Rhinichthys osculus subspecies

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General Information

Common Name:

Santa Ana speckled dace

FID:

CRO07

Status:

Conservation Status in California: Class 1, Endangered (Moyle et al. 2011). Santa Ana speckled dace are highly vulnerable to extinction in their native range within the next 50 years. Their distribution is largely restricted to the headwaters of the Los Angeles, Santa Ana, and San Gabriel rivers. These areas are, and will increasingly become, prone to catastrophic fire.

Life History:

Life History: Little has been published on the life history of Santa Ana speckled dace so this account is largely based on information from other dace populations. The variability in body shape has allowed speckled dace to exploit a wide variety of habitats. The Santa Ana dace has a fairly streamlined body form (for a speckled dace) that indicates adaptation for living in flowing water (Moyle 2002). Although speckled dace are usually found in loose groups in appropriate habitats, such as rocky riffles, they avoid large shoals except while breeding. They can be active both day and night although, Moyle (unpubl. data) found that Lahontan speckled dace were more nocturnal in their habits when subjected to heavy bird predation in streams. Their activity is also mediated by stream temperatures, apparently staying active all year if stream temperatures remain above 4?C, which would be typical of streams inhabited by Santa Ana dace (Moyle 2002).
Speckled dace generally forage on small benthic invertebrates, especially taxa common in riffles including hydropsychid caddisflies, baetid mayflies, and chironomid and simuliid midges, but will also feed on filamentous algae on occasion (Li and Moyle 1976; Baltz et al. 1982; Hiss 1984, Moyle et al. 1991). Their subterminal mouth, pharyngeal tooth structure, and short intestine are characteristic of small invertebrate feeders. Not surprisingly, diet varies according with prey availability and speckled dace in general prey opportunistically on the most abundant small invertebrates in their habitat, which may change with season. Preference of forage items may also be influenced by the presence of other fishes that share similar habitats (e.g. sculpin, steelhead). Speckled dace in the Clearwater River, Idaho, shifted their diets to predominantly detritus in the presence on Paiute sculpin (Cottus beldingi) during the spring and early summer, perhaps as a mechanism of niche specialization to reduce competition (Johnson 1985).
Length frequency analyses have determined age and growth patterns. By the end of their first summer, dace grow to 20-30 mm SL (Moyle 2002), growing an average of 10-15 mm/yr in each subsequent year. Females tend to grow faster than males. However, growth rates can decrease in the presence of extreme environmental conditions, high population densities and limited food supply (Sada 1990). Slight changes in growth rates are also positively correlated with changes in temperature, as seen in the Colorado River (Robinson and Childs 2001). Life expectancy is approximately 3 years where maximum sizes do not exceed 80 mm FL, which is typical of Santa Ana speckled dace. Elsewhere, dace may reach 110 mm FL and live up to six years (Moyle 2002). Dace reach maturity by their second summer, with females producing 190-800 eggs depending on size and location (Moyle 2002). Presumably, Santa Ana speckled dace are at the low end of this range. Spawning is probably induced by rising water temperatures and/or high flow events, suggesting the Santa Ana speckled dace most likely spawn in March-May. Spawning in lakes occurs primarily over shallow areas of gravel within the lake or upstream in the edges of riffles of inlet streams. Groups of males will clear an area of algae and detritus and then surround a female when she enters the area. Females release eggs underneath rocks or near the gravel surface while males release sperm (John 1963). Eggs settle into interstices and adhere to the gravel. At temperatures of 18-19?C, eggs hatch in 6 days, but larvae remain in the gravel for another 7-8 days (John 1963). Fry in streams congregate in warm shallow areas, often in channels with rocks and emergent vegetation.
When extreme conditions such as floods, droughts or winter freezing eliminate local populations, speckled dace from nearby areas can readily recolonize or repopulate available habitats if there is access (Sada 1990, Pearsons et al. 1992, Gido et al. 1997). Densities of speckled dace in the Colorado River, Arizona, after a flood returned to pre-flood levels after eight months, as a function of reinvasion and reproduction from upstream and stream margin areas (Valdez et al. 2001).

Habitat Requirements:

Habitat Requirements: Santa Ana speckled dace are found mainly in perennial streams fed by cool springs that maintain summer water temperatures below 20?C (CDFG 1995), although speckled dace in other regions of the west tolerate temperatures of 26-28°C. Surveys of trout streams in the Los Angeles basin indicate that the dace occupy shallow riffles dominated by gravel and cobble. Their habitat in the West Fork of the San Gabriel River was described as shallow (average depths of 15-30 cm) gravel-cobble dominated riffles with overhanging riparian vegetation (Deinstadt et al. 1990). Feeney and Swift (2008), however, characterized their preferred habitat as pools of low-gradient streams (0.5-2.5% slope) with sand to boulder substrates in slow-moving waters, noting that they were also found in the stream margins of fast-moving water.

