 Atherinops affinis
 Distribution of topsmelt in San
Francisco Bay
Topsmelt range from Vancouver Island, British Columbia to the
Gulf of California. Topsmelt are a pelagic, schooling species found in shallow bays,
estuaries, sloughs and kelpbeds. Within San Francisco Bay, topsmelt are particularly
abundant in the shallow subtidal and intertidal waters of South Bay. They are not
commercially important, but are a minor component of the recreational pier fishery.
In San Francisco Bay topsmelt spawn from April to October, with a peak in May and June.
Many juveniles and adults stay in the Bay year-round, although some emigrate to the
nearshore coastal area during fall and winter. Topsmelt become sexually mature when
one-year old, at size of 100 to 110 mm. Topsmelt live from six to nine years, with a
maximum length of 366 mm.
Topsmelt feed primarily on plant material, but also consume small crustaceans and some
benthic invertebrates. They are an important prey for many piscivorous birds and fishes.
Topsmelt young-of-the-year (YOY) abundance indices have been relatively low all years
except for 1985 and 1987. We have no hypothesis as to what factors may be controlling
abundance of topsmelt in the Bay. Annual abundance indices
for YOY topsmelt are generated from the San Francisco Bay
Monitoring Program using midwater trawl data.
|
