, which drains Tam Valley into upper Richardson's Bay Richardson Bay is an important ecological area being managed by Audubon California as the Richardson Bay Audubon Center & Sanctuary. Birds are abundant in Richardson Bay, with over one million migratory visitors each winter, many of whom utilizing the upper mudflats and Bothin Marsh associated with the area west of the
U.S. Route 101. In addition to being designated a high score
IBA, Richardson's Bay has been dedicated as a Hemispheric Reserve of the Western Shorebird Network. Migrating birds that winter regularly at Richardson's Bay include
least sandpiper,
western sandpiper,
spotted sandpiper,
American avocet,
dunlin,
marbled godwit,
greater yellowlegs,
willet,
long-billed curlew and
dowitchers. A special resident of Bothin Marsh, Blackies' Creek mouth and DeSilva Island is the
California clapper rail, a non-migratory
endangered species. Common year around residents of the Richardson Bay Sanctuary include
great blue heron,
snowy egret, and
great egret;
mallard;
red-tailed hawk and
turkey vulture;
killdeer and
western gull;
mourning dove and
rock dove;
Anna's hummingbird. Common residents
Passeriformes include
scrub jay,
American crow,
chestnut-backed chickadee,
bushtit,
Bewick's wren,
house sparrow,
red-winged blackbird,
house finch,
California towhee and
song sparrow. Fishery characteristics of Richardson Bay include a
Pacific herring fishery and
oyster beds. The herring
fishing fleet serving all of San Francisco Bay is based in Richardson Bay at the Sausalito harbor. This herring fishing is overseen by the
California Department of Fish and Game; the herring population is in a downward trend, although not from excessive
fishing pressure with the net techniques in use, but rather from ocean environmental factors. Herring spend most of their lives in the open ocean and come to Richardson Bay and other estuaries for winter spawning in the shallow protected waters. In Richardson Bay their eggs attach to assorted surfaces such as eelgrass, piers or
rip rap. After the eggs hatch, the herring
larvae consume
plankton; before hatching the eggs are subject to predation by
gulls at low tide and
sturgeon and other assorted estuarine fauna at higher tides. Regarding the oyster beds, an experimental program is underway as of 2006, in which foreign oyster shells (biologically inert) are bagged and em-placed in underwater locations to serve as larval substrates, in order to assist the native oysters in propagating. Locally oysters are preyed upon by the
bat ray and certain
crabs. The extensive
mudflats of Richardson Bay provide a rich
habitat for
marine invertebrates. Many of the species are found elsewhere in San Francisco Bay. Characteristic organisms include burrowing
clams,
polychaete worms, decapod
crustaceans,
amphipods,
phoronids and
anemones. A field survey conducted on a broad mudflat along the Strawberry/Belvedere shoreline found species associated with rocks including:
bivalves, (
Macoma balthica,
Mya arenaria and
Mytilus edulis); the
sea snail Littorina planaxis; the
crab Hemigrapsis oregonensis; the
isopod Sphaeroma quoyanum; the
barnacles
Balanus glandula and
Balanus amphitrite; the
nemertean Lineus ruber; and the
anemones
Diadumene leucolena and
Haliplanella luciae. Mammals visiting Richardson Bay include the
harbor seal, which hauls out on
DeSilva Island and on the Tiburon shore near the Richardson Bay Audubon Sanctuary headquarters. The
endangered salt marsh harvest mouse is also thought to be present. Flora include
intertidal and upland species. Probably the most notable feature is the extensive
eelgrass population at the tideland perimeter of Richardson Bay. This eelgrass occurrence in Richardson Bay is considered one of the most sizeable stands in Northern California, and it is being restored, leading to further extent of this habitat. There is an extensive
pickleweed habitat at the western end of the bay, where many acres of mudflat areas are exposed to
shorebirds at low tide at the efflux of
Pickleweed Inlet. Upland plants found at the perimeter of Richardson's Bay include
toyon,
coast live oak,
California bay, and native California
bunch grasses. On November 7, 2007, there was a large
oil spill in the
San Francisco Bay. This Cosco Busan oil spill was found to be lethal to herring fry in oiled versus non-oiled sites in Richardson Bay. This spill has greatly affected the
organisms in the
bay. ==Modern history==