Distribution:

Distribution: The ability of speckled dace to colonize new areas and adapt to different environments has resulted in their wide distribution. Speckled dace are the only native fish found in all major drainages in western North America. In California, their native range includes drainages in Death Valley (Amargosa River); Owens Valley; eastern Sierras (Walker River north to Eagle Lake); Surprise Valley; Klamath-Trinity basin; Pit River basin, including the Goose Lake watershed; Sacramento River basin, as far south as the Mokelumne River; San Lorenzo, Pajaro and Salinas River basins; San Luis Obispo, Pismo and Arroyo Grande Creek basins; Morro Bay; and San Gabriel and Los Angeles basins (Swift et al. 1993).
Santa Ana speckled dace historically inhabited streams in the upland areas of the Santa Ana, San Gabriel and Los Angeles rivers systems (CDFG 1995). They have since disappeared from many parts of their range, including the middle reaches of the Santa Ana River, Strawberry Creek (Santa Ana River), Mill Creek (Santa Ana River), and most of the Los Angeles River and San Jacinto River basins (Feeney and Swift 2008; G. Abbas, San Bernardino National Forest, pers. comm. 2008). Young of the year and 2 year old fish were found in City Creek (Santa Ana River) in 2008, a location from which speckled dace were thought to have gone extinct (G. Abbas, pers. comm. 2008). Their current distribution is thought to be restricted to only the headwaters of the Santa Ana and San Gabriel Rivers (CDFG 1995). A population was recently documented in Indian Creek, a headwater tributary of the San Jacinto River. Some fish were removed and held in captivity following the Esperanza Fire in 2006 to prevent total loss from flooding. They were reconfirmed as being present in 2007 and 2008 (G. Abbas, pers. comm. 2008). A few other populations of Santa Ana speckled dace were established through introductions into the Santa Clara and Cuyama Rivers, and River Springs, Mono County, although the introduction into the Santa Clara River is thought to have failed.

Abundance Trends:

