Biology Reference
In-Depth Information
Herring roe (eggs) on
blades of eelgrass. Roe
from San Francisco Bay
are particularly prized by
Japanese food buyers,
who value their unusual
golden hue.
crawl, swim, or ride the flood tides, or bottom current, through the
Golden Gate. If parental timing and placement is off, these youngsters end
up in other near-shore areas up and down the coast. Those larvae and ju-
veniles that do maneuver themselves into San Francisco Bay find a shel-
tered, relatively warm, and food-filled place to grow up.
Entering the bay is one thing; managing to stay there is another. “There's
no species that comes into San Francisco Bay to reproduce, or that is resi-
dent here, that hasn't got some mechanism or strategy to keep their young
here, some way of reducing their chances of being carried out the Golden
Gate or up and down the coast by tides or currents,” says biologist Kathy
Hieb of the California Department of Fish and Game. Hieb conducts a
longstanding survey of bay life every month to monitor estuary health.
Some of these staying strategies include producing sticky eggs, build-
ing nests, bearing live young in safe shallows, and timing reproduction to
coincide with currents or tides headed in the right direction. Such strate-
gies are one reason species that live in and around estuaries are so special.
“They sense which way is upstream. There's some gradient beyond just
salinity, something in estuarine water like dissolved organics and plant
materials, that they can detect using their olfactory senses,” Hieb says.
Fundamental Food
The slate-grey waters of the bay can be considered a soup made up of nu-
trients, sediment, and microscopic organisms called plankton. The calo-
ries these minute creatures produce provide an essential foundation for all
life in the bay and coastal ocean. Without plankton, the bay and ocean
would offer little to eat.
A wide variety of bay creatures graze directly on plankton. These range
from adult anchovies and herring to barnacles and larval fishes. Plank-
ton not eaten while still alive sink to the bay floor and support filter-
