California sea lion below Bonneville Dam
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Questions
and Answers: Columbia River sea lions
1) Why are California sea lions a concern on the Columbia River?
On the Columbia
River, a robust and growing population of California sea lions is
preying
on endangered and threatened stocks of salmon and steelhead that are
listed for protection under the federal Endangered Species Act (ESA).
Sea lion predation is occurring throughout in the lower river system,
but the problem is especially acute below Bonneville Dam where returning
salmon and steelhead congregate as they prepare to move up the dam’s
fish ladders to spawn upstream.
Fish managers are
also concerned about increasing predation by sea lions on mature sturgeon
below Bonneville Dam and on listed salmon and steelhead runs in the
Willamette River and other tributaries to the Columbia River. Human
safety is also a concern. In recent years, there have been numerous
reports of these powerful animals swamping boats and biting people along
the Pacific coast.
2) Are California
sea lions native to the Columbia River?
California sea lions are
found all along the west coast of the North America from Mexico to
southeast Alaska including the mouth of the
Columbia River. However, in recent years their numbers and distribution
have increased significantly in the Columbia River system all the way
upriver to Bonneville Dam. Until the early 1980s, it was uncommon to
see a California sea lion in the Columbia River. Since then, migrant
animals from California and Mexico have appeared in the river seasonally
from January to late May in dramatically increasing numbers – first
in the river estuary, then in the tributaries and finally upriver to
Bonneville Dam, 145 miles from the river mouth. A 2006 survey conducted
by the Washington Department of Fish and Wildlife (WDFW) estimated
up to 1,200 California sea lions and 1,000 Steller sea lions in the lower
Columbia River.
California sea
lions are a distinct species from Steller sea lions. Unlike
California
sea lions, Steller sea
lions are present year-round
in the Columbia River, but seldom move upriver past the mouth of
the Cowlitz River at Longview (River Mile 70). The Steller sea lions’ diet
relies more on marine fish than on salmon and steelhead. Steller
sea lions are not a target of lethal removal efforts.
3) What fish
are at risk from sea lions in the Columbia River?
The population of
greatest concern is the Upper Columbia Spring Chinook run, which is
listed as endangered under the Endangered Species Act (ESA). Snake River
Spring/Summer Chinook, listed as threatened under the ESA, are also
highly vulnerable to predation by sea lions feeding in spring immediately
downriver from Bonneville Dam. Other ESA-listed salmon and steelhead
populations passing through the lower Columbia River when sea lions
are feeding include Lower Columbia River Chinook, Lower Columbia River
steelhead, Middle Columbia River steelhead, Snake River Basin steelhead,
Upper Willamette River Chinook and Upper Willamette River steelhead.
All are listed as threatened under the ESA.
4) Are other
impacts to ESA-listed salmon and steelhead being addressed?
Yes. There has
been an extraordinary and growing effort in this region to protect
and recover
salmon and steelhead populations. Recovery plans are being developed
in every watershed to restore important habitat, improve dam passage
survival, reform hatchery programs to assist wild fish populations,
and reshape fisheries by focusing on selectively harvesting healthy,
hatchery fish. The people of the Northwest have supported restoration
efforts, and borne the costs, because of the importance of salmon to
our heritage, the cultural value to Native Americans, and the economic
value of salmon to our fishing communities.
5) How do
fish managers know that California sea lions are preying on protected
fish?
Since 2002, the
Army Corps of Engineers has recorded the number of salmon and steelhead
consumed by California sea lions annually from January through May immediately
below Bonneville Dam. In 2005, for example, the Corps watched sea lions
consume 3,023 fish in a year when ESA-listed upriver chinook stocks
made up 14.5 percent of the run.
Besides recording
the number of fish taken, the U.S. Army Corps of Engineers also documented
a sharply increasing number of sea lions foraging at the dam. That
number has grown from six sea lions in 2001, to 31 in 2003, to approximately
100 sea lions annually since 2004. Until the mid-1970s, California
sea lions were seldom seen anywhere on the Columbia River.
The Corps’
data only includes observations of fish taken by sea lions above water
immediately below Bonneville Dam. A biometric model, based on California
sea lions’ metabolic needs, indicates that 100 animals feeding
in that area may consume as many as 13,000 salmon each spring. In addition,
sea lions are foraging in the other 140 miles of the lower river,
and in tributaries.
6) What would
happen if California sea lions were allowed to continue foraging in the
lower river?