Trends in Abundance: Population estimates of Santa Ana speckled dace were not found. However, their abundance is likely a small fraction of what it was and populations have disappeared from two of five streams in which they were historically present (G. Abbas, pers. comm. 2008; Metcalf et al., unpubl.). Perhaps eight populations remain, mostly small and isolated from one another. The California Department of Fish and Game declared their numbers so diminished that they were in danger of extinction (CDFG 1995).
Swift et al. (1993), CDFG (1995) and Abbas (pers. comm. 2008) summarized the abundance of specific populations by location. Their findings are summarized below:
Big Tujunga Creek (Los Angeles River). Dace once inhabited the creek for 10-20 km below Big Tujunga Dam, and were thought to be extinct due to drought conditions and the establishment of red shiner (Cyprinella lutrensis) (CDFG 1995). Red shiners directly compete for food and space with dace and prey on dace eggs. Recent (2002-2005) surveys found only a few (10s) speckled dace at this and other locations in the Los Angeles River basin (Tujunga Wash, Haines Canyon; G. Abbas, pers. comm. 2008).
Fish Canyon (San Gabriel River). This population was thought to be extinct (CDFG 1995). Only 6-7 fish were seen in 1988. Optimal dace habitat has been infringed upon by a rock quarry operation. However, current quarry operations are focused on restoring the streambed in order to improve dace habitat (G. Abbas, pers. comm. 2008). Specimens were collected from this site in 2007 by ECORP. Morris dam isolates this population from other dace in the San Gabriel River, preventing genetic flow and recruitment between populations. Some recent (2002, 2006 and 2007) surveys established their presence in this location while others did not (2005; G. Abbas, pers. comm. 2008) The Forest Service was provided specimens by the rock quarry consultant and these are being analysed by Anthony Metcalf at Cal State San Bernardino to determine genetic relationships (G. Abbas, pers. comm. 2008).
West, North, and East Forks San Gabriel River. These areas constitute the best dace habitat (CDFG 1995). Populations in the West Fork in 1990 (Deinstadt et al. 1990) likely numbered less than 2000. Habitat in the West Fork is vulnerable to high water and sediment releases from the Cogswell Reservoir which is managed for flood control. As of 1995, the West Fork was still recovering from major sediment releases from 1981 and 1991. These sediments smothered most of the habitat used by dace until it was flushed out by rainfall and dam water releases in 1988. Surveys found 29 dace in a 68 m section of stream (3 pass electrofisher, Deinstadt pers. comm. in CDFG 1995), in 1993. Surveys in 2006 found dace only one of three locations sampled (G. Abbas, pers. comm. 2008). Dace were also abundant upstream of the reservoir in 2005. Surveys (2005) of the North Fork found dace in one of the two days of sampling. Suveys (2005) also documented the presence of 100s of speckled dace in Cattle Creek (G. Abbas, pers. comm. 2008).
Santa Ana River. Speckled dace are assumed to be extirpated from most of the Santa Ana River (CDFG 1995, Moyle 2002). They were last seen near Rialto in 2001 (G. Abbas, pers. comm., 2008). Only a few specimens (usually Lytle Creek Mainstem. (excerpt from Abbas 2008) The stronghold area for Santa Ana speckled dace is currently in the mainstem reach from Millers Narrows downstream to Turk Point (approximately 1.4 river miles). The Forest Service has qualitatively monitored this reach since at least 1999. Santa Ana speckled dace have been there throughout this period with significant population fluctuations in response to drought induced low flows, major flooding (periods of declining population densities), and a couple years of sustained moderate flows (period of rapid population density increases). This reach is currently the species stronghold for this watershed, being the only place where they have persisted, and must be diligently protected from disturbance and enhanced at every opportunity. This stronghold reach is regularly threatened by encroachment into the wash by heavy equipment by a variety of forest users to protect infrastructure including public roads, public utilities and private access routes. There is perennial water above Millers Narrows in the mainstem up to the confluence with the Middle Fork, but dace were absent here between at least 1999 and 2005.
In 2005 the Forest Service, CDFG and Fontana Union Water Company Consultant Jonathan Baskin conducted a reintroduction of approximately 1000 Santa Ana speckled dace from the lower mainstem of Lytle Creek to the Applewhite Picnic Area on the North Fork of Lytle Creek. In 2007 Southern California Edison reported capture of Santa Ana speckled dace in their diversion works above Millers Narrows suggesting that some of the fish from the North Fork reintroduction had survived and migrated downstream (3.2 river miles) to this location. With this information we can now consider all of the mainstem above Turk Point occupied by Santa Ana speckled dace.
In 2007 the Forest Service and CDFG conducted a translocation of approximately 1300 Santa Ana speckled dace from the lower mainstem of Lytle Creek to the North Fork at Applewhite Picnic area.
In 2005 and 2006 sustained year-round flows from Turk point down to the Fontana Union Water Company (FUWC) diversion (1.8 river miles) resulted in an extreme expansion of speckled dace throughout the reach with yoy rearing in the settling pond at FUWCs intake structure (adults were also noted in the raceways of the intake structure). With this knowledge we can assume that in years when there are flows below Turk Point, that reach of the mainstem is occupied by Santa Ana speckled dace.
North Fork Lytle Creek. The Middle Fork Lytle Creek is a high quality water source for this watershed, consistently producing perennial waters over a 2 mile reach which supports a popular rainbow trout fishery. Beginning near the National Forest boundary with the community of Scotland there is a reach of the South Fork mapped as intermittent for approximately 0.6 river miles. However this reach has rarely gone dry and also supports a popular trout fishery. In 2007 the Forest Service and CDFG conducted a reintroduction of approximately 500 Santa Ana speckled dace from the lower mainstem of Lytle Creek to the Middle Fork just a few hundred meters upstream of the Scotland boundary. Surveys by the Forest Service confirmed the persistence of these fish into 2008 but no assessment of their migration from the introduction point was conducted. There is high quality habitat available from the forest boundary with Scotland upstream at least 2.6 river miles. There are no significant fish passage barriers known within this reach so the full 2.6 mile reach above Scotland is now considered Santa Ana Speckled dace habitat.
Cajon Creek. (tributary to Lytle Creek) Dace appear to be abundant in this drainage, predominantly congregated upstream and downstream of Interstate 15 (CDFG 1995). Their presence was also documented by surveys in 2005 (G. Abbas, pers. comm. 2008). There have been several recent fires in the area. Hazardous waste spills from trucks and trains using the transportation corridor threaten aquatic habitat in this watershed. The San Bernardino National Forest, Fish and Game, and BNSF Railroad have been moving fish into headwater tributaries to protect them from highway or railway spills.
City Creek. Dace were seen in September of 2003, following the Bridge fire. No dace were found following the devastating Old Fire (October of 2003) and subsequent flooding. Several surveys were conducted 2005, 2006, and 2007 and no dace were found. However, in 2008 a small population was found in the West Fork and reconfirmed in 2009.
East Fork City Creek. Dace were observed immediately after the Bridge Fire in 2003 (G. Abbas, pers. comm. 2008). Fewer dace were seen after the Old Fire in October 2003, and none after subsequent flooding in December 2008. No dace were seen in 2004, 2005, 2006 and 2007.
Mill Creek. Dace were found in the 1980s but not in 1990 (CDFG 1995). Speckled dace were thought to be extirpated from Mill Creek (CDFG 1995), but a few were observed in a small pool created by a man-made grade control structure in 2007 (G. Abbas, pers. comm. 2008). However, dace were not seen in 2008 and are assumed to be extinct from Mill Creek (G. Abbas, pers. comm. 2008).
Plunge Creek. Speckled dace were observed in 2001 (9 individuals) and 2005 (G. Abbas, pers. comm. 2008). Dace were collected in 2004 to protect them from potential flooding. They were returned to the stream after the threat of flooding passed. (Abbas pers. comm. 2008)
Strawberry Creek. A small population was found in 1992 by the U.S. Forest Service (C. Swift pers. comm. in CDFG 1995). Surveys did not observe any in 2005 or 2006 (G. Abbas, pers. comm. 2008). Several surveys following the 2003 Old fire and Christmas Flood did not find dace. They are presumed extinct from Strawberry Creek.
Silverado Canyon. Although dace were found in 1987, none were found in the same or nearby areas in 1990 (CDFG 1995) or 2005 (G. Abbas, pers. comm. 2008).
San Jacinto River. Dace were recorded in 15-30 km of stream but not since the mid-1980s (T. Haglund, in CDFG 1995). Large portions of the river and the lower portion of its tributaries are now dry in the summer. Surveys in 2005 did not find speckled dace in the mainstem or in the North and South Forks (G. Abbas, pers. comm. 2008).
Indian Creek. (Headwater tributary of San Jacinto River) In 2006, some Santa Ana speckled dace found in Indian Creek were relocated to the Riverside-Corona RCD for captive breeding after the Esperanza Fire (G. Abbas, pers. comm. 2008). Fish survived the fire and the population is recovering. The population has been able to sustain itself following the fire due to the lack of big flooding events.
Santiago Creek. (Santa Ana River) Surveys in 2005 did not find speckled dace within the mainstem or tributaries (Harding Canyon Creek, Silverado Creek; G. Abbas, pers. comm. 2008).

