Draft Recovery Plan 

for the Santa Ana Sucker 

(Catostomus santaanae)

U.S. Fish & Wildlife Service

Photo courtesy of USFWS/Christine Medak and Kai Palenscar 

Draft Recovery Plan for Santa Ana Sucker

(Catostomus santaanae)

Region 8

U.S. Fish and Wildlife Service

Sacramento, California

Approved: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Regional Director, Pacific Southwest Region, Region 8, 

U.S. Fish and Wildlife Service

Date: XXXXXXXXXXXXXXXXX

i

Disclaimer

Recovery plans delineate such reasonable actions as may be necessary, based upon the best 

scientific and commercial data available, for the conservation and survival of listed species. 

Plans are published by the U.S. Fish and Wildlife Service (Service), sometimes prepared with the 

assistance of recovery teams, contractors, State agencies, and others. Recovery plans do not 

necessarily represent the view, official positions or approval of any individuals or agencies 

involved in the plan formulation, other than the Service. They represent the official position of 

the Service only after they have been signed by the Regional Director. Recovery plans are 

guidance and planning documents only; identification of an action to be implemented by any 

public or private party does not create a legal obligation beyond existing legal requirements. 

Nothing in this plan should be construed as a commitment or requirement that any Federal 

agency obligate or pay funds in any one fiscal year in excess of appropriations made by Congress 

for that fiscal year in contravention of the Anti-Deficiency Act, 31 U.S.C. 1341, or any other law 

or regulation. Approved recovery plans are subject to modification as dictated by new finding, 

changes in species status, and the completion of recovery actions. 

Literature Citation Should Read as Follows:

U.S. Fish and Wildlife Service. 2014. Draft Recovery Plan for the Santa Ana sucker. U.S. Fish 

and Wildlife Service, Pacific Southwest Region, Sacramento, California. v + 61 pp.

An electronic copy of this draft recovery plan will be made available at:

http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=E07W

Additional copies may be obtained from: 

Carlsbad Fish and Wildlife Office

2177 Salk Avenue 

Carlsbad, CA 92008

Office phone: 760–431–9440
ii

Acknowledgements

The recovery planning process has benefited from the advice and assistance of many individuals, 

agencies, and organizations over the past several years. This Draft Recovery Plan for the Santa 

Ana sucker was compiled by Christine Medak, Kai Palenscar, Jesse Bennett, Tony McKinney, 

and Bradd Bridges at the Carlsbad Fish and Wildlife Office (CFWO). Former CFWO staff that 

also contributed to preparation and drafts of this Recovery Plan include: Carey Galst, Heather 

Dyer, Jason Stayer, and Ayoola Folarin. 

We also thank our partners who have played an active role in Santa Ana sucker conservation. 

Numerous agencies provided information through surveys and research, and helped to restore 

habitat and implement recovery actions. Their support over the years has contributed to a better 

understanding of this species, which has subsequently helped to develop a draft Recovery Plan. 

We appreciate these efforts and look forward to continued cooperation with our external partners 

as we continue to refine methodologies and implement actions that support recovery of the Santa 

Ana sucker. 
iii

EXECUTIVE SUMMARY

Current Species Status

The Santa Ana sucker (Catostomus santaanae) is one of only a few native fishes 

currently extant in southern California. It is listed as a threatened species under the Endangered 

Species Act of 1973, as amended (Act) (USFWS 2000); its range is restricted to the Los Angeles, 

San Gabriel, and Sana Ana River Basins. Critical habitat was designated for this species on 

December 14, 2010 (USFWS 2010). 

Threats

The primary threat to Santa Ana sucker is ongoing, rangewide hydrological modifications 

which lead to degradation and loss of habitat. Additionally, isolation by impassable barriers or 

unsuitable habitat limits gene flow within the watershed, thus increasing the vulnerability of 

small occurrences to a range of stochastic (random) factors. 

Recovery Strategy

Due to the rangewide, large-scale hydrological modifications, the most pressing threat to 

the species is the lack of suitable habitat necessary to increase population resiliency (ensure a 

large enough population to withstand stochastic events) and redundancy (a sufficient number of 

populations to ensure the species can withstand catastrophic events). Therefore, the highest 

priority for the recovery of Santa Ana sucker is implementation of management actions to restore 

and improve habitat conditions throughout the current range of the species. These actions 

include initiating studies that will lead to a thorough understanding of the implications of past 

and current hydrological modifications throughout the range of the species; controlling nonnative 

species; minimizing recreation pressures; improving water quality; employing adaptive 

management techniques to address the uncertainties of global climate change; and involving 

stakeholders and partners in all applicable conservation and management actions. 

Given the substantial reduction in the range of the species, the currently occupied areas, 

particularly in the Santa Ana River watershed, will likely not be sufficient to provide the 

resiliency and redundancy necessary for recovery. Additionally, representation (maintaining the 

breadth of the genetic makeup to conserve the adaptive ability of the species) is a concern due to 

the small population size within each watershed. To reduce the risk of extirpation, while 

determining appropriate actions to manage threats within the current range, areas not currently 

accessible to the fish should be assessed for potential reintroduction. Increasing the extent of 

occupied habitat will improve the representation, resiliency, and redundancy of Santa Ana 

sucker, thereby improving the status of the species.

The long term viability of the Santa Ana sucker will require maintenance of genetic 

variability through protection and preservation of historical population and habitat distributions. 

Healthy viable populations within each of three defined Recovery Units (RU): Santa Ana River 

RU; Los Angeles River RU; San Gabriel River RU will be necessary to recover the species.

Recovery Goal and Objectives

The goal of this recovery plan is to control or reduce threats to Santa Ana sucker to the 

extent that it no longer requires protections afforded by the Act and therefore, warrants delisting. 
iv

Based on the recovery strategy and current threats to the species the following objectives are 

identified. Work with landowners and other stakeholders to:

1. Develop and implement a rangewide monitoring protocol to accurately and consistently 

document populations, occupied habitat, and threats.

2. Conduct research projects specifically designed to inform management actions and 

recovery.

3. Increase the abundance and develop a more even distribution of Santa Ana sucker within 

its current range by reducing threats to the species and its habitat.

4. Expand the range of the Santa Ana sucker by restoring habitat (if needed), and 

reestablishing occurrences within its historical range.

Delisting Criteria

Factor A: Present or Threatened Destruction, Modification, or Curtailment of Habitat or 

Range

A.1 Adequate amounts of suitable habitat are restored, protected, and managed within each 

recovery unit to support viable populations (see Recovery Criteria E.3) of all life stages of Santa 

Ana sucker and provide resiliency and redundancy to protect against catastrophic events 

throughout the current range of the species. 

Factor C: Predation

C.1 Management is implemented to reduce competition and predation by nonnative species to

levels determined to be necessary for the maintenance of viable Santa Ana sucker populations.

Factor E: Other natural or manmade factors affecting its continued existence 

E.1 The current range of the species is expanded through modification or removal of existing 

barriers, restoration of suitable habitat, and/or reintroduction of the species to areas within its 

historical range in a configuration that ensures reasonable certainty the remaining genetic 

makeup of the species has been preserved and can withstand catastrophic events in the 

watershed.

E.2. Occupied areas of each RU are genetically connected, through natural processes or 

management, to ensure population viability and genetic exchange.

E.3 Stable or increasing population averaged over 15 years within the Santa Ana River, Los 

Angeles River, and San Gabriel River Recovery Units, as defined below in the Recovery 

Program. 

E.4 A long-term monitoring and management plan is in place to evaluate the effectiveness of 

management actions to address ongoing threats and to identify new threats which may require 

implementation of adaptive management actions. 

Estimated Date and Cost of Recovery:

Date: 2040

Cost: $4,205,000 + TBD
v

Table of Contents

Disclaimer........................................................................................................................................ i

Acknowledgements......................................................................................................................... ii

EXECUTIVE SUMMARY.................................................................................................................... iii

LIST OF FIGURES ............................................................................................................................ vii

LIST OF TABLES ............................................................................................................................. vii

I. BACKGROUND ........................................................................................................................I-1

A. Species Description and Taxonomy...............................................................................I-1

B. Population Trends and Distribution...............................................................................I-2

1. Santa Ana River Watershed........................................................................................I-5

2. Los Angeles River Watershed ....................................................................................I-5

3. San Gabriel River Watershed .....................................................................................I-6

C. Life History and Ecology...............................................................................................I-7

D. Habitat Characteristics/Ecosystem.................................................................................I-7

E. Critical Habitat...............................................................................................................I-8

F. Reasons for Listing and Current Threats.......................................................................I-9

Factor A: Present or Threatened Destruction, Modification, or Curtailment of Habitat or 

Range.................................................................................................................I-10

Factor B: Overutilization for Commercial, Recreational, Scientific, or Educational 

Purposes............................................................................................................I-13

Factor C: Disease or Predation .........................................................................................I-14

Factor D: Inadequacy of Existing Regulatory Mechanisms ..............................................I-14

Factor E: Other Natural or Manmade Factors Affecting Its Continued Existence ...........I-15

G. Conservation Efforts....................................................................................................I-16

H. Summary......................................................................................................................I-17

II. RECOVERY PROGRAM ...........................................................................................................II-1

A. Recovery Strategy.........................................................................................................II-1

Recovery Units.................................................................................................................... II-2

B. Recovery Goal ..............................................................................................................II-8

C. Recovery Objectives.....................................................................................................II-8

D. Recovery Criteria ..........................................................................................................II-8

Delisting Criteria................................................................................................................ II-9

III. RECOVERY ACTION NARRATIVE AND IMPLEMENTATION SCHEDULE................................... III-1

A. Recovery Action Narrative ......................................................................................... III-2
vi

B. Implementation Schedule.......................................................................................... III-12

IV. LITERATURE CITED .............................................................................................................IV-1
vii

LIST OF FIGURES

Figure 1 Locator map ................................................................................................................I-3

Figure 2 Santa Ana River Watershed Recovery Unit: La Cadena Reach ...............................II-4

Figure 3 Santa Ana River Watershed Recovery Unit: Imperial and Prado Reaches ..............II-5

Figure 4 Los Angeles River Watershed Recovery Unit...........................................................II-6

Figure 5 San Gabriel River Watershed Recovery Unit ............................................................II-7

LIST OF TABLES

Table 1 Studies and activities funded and carried out for the conservation of the Santa Ana 

sucker........................................................................................................................I-18

Table 2 Implementation Schedule – Actions to be completed across all recovery units (Santa 

Ana River, Los Angeles River, and San Gabriel River Recovery Units) ............. III-14

Table 3 Implementation Schedule – Santa Ana River Recovery Unit................................ III-15

Table 4 Implementation Schedule – Los Angeles River Recovery Unit ........................... III-18

Table 5 Implementation Schedule – San Gabriel River Recovery Unit ............................ III-20
viii
I-1

I. BACKGROUND

We, the U.S. Fish and Wildlife Service (Service), listed the Santa Ana sucker 

(Catostomus santaanae) as threatened in southern California, in the Los Angeles, San Gabriel, 

and Sana Ana River Basins on April 12, 2000 (USFWS 2000), under the Endangered Species 

Act of 1973 (Act), as amended. Critical habitat was designated for this species on December 14, 

2010 (USFWS 2010). A threats assessment and review of the biological status was conducted in 

a 5-year status review for the species in 2011 (USFWS 2011). Santa Ana sucker is assigned a 

Recovery Priority Number of 5C, which indicates the species faces a high degree of threat, has a 

low potential for recovery, and has taxonomic status as a species (USFWS 1983a; 1983b). The 

“C” indicates conflict with construction or other development projects or other forms of 

economic activity. Additionally, a recovery outline for Santa Ana sucker was approved on 

March 30, 2012 (USFWS 2012).

Santa Ana suckers are one of only a few native fishes currently extant in southern 

California and their distribution has been reduced in the three watersheds where they occur. The 

primary threat to Santa Ana sucker is habitat loss, degradation, and modification through 

hydrological modifications rangewide. Additionally, isolation by impassable barriers or 

unsuitable habitat limits gene flow within and between watersheds, thus increasing the 

vulnerability of small occurrences to a range of environmental and genetic stochastic factors. 

Recovery plans focus on restoring the ecosystems on which a species is dependent or 

reducing threats to the species. Recovery plans constitute an important Service document that 

serves as a logical path to recovery of the species based on what we know about the species’ 

biology and life history, and threats to the species. Recovery plans help to provide guidance to 

the Service, States, and other partners on methods of minimizing threats to listed species and 

measurable objectives against which to measure progress towards recovery. Recovery plans are 

advisory documents, not regulatory documents, and cannot substitute for the determinations and 

promulgation of regulations required under section 4(a)(1) of the Act. A decision to revise the 

status of, or remove a species from the Federal List of Endangered and Threatened Wildlife (50 

CFR 17.11) is ultimately based on an analysis of the best scientific and commercial data 

available, regardless of whether that information differs from the recovery plan.

The following discussion summarizes characteristics of Santa Ana sucker biology, 

demography and distribution, population status, and threats that are relevant to recovery. 

Additional information is available in the critical habitat rule, 5-year review, and recovery 

outline for the species (USFWS 2010; USFWS 2011; USFWS 2012), and associated literature.

A. Species Description and Taxonomy

Santa Ana sucker is a small, short-lived member of the sucker family of fishes 

(Catostomidae), named so primarily because of the downward orientation and anatomy of their 

mouth parts, which allow them to suck up algae, small invertebrates, and other organic matter 

with their fleshy, protrusible (extendable) lips (Moyle 2002, p. 179). Santa Ana sucker was 

described in 1908 by Snyder as Pantosteus santa-anae from the Santa Ana River near Riverside, 

California (Snyder 1908, p. 33). Smith (1966, pp. 53–58) amended the specific name to 
I-2

eliminate the hyphen and relegated Pantosteus to a subgenus of Catostomus, which represented a 

new combination. Recent work has been conducted to investigate the phylogenetic relationships 

between suckers in western North America (Unmack et al. 2014), but there is still some 

uncertainty where Catostomus santaanae would be placed. Currently, the taxonomic 

classification of Santa Ana sucker is Catostomus santaanae and has not changed since it was 

listed.

Santa Ana suckers are generally less than 6.3 inches (in) (16 centimeters (cm)) in length; 

however, they have been collected at lengths up to 8 in (20.3 cm) (RCRCD 2010, p. 3). Males 

and females appear to grow at an equivalent rate (Greenfield et al. 1970, p. 174; Moyle 2002, p. 