Left unchecked,
California sea lions could undermine the recovery of threatened and
endangered salmon and steelhead runs moving through the lower Columbia
River. For some stocks, recovery efforts involving reduced fishing opportunities
have been under way for decades. Since the 1990s, recovery efforts have
expanded to include mitigation efforts and billions of dollars in public
investment.
Previous experience
with California sea lions at Seattle’s Ballard Locks demonstrates
the risk these animals can pose to vulnerable fish stocks. From the
early 1980s through the mid-1990s, resource managers tried a variety
of
methods to deter sea lions from preying on Lake Washington winter steelhead.
Those efforts were unsuccessful, and sea lion predation continued
until
the run was effectively destroyed. Today, Lake Washington winter steelhead
remain at critically low levels and the population is not expected
to
recover. With sea lion numbers and predation increasing on the lower
Columbia River, fish managers fear some Columbia and Snake River
stocks
could meet the same fate.
7) What steps
have been taken to deter sea lions from preying on salmon?
In the spring of
2005 and again in 2006, the Washington Department of Fish and Wildlife
(WDFW), the Oregon Department of Fish and Wildlife (ODFW) and other
partners made a concentrated effort to drive California sea lions away
from the area below Bonneville Dam. Partners in this effort included
the Columbia River Inter-Tribal Fisheries Commission, National Marine
Fisheries Service (NMFS) and the U.S. Army Corps of Engineers. Despite
hazing tactics that included underwater firecrackers,
acoustic
devices and boat hazing, the sea lions returned to the area within
a short period.
8) Why can't
sea lions be relocated from the Columbia River?
Previous efforts
to relocate sea lions have been largely unsuccessful because sea lions
frequently return to the site of capture. The experience with sea lions
at the Ballard Locks in Seattle in the late 1980s is a prime example. In 1988 and 1989,
resource managers captured a total of 39 California sea lions that had been foraging
at the Ballard Locks and transported them to the outer Washington coast
near Long Beach where they were released. Within a few weeks of the time they were released,
29 of those animals returned to
the Locks to resume preying on salmon and steelhead in Shilshole Bay.
The result was much the same the following year, when resource managers
transported six California sea lions back to their breeding area off
the coast of southern California. Three of those animals returned to
Puget Sound within 45 days and a fourth was sighted in the Columbia
River.
Three California sea lions that had been foraging near the Locks were
captured and transferred to SeaWorld in Orlando, Fla., in 1996. Resource
managers have initiated contact with accredited zoological facilities
about the possibility of taking additional animals, but it is unlikely
that demand will be sufficient to ease predation on protected salmon
and steelhead populations on the Columbia River. A final determination
on whether any California sea lions could be moved to captivity would
be made by NMFS, based on the federal agency's assessment of the adequacy
of captive facilities as well as the risk of possibly exposing healthy
captive animals to diseases carried by wild animals.
9) What additional
steps will be taken to control California sea lions on the Columbia River?
Active intervention
and additional wildlife-management methods are required to restore
balance
between the growing number of California sea lions and endangered and
threatened stocks of salmon and steelhead. The states of Washington
and Oregon plan to expand hazing efforts in the spring of 2007, shifting
to daily deterrence efforts as compared to last year’s four
days on, four days off hazing schedule. In addition, Washington,
Oregon and
Idaho have petitioned the federal government for authority to use lethal
means if necessary to remove individual sea lions from the vicinity
of the dam, and to remove marked sea lions that have preyed on salmon
near the dam. The states are applying for this removal authority
under
Section 120 of the Marine Mammal Protection Act.
The states’
Section 120 application is subject to a federal review process that
could take several years. A congressional effort is under way to allow
the states to manage the sea lion predation problem in the interim.
U.S. Reps. Brian Baird, Doc Hastings and Norm Dicks of Washington, and
Greg Walden of Oregon have introduced legislation in Congress that—if
successful—could allow the states and four Columbia River Indian
tribes to lethally removal a limited number of Columbia River sea lions
as early as this spring.
10) What
actions would Section 120 authority allow?
If authority is
granted under Section 120 of the Marine Mammal Protection Act, state
resource managers would be allowed to remove a limited number of California
sea lions that have been identified as preying on salmon and steelhead
in the area below Bonneville Dam. The actual number of California sea
lions that might be removed would depend on various factors, but it
would be less than 1 percent of the number that could be lethally removed
without affecting the over-all health of the population. Lethal removal
would be conducted using the most humane methods available, following
the recommendations of an interagency committee that will include wildlife
veterinarians. Renewed efforts to haze the sea lions away from the
dam area would
precede any lethal removal, and an evaluation period would follow.
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