Fish Species at Risk
Pacific Lamprey Entosphenus tridentatus (FSC)
Large (to 2 feet long) parasitic lamprey that migrates to the ocean to mature. The blind larvae rear in bottom mud for 2-4 years before transforming to adult body form (developing eyes and parasitic sucking disk) and migrating to the ocean. They return in winter, but not necessarily to their natal stream, after 2 years in the ocean. They are restricted to larger streams of the region (Pescadero, Soquel, Llagas, Uvas and Coyote creeks, San Lorenzo and Guadalupe rivers), and are relatively uncommon except in the San Lorenzo River. Lampreys have declined for some of the same reasons that steelhead and salmon have (water diversions, channelization and dams that affect migration and rearing conditions). Lampreys are able to surmount some barriers that block steelhead (such as the spillway of Uvas Reservoir) and are sometimes able to complete their life cycle in freshwater if landlocked by dam construction.
Coho Salmon Oncorhynchus kisutch (SE, FE)
Coho are found in cool coastal streams with flat reaches containing good woody pools (Pescadero, Gazos, Waddell, Scott and San Vicente creeks). They were formerly more widespread, but still rare compared to steelhead, which use a much wider variety of habitats. Coho are sensitive to nest destruction by winter storms because of early spawning (January and February) and to access problems due to early winter drought. Wild females almost always spawn and die as 3-year olds, so year classes are distinct and subject to loss from storms or drought. Even in streams where they are present, one or more year classes may have been lost (i.e. the 1994/1997/2000 year class was gone from all but Scott Creek, where it was scarce in 2000). Accelerated growth in hatcheries (such as the Big Creek hatchery in the Scott Creek watershed) can produce 2-year old spawning females to potentially fill in lost year classes. In addition, in years of extremely high coho abundance (Scott Creek in 2002) many coho grow slowly and some may spend two years in freshwater; this may result in 4-year old fish to fill in weak or missing year classes. Coho salmon in the bioregion streams were nearly eliminated by poor ocean conditions in 2005 and 2006, and subsequent dismal adult returns. Runs are being rebuilt with captive brood stock and captive juvenile rearing at the Kingfisher Flat / Big Creek Restoration Hatchery. For additional information on coho salmon, go to Salmonids of the Santa Cruz Mountains.
Chinook Salmon Oncorhynchus tshawytscha (CSC)
Chinook are large salmon of larger north coast and Central Valley streams, with separate fall, late-fall, winter and spring spawning runs. Spring and winter runs are federally listed. Anecdotal records indicate that Chinook were originally present in some south Bay streams, at least occasionally (such as during wet periods). The marginal original stocks were probably eliminated by diversions, dam building and severe pollution in south San Francisco Bay. However, runs of several hundred fall-run fish now annually enter Coyote Creek and the Guadalupe River in Santa Clara County. The recent runs apparently originated as strays from Central Valley streams and hatcheries, and much of each run is probably still strays. However, some successful spawning and smolt production has occurred in both streams. For additional information on Chinook salmon, go to Salmonids of the Santa Cruz Mountains.
Steelhead Oncorhynchus mykiss (FT)
Steelhead are still present in most coastal and some San Francisco Bay streams (San Francisquito, Stevens and Penitencia creeks and the tributaries of the Guadalupe River), although numbers have been substantially reduced by sedimentation, water diversion and dam construction. They are able to use steeper, faster habitats than coho, and can also use warmer stream habitats if fast-water riffles are present as feeding areas. Summer lagoons and some seasonal on-channel ponds can often provide important rearing habitat if water temperatures are not too warm and food is abundant. Poor access and reduced stream flows temporarily reduce abundance during droughts, but populations generally rebound quickly because of flexible freshwater and ocean life history. They commonly occur as resident (non-migratory) rainbow trout above natural and man-made barriers. Resident fish above complete natural barriers and most large reservoirs (except Uvas Reservoir) are not included in the federal listing. For additional information on steelhead, go to Salmonids of the Santa Cruz Mountains.
Speckled Dace Rhinichthyes osculus
Speckled dace are widespread as several probable subspecies in California, but have been lost from most San Francisco Bay area sites (Alameda, Coyote and Llagas creeks and the Pajaro River). Dace are present only in the San Lorenzo River watershed, where they are reasonably common in riffles of the river and low gradient tributaries. Dace are small (to 4 inches) benthic-feeding insectivores found in warm (San Benito River) or cool (San Lorenzo River) streams. They are usually rare or absent where sculpins, another benthic insectivore, are common.
Sacramento Perch Archoplites interruptus (FSC, CSC, possibly extirpated)
Originally present in the Pajaro River, Coyote Creek and other lowland streams connected to the Central Valley, this species has been extirpated from almost all of its native range due to the introduction of more competitive sunfishes from the eastern U.S. Sacramento perch have been introduced outside their native range in California (including Crowley Lake east of the Sierra and Clear Lake in Modoc County) and into other western and mid-western states (including Pyramid Lake in Nevada) because they often do relatively well in alkaline habitats stressful to other species. If reproducing populations of Sacramento perch are present in the bioregion, they are probably in farm ponds.
Tule Perch Hysterocarpus traski
This freshwater member of the surf perch family was extirpated from Coyote Creek and the Pajaro River, but is still common in the Sacramento River delta and portions of the central valley (including San Luis Reservoir). Recently tule perch have been captured in Coyote Creek and in the Guadalupe River system, apparently entering the streams from the San Felipe Pipeline (from San Luis Reservoir) and other water distribution pipelines. Their reappearance restores a species mostly lost from the bioregion (they persisted in Lake Merced near San Francisco), but also indicates that other fish and invertebrates, including exotic invaders, can enter Santa Clara Valley streams from the Central Valley.
Tidewater Goby Eucyclogobius newberryi (FE)
This very small (<2 inch) fish is restricted to coastal lagoons, and apparently capable of only limited short-distance movements along the coast. Gobies avoid strong stream flow and tidal action, and heavily depend upon summer sandbar formation to produce calm water conditions for summer breeding (ecologically, it is a lagoon goby rather than a "tidewater" goby). When sandbars fail to form, the summer population explosions of this "annual" fish usually do not occur. Gobies are tolerant of a wide range of salinities (fresh to hypersaline), temperatures and dissolved oxygen conditions, but have been lost from lagoons without backwater habitats to serve as winter high flow refuges (including Waddell Creek, where they were later reintroduced). Some populations (Moran Lagoon and Soquel and Aptos creeks) may be lost in flood years and be reestablished from closely adjacent more secure populations (Corcoran Lagoon). Eight populations easily came through recent flood and drought years, and are probably relatively secure (San Gregorio, Pescadero, Arroyo de los Frijoles, Waddell, Scott, Baldwin, Wilder, Corcoran). They are apparently present at 9+ other "at risk" sites that are subject to severe flood or drought impacts (San Lorenzo, Laguna, Lombardi, Younger, Moores, Moran, Soquel, Aptos, Pajaro). Click to read "Genetic Variation and Population Structure of Tidewater Goby Populations in Central California".