183). Their jaws have cartilaginous scraping edges inside the lips. Their color is silvery-white

on the belly and dark gray on the sides and back, with irregular dorsal blotches on the sides and 

faint patterns of pigmentation arranged in lateral stripes. Membranes connecting the rays of the 

caudal (tail) fin are pigmented, but the anal and pelvic fins usually lack pigmentation (Moyle 

2002, p. 182). 

Spawning tubercles (raised growths on sexually mature fish), particularly at the 

beginning of the breeding season, are present on most parts of the body of breeding males and 

are heaviest on the anal fin, caudal fin, and lower half of the caudal peduncle (narrow region of 

body immediately in front of the caudal fin). Female suckers grow tubercles on the caudal fin 

and caudal peduncle (Moyle 2002, pp. 182–183). 

B. Population Trends and Distribution

The Santa Ana sucker’s historical range includes the rivers and larger streams in southern

California emanating from the San Gabriel and San Bernardino Mountains in Ventura, Los

Angeles, Orange, Riverside, and San Bernardino Counties, including the mainstems and

tributaries from near the Pacific Ocean to the uplands of the Santa Ana River, Los Angeles 

River, and San Gabriel River watersheds (USFWS 2000, p. 19686) (Figure 1). Information 

about the occurrence of the Santa Ana sucker in many tributaries within its historical range is 

incomplete; however, it is likely that the species’ historical distribution within the watersheds 

varied from year to year depending on habitat suitability and access (for example, physical 

barriers or water availability) to these different areas. Thus, the distribution of the species 

expanded and contracted with changes in local conditions. Continuity between the main river 

channel and its tributaries allowed the species to vacate and recolonize areas in response to 

habitat suitability. Because historical data are not available to determine the upper limit of the 

species within each tributary, we consider the historical range to extend throughout the 

watersheds where the in-stream gradient does not exceed 7 degrees. 
I-3 

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I-4

The Santa Ana sucker is also found in the Santa Clara River (Santa Clara River 

watershed). However, we determined at the time of listing, because of its presumed introduced 

status, not to include the Santa Clara River population in the listed entity of Santa Ana sucker 

(USFWS 2000, p. 19687). The United States Geological Survey (USGS) is currently conducting 

an assessment of genetic distinctiveness for all occupied streams, including the Santa Clara 

River. However, we currently have no new information that clarifies the status of this species as 

native or nonnative to this river. Because they are not listed, the Santa Ana suckers in the Santa 

Clara River are outside the scope of this recovery plan. However, some research has been done 

on Santa Ana suckers in the Santa Clara River that is relevant to the species as a whole. Further, 

obtaining additional information on the status of these Santa Ana suckers may help inform 

recovery of the listed entity. 

The listing rule states that approximately 80 percent of the Santa Ana sucker’s historical 

range has been lost in the Los Angeles River watershed, 75 percent in the San Gabriel River 

watershed, and 70 percent in the Santa Ana River watershed (USFWS 2000, pp. 19687–19688). 

The upper limit of Santa Ana suckers in the Santa Ana, Los Angeles, and San Gabriel (West 

fork) Rivers is generally restricted by artificial barriers preventing their movement, such as 

artificial dams or grade control structures. Thus, the current range of the species in these 

watersheds is restricted or curtailed compared to what it was historically. If these artificial 

barriers did not exist, Santa Ana suckers would likely be able to, at least under certain streamflow conditions, move into other portions (or reaches) of the rivers in which they occur, as well 

as associated tributaries, up to some upper limit. However, in streams or rivers that are not 

restricted by artificial barriers, such as the San Gabriel River (North and East forks), the upper 

limit of where fish are likely to occur is determined by the in-stream gradient and the inability to 

physically swim upstream when a certain gradient is exceeded. Results from a GIS analysis 

suggest that Santa Ana suckers do not occur above areas where the in-stream slope exceeds 7 

degrees (USFWS 2009, p. 65065). Though the geographic range of the species has not changed 

since the time of listing, the spatial distribution of Santa Ana sucker has changed temporally, 

especially in the Santa Ana River watershed. 

Comprehensive surveys and population estimates for the historically or currently 

occupied geographic area of Santa Ana sucker are lacking. Historical records are too scarce to 

generate population estimates and while recent surveys are more numerous (for example, Drake 

1988, p. 52; Baskin et al. 2005, p. 1; Swift 2009, p. 3; Ecorp Consulting 2010b, p. 9; Saiki 2000, 

pp. 11–12; Chambers Group 2004, p. 3; Ecorp Consulting 2007, p. 9), a lack of consistent survey 

methodology between watersheds limits the ability to make meaningful comparisons of survey 

results over time or between different locations. The abundance of Santa Ana suckers has been

reduced in all three watersheds, because of the decrease in available habitat relative to the 

historical range of the species (Moyle and Yoshiyama 1992, p. 204). A brief discussion of the 

current range of the Santa Ana sucker in the Santa Ana River, Los Angeles River, and San

Gabriel River watersheds is included below.
I-5

1. Santa Ana River Watershed

Santa Ana sucker was historically documented throughout the upper and lower portions

of the Santa Ana River watershed including the mainstem from near the current location of 

Seven Oaks Dam to approximately 14 miles (mi) (22.5 kilometers (km)) below Prado Dam and 

multiple tributaries including City Creek, Warm Creek, Lytle Creek, Rialto Channel, Evans Lake 

drain, Tequesquite Arroyo, Sunnyslope Creek, Anza Park drain, and Chino Creek. 

In contrast to the species’ range in the Los Angeles and San Gabriel Rivers, where the 

extant populations are in the upper portions of the watershed, the species is confined to the 

lowlands of the Santa Ana River watershed. Barriers to migration restrict the range of the Santa 

Ana sucker to approximately 34 mi (55 km) from South La Cadena Drive to near California State 

Route 90. The extent of habitat suitable for spawning in the mainstem varies from year to year 

but ranged from approximately 2.6 to 6.0 mi (4.2 to 9.6 km) above Prado Dam between 2006 and 

2010 (USFWS 2011, p. 13). Substrate within the remainder of the mainstem above Prado Dam 

consists of greater than 90 percent silt and sand. We have no information to indicate that 

spawning is occurring below Prado Dam. The species is also known to occupy tributaries within 

this range, including Rialto Channel, Tequesquite Arroyo, Sunnyslope Creek, and Anza Park 

drain. Cumulatively, within the current range, these tributaries contain approximately 1.25 mi

(2.0 km) of suitable habitat for the species, with the remainder channelized for flood control. 

Rialto Channel is the only tributary where the habitat is consistently good quality for both 

foraging and spawning (0.30 mi, 0.48 km).

Yearly monitoring has occurred since 2001 in the Santa Ana River (near the junction of 

the Santa Ana River with California Highway 60 and upstream to Riverside Avenue) (SMEA 

2009, p. 1). Over this 10-year survey period, results indicate a decline in the annual average 

estimate of Santa Ana suckers (SMEA 2009, p. 2; SMEA 2010, pp. 2–3). In addition, regularly 

there have been low numbers of Santa Ana suckers at locations that historically had the highest 

abundances (SMEA 2010, pp. 1–2). Despite numerous survey efforts (for example, Haglund and 

Baskin 2004; RCRCD 2005, 2010; Baskin and Haglund 2008; Entrix, Inc. 2005; Ecorp 2009; 

Mills 2012), only six Santa Ana suckers have been captured below Prado Dam since 2001. 

2. Los Angeles River Watershed

Santa Ana sucker was historically documented throughout the upper and lower areas of 

the Los Angeles River watershed including the mainstem Los Angeles River near Universal City 

and Los Feliz Boulevard and the tributaries Big Tujunga Creek and Arroyo Seco Creek. 

However, the species has been extirpated throughout most of this watershed. Between 1938 and 

1960, 51 mi (82 km) of the Los Angeles River and numerous tributaries within the lower 

watershed were channelized and cement lined (Gumprecht 2001). Santa Ana sucker within this 

area was extirpated.

The species is currently confined to approximately 13 mi (21 km) of Big Tujunga Creek, 

in the upper portions of the Los Angeles River watershed between Hansen and Big Tujunga 

Dams, and to approximately 2.2 mi (3.5 km) of Haines Creek (a tributary to Big Tujunga Creek)

that is consistently occupied. Within the current range, there are other tributaries (for example, 
I-6

Little Tujunga Creek) that may be periodically occupied depending on availability of water in the 

creek, as well as habitat conditions. 

Habitat assessments conducted throughout Big Tujunga Creek indicate that the habitat 

suitability is variable throughout the system, but does contain areas of contiguous good and 

excellent habitat that are suitable for all life stages (Haglund and Baskin 2009). The density of 

Santa Ana suckers in Big Tujunga Creek is often low, likely due to the variability in habitat 

suitability (Ecorp Consulting 2010a, p. 5; Haglund and Baskin 2010, pp. 5–6). Some of this 

variability in habitat suitability may also be due to the periodic isolation of upper and lower 

reaches from a lack of perennial flow during dry summer months (Haglund and Baskin 2010, pp. 

1–2).

3. San Gabriel River Watershed

Santa Ana sucker was historically documented throughout the upper and lower portions 

of the San Gabriel River watershed including the mainstem San Gabriel River near Fish Canyon, 

Fish and Fern Canyon, Rio Hondo, San Jose Creek, West Fork, Bear Creek, North Fork, East 

Fork, Cattle Canyon Creek, and San Dimas Wash. By the late 1960s, the species was no longer 

found in the lower portions of the watershed (Miller 1968). The lower San Gabriel River was 

channelized for flood control purposes and does not provide suitable habitat for Santa Ana 

sucker. 

The species is now confined to approximately 26 mi (42 km) in the upper portions of the 

San Gabriel River watershed. It occurs above San Gabriel Dam in the West Fork (east of 

Cogswell Dam), Bear Creek, North Fork, East Fork, and Cattle Canyon Creek. Below San 

Gabriel Dam it occurs in approximately 1.5 mi (2.4 km) of San Dimas Wash, a tributary isolated 

from the San Gabriel River by approximately 10 mi (16 km) of cement lined channels and 

underground culverts. Distribution of Santa Ana sucker in West Fork and Cattle Canyon has 

decreased by several kilometers, compared to 1975 (O’Brien et al. 2011, p. 7). In addition, 

suckers were not observed in Big Mermaids Canyon, though they had been seen in 1991 surveys 

(Hagland and Baskin 1992).

Santa Ana suckers are more abundant and in better condition (length-weight relationship) 

in the San Gabriel River, compared to those in the Santa Ana River (Saiki et al. 2007, p. 98). 

The higher body condition may be attributed to more-suitable habitat characters such as 

intermediate water velocities, and commonality of pools and riffles with coarser bottom 

substrates, all of which may contribute to a better functioning system and more suitable habitat 

for Santa Ana suckers (Saiki et al. 2007, pp. 99–100). In the San Gabriel River, there are some 

distinct differences between the three forks of the river (north, west, and east), which seem to 

correlate with both fish abundance and life-stage occupancy (Tennant 2006, pp. 4–5, 9). The 

east fork, with faster flows and more abundant riffles supported more juveniles, where the west 

fork with deeper pools supported more of the adults (Tennant 2006, pp. 5–9). These differences 

in abundance and body condition are presumably related to better water quality, including lower 

temperature, lower specific conductance, and lower turbidity, and better habitat availability in 

the San Gabriel River system. 
I-7

Santa Ana suckers appear to be more abundant in the East Fork of the river than the West 

or North Forks (Tennant 2006, p. 6); however, Santa Ana suckers are consistently observed in all 

three forks (Haglund and Baskin 1992, p. 31; Haglund and Baskin 2003, p. 72; Tennant 2004, p. 

5; Tennant 2006, p. 5; Ecorp Consulting 2007, p. 9; Ecorp Consulting 2010b, p. 9). We consider 

the San Gabriel River population to be the most viable of the populations in the three watersheds. 

C. Life History and Ecology

Spawning occurs between mid-March to early-July, with peak activity usually in April 

(Moyle 2002, p. 183). For a small species of the sucker family, fecundity (number of eggs or 

offspring produced by an individual) of Santa Ana suckers is high and increases linearly with 

body weight (Greenfield et al. 1970, p. 170). Spawning takes place over gravelly riffles where 

fertilized eggs adhere to the substrate and hatch within 360 hours. Larvae measure 

approximately 0.28 in (7 millimeters (mm)) at hatching (Greenfield et al. 1970, p. 169). 

Greenfield et al. (1970, p. 170) found no gravid female Santa Ana suckers smaller than 1.9 in (49 

mm) or 0.07 ounce (2.05 grams). Santa Ana suckers in the Santa Clara River generally mature 

during their second summer and die at the end of their third summer at 3 to 4.3 in (75 to 110 

mm) standard length (Greenfield et al. 1970, p. 172). However, some individuals have been 

observed to survive through a fourth summer growing to a size of 5.6 to 6.0 in (141 to 153 mm) 

standard length (Greenfield et al. 1970, p. 172), and those in the San Gabriel River may survive 

into their fifth summer (Drake 1988, p. 56). Maximum age appears to vary among the 

watersheds, for unknown reasons, possibly due to the suitability of habitat and overall fish 

condition. Further investigation of age structure is necessary to fully understand the age, growth, 

and size relationship of Santa Ana sucker across its range.

D. Habitat Characteristics/Ecosystem

Santa Ana suckers occur in the watersheds draining the San Gabriel and San Bernardino 

Mountains of southern California. Their historical distribution extended from upper watershed 

areas to the Pacific Ocean; hence, they are capable of occupying habitats as diverse as mountain

streams and rivers in alluvial floodplains (relatively flat landform created by the deposition of 

sediment over a long period of time from one or many rivers) (Swift et al. 1993, pp. 119–121; 

Moyle 2002, p. 183). 

The streams that the Santa Ana sucker inhabits are generally perennial streams with water 

ranging in depth from a few inches to several feet and with currents ranging from slight to swift 

(Smith 1966, p. 57). These streams are naturally subject to periodic, severe flooding (Moyle 

2002, p. 183) and may experience extended periods of low flow as a result of drought conditions 

that are typical of southern California climate cycles (CRWQCB 1995, p. 1-4). However, there 

are also areas within the range of Santa Ana sucker that experience periods of no flow as a result 

of past and current hydrological modifications to the watershed (for example dams, diversions, 

or recharge basins) (CRWQCB 1995, p. 1-4). Adequate water quantity and quality are important 

for the persistence of the Santa Ana sucker throughout urbanized areas. Not only is the presence 

of water vital to the Santa Ana sucker, the volume and flow rate are important in shaping the 

watershed and facilitating delivery of coarse substrates to occupied areas. Periodic high-flow 

events (flood flows) are essential because they deliver new, coarse (gravel and cobble) substrate 
I-8

to currently occupied areas and reshape the channel to create the complex habitat needed to 

support all life history stages (for example, open sandy bars for juveniles and deep undercut 

banks and pools for adults). Additionally, perennial flows with suitable water quality and 

substrate are needed to support breeding, feeding, and sheltering. 

