Help Save the Delta Smelt!

Next week the California Fish and Game Commission will consider a Center for Biological Diversity petition to change the state listing of the delta smelt (Hypomesus transpacificus) from threatened to endangered species status. The Center and other conservation groups submitted an emergency petition in February for endangered status under the California Endangered Species Act, due to catastrophic declines of the smelt population. This fish species is currently listed as threatened under the state law.

The small, nearly translucent delta smelt is endemic to the west coast's largest estuary, the San Francisco Bay and Sacramento-San Joaquin Delta. Once one of the most common and abundant fishes in the Delta, the smelt population has declined 90 percent in the past two decades.

The delta smelt's slide toward extinction is an indication of an ecosystem in crisis. Of the original 29 indigenous fish species in the Delta, 12 have either been eliminated entirely or are currently threatened with extinction. Many of the fish species in the Delta are in rapid decline and scientists are now warning of an ecological crash — not only of fish populations but of the entire Delta food web.

These declines are due to increasing water diversions from the Delta and its tributary rivers for export, loss of habitat, increased competition and predation by introduced species, and impaired water quality from pesticides and other pollutants.

In recent years the delta smelt population has completely collapsed, and abundance levels the past three consecutive years have been the lowest on record. Delta smelt are on a rapid trajectory toward extinction and clearly need increased state and federal protection.

Please send a message to the Commission to immediately change the status of the delta smelt to endangered, on an emergency basis.

http://actionnetwork.org/campaign/delta_smelt

From the CA Depart Fish and Game Website:

The delta smelt is a small, slender-bodied fish, with a typical adult size of 2-3 inches (55- 70mm standard length) although some may reach lengths up to 5 inches (130mm). Live delta smelt have a steel blue sheen on the lateral sides and appear somewhat translucent. Like other members of the family Osmeridae, the delta smelt has an adipose fin (a small fleshy fin on the back between the dorsal fin and tail). Delta smelt are found only in the Sacramento-San Joaquin Estuary (the area where the Sacramento and San Joaquin Rivers flow into San Francisco Bay. They have been found as far upstream as the mouth of the American River on the Sacramento River and Mossdale on the San Joaquin River. They extend downstream as far as San Pablo Bay. Delta smelt are found in brackish water. They usually inhabit salinity ranges of less than 2 parts per thousand (ppt) and are rarely found at salinities greater than 14ppt.

During the late winter to early summer, delta smelt migrate to freshwater to spawn. Females only produce between 1000 and 2600 eggs which sink to the bottom and attach to the substrate. Larvae hatch between 10-14 days, are planktonic (float with the water currents), and are washed downstream until they reach areas near the entrapment zone where salt and fresh water mix. Delta smelt are fast growing and shortlived with the majority of growth within the first 7 to 9 months of life. Most smelt die after spawning in the early spring although a few survive to a second year. Delta smelt feed entirely on small crustaceans called zooplankton.

The delta smelt historically was one of the most common fish in the Sacramento-San Joaquin Estuary. Delta smelt abundance fluctuates greatly from year to year, however, information from seven independent data sets demonstrated a dramatic decline of the delta smelt population and low population levels from 1983 to 1992. In 1993 abundance increased in an apparent response to an increase in available habitat brought about by a wet winter and spring. Fall abundance of delta smelt is usually higher when low salinities of 2ppt or less occur in Suisun Bay in the preceding spring. The total number of delta smelt is not known, however, delta smelt are considered environmentally sensitive because they have a one year life cycle, unusually low fecundity for a fish with planktonic larvae, a limited diet, and reside primarily within the interface between salt and freshwater.