish is<BR>the same this year
as in 2002, it would mean fewer than 6,000 wild<BR>salmon in what has been the
largest salmon run on the West Coast.<BR><BR>The researchers were able to
distinguish between wild and<BR>hatchery-raised fish by analyzing the banding
patterns in fish ear<BR>bones, called otoliths. Like tree rings, characteristic
light and dark<BR>bands in the otoliths reflect daily growth increments, and the
width of<BR>the bands indicates growth rates. The differences observed
between<BR>otoliths from wild and hatchery-raised fish are the result
of<BR>differences in the availability of food at a critical transition in
the<BR>salmon life cycle, when the young fish (called fry) have used up
the<BR>food supply in their yolk sacs and must start feeding
themselves,<BR>Barnett-Johnson said.<BR><BR>"In the wild, they hide in the
gravel until they use up the yolk sac,<BR>and then there is a period of slower
growth while they learn to feed on<BR>aquatic insects. This abrupt transition
and slow growth are captured in<BR>the growth bands of the otolith,"
Barnett-Johnson said. "In the<BR>hatchery, there is an abundant supply of food,
so the transition is<BR>smoother and growth bands are wider."<BR><BR>Every fish,
therefore, carries an identifier of its origin as a natural<BR>tag in the
earbone, which has significant advantages over techniques for<BR>tagging fish,
she said. Coded wire tags (CWTs), for example, have been<BR>used to mark fish
for some studies. But only a small fraction of<BR>hatchery fish and even fewer
wild fish are tagged or marked in<BR>California, according to Barnett-Johnson.
Some small hatchery operations<BR>clip the fins of all hatchery fish so they can
be distinguished from<BR>wild fish, but fall-run chinook salmon are not marked
that way. As a<BR>result, there have not been good estimates of the proportion
of wild<BR>fish in the population until this study, she said.<BR><BR>"The only
other estimates out there pointed in the other<BR>direction--significantly more
wild fish than hatchery fish,"<BR>Barnett-Johnson said. "One study used CWT
recoveries from hatchery fish<BR>and estimated that 33 percent of adults
returning to rivers in the<BR>Central Valley were from hatcheries. The other
number floating around<BR>comes from counting the number of fish returning to
spawn in rivers<BR>versus returning to hatcheries, and this estimated the number
of 'wild'<BR>fish to be 3.5 times higher than hatchery returns."<BR><BR>One
reason these figures are so important is that they could affect the<BR>listing
of the fall run under the Endangered Species Act (ESA). The<BR>question of
whether hatcheries can help restore threatened and<BR>endangered salmon
populations or if they actually harm wild populations<BR>has long been a
controversial issue. It became a legal issue in 2001,<BR>when a federal judge
revoked the ESA listing of Oregon coast coho<BR>salmon, ruling that the National
Marine Fisheries Service (NMFS) should<BR>have included hatchery fish in the
population counts.<BR><BR>A more recent federal court ruling, however, concluded
that the health<BR>and viability of natural populations should be used as the
benchmark for<BR>ESA status determinations. That ruling has been appealed to the
U.S.<BR>Court of Appeals for the Ninth Circuit.<BR><BR>"The agency's policy on
counting hatchery fish has flip-flopped as a<BR>result of these different legal
decisions," Grimes said. "Now the focus<BR>is again on wild fish, and it doesn't
appear there are many of them.<BR>That could be bad news for fishing because, if
the fall run is listed<BR>under the Endangered Species Act, there would be no
legal harvest."<BR><BR>Fisheries experts blame unfavorable ocean conditions for
the dismally<BR>low returns of chinook and coho salmon to rivers and streams all
along<BR>the West Coast this year. In 2005, when this year's returning
salmon<BR>were juveniles just entering the ocean, food production in
the<BR>California Current was much lower than usual due to a delay in
the<BR>wind-driven upwelling of nutrient-rich water that sustains the food
web<BR>along the coast. A similar disruption of the normal upwelling
occurred<BR>the following year (see earlier press release at<BR></FONT><A
href=""><FONT face="Times New Roman"
size=3>http://press.ucsc.edu/text.asp?pid=971</FONT></A><FONT
face="Times New Roman" size=3>).<BR><BR>"We expect the returns to be as bad or
worse next year as they were<BR>this year," Grimes said. "The years when those
fish outmigrated into the<BR>ocean were the worst conditions that we've seen in
over 25 years of<BR>observing spring conditions."<BR><BR>Compounding the
situation is the degradation of the freshwater habitat<BR>for salmon in the
Sacramento River and the rest of the Central Valley<BR>drainage system, he said.
"There is no question that the river basin's<BR>capacity to produce salmon--the
quality of the habitat--has been<BR>degraded something awful, and it just
doesn't produce like it used to,"<BR>Grimes said. "We have these remnant
populations--that's all it is<BR>really. We're trying to manage what's
left."<BR><BR>Barnett-Johnson said the otolith technique offers a new tool
for<BR>monitoring the effectiveness of restoration efforts and tracking
the<BR>numbers of wild fish over time. By estimating the numbers of
hatchery<BR>and wild fish independently, the technique can help to
differentiate<BR>between effects on the population due to ocean conditions and
those due<BR>to freshwater conditions. That's because hatchery-raised fish don't
face<BR>the same hazards in the initial freshwater phase of their life
cycle<BR>that wild fish do, so they would be affected less by
freshwater<BR>conditions. Not only are hatchery fish protected and artificially
fed in<BR>the hatcheries, they also get a free ride downstream in tanker
trucks.<BR>The hazards associated with migrating downstream to the ocean range
from<BR>predators to the pumps that siphon water out of the rivers for
human<BR>use.<BR><BR>"Most of the hatcheries in the Central Valley put the fish
in tanker<BR>trucks and release them into the lower San Francisco Bay Delta, so
they<BR>bypass a lot of the mortality that occurs in the
rivers,"<BR>Barnett-Johnson said. "If freshwater mortality was a key factor
in<BR>population declines, we would expect to see hatchery and
wild<BR>populations responding differently."<BR><BR>Barnett-Johnson plans to use
the otolith technique to track changes in<BR>the composition of the salmon
population over time. Unfortunately,<BR>because her research depends on a
collaboration with commercial<BR>fishermen, the possible closure of the fishery
this year may mean that<BR>she will not be able to get any salmon otoliths to
analyze.<BR><BR>"At a time when we really need more information on the status of
wild<BR>populations, a complete closure would mean I can't conduct my
research<BR>to provide this estimate," she said.<BR><BR><BR>###<BR><BR>In
addition to Barnett-Johnson and Grimes, the coauthors of the paper<BR>are
Chantell Royer of Humboldt State University and Christopher Donohoe<BR>of the
NMFS Santa Cruz Laboratory. This research was supported by the UC<BR>Marine
Council and the Partnership for Interdisciplinary Studies of<BR>Coastal Oceans
(PISCO).</FONT><BR><BR><BR><BR><BR></FONT></DIV></BODY></HTML>