Santa Ana sucker utilize different substrate types throughout each life stage. The 

presence of coarse substrates, including gravel, cobble, or a mixture of gravel or cobble with 

sand, and a combination of shallow riffle areas and deeper runs and pools, provide optimal 

stream conditions (Haglund et al. 2001, p. 60; Haglund and Baskin 2003, p. 55; Thompson et al.

2010, p. 329). This species also prefers habitat containing in-stream or bank-side riparian 

vegetation that provides shade and cover, especially for larvae and juveniles. However, 

vegetation is less important for adults because they utilize larger, deeper pools, while riffles are 

more frequently utilized by larvae and juveniles (Moyle and Yoshiyama 1992, p. 202; Moyle 

2002, p. 183). Open stream reaches with shifting sandy substrates are typically less suitable for 

algae, an important food source (Saiki et al. 2007, p. 98) and hence, less suitable as habitat for 

Santa Ana suckers. Therefore, a stream system that contains the appropriate quantity of coarse 

substrates with some larger cobbles or boulders to provide the space for successful reproduction 

and juvenile development and growth of algae as a primary food source is important for a viable 

population of Santa Ana suckers.

Specific tolerances to water quality variables such as water temperature, dissolved 

oxygen, and turbidity have not been determined for Santa Ana sucker. However, they are most 

abundant in clear water at temperatures that are typically less than 72 oF (22 oC) (Moyle 2002, p. 

183). Mortality has been observed where water temperatures become elevated. High mortalities 

have been recorded in recent years in conjunction with extremely high air and water 

temperatures in both the Santa Ana River (water temperature of 91.0°F (32.8°C) during summer 

2010; SMEA 2010b, pp. 1–2) and Big Tujunga Creek (water temperatures above 80°F (26.7°C) 

during summer 2011; C. Galst 2011, pers. obs.; T. Hovey 2011, pers. comm.). The continued 

presence of Santa Ana suckers in the Santa Ana River demonstrates that they are able to tolerate 

elevated temperatures in the summer months and turbid conditions associated with high flows 

(Chadwick and Associates, Inc. 1992, p. 37; Saiki 2000, p. 25; Moyle 2002, p. 183). 

Tributaries, particularly those located near the confluence of occupied areas of the river 

mainstem, may also provide important habitat for Santa Ana suckers. Surveys have repeatedly 

reported the presence of adults in breeding condition (tuberculated) and juveniles along the 

margins in tributaries of the Santa Ana River (Chadwick and Associates, Inc. 1992, p. 49; 

Chadwick Ecological Consultants, Inc. 1996, p. 16; Haglund et al. 2002, pp. 54–60; SMEA 

2011, p. 1). This indicates that tributaries may provide shallow-water refuge for juveniles from 

larger predatory fish and may similarly act as refuge for juvenile and adult Santa Ana suckers 

during storm flows. Additionally, the species may be attracted to tributaries due to the relatively 

colder water temperatures typically found in these higher-order streams (Swift 2001, p. 26).

E. Critical Habitat

Critical habitat was originally designated for Santa Ana sucker on February 26, 2004 

(USFWS 2004). On December 14, 2010, critical habitat for the species was revised, designating 
I-9

critical habitat in Los Angeles, Orange, Riverside, and San Bernardino Counties, California

(USFWS 2010). The designated critical habitat includes approximately 9,331 ac (3,776 ha) of 

Federal, State, and private lands. Three units were designated (Unit 1: Santa Ana River, Unit 2: 

San Gabriel River, and Unit 3: Big Tujunga Creek (Los Angeles River)). Individual units are 

each intended to independently support a population of Santa Ana sucker in a functioning 

hydrologic system that provides suitable water quality, water supply, and coarse sediments. 

Primary constituent elements (PCEs) for the Santa Ana sucker are those physical and biological 

features that support life history functions essential to the conservation of the species and may 

require special management considerations or protection. These include primarily a functioning 

hydrological system that provides sources of water and course sediment necessary to maintain all 

life stages, including adults, juveniles, larvae, and eggs of Santa Ana sucker. A detailed 

description of the PCEs and the function of critical habitat for the species can be found within 

the 2010 final rule designating critical habitat (USFWS 2010).

F. Reasons for Listing and Current Threats

The following discussion is a brief summary of ongoing threats that continue to impact 

the Santa Ana sucker and its habitat. For additional information regarding the Santa Ana sucker, 

see the listing rule, revised critical habitat, 5-year review, and recovery outline (USFWS 2000; 

USFWS 2010; USFWS 2011; USFWS 2012). In determining whether to list, delist, or reclassify 

(change from endangered to threatened status, or threatened to endangered) a species under 

section 4(a) of the Act, we evaluate five factors: (A) the present or threatened destruction, 

modification, or curtailment of its habitat or range; (B) overutilization for commercial, 

recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of 

existing regulatory mechanisms; and (E) other natural or manmade factors affecting its continued 

existence.

The final listing rule (USFWS 2000, pp. 19686–19698) identified the following threats to 

Santa Ana sucker: habitat destruction, natural and human-induced changes in stream-flow, urban 

development and related land-use practices, intensive recreation, introduction of nonnative 

competitors and predators, and demographics associated with small population size. 

The 5-year review for Santa Ana sucker (USFWS 2011) and the Santa Ana sucker 

recovery outline (USFWS 2012) identified the following threats to Santa Ana sucker: 

modification, fragmentation, and loss of habitat attributed to dams, changes in water allocations, 

and other hydrological modifications; water quality degradation; impacts to habitat due to

recreation; wildfire; and potential effects of nonnative vegetation and predators, which are 

described below. The primary threat to Santa Ana sucker is rangewide modification, 

fragmentation, and loss of habitat through hydrological modifications. A detailed evaluation of 

all threats is included in the 2011 5-year review (USFWS 2011). Threats to Santa Ana sucker 

are summarized below under each of the five factors.
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Factor A: Present or Threatened Destruction, Modification, or Curtailment of Habitat or 

Range 

Currently, the threats to Santa Ana sucker’s habitat are primarily attributed to 

urbanization and the repercussions of human population growth in Los Angeles, Orange, 

Riverside, and San Bernardino Counties. Modification, fragmentation, and loss of habitat have 

been the primary reasons for the decline in Santa Ana sucker throughout its range and continue 

to be significant threats to the recovery of the species in portions of its range. We categorize 

Factor A threats (all of which are attributable to urbanization) to Santa Ana sucker’s habitat or 

range into the following categories: (1) Hydrological modifications, (2) water quality, (3) 

nonnative vegetation, (4) wildfire, (5) off-highway vehicle (OHV) use, and (6) mining activities. 

Hydrological Modifications

Human activities, such as construction of dams, water diversions, flood control channels, 

roads, and other impervious surfaces, have altered the hydrology of the watersheds throughout 

Santa Ana sucker’s range. These activities have impacted dispersal and modified habitat such 

that much of it is no longer suitable. The Santa Ana sucker remains in a very small portion of its

historical range and although no additional construction of barriers to dispersal or further 

fragmentation of Santa Ana sucker habitat has occurred since its listing, habitat degradation 

continues due to ongoing operations of flood control and water conservation facilities and 

permanent modifications to the watersheds. 

Not only is the presence of water vital to the Santa Ana sucker, the volume and flow rate 

are important in shaping the watershed and maintaining appropriate substrates in occupied areas. 

In the Santa Ana River, there are significant pressures put on the hydrologic process through 

water diversions and impediments, which may impact the suitability of available habitat for 

Santa Ana sucker. The water that provides the habitat for Santa Ana sucker throughout most of 

the year and all of the water during dry summer months primarily originates from discharges of 

treated wastewater (CRWQCB 2008, p. 1-11; USFWS 2008, pp. 2–3). In addition, current and 

future water diversions for human uses have appropriated most of the available water in the 

Santa Ana River watershed (CRWQB 2010, p. 2). The treatment plant discharges provide a 

constant source of water for Santa Ana suckers but may not be adequate to maintain the complex 

diversity of habitat variables (for example, sufficient sediment with appropriate grain size for 

spawning, pools, riffles, shallow stream margins, undercut banks, emergent aquatic vegetation, 

and riparian vegetation) necessary to support each life stage of the species. Water flow in Big

Tujunga Creek and in the West Fork of the San Gabriel River are also regulated by dams but the 

extent that altered hydrology may threaten the Santa Ana sucker in the San Gabriel River or Big 

Tujunga Creek is not well understood. Unregulated flows are available to maintain habitat for 

the Santa Ana sucker in the East and North forks of the San Gabriel River and its associated 

tributaries. Several unregulated tributaries also flow into Big Tujunga Creek.

The delivery of coarse substrates (for example, cobble and gravel) to occupied habitat is 

reduced in all three watersheds by dams and regulated flows. The accumulation of sediment 
I-11

above dams may also be altering habitat for the Santa Ana sucker. As sediment accumulates 

above the dam, the actively flowing stream channel gradually converts to a still-water marsh. 

Marsh habitat favors nonnative animals, such as largemouth bass (Micropterus salmoides), that 

are predators on the Santa Ana sucker (USACE 2001, p. 4-28), and the fine substrate that settles 

out in still water does not support breeding and foraging habitat for Santa Ana sucker. In 

particular, Prado Dam may be altering habitat for Santa Ana sucker in the Santa Ana River. 

Based on surveys conducted annually since 2006, the river channel is predominantly sand 

substrate upstream for a minimum of 18.5 mi (29.8 km) above Prado Dam, which is 76 percent 

of the remaining perennial stream habitat for Santa Ana sucker above the dam. The amount of 

suitable habitat varied annually between 2006 and 2010, ranging from approximately 2.6 to 6.0 

mi (4.2 km to 9.6 km) (USFWS 2011, p. 13).

Flood control infrastructure (for example, levees, culverts, bank protection) designed to 

protect urban development may require regular maintenance. Maintenance that requires frequent 

disturbance to the stream channel can degrade habitat for Santa Ana sucker by 

removing/displacing substrate, impacting aquatic and riparian vegetation, and increasing the 

distribution of nonnative vegetation. Remaining spawning habitat in the Santa Ana River is 

largely contained between flood control levees, where maintenance of the levees includes 

relocation of the river channel when it approaches the levees.

Hydrological modifications that limit the dispersal of Santa Ana suckers include flood 

control dams, drop structures, recreational dams, road crossings (for example, culverts) and 

levees. Large dams, such as Prado Dam, severely limit connectivity between Santa Ana suckers, 

only allowing limited unidirectional migration downstream. Recreational dams, such as lowflow barriers constructed out of rocks, vegetation, or other debris to create pools for recreation, 

create barriers during low-flow conditions but may be passable during higher-flow conditions. 

Culverts and other road crossings may prevent access into tributaries or limit connectivity within 

the main river channel. Levees can prevent access to portions of the floodplain that were 

historically occupied by the species.

Water Quality

Wastewater-dominated rivers, like the Santa Ana River, are subject to increased inputs of 

regulated and unregulated contaminants (Kolpin et al. 2002, pp. 1202–1211; Jenkins et al. 2009, 

p. 39), which degrade water quality and habitat suitability. Contaminants in water discharged 

from sewage treatment facilities may be amplified because of the limited availability of cleaner, 

natural water to flush out or dilute residual chemicals. Degraded water quality affects this 

species primarily in the Santa Ana River, but may occur in association with recreational use in 

the other watersheds. Other water quality impacts to Santa Ana suckers include (but are not 

limited to): elevated temperatures and changes in hydrological regime attributed to global 

climate change, low oxygen levels attributed to increased nutrients causing algal blooms, and 

increased ammonia levels that are toxic to fish. Each of these scenarios may result in 

degradation of water quality in occupied habitat and elevated stress of the fish, lower 

reproductive input, or death. 
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Nonnative Vegetation

Aquatic habitat may be modified by the presence of nonnative vegetation in a variety of 

ways. Arundo donax (giant reed) is a nonnative, aquatic, perennial reed-like grass (Poaceae). It 

is commonly found growing along lakes, streams, and other wetted areas, but once established it 

can survive long periods of drought. Compared to other riparian vegetation, it is known to use 

excessive amounts of water to supply exceptionally high growth rates (Bell 1997, p. 104). This 

species is considered a primary threat to riparian corridors because of its ease of establishment 

and ability to alter the hydrology of the system. Arundo donax tends to form large, continuous, 

clonal rhizome masses that stabilize river or stream banks, altering the flow regime of the 

system, and preventing natural dynamic processes such as stream meandering, and, deposition 

and scouring of sediments (Bell 1997, p. 106). The modification of in-stream habitat by Arundo 

donax can also reduce the suitability of habitat for Santa Ana sucker and increase the potential to 

support nonnative aquatic predators (see Factor C: Predation below). 

A nonnative, invasive, filamentous red alga (Compsopogon coeruleus) was recently 

identified in the Santa Ana River in 2014 (Spoo-Chupka 2014). This red alga has likely been 

introduced into the Santa Ana River multiple times. The first record for this species in the Santa 

Ana River was from 2012, where it was found near Yorba Linda Boulevard, Yorba Linda, 

California (Sheath and Stancheva 2014.). The second and most recent observation in the Santa 

Ana River was made in February 2014 where it was found in the discharge pool of the Rapid 

Infiltration and Extraction Facility (RIX), City of Colton, California. The RIX discharge pool 

appears to be an introduction location, as the alga has not been found to occur upstream from this

location. It attaches to hard substrates and exists as an aquatic epilith (growing on rocks) or 

epiphyte (growing on plants). In the upper Santa Ana River the red alga was more abundant in 

areas composed of cobble or gravel substrate and less abundant in areas dominated by sand (C. 

Medak and K. Palenscar 2014, pers. obs.). 

