Biology Reference
In-Depth Information
have the ability to swim under their own power. Like Dungeness Crabs,
they hatch in the ocean and catch a ride on bottom currents into the bay to
fatten and grow.
Larval flatfish drift at the whim of the currents for the first weeks—or
sometimes months—of life. The longer the time spent adrift, the farther
they are likely to travel from where their parents placed them as eggs. In
one year, currents and El Niño conditions are known to have carried Cali-
fornia Tongue Fish larvae all the way to Washington before they could
settle near shore.
If and when larval flatfish do manage to find their way to the Golden
Gate, research has shown that larger pulses of young flatfish enter the bay
on flood tides during a new moon at night—a smart move. As Kathy Hieb
says, “You don't want to be seen and eaten right away.”
Once in the bay, halibut often head into the South Bay, looking for the
warmest water they can find. But like most other flatfish species, as they
grow halibut move into deeper, saltier main channels and Central Bay
zones. Once they've reached one to four years old—it varies by species—
flatfish start moving back out to the ocean. Whereas sole, Sand Dabs, and
flounder rarely return to the bay, halibut may travel back and forth be-
tween the coast and bay following prey.
As adults, California Halibut will weigh about 40 pounds, only a third
the size of their Pacific Halibut cousins. These ocean halibut are the ones
that regularly end up in a steaklike filet covered in beer batter or a bal-
samic reduction.
California Halibut in San Francisco Bay do better in warm-water re-
gimes. According to Baxter, you can look back over the decades and see how
local halibut have fared just by studying ocean conditions. Halibut numbers
dropped in the 1960s and early 1970s, when coastal waters were relatively
cold. But warming periods in the early 1980s supported a decent local hali-
but fishery later in the decade. Warm-water periods ratcheted up the popu-
lation another notch in following years, and a subsequent warm-water
period in the mid-2000s helped maintain this higher population level.
Salmon
One of the signature species of the bay's watershed is the muscular, sil-
very pink, yard-long Chinook Salmon. Chinook ( Oncorhyncus tshawy-
tscha ) migrate from the ocean, through the bay, and to the upper reaches
of the Sacramento and San Joaquin rivers and their tributaries to spawn.
Most of their historic spawning grounds are now blocked by dams. But
salmon still work their way through the watershed to get as close as they
can to the stream of their birth, and many now spawn in the main stem
rivers below dams.
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