Federal listing status indicates the species’ standing under the Federal Endangered Species Act and State listing status indicates the species’ standing under the California Endangered Species Act.
CENTRAL VALLEY STEELHEAD
Steelhead are a type of salmonid that, unlike most other salmonids, are able to spawn more than once during their lifetime. Steelhead are able to live as long as 11 years and grow as large as 55 pounds . The distinct population segment of steelhead considered threatened includes all naturally spawned populations of steelhead in the Sacramento and San Joaquin Rivers and their tributaries.
It is estimated that before 1850 the Central Valley steelhead runs were between 1 and 2 million; this number has been reduced to 3,600 . Even though steelhead seem to be broadly distributed in Sacramento River tributaries, the large majority of historic spawning areas are currently located upstream of impassable dams. Currently, it is estimated that more than 95 percent of its historical spawning habitat is inaccessible to the Central Valley steelhead . Presently, no recovery plan has been completed for this distinct population segment.
CENTRAL VALLEY AND SACRAMENTO RIVER CHINOOK SALMON
(spring, fall, late-fall, and winter runs)
Federal Listing Status: Winter-run are endangered and spring-run are threatened.
State Listing Status: Winter-run are endangered and spring-run are threatened.
Chinook salmon mature at about 36 inches and 30 pounds; adults often exceed 40 pounds . The spawning migration of Chinook from ocean to freshwater takes place over seasonal runs. Chinook salmon spend anywhere from 3 months to 2 years in fresh water and 2 to 4 years at sea .
Significant commercial fishing was once supported by fall-run Chinooks, but starting in 2003 fall-run populations have collapsed . Currently, access to historic spawning areas in the Central Valley is impeded by dams on each major river . Usually, the temperature and volume of water released from these dams is inadequate to meet the needs of young salmon.
In order for Chinook to complete their migration they must travel through the Delta and San Francisco Bay twice, when they migrate out to sea and when they return to freshwater for spawning. On average, around half of Central Valley watershed runoff to the Bay is redirected from rivers or exported from the Delta . This significantly degrades the habitats in which Chinook salmon s migrate through.
The delta smelt is a slim bodied smelt, about 2 to 2.8 inches long that is endemic to the upper Sacramento-San Joaquin estuary. It mostly inhabits the part of the estuary in which freshwater mixes with saltwater, excluding its mating season, which occurs during the early spring months.
The delta smelt is very vulnerable to changes in environmental conditions because of its low ability for reproduction and 1-year life cycle. Four important threats to the smelt are direct entrainments by State and Federal water export facilities, summer and fall increases in salinity, summer and fall increases in water clarity, and effects from introduced species . Although the delta smelt was a once common fish in the Sacramento-San Joaquin estuary, its current population is much smaller than it was historically.
Green Sturgeon’s lifespan is 60 to 70 years, and as adults can weigh up to 350 pounds and be 4.5 to 6.5 feet long . In 2006, green sturgeon were listed as threatened species by the National Marine Fisheries Service under the Federal Endangered Species Act. The green sturgeon populations included in this listing are the populations spawning and living in and the Sacramento River, and living in the Sacramento-San Joaquin Delta and the San Francisco Bay Estuary.
The largest reason for the decline in green sturgeon populations in these areas is the reduction of the spawning area to a limited section of the Sacramento River . Other threats include insufficient freshwater flow rates in spawning areas, contaminates (such as pesticides), bycatch of green sturgeon in fisheries, water development projects that affect migration or decrease habitat quality, small population size, and possible poaching . Selenium is also a threat to green sturgeon (see white sturgeon below).
Federal Listing Status: Not Listed
State Listing Status: Not Listed.
The white sturgeon is the largest freshwater fish in North America. It can reach a maximum length of 20 feet and a maximum weight of over 1,000 pounds.
Unlike the green sturgeon, which is federally listed as threatened, the white sturgeon is not listed. Despite the white sturgeon’s non-listing, the American Fisheries Society considers their survival in California dependent on conservation initiatives taken to protect them . Environmental factors that could contribute to the reduction in white sturgeon include delta pumping, which removes and adjusts water flow levels, and the introduction of new species into the white sturgeon habitat .
Another environmental characteristic posing a threat for white sturgeon is the high selenium concentration in the San Pablo Bay, where many white sturgeons spend their entire lives. San Pablo Bay stands as the part of the San Francisco Bay with the highest selenium concentrations. This high level of concentration can affect white sturgeons through the food chain. White sturgeons mainly eat clams in the bay. These clams, such as the introduced Asian Clam, are great bioaccumulators of selenium. The levels of selenium that white sturgeons receive from this food source significantly impact their reproductive abilities. Concentrations of selenium in developing white sturgeon ovaries have been found to contain seven times the threshold for reproductive toxicity in fish.
SACRAMENTO SPLIT TAIL
Federal Listing Status: Not Listed.
State Listing Status: California species of special concern
The U.S. Fish and Wildlife Service published in the Federal Register in 2010 a conclusion that the Sacramento splittail did not warrant protection under the Endangered Species Act . Even though habitat loss for the splittail has occurred over the years, current data fails to demonstrate a significant long-term decline of the splittail population in the Central Valley .
The longfin smelt is an estuarine fish that usually measures 3.5 to 4.3 inches . The distinct population segment of longfin smelt in the San Francisco Bay-Delta is currently not considered endangered or threatened under the Federal Endangered Species Act. A finding published in 2012 found that although other higher priority species should be addressed in conservation measures instead of the longfin smelt, longfin smelt still warrant consideration for protection under the Federal Endangered Species Act . Despite the longfin smelt’s federal unlisted status, the population of longfin smelt in the San Francisco Bay-Delta is at its lowest point in its 40-year recorded history .