One concern is that the presence of this nonnative red alga has reduced the available 

foraging and spawning habitat for the Santa Ana sucker because it grows very rapidly, up to 10 

centimeters per day (Palenscar 2014a, pers. obs.), and creates dense carpets of filaments that 

cover the bottom via layering. Santa Ana sucker are not known to forage on or spawn within 

filamentous algae. When conducting a snorkel survey in the Santa Ana River in late February 

2014, fewer Santa Ana sucker were observed in areas where the alga was abundant (Medak and 

Palenscar 2014, pers. obs.). This rapid invasion of a nonnative species has altered vital Santa 

Ana sucker habitat throughout most of its occupied range within the upper portion of the Santa 

Ana River as well as potentially altering ecosystem processes. There was approximately 0.5 mi 

(0.8 km) of suitable spawning habitat within the Santa Ana River in February 2014 (Medak and 

Palenscar 2014, pers. obs.). 

Wildfire

Wildfire may impact riparian vegetation throughout occupied and unoccupied reaches of 

all three watersheds by eliminating vegetation that shades the water and moderates water 

temperature, or by producing silt-and-ash-laden runoff that can significantly increase turbidity of 

rivers. The loss of riparian vegetation may impact water transport, sediment transport, water 
I-13

quality, and flow regime. Large wildfires may threaten aquatic species by isolating populations 

and causing local extirpations. Wildfire has the potential to impact the Santa Ana sucker 

throughout its range, but impacts are expected to be localized and temporary. Therefore, we do 

not consider wildfire to be a substantial threat at this time. 

Off-highway Vehicle Use

OHVs impact both riparian and in-stream habitat that is important for Santa Ana suckers. 

Users of OHVs may drive along the banks of rivers, which can degrade bank stability and lead to 

erosion, and damage riparian plant communities that provide shade over the river and increase 

bank stability. OHVs may also drive through the river and disturb sediments, create increased 

turbidity, potentially crush Santa Ana suckers, and otherwise disturb substrates that Santa Ana 

suckers require for feeding and rearing young. OHV use primarily occurs in the San Gabriel 

Canyon OHV area, at the confluence of the East and West Forks of the San Gabriel River and 

above Mission Avenue, in the Santa Ana River. The San Gabriel Canyon OHV area is currently 

being managed by the USFS to reduce impacts to the species and is monitored to determine the 

effectiveness of management actions (For example, Ecorp Consulting 2010b). OHV use in the 

Santa Ana River is unauthorized. Although OHV use is currently not considered a substantial 

threat, it has the potential to significantly impact Santa Ana sucker in absence of specific 

management actions and enforcement. 

Mining Activities

Sand and gravel are used as construction aggregate for public works projects such as 

roads and highways and a multitude of other commercial uses (Kondolf 1997, p. 540). In-stream 

mining alters the channel geomorphology and bed elevation, and can require water diversion, 

clearing, and excavation (Kondolf 1997, p. 541). The practice of in-stream mining may induce 

channel incision and erosion, but more importantly for Santa Ana suckers, mining for gravel and 

sand removes necessary substrates from the watershed and discharges fine residual sediment 

back into the watershed. These activities have occurred in the Santa Ana River upstream of 

occupied habitat areas. Additionally, suction dredging to find precious minerals is generally a 

recreational activity that occurs most frequently on U.S. Forest Service (USFS) lands. These 

activities have been known to occur in the San Gabriel River and Los Angeles River watersheds; 

however, as of August 6, 2009, California Department of Fish and Wildlife (CDFW) imposed a 

moratorium on instream suction dredging until the State of California completes a court-ordered 

environmental review, and adopts a permitting program (CDFW website viewed October 14, 

2010). Sluicing and high banking, techniques also used to find precious minerals, are likely 

occurring in the San Gabriel River and to a lesser extent in Big Tujunga Creek (Welch 2010, 

pers. comm.). While mining is not currently considered a substantial threat, changes in 

restrictions that increase the rangewide extend of mining activities could have a substantial 

impact on the species. 

Factor B: Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

The 2000 listing rule indicated that CDFW reported the illegal harvest of Santa Ana 

suckers with gill and throw nets in the Santa Ana River below Prado Dam (M. Maytorena, 
I-14

CDFW, 1997, pers. comm.). Since listing, we received information that Santa Ana suckers may 

be a food source for people living in encampments along the Santa Ana River and there may be a 

correlation of this illegal activity to the observed decline in Santa Ana suckers with proximity to 

these camps (RCRCD 2007, p. 13). However, the relative impact of illegal harvesting of the 

species is unknown. We have no information indicating that overutilization of Santa Ana sucker 

in the San Gabriel River or Los Angeles River watersheds has historically or is currently a 

substantial threat to Santa Ana sucker.

Factor C: Disease or Predation 

We have no information indicating that disease is a substantial threat to the continued 

existence of Santa Ana suckers throughout its range.

Nonnative predators, such as bass and sunfish (Family Centrarchidae), tilapia (Family 

Cichlidae), carp (Family Cyprinidae), and catfish (Family Ictaluridae), have been reported in 

each of the watersheds currently occupied by Santa Ana sucker (Allen 2003, p. 6; Chambers 

Group 2004, p. 6-3; RCRCD 2006, p. 11; Morrissey 2009, p. 7; Ecorp Consulting 2010a, p. 7; 

Ecorp Consulting 2010b, p. 9). The American bullfrog (Rana catesbeiana), another potential 

predator, has also been observed in Big Tujunga (Haines Creek) (Ecorp Consulting Inc. 2013, 

pp. 29–31) and the Santa Ana River near the confluence with Rialto Channel (Palenscar 2014b, 

pers. obs.). The relative abundance of Santa Ana suckers appears to decrease with increasing 

numbers of exotic fish (Swift 2001, p. 29; Ecorp Consulting Inc. 2013, p. 19). An increase of 

nonnative predators would suggest increased predation pressures, which could further impact 

Santa Ana sucker; however, further study is needed to determine the quantity of Santa Ana 

suckers consumed by nonnative predators to better describe the magnitude of this threat. 

Factor D: Inadequacy of Existing Regulatory Mechanisms

In the listing rule, regulatory mechanisms thought to have some potential to protect Santa 

Ana sucker included: (1) California Endangered Species Act (CESA) (where the Santa Ana 

sucker occurred in areas where State-listed species are located), (2) California Environmental 

Quality Act (CEQA), (3) National Environmental Policy Act (NEPA), (4) Clean Water Act 

(CWA), (5) the Act (where, prior to listing, Santa Ana sucker co-occurred with other federally 

listed species), and (6) land management or conservation measures by Federal, State, or local 

agencies or by private groups and organizations (USFWS 2000, pp. 19686–19698). The listing 

rule provides an analysis of the potential level of protection provided by these regulatory 

mechanisms. 

The status of regulatory mechanisms and their adequacy for protection of Santa Ana 

sucker remains largely unchanged since listing. Several State and Federal mechanisms provide a 

conservation benefit to Santa Ana sucker. However, the Act is the primary Federal law that 

provides protection for this species since its listing as threatened in 2000. Critical habitat was 

revised in 2010 and was designated throughout the range of the Santa Ana sucker, including 

unoccupied areas essential for the conservation of the species. The Western Riverside County 

Multiple Species Habitat Conservation Plan (Western Riverside County MSHCP), under which 

Santa Ana sucker is a covered species, was permitted and is currently being implemented. The
I-15

MSHCP affords protection to the species and its habitat in a portion of its range above Prado 

Dam. 

Other Federal and State regulatory mechanisms provide discretionary protections for the 

species based on current management direction, but do not guarantee protection for the species 

absent its status under the Act. We are not aware of any new regulatory mechanisms that have 

been enacted since the time of listing that would preclude the need for protection of the species 

under the Act. Therefore, in absence of the Act, other laws and regulations have limited ability 

to protect the species.

Factor E: Other Natural or Manmade Factors Affecting Its Continued Existence 

The majority of the Santa Ana sucker’s historical range was lost prior to listing, and the 

distribution of this species has continued to constrict in portions of the San Gabriel River and 

Santa Ana River watersheds. Small population size may be the result of several conditions, 

including their inability to recolonize previously occupied areas and lack of redundant tributaries 

or refuge habitat to prevent extirpation due to catastrophic events. Survey data indicate that fish 

density is likely decreasing in areas in the Santa Ana River (SMEA 2009, p. 1) and tends to be 

variable in Big Tujunga Creek (Ecorp Consulting 2010a, p. 5; Haglund and Baskin 2010) and 

San Gabriel River (O’Brien et al. 2011, p. 10)). Small populations of Santa Ana sucker are more 

vulnerable to extirpation during stochastic events, such as flood, fire, or sustained drought. 

Given the impact these events could have on any of the three watersheds where Santa Ana 

suckers exist, they represent a potential threat to the species as a whole

 

Current climate change predictions for terrestrial areas in the Northern Hemisphere 

indicate warmer air temperatures, more intense precipitation events, and increased summer 

continental drying are predicted by the year 2100 (Field et al. 1999, p. 1; Cayan et al. 2005, pp. 

7–8; IPCC 2007, pp. 8–9). While Santa Ana suckers are capable of withstanding elevated water 

temperatures (Saiki et al. 2007, pp. 98–99), their lethal upper temperature limit is unknown. Fish 

are generally more stressed at the upper extremes of their temperature range and though they 

may be able to survive, elevated temperature is an example of a stressor that may affect them 

through decreased growth and reduced disease resistance (Barton et al. 2002, pp. 111–148). All 

life stages of Santa Ana suckers require cool water (Saiki et al. 2007, pp. 99–100). However, 

connectivity within the watersheds may be exacerbated by the predicted decreases in annual 

precipitation and fish may not have access to areas with cool, clean water because of the lack of 

water or barriers to dispersal. Increasing air temperatures and decreasing precipitation levels, 

predicted to occur as a result of global climate change, are likely to impact the availability of 

suitable cooler-water habitat. Therefore, though difficult to quantify, change in global climate 

may impact the Santa Ana sucker throughout its range. 

Summary

The primary threat to Santa Ana sucker is rangewide habitat loss, degradation, and 

modification through hydrological modifications. The loss of available habitat (caused by dams, 

changes in water allocations, and other hydrological modifications) combined with other 

increasing threats (such as water quality degradation, impacts to habitat from recreation, and 
I-16

potential effects of nonnative vegetation and predators) have a cumulative effect on Santa Ana 

sucker and its habitat. Additionally, isolation by impassable barriers or unsuitable habitat limits 

gene flow, thus increasing the vulnerability of small populations to a range of environmental and 

genetic stochastic factors.

Threats are likely to continue with the increasing pressure for water conservation 

(storage) for human use through dams and water diversions, as well as continuing impacts of 

urbanization, recreation, degraded and fragmented habitat, degraded water quality, vulnerability 

of small populations, and, potentially, global climate change. However, the scope and severity 

of impacts to the Santa Ana sucker vary within the three watersheds. 

The Santa Ana River watershed has been highly modified as a result of changes to the 

hydrology from urban development and barriers, such as Prado Dam and Seven Oaks Dam. The 

distribution of Santa Ana suckers is limited primarily to a few miles of the mainstem below

South La Cadena Drive and a few small tributaries, where suitable spawning habitat exists. The 

system is largely channelized and the extent of suitable habitat is constrained by a reduction of 

water and sediment from upstream sources. Water quality is variable and may impact the sucker 

throughout its range. Nonnative species, including aquatic predators and the newly identified 

invasive alga, also pose serious threats and continue to degrade habitat in the Santa Ana River. 

The range of Santa Ana sucker in the Los Angeles River watershed was reduced by about 

80 percent at the time of listing and is now limited to an area confined between Hansen Dam and 

Big Tujunga Dam (USFWS 2000; O’Brien and Stephens 2009). Flows regulated by Big 

Tujunga Dam affect water and sediment transport in Big Tujunga Creek; however, unregulated 

flows are available from several tributaries. The adequacy of existing water and sediment 

sources to maintain habitat for Santa Ana sucker is not well understood. Many road crossings, 

recreational dams, and culverts limit fish passage and contribute to habitat degradation. 

Nonnative predators are abundant in Haines Creek and gain access to the system from the 

Tujunga ponds. 

The San Gabriel River watershed provides much suitable habitat for the Santa Ana sucker 

with abundant cobble and good flows. Although the hydrology has been altered on the West 

fork of the San Gabriel River by Cogswell Dam, unregulated flows are available to maintain 

habitat for the Santa Ana sucker in the East and North forks and associated tributaries. 

Recreational activities (swimming, fishing, off-highway vehicle use) are extensive and contribute 

to the degradation of habitat. Recreational dams are abundant in the lower portions of the North, 

East, and West forks and require management to reduce potential impacts to Santa Ana sucker. 

Predators have been reported in the watershed and may gain access from Cogswell and San 

Gabriel reservoirs. Nonnative plants are present in the lower portions of the East and West forks

and may contribute to habitat degradation. 

G. Conservation Efforts

Since listing, surveys for Santa Ana sucker have been conducted in various portions of its range. 

Species-specific projects have also been conducted in each of the three watersheds where Santa 

Ana sucker occur. There have been studies exploring life history parameters, population 
I-17

dynamics and demographics, habitat assessments, environmental conditions, and possible 

restoration sites. These studies have been important for making decisions regarding the status of 

the species and the current conditions within each of the watersheds. Other activities have also 

occurred for the benefit of Santa Ana sucker such as removal of nonnative vegetation and 

nonnative predators. Examples of these activities and past research are listed in Table 1 below.

There are currently 18 individuals (or companies) permitted to conduct recovery 

activities for the Santa Ana sucker under section 10(a)(1)(A) of the Act. Most recovery permits 

cover presence/absence surveys that generally allow for capture, handling, and release of 

individuals encountered while conducting authorized surveys. Additionally, some permittees are 

authorized to conduct more invasive activities, such as collecting biological samples (fin clips), 

measuring/weighing individuals, or collecting specimens. Recovery of Santa Ana suckers is 

being achieved in part through on-the-ground recovery actions, implementation of management 

plans, and through active cooperation with partners through sections 7 and 10 of the Act.

H. Summary

Historical Santa Ana sucker habitat has been drastically degraded and fragmented from 

hydrological modifications, resulting in the species’ reduced geographic range and vulnerability 

to stochastic events. Increased distance between suitable habitats has likely resulted in reduced 

genetic exchange between populations and reduced ability to colonize new or previously 

occupied habitat. Life history traits of the sucker (for example, early sexual maturity, protracted 

spawning period, high fecundity) are conducive to re-colonization; however, it appears (based on 

our evaluation of the results of studies investigating availability of suitable habitat (Thompson et 

al. 2010)) that reintroductions are likely needed to provide resilience and redundancy for the 

species to recover. Reintroduction to existing or restored habitat may be a viable option to 

increase distribution and abundance if suitable habitat is available. The sucker is dependent on 

habitat that has been, and continues to be, under developmental pressures. Protection and active 

management are needed to improve and restore suitable habitat in order to prevent further 

decline and to enable recovery of the species. Additionally, research, monitoring, and nonnative 

species removal are already underway and should be expanded throughout the species range. 