Description:

Description: Speckled dace are small cyprinids, usually measuring 8-11 cm SL (Moyle 2002). Although physically variable, they are characterized by a wide caudal peduncle, small scales (47-89 along lateral line), and pointed snout with a small subterminal mouth. Larvae have deep bodies, small eyes, overhanging snout and are characterized by 35-41 myomeres, and distinctive coloration (Feeeney and Swift 2008). As larvae, they have large distinctive spots located on the sides of the bottom portion of the caudal peduncle and a wedge-shaped patch of spots on top of the head. Larvae have functioning eyes, mouth and gas bladder by the time the notochord flexes at about 7-9 mm TL. A noticeable band of pigment running just below the lateral midline is visible at about 9 mm. The terminal mouth of larvae becomes subterminal at about 9.7 mm. The pectoral fins remain unpigmented until the later stages of larval development. Later stages also develop a distinctive spot on the base of the caudal fin. Scales appear when dace reach 13 mm FL (Jhingran 1948). Once fully developed, the dorsal fin usually has 8 rays and originates well behind the origin of the pelvic fins (Moyle 2002). The anal fin has 6-8 rays. Pharyngeal teeth (1,4-4,1 or 2,4-4,2) are significantly curved with a minor grinding surface. The maxilla usually has a small barbel at each end. The snout is connected to the upper lip (premaxilla) by a small bridge of skin (frenum). Most fish larger than 3 cm have distinctive dark speckles on the upper and sides of the body, a dark lateral band that extends to the snout, and a spot on the caudal peduncle. The rest of the body is dusky yellow to olive, with the belly being a paler color. Breeding adults of both sexes have fins tipped by orange or red, while males also have red snouts and lips, and tubercles on the head and pectoral fins.

Taxonomy

Family:

Cyprinidae

Genus:

Rhinichthys

Species:

osculus

Scientific Name:

Rhinichthys osculus subspecies

Taxonomic Relationships:

