Biology Reference
In-Depth Information
they become treasures for beachcombers. Molting happens about 12 times
as Dungeness Crabs grow from larvae to teenagers in the bay. Dungeness
Crabs in San Francisco Bay molt more frequently than those reared in the
near-shore coastal zone, thanks to both higher temperatures in the bay
that allow them to grow faster and the availability of more food. They also
mature and grow faster in rich bay waters than anywhere else along the
Pacific Coast.
Dungeness are carnivores. While they're in the bay, the amount of hab-
itat available determines how many will survive. Kathy Hieb describes it as
follows: “If there's not enough food and not enough space, crabs will eat
each other. If you're four weeks older than the next crab, you might be two
inches across when the younger one is half an inch across—big enough to
make a snack of the kid next door.” One crab can only eat another if the
latter has recently molted and therefore has a soft shell.
Although many of the crabs available in local restaurants and markets
traveled into bay waters to mature, any Dungeness Crab caught in the bay
must be thrown back. The law is among many designed to prevent the spe-
cies from becoming overfished. So the animals waving their claws at sea-
food shoppers were actually trapped outside the Golden Gate.
San Francisco Bay is home to at least 120 species of fish, the majority of
which are natives. Some live there year-round, whereas some linger only
when young, using the bay as a nursery. Others use the estuary as a migra-
tion corridor to and from spawning and rearing grounds.
Most abundant among the bay's fish are the shimmering schools of an-
chovies, herring, and other small silver fish. Some may be fully grown, and
others may be the young of larger fish. In certain seasons, the bay is full of
fish not much longer than a human pinky finger.
The flatfish living on the bay bottom look as though they belong in a
two-dimensional world. No thicker than a flapjack, flatfish see the world
from a unique perspective, having eyes on only one side of their body.
Among the bay's most common flatfish are California Halibut, English
Sole, and Starry Flounder.
The strongest, fastest fish may be salmon—one of several anadromous
fish that lead a two-part life, as adults in the ocean and as spawners and
juveniles in the estuary's rivers. Salmon, Steelhead Trout, and Green and
White Sturgeon are the primary native anadromous fish in the estuary sys-
tem, but Striped Bass—a non-native—may be the most familiar as a favor-
ite with anglers.