Key challenges will be developing a recovery strategy that can be implemented in a system 

where there are continuing human-use water needs and requirements for flood control operation 

to maintain human health and safety.
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Table 1: Studies and activities funded and carried out for the conservation of the Santa 

Ana sucker.

Santa Ana River

Year Title Reference

1992 Santa Ana River use-attainability analysis Chadwick and Associates 

1992

1996 Current status of the Santa Ana sucker in the Santa Ana 

River

Chadwick Ecological 

Consultants Inc. 1996

1999 Conservation program for the Santa Ana sucker in the 

Santa Ana River Baskin and Haglund 1999

2000

Water quality and other environmental variables 

associated with variations in population densities of the 

Santa Ana sucker. In the Santa Ana and San Gabriel Rivers 

Saiki 2000

2001 Santa Ana sucker survey/seining in the Santa Ana River Baskin and Haglund 2001

2001

The Santa Ana sucker in the Santa Ana River: distribution, 

relative abundance, spawning areas, and impact of exotic 

predators

Swift 2001

2001-2009 Implementation of the Santa Ana sucker Conservation 

Program for the Santa Ana River

Haglund et al. 2001, 2002, 

2003, 2007, 2010; 

Haglund and Baskin 2004

2002

Evaluation of Santa Ana sucker (Catostomus santaanae) 

habitat and water quality changes in the Santa Ana River 

as a result of temporary shutdowns at the Rapid 

Infiltration and Extraction Plant

Allen 2002

2003

Evaluation of Santa Ana Sucker (Catostomus santaanae) 

spawning success in the Santa Ana River and the potential 

effects on temporary shutdowns at RIX

Allen 2003

2004

Assessment of the influence of hydrology and sediment 

transport in the Santa Ana River on Santa Ana sucker 

habitat

Humphrey et al. 2004

2006-2009 Santa Ana sucker research and population augmentation 

project 2006-2008 Annual Report

RCRCD 2006, 2007, 2008,

2009

2007 Santa Ana Watershed Association 2007 annual report SAWA 2007

2009

45-day survey report on pre-construction 

presence/absence surveys for the Santa Ana sucker 

(Catostomus santaanae) at three locations on the Santa 

Ana River

Ecorp Consulting 2009

2010 Feasibility of the Restoration of Sunnyslope Creek for 

Santa Ana suckers SAWA 2010

2010

Influence of habitat dynamics on the distribution and 

abundance of the federally threatened Santa Ana sucker, 

Catostomus santaanae, in the Santa Ana River

Thomson et al. 2010
I-19

Year Title Reference

2011 Draft Seven Oaks Dam Gate Test USACOE 2011

2011 The Riverside North Aquifer Storage and Recovery Project 

on the Santa Ana Sucker AECOM 2011

2011 Sunnyslope nonnative electro-shocking report RCRCD 2011

2012 Sunnyslope Creek native fish habitat restoration project 

monitoring report OCWD 2012

2012-2014 Fish passage barrier identification and assessment 

throughout the range of Santa Ana sucker Baskin 2014

2012-2014 USGS analysis of the population genetics of the Santa Ana 

sucker Ongoing

2013-2014 Relative Abundance and habitat surveys by SAWA SAWA 2014

2014

Ongoing monitoring initiated in Santa Ana River by the 

Service to assess effects of nonnative red alga on Santa 

Ana sucker

Ongoing

Big Tujunga River

Year Title Reference

2001 Lower Big Tujunga stream pool location survey Andresen 2001

2002 Fish survey of Big Tujunga Creek below Big Tujunga Dam 

No. 1 with special reference to Santa Ana sucker Swift 2002

2004 Report - Los Angeles River Haines Creek Fish Survey for 

LACDPW Baskin and Haglund 2004

2007-2008 Santa Ana sucker (Catostomus santaanae) habitat 

suitability survey 2007-2008 Big Tujunga Creek EDAW and SMEA 2009

2008-2009 Santa Ana Watershed Association 2008-2009 annual 

report

SAWA 2009

2009 Data summary of the 2009 fish surveys in the Big Tujunga 

Creek Basin

O'Brien and Stephens 

2009

2010 Report for the Santa Ana sucker (Catostomus santaanae) 

survey and relocation effort in the Big Tujunga Ecorp Consulting 2010a

2010

Santa Ana sucker (Catostomus santaanae) and 

macroinvertebrate baseline survey 2009, Big Tujunga 

Creek

Haglund and Baskin 2010
I-20

San Gabriel River

Year Title Reference

2001-2006 Surveys for the Santa Ana sucker (Catostomus santaanae) 

on the San Gabriel River Tennant 2001, 2004, 2006

2002 Status of the Santa Ana sucker and Santa Ana speckled 

dace in the U.S. Forest Service San Gabriel River OHV area Haglund and Baskin 2002

2003

Final Report Habitat and resource utilization by the Santa 

Ana sucker (Catostomus santaanae) and the Santa Ana 

speckled dace in the east fork of the San Gabriel River

Haglund and Baskin 2003

2004 Estimating leakage from Cogswell Dam (West Fork San 

Gabriel River) Ally 2004a

2004

Survey of selected stream parameters in the East Fork San 

Gabriel River and its tributary Cattle Canyon, and in the 

North Fork San Gabriel

Ally 2004b

2004

Results of electrofishing surveys done in the San Gabriel 

River (West, North, and East Forks) and tributaries Bear 

Creek and Cattle Canyon during June and July 2003

Ally 2004c

2004 Results of electrofishing surveys done in four streams of 

the San Gabriel River drainage in June 2004 Ally 2004d

2007 Fish population and habitat surveys San Gabriel Canyon 

OHV area Ecorp Consulting 2007

2008 Update for the Santa Ana sucker located in San Dimas 

Canyon East Fork Chambers Group 2008

2010

Santa Ana sucker population and habitat monitoring 

surveys in the U.S. Forest Service San Gabriel Canyon OHV 

area

Ecorp Consulting 2010b

2011 Status of fishes in the upper San Gabriel River basin O'Brien et al. 2011

2012 45 day report for the Santa Ana sucker capture and 

relocation activities below the San Dimas Dam Chambers Group 2012a

2011-2012 Santa Ana sucker surveys in USFS OHV area, San Gabriel 

River, Angeles National Forest

Chambers Group 2011,

2012b
II-1

II. RECOVERY PROGRAM

This section describes the Santa Ana sucker recovery program by outlining a strategy, 

identifying where recovery will occur (recovery units), defining the recovery goal and objectives, 

and delineating criteria to remove the Santa Ana sucker from the list of threatened and 

endangered species (delist the species).

RECOVERY PRIORITY NUMBER

The recovery priority number for Santa Ana sucker is 5C. This number indicates the 

species faces a high degree of threat, has a low potential for recovery, and has taxonomic status 

as a species. The high degree of threat is due to potential loss of water supply, pollution, the 

highly urbanized nature of the Santa Ana River, significant pressure placed on the species by 

recreational use and flood control restrictions, predation by introduced predators, and 

susceptibility of small populations to random catastrophic events. The low potential for recovery 

is due to the significant amount of effort needed to secure the required water supply, restore 

habitat, and secure funding for research and water quality standard revisions needed to protect 

Santa Ana sucker from pollution. The “C” indicates conflict with construction or other 

development projects or other forms of economic activity, specifically water conservation and 

flood control projects and associated infrastructure (for example, dams, diversions, and drop 

structures).

A. Recovery Strategy

Due to the rangewide large-scale hydrological modifications, the most pressing threat to 

the species is the lack of suitable habitat necessary to increase population resiliency (ensure a 

large enough population to withstand stochastic events) and redundancy (a sufficient number of 

populations to ensure the species can withstand catastrophic events). Therefore, the highest 

priority for the recovery of Santa Ana sucker is implementation of management actions to restore 

and improve habitat conditions throughout the current range of the species. These actions 

include initiating studies that will lead to a thorough understanding of the implications of past 

and current hydrological modifications throughout the range of the species; controlling nonnative 

species; minimizing recreation pressures; improving water quality; employing adaptive 

management techniques to address the uncertainties of global climate change; and involving 

stakeholders and partners in all applicable conservation and management actions. 

Given the substantial reduction in the range of the species and the threats associated with 

small population size (see Factor E, Small Population Size), the currently occupied areas

(particularly in the Santa Ana River watershed) will likely not be sufficient to provide the 

resiliency and redundancy necessary for recovery of the species. Additionally, representation 

(maintaining the breadth of the genetic makeup to conserve the adaptive ability of the species) is 

a concern due to the small population size within each watershed. To reduce the risk of 

extirpation, while determining appropriate actions to manage threats within the current range, 

areas not currently accessible to the fish should be assessed for potential reintroduction. 

Increasing the extent of occupied habitat will improve the representation, resiliency, and 

redundancy of Santa Ana sucker, thereby improving the status of the species. 
II-2

Recovery Units

The establishment of Recovery Units (RU) is an effective tool for species that are 

divisible into geographically or otherwise identifiable units that are essential to the recovery of 

the species. Recovery Units are areas that are individually necessary for long-term sustainability 

of the species and serve to facilitate species recovery. Recovery goals, and criteria to reach those 

goals, are set for each RU and when accomplished should be considered as indicators that the 

species could be delisted. Recovery actions will be prioritized differently between recovery units 

depending on the magnitude and intensity of threats. For example, hydrological modifications 

from dams impact the species and its habitat in all three watersheds. However, in the Santa Ana

and Los Angeles River watersheds the construction and operation of large dams have impacted 

the habitat suitability to a greater extent than in the San Gabriel River watershed. In contrast, the 

construction of recreational dams is more prevalent in the San Gabriel and Los Angeles River 

watersheds, compared to the Santa Ana River watershed. Therefore, each action is assigned a 

priority relative to its need within each recovery unit. 

All of the Recovery Units are necessary for the recovery of the Santa Ana sucker and 

provide redundancy in order to maintain its historical population and habitat distributions, as 

well as protection of the genetic variability. We believe that to achieve recovery of the Santa 

Ana sucker the species must possess healthy, viable populations within each of the three RUs: 

(1) Santa Ana River RU; (2) Los Angeles River RU; (3) San Gabriel River RU (See Figure 1 for 

site map of Santa Ana River, Los Angeles River, and San Gabriel River watersheds which are 

equivalent to the RUs). Within each of the three RUs we have also defined several reaches of 

the mainstem and its associated tributaries, which lack connectivity due to barriers to fish 

passage. 

Santa Ana River Watershed Recovery Unit (SARW-RU)

The SARW-RU includes the Santa Ana River, tributaries, and areas being considered for 

possible reintroduction (*).

SARW-RU REACHES:

• La Cadena Reach: Santa Ana River above South La Cadena Drive and its connecting 

tributaries* (for example, Santa Ana River above Seven Oaks Dam*, Mill Creek*, Lytle 

Creek*, Cajon Wash*, City Creek*, Plunge Creek*, Warm Creek*, Mountain Home 

Creek*, Bear Creek*, Alder Creek*) (Figure 2).

• Prado Reach: Santa Ana River between Prado Dam and the drop-structure at South La 

Cadena Drive and its connecting tributaries (for example, Sunnyslope Creek, Tequesquite 

Arroyo, Hole Creek, Anza Drain, Rialto Channel, Temescal Creek*, Chino Creek*, San 

Antonio Creek*, Cucamonga Creek*, Day Creek*, and other potential restorable 

tributaries) (Figure 3).

• Imperial Reach: Santa Ana River from California State Route 90 to Prado Dam and its 

connecting tributaries (for example, Aliso Creek*). (Figure 3).
II-3

Los Angeles River Watershed Recovery Unit (LARW-RU)

The LARW-RU includes Big Tujunga Creek, Little Tujunga Creek, Haines Creek, and 

areas being considered for possible reintroduction (*) 

LARW-RU REACHES:

• Big Tujunga Reach: Big Tujunga Creek above Big Tujunga Dam and its connecting 

tributaries (for example, Fall Creek*, Mill Creek*) (Figure 4).

• Hansen Reach: Big Tujunga Creek between Big Tujunga Dam and Hansen Dam and its 

connecting tributaries (for example, Little Tujunga Creek, Haines Creek, Gold Creek, 

Delta Canyon Creek, Stone Canyon Creek, Vogel Canyon Creek, Clear Creek) (Figure 

4).

• Los Angeles Reach: Los Angeles River down to the Los Angeles/arroyo Seco 

confluence and its connecting tributaries (for example, Arroyo Seco Creek*, Pacoima 

Canyon Creek*) (Figure 4).

San Gabriel River Watershed Recovery Unit (SGRW-RU)

The SGRW-RU includes the East, North, and West forks of the San Gabriel River, Bear 

Creek, Cattle Canyon Creek, San Dimas Wash, and areas being considered for possible 

reintroduction (*).

SGRW-RU REACHES

• Cogswell Reach: West Fork of the San Gabriel River above Cogswell Dam* (Figure 5).

• San Gabriel Reach: The San Gabriel River, north of San Gabriel Dam, from Cogwsell 

Dam to the easternmost section of Cattle Canyon Creek. This reach includes the East 

(including area above the “Bridge to Nowhere”*), North, and West forks of San Gabriel 

River and its connecting tributaries (for example, Bear Creek, Big Mermaids Creek, 

Cattle Canyon Creek) (Figure 5).

• Whittier Reach: San Gabriel River from above Whittier Narrows Dam to Morris Dam 

and its connecting tributaries (for example, San Dimas Wash, Fish Creek*, Dalton 

Creek*, Santa Anita Creek*, Monrovia Creek*) (Figure 5).
II-4 

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II-5 

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II-6 

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II-7 

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II-8

B. Recovery Goal

The goal of this recovery plan is to control or reduce threats to Santa Ana sucker to the 

extent that it no longer requires protections afforded by the Act and, therefore, warrants delisting. 

C. Recovery Objectives

Based on the recovery strategy and current threats to the species the following objectives 

are identified. Work with landowners and other stakeholders to:

1. Develop and implement a rangewide monitoring protocol to accurately and consistently 

document populations, occupied habitat, and threats.