Taxonomic Relationships: The genus Rhinichthys is widely distributed and abundant in North America and has eight recognized species. However, most species are highly variable and may encompass complexes of unrecognized species or subspecies (Moyle 2002). Early taxonomists described different forms as separate species but later lumped them together when the flexible nature of the species was discovered. For example, Jordan and Evermann (1896) described 12 separate species which were later collapsed into a single species (Hubbs et al. 1974). However, subspecies, many of which were formerly recognized as full species, continue to be recognized on the basis of their location and isolation, provided good names exist for them. Although widely distributed, evidence continues to mount in support of the concept that speckled dace populations throughout the west have long independent evolutionary histories, with distinctive adaptations to local environments. Relationships among the various lineages still await being resolved with modern molecular and morphometric techniques. In Oregon, speckled dace collected from 5 river basins exhibited high levels of divergence (0.82) among locations, and high genetic diversity (0.2, nucleotide diversity) within basins (Pfrender et al. 2004). Similarly, Oakey et al. (2004) found that speckled dace collected throughout the western United States were significantly different between sub-basins, consistent with the idea that local populations are characterized by long isolation from other populations. Based on the findings of their phylogenetic studies, Pfrender et al. (2004) proposed that populations within different basins should be considered as different Evolutionarily Significant Units for the purposes of management.
The Santa Ana speckled dace is one form that is thought to merit subspecies or even species designation due to its distinctive morphology (Cornelius 1969, Hubbs et al. 1979) and genetics. Although the subspecies has not yet been formally described, preliminary electrophoretic analysis supports the conclusion that this form is distinctive (T.R. Haglund, University of California, Los Angeles, pers. comm. 1996, T. Metcalf, Calif. State Univ., San Bernardino, pers. comm. 2008). Initial mtDNA sequence analysis strongly suggests that Santa Ana speckled dace is genetically distinct from other speckled dace in California (Metcalf et al., unpubl). Studies also suggest that this form is more closely related to speckled dace in the Colorado River basin than dace in northern California, as a result of a split in clades approximately 3.6 mya (Oakey et al. 2004, Smith and Dowling 2008). Furthermore, speckled dace in the Los Angeles basin (Santa Ana and San Gabriel Rivers) were not found to be closely related to those in the Owens or Armagosa Rivers. Smith and Dowling (2008) indicate that populations of speckled dace in the Los Angeles basin have been isolated long enough (through the Pleistocene) to develop unique morphological characters. The long phylogenetic branch lengths associated with the speckled dace from the Los Angeles basin suggests that these fish have undergone rapid molecular evolution. Oakney et al. (2004) also determined that speckled dace from the Santa Ana and San Gabriel Rivers formed a monophyletic lineage.

Taxonomic Unit:

subspecies

Ratings

Major Dam Rating:

high

Major Dams Explanation:

Dams and reservoirs are found in all major drainages.

Agriculture Rating:

med

Agriculture Explanation:

Agricultural runoff is a source of pollution in some streams.

Grazing Rating:

N/A

Rural Rating:

N/A

Urbanization Rating:

high

Urbanization Explanation:

Urbanization and suburbanization has encroached on lower and middle stream reaches. Streams have been channelized and lined in all major drainages, preventing repopulation of streams that have been scoured by post-fire floods.

Instream Mining Rating:

Low

Instream Mining Explanation:

Mining activities can displace dace from preferred habitat (e.g., East Fork San Gabriel River).

Mining Rating :

low

Mining Explanation:

Rock quarry in Fish Canyon is encroaching on speckled dace habitat.

Estuarine Alteration Rating:

N/A

Transportation Rating:

High

Transportation Explanation:

Roads exist along most speckled dace streams, with effects ranging from siltation to toxic run-off and barriers to upstream movement.

Logging Rating:

low

Logging Explanation:

Some forest thinning in the headwaters (National Forest land).

Fire Rating:

high

Fire Explanation:

Fire frequency, duration and intensity increased in southern California in the last 20+ years, increasing the risk of debris torrents and landslides.

Recreation Rating:

med

Recreation Explanation:

Heavy recreational use may displace and stress fish and alter habitats.

Harvest Rating :

N/A

Hatcheries Rating:

N/A

Alien Species Rating:

high

Alien Species Explanation:

Bass introduced to reservoirs prey on speckled dace. Giant reed has decreased the habitat quality of many streams through encroachment.

Scores

Distribution Score:

Area Occupied Score:

Area Occupied Justification:

Distribution restricted to the headwaters of the Los Angeles, Santa Ana and San Gabriel Rivers.

Pop Size Score:

Pop Size Justification:

Most populations are small (50-100), with some being supplemented by a captive breeding program.

Intervention Dependence Score:

Intervention Dependence Justification:

Captive breeding program already used to sustain population in the Santa Ana River basin and intensive management of streams is needed to prevent extinction.

Tolerance Score:

Tolerance Justification:

Seems to need cooler water than most speckled dace. Water quality conditions now often exceed tolerances of speckled dace in general.

Genetic Risk Score:

Genetic Risk Justification:

Small isolated populations are vulnerable to genetic drift.

Climate Change Score :

Climate Change Justification:

Because most populations are in small streams in a dry region there is extreme range-wide vulnerability to climate change.

Threats Score :

Threats Justification:

Many factors with high degree of threat (Table 1).

