Biology Reference
In-Depth Information
CHINOOK POPULATIONS UNDERWATER
See Figure 12 (opposing page) for graphic on salmon runs of concern.
Chinook Salmon were once among California's most numerous fish. Not so
long ago, the fall run of fish alone returned to the tributaries of the Sacra-
mento River to spawn in numbers up to 200,000 strong. Runs up- and down-
river in other seasons, though smaller, confirmed salmon's early abundance in
the bay's watershed. Since the 1990s, human alterations to their habitat, as
well as diminished food supplies in the ocean and freshwater flows in their
streams of origin, have taken a catastrophic toll. The winter run of salmon has
been in bad shape since 1989, and has been on the endangered species list
since 1994, when only a few hundred fish remained. Other runs are showing
signs of stress, too. The spring run, whose numbers have hovered between
10,000 and 20,000 since 2000, has joined the winter run on the endangered
list. Even the fall run, which is regularly restocked with the help of hatcheries,
is a mere shadow of migrations that were once so numerous that historic ac-
counts claimed they “paved” the rivers. In 2002, 775,000 adults returned to
the Sacramento River to spawn, but by 2009 only 39,500 adults returned to
the Sacramento River, leading to fishery closures.
areas now lacked enough water and gravel for the salmon to build their
redds (a gravel “nest”). Elsewhere in the watershed, salmon and other fish
suffered from high water temperatures, reversed flows on rivers as the
state sent water south, and “entrainment” (getting caught up and/or killed)
in pumps and unscreened water diversions. More than twenty million fish
are drawn into state and federal pumping plants every year.
In the first half of the 1990s, Chinook Salmon and Delta Smelt were
both placed on the federal threatened and endangered species list. The
listings brought the needs of fish into conflict with big cities and big
business. Californians of every kind went to war over water. In general,
the war has raged among a triangle of three powerful interests, according
to author John Hart: “On one side of the triangle are the demands of San
Joaquin Valley agriculture, which seeks always to have as much water as
possible pumped south. . . . On the second side are the state's burgeoning
urban regions. They need water too, and in the past have often lined up
alongside farmers in support of more dams and diversions. . . . On the
triangle's third side are people whose interests somehow lie with a
healthier bay-delta estuary [including fishermen, scientists, environ-
mental groups, hunters, recreationists]. . . . These various people want
more water, or anyway not one drop less, to flow westward toward the