2. Conduct research projects specifically designed to inform management actions and 

recovery.

3. Increase the abundance and develop a more even distribution of Santa Ana sucker within 

its current range by reducing threats to the species and its habitat.

4. Expand the range of the Santa Ana sucker by restoring habitat (if needed), and 

reestablishing occurrences within its historical range.

D. Recovery Criteria

An endangered species is defined in the Act as a species that is in danger of extinction 

throughout all or a significant portion of its range. A threatened species is one that is likely to 

become endangered within the foreseeable future throughout all or a significant portion of its 

range. When we evaluate whether or not a species warrants downlisting or delisting, we 

consider whether the species meets either of these definitions. A recovered species is one that no 

longer meets the Act’s definitions of threatened or endangered due to amelioration of threats.

Determining whether a species should be downlisted or delisted requires consideration of the 

same five categories of threats which were considered when the species was listed and which are 

specified in section 4(a)(1) of the Act.

Recovery criteria are conditions that, when met, indicate that a species may warrant 

downlisting or delisting. Thus, recovery criteria are mileposts that measure progress toward 

recovery. Because the appropriateness of delisting is assessed by evaluating the five categories 

of threats identified in the Act, the recovery criteria below pertain to and are organized by these 

categories. These recovery criteria are our best assessment at this time of what needs to be 

completed so that the species may be removed from the list entirely. Because we cannot 

envision the exact course that recovery may take and because our understanding of the 

vulnerability of a species to threats is very likely to change as more is learned about the species 

and its threats, it is possible that a status review may indicate that delisting is warranted before

all recovery criteria are met. Conversely, it is possible that the recovery criteria could be met 
II-9

and a status review may indicate that delisting is not warranted; for example, a new threat may 

emerge that is not addressed by the recovery criteria below. 

Delisting Criteria

Recovery occurs when threats outlined in the Reasons for Listing and Continued 

Threats sections have been sufficiently ameliorated based on the criteria enumerated below. 

Recovery for Santa Ana sucker is not defined in terms of absolute numbers of fish, but by the 

number of protected and managed occurrences (existing and reestablished) that are sustained via 

natural processes and demography as well as ongoing management. The recovery criteria 

presented below represent our best estimate for measuring when the recovery objectives have 

been met. Unless stated explicitly, criteria are applicable to all recovery units and delisting will 

be considered for Santa Ana sucker when the following conditions have been met in each of the 

recovery units, including the Santa Ana River, Los Angeles River, and San Gabriel River RUs:

Factor A: Present or Threatened Destruction, Modification, or Curtailment of Habitat or 

Range

A.1 Adequate amounts of suitable habitat are restored, protected, and managed within each 

recovery unit to support viable populations (see Recovery Criteria E.3) of all life stages of Santa 

Ana sucker and provide resiliency and redundancy to protect against catastrophic events 

throughout the current range of the species. 

Factor C: Predation

C.1 Management is implemented to reduce competition and predation by nonnative species to

levels determined to be necessary for the maintenance of viable Santa Ana sucker populations.

Factor E: Other natural or manmade factors affecting its continued existence 

E.1 The current range of the species is expanded through modification or removal of existing 

barriers, restoration of suitable habitat, and/or reintroduction of the species to areas within its 

historical range in a configuration that ensures reasonable certainty the remaining genetic 

makeup of the species has been preserved and can withstand catastrophic events in the 

watershed.

E.2. Appropriate gene flow is maintained between occupied areas of each RU, through natural 

processes or management, to ensure population viability and genetic exchange.

E.3 Stable or increasing population averaged over 15 years within each RU and occupancy in 

each of the following areas:

Santa Ana River Watershed Recovery Unit –

 Santa Ana River in the Prado Reach and Imperial Reach;
II-10

 Four tributaries in the Prado Reach and/or Imperial Reach (for example

Tequesquite Arroyo, Anza Drain, Hole Creek, Evans Drain, Sunnyslope Creek, Day 

Creek, Aliso Creek); and

 Three tributaries in the La Cadena Reach (for example City Creek, Lytle Creek, 

Cajon Wash, Alder Creek, Plunge Creek, Santa Ana River above Seven Oaks 

Dam). 

Los Angeles River Watershed Recovery Unit –

 Big Tujunga Creek in the Hansen Reach;

 Two tributaries in the Hansen Reach (for example, Haines Creek, Little Tujunga 

Creek); and

 One tributary in either the Big Tujunga Reach or Los Angeles Reach (for example, 

Fall Creek, Mill Creek, Arroyo Seco Creek).

San Gabriel River Watershed Recovery Unit –

 The East, West, and North forks of San Gabriel River in the San Gabriel Reach;

 Three tributaries in the San Gabriel Reach (for example, Bear Creek, Big Mermaids 

Creek, Cattle Canyon Creek); and

 Either the Cogswell Reach, the East Fork above the “Bridge to Nowhere”, or one 

tributary in the Whittier Reach (for example, San Dimas Wash, Fish Canyon 

Creek).

E.4 A long-term monitoring and management plan is in place to evaluate the effectiveness of 

management actions to address ongoing threats and to identify new threats which may require 

implementation of adaptive management actions. 
III-1

III. RECOVERY ACTION NARRATIVE AND IMPLEMENTATION

SCHEDULE

The actions identified below are those that, in our opinion, are necessary to bring about 

the recovery of Santa Ana sucker and ensure its long-term conservation. However, these actions 

are subject to modification as dictated by new findings, changes in species status, and the 

completion of other recovery actions. We anticipate this recovery plan will be evaluated 

periodically to determine if the objectives are being achieved, and will be updated as necessary 

to incorporate new information.

Each action has been assigned a priority according to our determination of what is most 

important for the recovery of these species based on the life history, ecology, and threats (see the 

Background section of this document) and the following definitions of the priorities: 

Priority 1: An action that is taken to prevent extinction or to prevent the species from declining 

irreversibly.

Priority 2: An action that is taken to prevent a significant decline in species population/habitat 

quality or some other significant negative impact short of extinction. 

Priority 3: All other actions necessary to provide for full recovery of the species. 

 

There are several factors that are pertinent to consider when assigning priority numbers to 

these actions. First, Santa Ana suckers within Santa Ana and Los Angeles River watersheds are 

more at risk than in the San Gabriel River watershed, because the extent of suitable habitat is 

lower due to the construction and operation of large dams, making populations in these two 

watersheds at higher risk of local extirpation. There are also fewer unaltered tributaries available

in the Santa Ana and Los Angeles River watersheds, compared to the San Gabriel River. In 

contrast, the hydrology in a large portion of the current range in the San Gabriel River remains 

unaltered (east and north forks and associated tributaries). 

Priorities for each action will therefore vary within each watershed, depending on the 

magnitude and scope of the threats. The timing of actions may also be affected by the 

availability of funding, landowner permission, and the extent of information required to address 

the threat. Some threats may require specific research in order to inform management actions 

(for example, the timing and extent of flows needed to maintain suitable habitat conditions) 

while others can be addressed based on the current information available (for example, control of 

unauthorized OHV activity in occupied habitat). Recovery actions will be implemented in 

coordination with the landowners and other stakeholders within each watershed. Therefore, 

implementation tables were created separately for each watershed to determine priority actions 

necessary for recovery. While some threats are similar across the range of the species, separate 

tables will enable managers to focus on implementation of actions that are most pertinent for 

recovery of the Santa Ana sucker in their watershed. 
III-2

The Recovery Action Narrative provides details of the actions necessary to achieve Santa 

Ana sucker recovery. The priorities within each Recovery Unit are specified in Tables 2, 3, and 

4 following this section. 

The numeric recovery priority system follows that of all Service recovery plans. Actions 

may be assigned Priority 1 where they are needed to prevent extinction or stabilize and secure 

populations or ecological functions undergoing irreversible degradation. Actions are labeled 

Priority 2 if they are needed to prevent the significant decline of the species or habitat. Priority 3 

actions include other actions necessary for the full recovery of the species. Because situations 

change over time, priority numbers must be considered in the context of past and potential future 

actions at all sites. Therefore, the priority numbers assigned are intended to guide, not to 

constrain, the allocation of limited conservation resources.

A. Recovery Action Narrative

1. Develop and implement a rangewide monitoring protocol to accurately and 

consistently document populations, occupied habitat, and threats. 

A standard protocol for monitoring Santa Ana sucker is needed to evaluate the efficacy of 

Recovery Actions and progress towards meeting Recovery Criteria. It will also allow for 

comparison of the relative status of the species in each watershed.

1.1 Develop a rangewide monitoring protocol. The protocol should include the 

following components (Priority 2): 

• Metrics related to the status of the Santa Ana sucker population (for example, 

abundance, age structure, and distribution). 

• Metrics related to the suitability of habitat for each life stage (for example, 

water quality, water quantity, substrate, and food sources). 

• Metrics related to the status of threats (for example, hydrological 

modifications and barriers to dispersal, water quality, nonnative vegetation, 

and OHV use). 

• Standardized data sheets.

1.2 Review and update the monitoring protocol to reflect new information as it 

becomes available. For example, research that leads to a better understanding of 

life history strategies, such as patterns of migration, growth, reproduction, and 

recruitment, may result in changes to metrics used to define suitable habitat for 

each life stage. (Priority 3)

2. Conduct biological research to inform management actions and recovery for the 

Santa Ana sucker. 
III-3

There are numerous gaps in our understanding of Santa Ana sucker biology and ecology. 

Research is needed to identify optimum habitat conditions and to identify how to best 

minimize impacts caused by reduced water quality, altered hydrology, nonnative species, 

and small population size. 

2.1 Water Quality – Determine the sensitivity of Santa Ana sucker to water quality 

variables that may be altered by hydrological modification or regulated 

discharges. Variables may include water temperature, thermal fluctuations, 

dissolved oxygen, turbidity, nitrates/nitrites, total dissolved solids, perchlorate, 

chlorine, sulfides, ammonia, various metals, and other organic compounds 

2.1.1 Evaluate sensitivity to environmental conditions in the Santa Ana River 

RU (Priority 2). 

2.1.2 Evaluate sensitivity to environmental conditions in the Los Angeles River 

RU (Priority 2). 

2.2 Hydrology – In areas with modified hydrology, determine hydrological processes 

necessary to maintain breeding, feeding, and sheltering habitat for the species. 

Research should also focus on the timing and magnitude of flows that will 

maintain the complex diversity of habitat variables necessary to support each life 

stage (for example, sufficient sediment with appropriate grain size for spawning, 

pools, riffles, shallow stream margins, undercut banks, emergent aquatic 

vegetation, and riparian vegetation). The historical flow regime should be 

evaluated to determine the hydrological conditions that led to the creation of 

suitable habitat for the species and should be restored to the extent possible.

2.2.1 Evaluate hydrological processes in the Santa Ana River RU (Priority 1).

2.2.2 Evaluate hydrological processes in the Los Angeles River RU 

(Priority 1).

2.2.3 Evaluate hydrological processes in the San Gabriel River RU (for example

West fork) (Priority 3).

2.3 Sediment Transport – In areas with modified hydrology, evaluate sediment 

sources and transport to determine if sufficient sediment is available to maintain 

appropriate gradient and substrate composition for the species.

2.3.1 Evaluate sediment transport in the Santa Ana River RU (Priority 1).

2.3.2 Evaluate sediment transport in the Los Angeles River RU (Priority 3).

2.3.3 Evaluate sediment transport in the San Gabriel River RU (Priority 3).
III-4

2.4 Suitable Habitat – Determine the habitat conditions (for example, gradient, water 

quality, water velocity, and substrate) that are conducive to supporting the Santa 

Ana sucker.

2.4.1 Determine optimal habitat conditions for spawning. Research should 

focus on how Santa Ana sucker reproduction is affected by gradient, 

substrate composition, water velocity, water quality, and any other 

relevant aspect of its habitat. This may include studies related to 

spawning cues, spawning behavior, egg adhesion, and viability of eggs, in 

relation to changing environmental conditions (Priority 2). 

2.4.2 Determine optimal conditions for feeding. Research should include 

identification of food resources and habitat conditions necessary to sustain 

food resources (for example, water flow, water quality, and substrate) and 

feeding. Research should address food resources necessary to sustain all 

life stages (Priority 2).

2.5 Nonnative Species – Determine how habitat suitability can be improved through 

reduction of nonnative aquatic species and nonnative riparian vegetation.

2.5.1 Identify management actions that will ameliorate potential impacts of 

nonnative predators on Santa Ana sucker. Identify which life stages and 

under what circumstances Santa Ana suckers are most susceptible to 

predation (for example monitor stomach contents of predators). 

2.5.1.1 Identify actions to ameliorate impacts of predation in the Santa 

Ana River RU (Priority 2).

2.5.1.2 Identify actions to ameliorate impacts of predation in the Los 

Angeles River RU (Priority 2).

2.5.1.3 Identify actions to ameliorate impacts of predation in the San 

Gabriel River RU (Priority 3).

2.5.2 Determine if habitat conditions for Santa Ana sucker can be improved 

through the removal/management of nonnative riparian vegetation (for 

example, Arundo donax and Tamarix ramosissima) (Priority 3).

2.5.3 Investigate the extent of impacts of invasive red algae (Compsopogon 

coeruleus) to Sana Ana sucker habitat within the Santa Ana River 

Recovery Unit. If impacts are found to be significant, investigate 

management actions to remove or treat this nonnative to reduce impacts to 

the sucker where it occurs (Priority 1). 

2.6 Genetics – Ensure the natural genetic diversity across the range of the species is 

preserved.
III-5

2.6.1 Determine the genetic variation within and between watersheds where 

Santa Ana sucker occur (Priority 2).

2.6.2 Determine the status of Santa Ana sucker in the Santa Clara River. 

Additional information is needed from genetic studies to verify whether 

the species was artificially introduced into that watershed or if it occurs 

there naturally and should be considered part of the listed entity 

(Priority 3).

2.7 Captive Propagation – Captive propagation may be necessary to assist in the 

recovery of the species (for example, Santa Ana River Recovery Unit) due to the 

limited extent of suitable spawning habitat.

2.7.1 Use data available from monitoring activities and studies of Santa Ana 

sucker genetics, demography, life history, and ecology to determine if 

captive propagation would be needed to obtain the number of fish of 

appropriate genetic makeup needed to reestablish occurrences or a refuge 

population (Priority 1).

2.7.2 Determine the methodology necessary for captive propagation of Santa 

Ana suckers and rearing of all life stages (Priority 1). 