Certainty:

Certainty Justification:

Information is largely from experts who work closely with the Santa Ana speckled dace.

Other Information

R5 Summary:

Forest Service - Pacific Southwest regional (R5) summary: Santa Ana speckled dace are native to Angeles (Big Tujunga Creek, Los Angeles River basin and upper San Gabriel River watershed) and San Bernardino (upper Santa Ana River watershed) National Forests. CNDDB records Santa Ana sucker from Santiago Creek on Cleveland National Forest but the status of this population is uncertain. See forest-level maps and R5 distribution spreadsheet for HUC12-specific range data for this species on R5 lands.

Threats:

Nature and Degree of Threats: Threats to the Sana Ana speckled dace and their habitat include 1) dams and diversions; 2) habitat degradation, especially factors associated with urbanization; 3) grazing; 4) agriculture; 5) mining; 6) recreation; 7) wildfire; and 8) alien species (Swift et al. 1993, CDFG 1995, Moyle 2002, Swift 2005; Table 1).
Dams and diversions. Virtually all Santa Ana speckled dace streams contain one or more dams and diversions, so flows are generally depleted and natural flow regimes altered. Cogswell dam and reservoir on the West San Gabriel River is a particular problem because it blocks movement upstream and downstream and captures large amounts of sediment, which smother habitat (and dace) when released from the dam.
Agriculture. Agriculture is not much of a problem in the basins any more because much of the agricultural land has been urbanized. However, runoff from remaining dairy and citrus operations is a source of pollution in some streams.
Habitat degradation. Most portions of the Los Angeles, Santa Ana and San Gabriel Rivers not in public lands are highly urbanized. Extensive river channelization and impoundment has occurred in the middle and lower reaches of all rivers for flood control. These changes result in the loss of ecological value by changing the streams from riparian corridors to canals. Urbanization also has caused degradation in the water quality of these rivers. The Los Angeles River (lowest reach) is identified as impaired for pH, ammonia, lead, coliform, trash, scum algae, total dissolved solids and turbidity.
(http://ceres.ca.gov/wetlands/geo_info/so_cal/los_angeles_river.html)
The State Water Resources Control Board lists the sections of the Santa Ana River as impaired by heavy metals, pathogens, bacteria, and nutrients (www.waterboards.ca.gov). They also list sections of the San Gabriel River as impaired by bacteria, pH, and heavy metals (lead, copper). The effects of urbanization on water quality are compounded by agricultural nonpoint sources of pollution that also increase nutrient and bacteria concentrations.

Threat Caption:

Table 1. Major anthropogenic factors limiting, or potentially limiting viability of Santa Ana speckled dace populations in California, where a factor rated high is a major limiting factor, a factor rated intermediate is a factor that has the potential to be a major limiting factor but has had only a moderate effect so far on population viability, and a factor rated low has a low or unknown effect on population viability. Certainty of these judgments is moderate. See methods section for explanation of rating procedures.

Wildfire. Recent wildfires, and subsequent debris torrents, in southern California destroyed speckled dace habitat in 2004, 2006 and 2008 (Metcalf et al. unpubl.; G. Abbas, pers. comm. 2008). Predictions are that fire frequency, intensity and duration will increase over the next century due to increasing temperatures and changes in precipitation patterns (Fried et al. 2004, Lenihan et al. 2008, Westerling and Bryant 2008). Catastrophic fires can accelerate the delivery of fine sediment to streams thereby degrading the permeability of stream substrates. Fires also remove riparian vegetation along streams, increasing the amount of solar radiation reaching streams so that water temperatures are further increased. Streams scoured during large floods after large fires cannot be reoccupied by natural upstream movement due to barriers that now exist in the valleys where the streams have been channelized and road crossings created. Flood control and water spreading dams also create barriers to upstream movement and repopulation after fires/floods.
Alien species invasions. Alien fish species are common in the reservoirs and highly altered stream reaches of the Los Angeles, Santa Ana and San Gabriel River systems. Brown (Salmo trutta) and rainbow (Oncorhynchus mykiss) trout, and red shiners can directly compete with or prey on speckled dace (CDFG 1995, http://www.dfg.ca.gov/news/stocking/). Bass (Micropterus spp.) may also prey on native cyprinids. Alien aquatic vegetation can also alter the quality of speckled dace habitat. The presence of Arundo donax has decreased the quality of aquatic habitat in some sections of the the Santa Ana River so that it is no longer suitable to native fishes, including speckled dace (Bell 1997). Stream reaches where A. donax dominates the riparian vegetation are characterized by increases in pH and ammonia, and decreases in dissolved oxygen. Although efforts are underway to remove A. donax from many streams in southern California (http://www.smslrwma.org/invasives/Arundo/ADRegionalMap.html), it is difficult to remove and is present in all watersheds where the Santa Ana speckled dace is found.
Recreation. Heavy recreational use in streams, including camping, dambuilding for waterplay, swimming, and off-road vehicle use, may displace fish from optimal habitats and further stress fish in suboptimal habitat. Swift (2003) expressed concern over the impacts of recreational use on fish in the Santa Ana River. There is also concern over recreation impacts to the streams in the San Gabriel River, and Lytle Creek Mill Creeks.
Mining. Speckled dace in Cattle Creek (tributary to the East Fork San Gabriel River) may be adversely influenced by mining operations (CDFG 1995). A rock quarry in Fish Canyon is encroaching on speckled dace habitat. However, the mining company is in the process of restoring fish habitat. Suction dredging in San Gabriel and Cajon Wash and Lytle Creek is a concern for dace and other aquatic species.

Climate Effects:

Effects of Climate Change: The most noticeable and widespread impacts of climate change on aquatic habitats in southern California will be the continued increase in water temperatures, and changes to the frequency and timing of drought and flooding events. Water temperatures will increase by approximately 0.7?C by 2099, based on conversion factors developed by Eaton and Scheller (1996). Although this increase is seemingly small, it may be significant to fish already exposed to summer temperatures above 20?C. For example, elevated temperatures may stress fish so that autoimmune function is repressed, making them more susceptible to disease. White spot disease was already detected infecting speckled dace collected from the East Fork San Gabriel River (Warburton et al. 2001).
Elevated air temperatures associated with climate change will change the periodicity and magnitude of peak and base flows in streams. Predictions are that stream flow will increase in the winter and early spring and decrease in the fall and summer (Knox and Scheuring 1991, Field et al. 1999, Stewart et al. 2004, Stewart et al. 2005, CDWR 2006, Knowles et al. 2006). Hydrographs that mimic natural flow regimes more closely may actually benefit speckled dace populations as their densities can reestablish faster than those of alien fish species (Gido et al. 1997, Valdez et al. 2001, Propst and Gido 2004). However, decreases in summer base flows can further isolate speckled dace populations. Dace in Cajon Creek, North Fork Lytle Creek, West Fork City Creek, Silverado Canyon and the San Jacinto River become isolated by the presence of dry stream reaches during most of the year, preventing repopulation and genetic mixing between stocks (CDFG 1995). Lastly, fire frequency, intensity and duration will almost certainly increase over the next century due to increasing temperatures and changes in precipitation patterns (Fried et al. 2004, Lenihan et al. 2008, Westerling and Bryant 2008), further threatening the stability and quality of speckled dace habitat.

Metrics Caption:

Table 2. Metrics for determining the status of Santa Ana speckled dace, where 1 is a major negative factor contributing to status, 5 is factor with no or positive effects on status, and 2-4 are intermediate values. See methods section for explanation of scoring protocol.

Management Recommendation:

Management Recommendations: Endangered species listing of this distinctive dace at the federal level has been denied for esoteric reasons of taxonomy, so a high priority for the Santa Ana speckled dace is to have it formally recognized as a distinct taxon. Existing morphological and genetic evidence indicates that it clearly qualifies as a Distinct Population Segment or Evolutionarily Significant Unit, designations that have been frequently used to list endangered salmon and steelhead populations. The State of California should use the existing evidence to list it as a threatened or endangered species. Beyond that, funding should be found to complete genetic and morphological studies quickly and to get those studies published in the peer-reviewed literature.
In the meantime, it is important to keep the Santa Ana speckled dace from plunging to extinction. This will take a multi-pronged recovery process that includes the following
Give special protection to all streams from which Santa Ana speckled dace have been observed in the past 20 years, by declaring them native fish management areas (Moyle and Yoshiyama 1994) and halting harmful activities where possible.
Establish an annual monitoring program for streams that are known to contain dace as well as for streams that have contained dace in the last 20 years. Wherever possible, generate a population estimate so that trends can be determined.
Develop a Santa Ana speckled dace recovery plan to prioritize stream restoration and other actions needed to sustain dace populations. Begin work on recommended actions as soon as possible. Some of the actions that are possible are listed below.