2.7.3 If captive propagation is needed, assemble the necessary information to 

comply with the Fish and Wildlife Service’s captive propagation policy, 

including development of a captive propagation plan that includes the 

following information (Priority 1): 

• Location of facility.

• Number and origin of fish required for propagation.

• Methodology used for care and propagation. 

• Number of reproductive crosses needed. 

• Target number of fish to be produced.

3. Increase the abundance and distribution of the Santa Ana sucker within its current 

range by reducing threats to the species and its habitat. 

Work with partners to plan and implement management for the Santa Ana sucker in each 

Recovery Unit. Management should include the implementation of Recovery Actions 

aimed at reducing threats to the species and its habitat. The abundance and distribution 

of Santa Ana suckers have been reduced in all watersheds as a result of modification or 

destruction of suitable habitat. Protection, restoration, and management of habitat within 
III-6

the current range of the species are critical to maintaining a stable population within each 

watershed. Many actions listed below will help to address multiple threats. 

 

3.1 Ameliorate hydrological modifications due to flood control and water 

conservation operations. Based on the results of hydrology, sediment transport, 

and life history studies, secure sufficient water flows and sediment to maintain 

habitat for all life stages of the Santa Ana sucker. Natural hydrological functions 

should be mimicked to the extent possible and habitat managed to simulate 

natural processes as necessary in areas with regulated discharge to maintain 

suitable habitat for the species.

3.1.1 Prepare and implement a management plan to determine where flows are 

inadequate to sustain Santa Ana sucker habitat, and restore habitat through 

a combination of the following:

• Reduce water diversions to provide water flows sufficient to 

maintain habitat for Santa Ana sucker.

• Provide supplemental water flow from potable water supplies to

restore or create habitat.

• Work with partners to improve habitat conditions through 

modification of dam/diversion operations. Changes in operations 

(amount and timing of releases) may contribute to restoration of a 

more natural system of water and sediment transport, which would 

improve habitat quality for the Santa Ana sucker. 

• Manage sediment supply and distribution (for example, use sluice 

gates or other mechanisms to allow sediment transport through 

detention facilities) to sustain and improve habitat.

• Restore natural gradient in streams where flood control structures 

have altered the natural gradient.

• Manage vegetation and channel configuration to emulate 

conditions caused by flood-related disturbances.

3.1.1.1 Prepare and implement management plan to address flood control 

and water conservation operations in the Santa Ana River RU

(Priority 1).

3.1.1.2 Prepare and implement management plan to address flood control 

and water conservation operations in the Los Angeles River RU

(Priority 2).
III-7

3.1.1.3 Prepare and implement management plan to address flood control 

and water conservation operations in the San Gabriel River RU

(Priority 3).

3.1.2 Reduce disturbance associated with flood control infrastructure 

maintenance. Work with our partners to determine if operation or design 

of flood control facilities could be altered to reduce the frequency of 

disturbance to the Santa Ana sucker and its habitat. 

• Evaluate and change flood control facility maintenance practices to 

reduce the frequency of disturbance required.

• Redesign levees/embankments to eliminate the need for frequent 

repairs associated with annual storm flows.

• Enlarge or redesign culverts to provide more efficient sediment 

transport. 

3.1.2.1 Reduce disturbance associated with flood control maintenance in 

the Santa Ana River RU (Priority 2).

3.1.2.2 Reduce disturbance associated with flood control maintenance in 

the Los Angeles River RU (Priority 3).

3.1.2.3 Reduce disturbance associated with flood control maintenance in 

the San Gabriel River RU (Priority 3).

3.2 Ameliorate hydrological modifications that create fish passage barriers. Reduce 

barriers to fish passage within currently occupied habitat to restore connectivity 

between populations and access to suitable habitat. Barriers to fish movement 

also have the potential to directly impact habitat for the Santa Ana sucker by 

changing the stream gradient, and altering hydrology. Determine which barriers 

to remove or modify to improve connectivity and reduce impacts to fish dispersal 

and sediment transport; implement removal or modification of identified barriers.

• Recreational Dams. Identify and remove recreational dams that are 

barriers to dispersal or otherwise impact Santa Ana sucker, post signs 

prohibiting the construction of recreational dams, and create educational 

brochures for distribution on public lands.

• Road Crossings. Create low flow channels or fish ladders within cement 

aprons under bridge crossings. Install bridges or culverts of a size and 

configuration that will allow fish passage over a wide range of flow levels.

• Access into tributaries. Reestablishing connection of tributaries to the 

mainstem will provide additional habitat and refuge for the Santa Ana 
III-8

sucker, especially juvenile suckers (for example, in Sunnyslope Creek). 

Remove cement barriers or cement lining in channels to increase access 

and habitat suitability (for example, in Day Creek and Evans Drain). 

Reestablish tributary flow rates sufficient to keep channel clear of 

vegetation and suitable for Santa Ana sucker.

• Access to the floodplain. Acquire (if necessary) and resort hydromorphologic process to lands within the floodplain, such as abandoned 

golf courses and other areas where artificial fill has been placed.

3.2.1 Address specific fish passage barriers in the Santa Ana River RU

(Priority 2).

3.2.2 Address specific fish passage barriers in the Los Angeles River RU

(Priority 3).

3.2.3 Address specific fish passage barriers in the San Gabriel River RU

(Priority 3).

3.3 Ameliorate reduced water quality. Based on the results of water quality studies 

(Recovery Action 2.1), ensure the water quality of flows altered by hydrological 

modification and regulated discharges are improved, as necessary, to provide 

water quality suitable for the Santa Ana sucker.

• Maintain water quality standards as defined by the Regional Water Quality 

Control Board to support Santa Ana sucker.

• Identify and implement dam operations that maintain suitable water quality 

for Santa Ana sucker.

• Integrate appropriate water quality standards into long-term monitoring 

program

3.3.1 Provide water quality suitable for the Santa Ana sucker in the Santa Ana 

River RU (Priority 2).

3.3.2 Provide water quality suitable for the Santa Ana sucker in the Los Angeles 

River RU (Priority 3).

3.3.3 Provide water quality suitable for the Santa Ana sucker in the San Gabriel 

River RU (Priority 3).

3.4 Ameliorate competition and predation by nonnative species to levels determined 

to be necessary for the maintenance of viable Santa Ana sucker populations 
III-9

3.4.1 Manage nonnative predators, as necessary (based on the results of research 

conducted under Recovery Action 2.5.1) to reduce impacts caused by 

these species. Potential strategies include:

• Work with partners to alter dam operations to help suppress 

nonnative species by periodically increasing flow releases when 

there is an abundance of nonnative species.

• Reduce the extent of habitat available to support nonnative 

predators (for example, remove recreational dams and nonnative 

riparian vegetation).

• Reduce the introduction of nonnative predators into habitat for 

Santa Ana sucker (for example, install fish screens to prevent 

escape of nonnative predators from ponds and artificial wetlands)

3.4.1.1 Manage predators in the Santa Ana River RU (Priority 2).

3.4.1.2 Manage predators in the Los Angeles River RU (for example,

Haines Creek) (Priority 2).

3.4.1.3 Manage predators in the San Gabriel River RU (Priority 3).

3.4.2 Manage nonnative vegetation, as necessary (based on the results of 

research conducted under Recovery Actions 2.5.2 and 2.5.3) to reduce 

impacts to Santa Ana sucker habitat caused by nonnative vegetation (for 

example, Arundo donax, Tamarix ramosissima, and Compsopogon 

coeruleus).

• Remove nonnative riparian vegetation in areas that will improve 

habitat conditions for Santa Ana sucker.

• Coordinate with existing nonnative riparian vegetation removal 

programs to target areas that will improve habitat conditions for 

Santa Ana sucker.

• Control the extent of the invasive algae by drying, chemical 

treatment, managing flows, or altering water quality.

3.4.2.1 Manage nonnative vegetation in the Santa Ana River RU (Priority 

1).

3.4.2.2 Manage nonnative vegetation in the Los Angeles River RU

(Priority 3).
III-10

3.4.2.3 Manage nonnative vegetation in the San Gabriel River RU

(Priority 3). 

3.5 Ameliorate impacts to habitat from recreational activities (for example, OHV use, 

swimming/bathing, fishing, and mining). Strategies should consider the timing, 

frequency, location, and magnitude of activities that can be implemented in 

occupied habitat for the Santa Ana sucker without causing a decline in productivity 

within the watershed. Develop and implement strategies to reduce impacts through 

outreach and regulated access:

• Limit the number of activity permits issued and implement timing 

restrictions.

• Reduce the number of access points.

• Increase the number of trash facilities and the frequency of trash 

collection.

• Install signs informing the public of authorized activities.

• Patrol and issue tickets for unauthorized activities.

• Develop educational programs and brochures.

3.5.1 Manage recreation in the Santa Ana River RU (for example OHV activity) 

(Priority 2).

3.5.2 Manage recreation in the Los Angeles River RU (for example, swimming, 

mining, OHV activity) (Priority 2).

3.5.3 Manage recreation in the San Gabriel River RU (for example, swimming, 

mining, OHV activity) (Priority 2). 

4. Increase the range of the Santa Ana sucker by restoring habitat (as needed), and 

reestablishing occurrences within its historical range.

The abundance and distribution of the Santa Ana sucker has been reduced by 

modification and destruction of suitable habitat. Reestablishment of Santa Ana sucker in 

areas currently outside of the range of the species is needed for recovery. In order to 

reestablish occurrences, areas within the historical range of the species will need to be 

restored, protected, and managed to provide habitat suitable for all life stages of Santa 

Ana sucker. Expansion of the range can occur passively through removal of barriers to 

dispersal or it can occur through active reintroduction of the Santa Ana sucker to habitat 

within its historical range. 
III-11

The extent of additional occupied habitat that will be needed for the recovery of the 

species within each watershed is related to the extent of threats within the current range 

and the potential to manage those threats. An expanded range, including refuge 

populations, provides resiliency where threats within the current range cannot be reduced 

effectively or to an extent needed to maintain a stable population. We will prioritize 

locations for potential reintroduction, based on the ability to reduce threats in the current 

range in a timely and effective manner. 

The planning and implementation of projects involving the expansion of the range of the 

species will involve cooperation with stakeholders, including, but not limited to private 

landowners, local resource management agencies, and State, and Federal agencies. 

Expansion of the species range will generally occur as follows: 

4.1 Assess habitat within the historical range that can be restored and made 

suitable for passive range expansion or reintroduction of Santa Ana sucker. The 

highest priority should be given to areas within the historical range that contain 

the known habitat requirements (described in the Habitat and Ecosystem section 

above) or can be restored with reasonable effort to provide these characteristics.

4.1.1 Assess areas within the Santa Ana River RU for potential range expansion. 

Areas to be considered for possible reintroduction include: Aliso Creek, 

Temescal Creek, Chino Creek, San Antonio Creek, Cucamonga Creek, 

Day Creek, Alder Creek, Santa Ana River above Seven Oaks dam, Mill 

Creek, Lytle Creek, Cajon Wash, City Creek, Plunge Creek, Warm Creek, 

Mountain Home Creek, Bear Creek, and other potential tributaries

(Priority 1).

4.1.2 Assess areas within the Los Angeles River RU for potential range 

expansion. Areas to be considered for possible reintroduction include: 

Fall Creek, Mill Creek and Arroyo Seco Creek, and Pacoima Wash

(Priority 3).

4.1.3 Assess areas within the San Gabriel RU for potential range expansion. 

Areas to be considered for possible reintroduction include: upstream 

from Cogswell Dam, East For San Gabriel River above the Bridge to 

Nowhere, Fish Creek, Dalton Creek, Santa Anita Creek, and Monrovia 

Creek (Priority 3).

4.2 Plan and implement habitat restoration and reintroductions using data 

obtained from habitat assessments of potential range expansion areas. Restoration 

and reintroduction plans should include the following information to assist in 

evaluating how the actions may benefit the Santa Ana sucker:

• A description of existing habitat conditions (for example, water quality, 

hydrology, stream gradient, substrate, cover, and other habitat variables 

determined to be important for supporting the species).
III-12

• A description of potential threats to the species (for example, altered 

hydrology, nonnative species, recreation, poor water quality).

• The methodology for restoration of suitable habitat (if necessary).

• Number, age class(s), and origin of fish to be relocated (if necessary). The 

origin of fish should be based on the results of genetic analysis (Recovery 

Task 2.6.1) to ensure the proposed relocation does not alter the natural 

genetic diversity across the range of the species.

• Methods for transport and release of fish (if necessary).

• Timing of project implementation.

• Pre- and post-project monitoring strategy to assess effectiveness of the 

habitat restoration or reintroductions. Monitoring should be conducted for 

a sufficient period to determine if the project resulted in persistent 

occurrences of healthy fish (for example, abundance, distribution, age 

classes).

• Long-term management activities required to maintain the species within 

the expanded range and to address ongoing threats as described in 

Objective 3 above. Adaptive management strategies should be 

incorporated as needed to address new threats as they are identified. For 

isolated occurrences, management should consider future introductions 

that may be necessary to ensure minimal genetic drift, genetic bottlenecks, 

and other risks associated with low genetic variability.

4.2.1 Prepare and implement range expansion plan(s) for the Santa Ana River 

RU (Priority 1).

4.2.2 Prepare and implement range expansion plan(s) for the Los Angeles River 

RU (Priority 3).

4.2.3 Prepare and implement range expansion plan(s) for the San Gabriel River 

RU (Priority 3).

B. Implementation Schedule

The following implementation schedule outlines actions and estimated costs for this draft 

recovery plan. This schedule prioritizes actions, provides an estimated timetable for 

performance of actions, indicates the responsible parties, and estimates costs of performing 

actions. Cost estimates are provided for the entire recovery period (estimated to be 25 years) as 

well as detailed for the first 5 years of the recovery period. These actions, when accomplished, 

should further the recovery and conservation of the listed species.
III-13

Key to additional terms and acronyms used in the Implementation Schedule:

Definition of action durations:

Number: The predicted duration of the action in years.

Ongoing: An action that is currently being implemented and will continue throughout the 

recovery period.

Continual: An action that is not currently being implemented but will be implemented 

continuously throughout the recovery period once begun.

Unknown: Either action duration or associated costs are not known at this time.