Stream restoration. Stream channelization and impoundment, and pollution have degraded aquatic habitats in the middle and lower reaches of all major drainages. Efforts (e.g. Los Angeles River Revitalization Project) should be made to reestablish the ecological function of these streams. Associated actions may include daylighting (unearthing and removing river channels from underground canals), riparian planting and managing flows to mimic natural flow regimes. Water treatment should be improved for any water discharged into streams. The establishment of wetlands along the streams could help meet both of these goals by removing toxins and increasing the biodiversity of riparian corridors.
Captive breeding program. Dace should be taken from multiple populations and, following a genetic management plan, used to enhance/establish a captive breeding program to prevent extinction and to provide fish for reintroduction into restored habitats. Potential reintroduction areas should be carefully considered for their risk to fire, disease and other threats.
Reintroduction into extirpated populations. Streams where dace have been lost due to flooding and other causes should be considered for repopulation from captively reared fish or fish salvaged or captured from adjacent healthy populations. Many of the lower sections of streams dry out in the summer leaving dace isolated in pools. These fish can be and have been moved upstream to repopulate areas where they have been blown out or extirpated due to other causes.
Expand the range into suitable habitat with barriers. Some situations exist where dace populations have never been present due to barriers preventing upstream movement. Suitable habitat exists above some of these barriers that would support populations of dace and make it less likely that the species could be lost during floods, hazardous material spills, and severe droughts. Expanding the range of the species in historically and currently occupied drainages would be desirable (e.g. South Fork of Lytle Creek, North Fork of the San Gabriel River, Cajon Wash, etc.).
Manage wildfire. Measures such as brush thinning and prescribed burning should be used and monitored to determine their efficacy in minimizing impacts form wildfire in National Forests (Keeley 2002, Keeley et al. 2004). Prescribed burning in smaller blocks over time can reduce the chances of burning entire watersheds and the intensity of burns as well as reduce the potential for flooding.
Reduce effects of alien species. Fish planted into reservoirs should be prevented from moving into streams, perhaps with the use of screens or gates. Bass, brown trout and red shiners should be eradicated from streams where they are established, where possible. Efforts should continue to remove giant reed, Arundo donax, throughout the range of the Santa Ana speckled dace.
Reduce effects of agricultural and urban areas. Settling ponds, wetlands and other additional wastewater treatments should be used where point sources of pollution are identified. Living riparian buffers (riparian vegetation, wetlands) should be designated along stream channels in order to mitigate the effects of nonpoint source pollution. The use of chemicals that are nontoxic to aquatic organisms should be advocated and implemented.
Limit recreational use. Recreational use of speckled dace streams should be limited until dace populations recover. Area closures should be implemented if necessary to protect habitat integrity. However, limitations should be associated with educational programs and use of volunteers in stream restoration efforts.
Reduce effects of grazing. If grazing is deemed necessary in speckled dace watersheds, grazing allotments should be monitored before, during and after use. Permittees should be held responsible for preventing extended use of stream areas (through the establishment of minimum vegetative cover, vegetation height etc). Alternate water sources should be provided and streams fenced where streams are being heavily impacted by livestock.
Eliminate mining. Mining of all sorts should be eliminated from watersheds occupied by Santa Ana speckled dace if the mining has the potential to alter the streams in any way.
Plan for climate change. Climate change will exacerbate all existing threats to the Santa Ana speckled dace and will be interacting with all implemented actions. To err on the side of caution, managers should manage for the threats and conditions that they may encounter in the next decades rather than those that they are experiencing now.

Species Status

Lifestyle:

KatzMoyle Status:

1-Endangered

CA Status:

SC1

FS Sensitive Status:

Status Determination:

Status Determination. Score = 1.6 The Santa Ana speckled dace is clearly in danger of extinction in the next 50 years (Table 2). Listing of the Santa Ana speckled dace under the federal Endangered Species Act, however, was denied after being petitioned in 1994, because it had not been described as a separate taxon from other speckled dace in the southwest (61FR4722). Recent genetic and phylogenetic studies suggest this form to be distinct from other speckled dace in California (Oakey et al. 2004; Smith and Dowling 2008; Metcalf, unpubl.) so it clearly could be listed as a Distinct Population Segment or an Evolutionarily Significant Unit. Its extinction is likely unless special protection is given (Swift et al. 1993, Moyle et al. 1995, Moyle 2002). The range of this form has been and continues to be dramatically diminished due to urbanization in the Los Angeles region. It is considered by the American Fisheries Society as a threatened species (Jelks et al. 2008). Santa Ana speckled dace are a Region 5 U.S. Forest Service Sensitive Species in the four southern California National Forests (Los Padres, Angeles, San Bernardino, Cleveland). The California Natural Diversity Database ranks speckled dace as secure at the global scale (G5) but the Santa Ana subspecies as imperiled (T1S1; www.natureserve.org).

Spatial Data

Associated Files:

Species ID	CRO07
All Files	Download
Extant Range - Expert Opinion	KMZ SHP
Observed	KMZ SHP
Historic Range - Expert Opinion	KMZ SHP
Translocated - Expert Opinion
Translocated - Observed