Responsible Parties: 

Responsible parties are those partnering agencies who may voluntarily participate in any 

aspect of implementation of particular tasks listed within this draft recovery plan. Responsible 

parties may willingly participate in project planning, funding, staff time, or any other means of 

implementation. The identification of responsible parties for specific tasks (Tables 2-4) is not 

intended to limit involvement by other parties or to require the involvement of the party 

identified. Key land managers, land owners, or other stakeholders that have been identified in 

the implementation schedule:

• California Department of Fish and Wildlife (CDFW)

• City of Riverside (Riverside)

• County of Los Angeles Department of Public Works (LACDPW)

• Los Angeles County Department of Parks and Recreation (LACDPR)

• Inland Empire Resource Conservation District (IERCD)

• Orange County Flood Control District (OCFCD)

• Orange County Water District (OCWD)

• Private landowners (Private)

• Regional Water Quality Control Board (RWQCB)

• Riverside-Corona Resource Conservation District (RCRCD)

• Riverside County Flood Control and Water Conservation District (RCFCWCD)

• Santa Ana Watershed Association (SAWA)

• San Bernardino County Flood Control District (SBCFCD)

• Santa Ana Watershed Protection Authority (SAWPA)

• Southern California Edison (SCE)

• U.S. Army Corps of Engineers, Los Angeles District (USACE)

• U.S. Fish and Wildlife Service (USFWS)

• U.S. Geological Survey (USGS)

• U.S. Forest Service (USFS)

Please note, additional Responsible Parties may be added in the final Recovery Plan subsequent 

to coordination and collaboration with our partners on specific recovery actions. 
III-14

Table 2: Implementation Schedule – Actions to be completed across all recovery units (Santa Ana River, Los Angeles River, 

and San Gabriel River Recovery Units).

Santa Ana River, Los Angeles River, and San Gabriel River Recovery Units

Action 

number Priority Description Responsible 

Parties1

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Total cost of 

action for 

FY1 FY2 FY3 FY4 FY5 Total recovery

1.1 2 Develop a rangewide monitoring 

protocol. USFWS 1 50 50 50

1.2 3

Review and update the monitoring 

protocol to reflect new information 

as it becomes available.

USFWS Continual TBD TBD

2.4.1 2 Determine optimal habitat conditions 

for spawning. 

USFWS

CDFW 2 100 100 200 200

2.4.2 2 Determine optimal conditions for 

feeding.

USFWS

CDFW 2 100 100 200 200

2.5.2 3

Determine if habitat conditions for 

Santa Ana sucker can be improved 

through the removal/management of 

nonnative riparian vegetation. 

RCRCD

SAWA

USFS

2 50 50 100 100

2.6.1 2

Determine the genetic variation 

within and between watersheds 

where Santa Ana sucker occur.

USGS 1 50 50 50

2.6.2 3 Determine the status of Santa Ana 

sucker in the Santa Clara River.

USFWS

CDFW

USGS 

1 50 50 50

 1 The identification of responsible parties for specific tasks (Tables 2–5) is not intended to limit involvement by other parties or to require the 

involvement of the party identified. 
III-15

Table 3: Implementation Schedule – Santa Ana River Recovery Unit.

Santa Ana River Recovery Unit

Action 

number Priority Description Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars) Total cost of action 

for recovery FY1 FY2 FY3 FY4 FY5 Total

2.1.1 2 Evaluate sensitivity to environmental 

conditions in the Santa Ana River RU. 

USFWS

USGS

RWQCB

2 100 100 200 200

2.2.1 1 Evaluate hydrological processes in the 

Santa Ana River RU.

USGS

USACE 2 75 75 150 150

2.3.1 1 Evaluate sediment transport in the 

Santa Ana River RU.

USGS

USACE 1 75 75 75

2.5.1.1 2

Identify actions to ameliorate impacts 

of predation in the Santa Ana River 

RU.

OCWD

USACE 2 50 50 100 100

2.5.3 1

Investigate the extent of impacts of 

invasive red algae (Compsopogon 

coeruleus) to Santa Ana sucker habitat 

within the Santa Ana River RU. 

Investigate management actions to 

remove or treat this nonnative to 

reduce impacts to the sucker where it 

occurs. 

USFWS

RWQCB

USACE

CDFW

Unknown 60 60 120 120

2.7.1 1

Use data available from monitoring 

activities and studies of Santa Ana 

sucker genetics, demography, life 

history, and ecology to determine if 

captive propagation is required to 

obtain the number of fish of 

appropriate genetic makeup needed to 

reestablish occurrences or develop a 

refuge population.

USFWS Unknown TBD TBD
III-16

Action 

number Priority Description Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars) Total cost of action 

for recovery FY1 FY2 FY3 FY4 FY5 Total

2.7.2 1

Determine the methodology necessary 

for captive propagation of Santa Ana 

suckers and rearing of all life stages. 

RCRCD 2 75 75 150 150

2.7.3 1

If captive propagation is required, 

assemble the necessary information to 

comply with the captive propagation 

policy, including development of a 

captive propagation plan.

USFWS

CDFW

USGS 

1 50 50 50

3.1.1.1 1

Prepare and implement management 

plan to address flood control and 

water conservation operations in the 

Santa Ana River RU. 

USACE

OCFCD

RCFCWCD

SBCFCD

SCE

SAWPA

Unknown TBD TBD

3.1.2.1 2

Reduce disturbance associated with 

flood control maintenance in the Santa 

Ana River RU.

USACE

OCFCD

RCFCWCD

SBCFCD

Unknown TBD TBD

3.2.1 2 Address specific fish passage barriers 

in the Santa Ana River RU. TBD Unknown TBD TBD

3.3.1 2

Provide water quality suitable for the 

Santa Ana sucker in the Santa Ana 

River RU.

RWQCB

USACE Continual TBD TBD

3.4.1.1 2 Manage predators in the Santa Ana 

River RU.

OCWD

Riverside

USFS

CDFW

USFWS

Continual 50 25 25 25 25 150 275

3.4.2.1 1 Manage nonnative vegetation in the 

Santa Ana River RU.

IERCD

RCRCD

SAWA

OCFCD

OCWD

Continual 50 25 25 25 25 150 275
III-17

Action 

number Priority Description Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars) Total cost of action 

for recovery FY1 FY2 FY3 FY4 FY5 Total

3.5.1 2 Manage recreation in the Santa Ana 

River RU.

OCWD

OCFCD 

USACE 

Private

Continual 40 20 20 20 20 120 220

4.1.1 1

Assess areas within the Santa Ana 

River RU for potential range 

expansion..

USFWS

CDFW

USFS

2 50 50 100 100

4.2.1 1

Prepare and implement range 

expansion plan(s) for the Santa Ana 

River RU. 

USFWS

USACE

USFS

USGS

Continual TBD TBD
III-18

Table 4: Implementation Schedule – Los Angeles River Recovery Unit. 

Los Angeles River Recovery Unit

Action 

number Priority Description Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Total 

cost of 

action 

for 

recovery

FY1 FY2 FY3 FY4 FY5

Total

2.1.2 2

Evaluate sensitivity to environmental 

conditions in the Los Angeles River 

RU. 

LACDPW

RWQCB 2 100 100 200 200

2.2.2 1 Evaluate hydrological processes in the 

Los Angeles River RU.

USGS

LACDPW

USFS

2 50 50 100 100

2.3.2 3 Evaluate sediment transport in the Los 

Angeles River RU.

USGS

LACDPW

USFS

1 75 75 75

2.5.1.2 2

Identify actions to ameliorate impacts 

of predation in the Los Angeles River 

RU.

LACDPW

USFS 2 50 50 100 100

3.1.1.2 2

Prepare and implement management 

plan to address flood control and 

water conservation operations in the 

Los Angeles River RU. 

LACDPW

USFS Unknown TBD TBD

3.1.2.2 3

Reduce disturbance associated with 

flood control maintenance in the Los 

Angeles River RU.

LACDPW Unknown TBD TBD

3.2.2 3 Address specific fish passage barriers 

in the Los Angeles River RU. USFS Unknown TBD TBD

3.3.2 3

Provide water quality suitable for the 

Santa Ana sucker in the Los Angeles 

River RU.

LACDPW

RWQCB

USFS

Continual TBD TBD

3.4.1.2 2

Manage predators in the Los Angeles 

River RU (for example, Haines 

Creek).

LACDPW

USFS Continual 50 25 25 25 25 150 250
III-19

Action 

number Priority Description Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Total 

cost of 

action 

for 

recovery

FY1 FY2 FY3 FY4 FY5

Total

3.4.2.2 3 Manage nonnative vegetation in the 

Los Angeles River RU. LACDPW

USFS

Continual 50 25 25 25 25 150 250

3.5.2 2 Manage recreation in the Los Angeles 

River RU.

USFS

LACDPR Continual 40 20 20 20 20 120 220

4.1.2 3

Assess areas within the Los Angeles 

River RU for potential range 

expansion.

USFWS

CDFW

USFS

2 50 50 100 100

4.2.2 3

Prepare and implement range 

expansion plan(s) for the Los Angeles 

River RU. 

USFS

USFWS

CDFW

LACDPW

Continual TBD TBD
III-20

Table 5: Implementation Schedule – San Gabriel River Recovery Unit.

San Gabriel River Recovery Unit

Action 

number Priority Description Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Total 

cost of 

action 

for 

recovery FY1 FY2 FY3 FY4 FY5 Total

2.2.3 3

Evaluate hydrological processes in the 

San Gabriel River RU (for example, 

West fork).

USGS

LACDPW

USFS

2 50 50 100 100

2.3.3 3 Evaluate sediment transport in the 

San Gabriel River RU.

USGS

LACDPW

USFS

1 75 75 75

2.5.1.3 3

Identify actions to ameliorate impacts 

of predation in the San Gabriel River 

RU.

USFS

LACDPW 2 50 50 100 100

3.1.1.3 3

Prepare and implement management 

plan to address flood control and 

water conservation operations in the 

San Gabriel River RU. 

LACDPW

USFS Unknown TBD TBD

3.1.2.3 3

Reduce disturbance associated with 

flood control maintenance in the San 

Gabriel River RU.

LACDPW

USFS Unknown TBD TBD

3.2.3 3 Address specific fish passage barriers 

in the San Gabriel River RU.

USFS

Private

LACDPW

Unknown TBD TBD

3.3.3 3

Provide water quality suitable for the 

Santa Ana sucker in the San Gabriel 

River RU.

LACDPW

USFS

RWQCB

Continual TBD TBD

3.4.1.3 3 Manage predators in the San Gabriel 

River RU.

LACDPW

USFS Unknown TBD TBD
III-21

Action 

number Priority Description Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Total 

cost of 

action 

for 

recovery FY1 FY2 FY3 FY4 FY5 Total

3.4.2.3 3 Manage nonnative vegetation in the 

San Gabriel River RU. USFS Unknown TBD TBD

3.5.3 2 Manage recreation in the San Gabriel 

River RU. USFS Continual 40 20 20 20 20 120 220

4.1.3 3

Assess areas within the San Gabriel 

River RU for potential range 

expansion.

USFWS

CDFW

USFS

1 25 25 50 50

4.2.3 3

Prepare and implement range 

expansion plan(s) for the San Gabriel 

River RU. 

USFWS

CDFW

USFS

Continual TBD TBD
III-22
IV-1

IV. LITERATURE CITED

AECOM. 2011. Assessment of the Riverside north aquifer storage and recovery project on the 

Santa Ana sucker (Catostomus santaanae). Prepared for the City of Riverside. May 23, 

2011. 91 pp. 

Allen, B.C. 2002. Evaluation of Santa Ana sucker (Catostomus santaanae) habitat and water 

quality changes in the Santa Ana River as a result of temporary shutdowns at the rapid 

infiltration and extraction plant (RIX). Unpublished report prepared for the San 

Bernardino Municipal Water Department. November 2002. 47 pp.

Allen, B.C. 2003. Evaluation of Santa Ana sucker (Catostomus santaanae) spawning success in 

the Santa Ana River and the potential effects of temporary shutdowns at the rapid 

infiltration and extraction plant (RIX). Unpublished report prepared for the San 

Bernardino Municipal Water Department. 19 pp.

Ally, J.R. 2004a. Estimating leakage from Cogswell Dam (West Fork San Gabriel River). 

Department of Fish and Game, South Coast Region, Inland Fisheries, Northern Unit. 

Lost Alamitos, California. November 22, 2004. 18 pp.

Ally, J.R. 2004b. Survey of selected stream parameters in the East Fork San Gabriel River and 

its tributary Cattle Canyon, and in the North Fork San Gabriel. Department of Fish and 

Game, South Coast Region, Inland Fisheries, Northern Unit. Lost Alamitos, California. 

November 15, 2004. 42 pp.

Ally, J.R. 2004c. Results of electrofishing surveys done in the San Gabriel River (West, North, 

and East Forks) and tributaries Bear Creek and Cattle Canyon during June and July 2003. 

Department of Fish and Game, South Coast Region, Inland Fisheries, Northern Unit. 

Lost Alamitos, California. March 30, 2004. 38 pp.

Ally, J.R. 2004d. Results of electrofishing surveys done in four streams of the San Gabriel River 

drainage in June 2004. Department of Fish and Game, South Coast Region, Inland 

Fisheries, Northern Unit. Lost Alamitos, California. November 3, 2004. 26 pp.

Andresen, V. 2001. Lower Big Tujunga stream pool location survey. Angeles National Forest 

Summer 2001. August 6, 2001. 13 pp. 

Barton, B., J. Morgan, M. Vijayan. 2002. Physiological and condition-related indicators of 

environmental stress in fish, in Biological indicators of aquatic ecosystem stress. Ed. S. 

Adams. 

Baskin, J. N. 2014. Fish Passage Barrier Identification and Assessment Throughout the Range 

of Santa Ana Sucker. Prepared for the U.S. Fish and Wildlife Service. 2014. 51 pp.
IV-2

Baskin, J. N. and T. R. Haglund. 1999. Conservation program for the Santa Ana sucker in the 

Santa Ana River, Southern California. Prepared for the Santa Ana Watershed Project 

Authority. December 1999. 36 pp.

Baskin, J. N. and T. R. Haglund. 2001. Santa Ana sucker survey/seining in the Santa Ana River. 

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Office, Carlsbad, California. Dated September 17, 2010. Subject: impacts to Santa Ana 

suckers and their habitat within Angeles National Forest. 

U.S. Fish & Wildlife Service 

Pacific Southwest Region

Division of Listing, Recovery 

and Environmental Contaminants

2800 Cottage Way, Suite W-2606

Sacramento, CA 95825

http://www.fws.gov

October 2014