Revised Recovery Plan for 

the Lost River sucker and 

Shortnose sucker 

(Deltistes luxatus & Chasmistes brevirostris)

U.S. Fish & Wildlife Service
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

Cover Art:

Images of Lost River sucker and shortnose sucker © Joseph Tomelleri. 

Used with permission.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

Revised Recovery Plan for the Lost River Sucker (Deltistes luxatus) and

Shortnose Sucker (Chasmistes brevirostris)

Recovery Plan

First Revision

Original Version: March 1993

Pacific Southwest Region

U. S. Fish and Wildlife Service

Sacramento, California

Approved: ________________________________________

Regional Director, U.S. Fish and Wildlife Service, Region 8

Date: _____________________
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I. Disclaimer

Recovery plans delineate reasonable actions that are believed to be

required to recover and protect listed species. We, the U.S. Fish and Wildlife 

Service, publish recovery plans, sometimes preparing them with the assistance of 

recovery teams, contractors, State agencies, Tribal agencies, and other affected 

and interested parties. Objectives will be attained and any necessary funds made 

available subject to budgetary and other constraints affecting the parties involved, 

as well as the need to address other priorities. Costs indicated for action 

implementation and time of recovery are estimates and subject to change. 

Recovery Plans do not obligate other parties to undertake specific actions, and 

may not represent the views nor the official positions or approval of any 

individuals or agencies involved in recovery plan formulation, other than the U.S. 

Fish and Wildlife Service. Recovery Plans represent our official position only

after they have been signed by the Director or Regional Director as approved.

Recovery plans are released for public comment and submitted to peer review 

before we adopt them as approved final documents. Approved recovery plans are 

subject to modification as dictated by new findings, changes in species status, and 

completion of recovery actions.

Literature citation of this document should read as follows:

U.S. Fish and Wildlife Service. 2012. Revised recovery plan for the Lost River 

sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris). 

U.S. Fish and Wildlife Service, Pacific Southwest Region, Sacramento, 

California. xviii + 122 pp.

Additional copies may be obtained from:

U.S. Fish and Wildlife Service

Klamath Falls Fish and Wildlife Office

1936 California Avenue

Klamath Falls, OR 97601

541/885-8481

Electronic copies of this document will be available at: 

http://www.fws.gov/endangered/species/recovery-plans.html
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II. Acknowledgements

The recovery plan was prepared by Dr. Donald W. Sada, Desert Research 

Institute and Dr. Josh E. Rasmussen and Mark Buettner from the U.S. Fish and 

Wildlife Service, with the assistance of the Lost River and Shortnose Sucker 

Recovery Team, and in coordination with a recovery team subgroup comprised of 

stakeholders representing various interests in the area affected by the Recovery 

Plan.

The Service gratefully acknowledges the commitment and efforts of the 

members of the Shortnose Sucker and Lost River Sucker Recovery Team for their 

assistance during development of this revised recovery plan. 

Donald W. Sada, Ph.D.

(Team Leader)

Desert Research Institute

Larry Dunsmoor

Klamath Tribes

Christopher Keleher

Utah Department of Natural Resources

Dennis Lynch

U.S. Geological Survey

Douglas Markle, Ph.D.

Oregon State University

Graham Matthews

GMA Hydrology

Saxon Sharpe, Ph.D.

Desert Research Institute

Mark Stern

The Nature Conservancy

Scott VanderKooi

U.S. Geological Survey
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The Recovery Team and Service gratefully acknowledge key input and 

assistance by the following individuals during the revision of the recovery plan: 

Sandra Davis EcoResources Group

Eric Janney U.S. Geological Survey

Dave Sale EcoResources Group

Torrey Tyler Bureau of Reclamation

Additional thanks go to the following individuals for their participation in 

the stakeholder subgroup: 

Glenn Barrett Klamath County Natural Resource Advisory 

Committee

Lisa Brown Water Watch

Jim Carpenter Carpenter Design

Mark Hampton California Department of Fish and Game

Heather Hendrixson The Nature Conservancy

Dave Hogen Forest Service – Fremont/Winema National Forest

Becky Hyde Sprague River Water User

Nathan Jackson Klamath Watershed Partnership

Steve Kirk Oregon Department of Environmental Quality

Chris Leeseberg Klamath Tribes

Dave Mauser U.S. Fish and Wildlife Service – Klamath Basin 

Refuges

Roger Nicholson Resource Conservancy

Shannon Peterson Klamath Basin Rangeland Trust

Linda Prendergast PacifiCorp

Andrea Rabe Sprague River Water Resource Foundation

Rob Roninger Bureau of Land Management – Klamath Falls 

Resource Area

Roger Smith Oregon Department of Fish and Wildlife

Dave Solem Klamath Water Users Association, Klamath 

Irrigation District

Marshall Staunton Hatfield Upper Basin Working Group, Farmer 

Anita Ward Klamath Watershed Council

T.J. Woodley Klamath Soil and Water Conservation District

Teresa Wright Lava Beds – Butte Valley Resource Conservation 

District

Marty Yamagiwa Forest Service – Modoc National Forest
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III. Executive Summary

CURRENT SPECIES STATUS

We, the U.S. Fish and Wildlife Service (USFWS), listed Lost River sucker 

(Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) as endangered 

throughout their entire range on July 18, 1988 (USFWS 1988) under the 

Endangered Species Act of 1973, as amended. Both species are also listed as 

endangered by the States of Oregon and California. No critical habitat has been 

specified for these species. A recovery plan for both species was finalized on 

March 17, 1993 (USFWS 1993). A substantial amount of additional information 

is now available, and it is appropriate to revise the plan and incorporate this new 

information into the recovery program. 

Populations declined prior to listing due to habitat loss of approximately 

75 percent of historic range, restricted access to spawning habitat, overharvest, 

and increased rates of mortality resulting from entrainment1 in water 

management structures and severely impaired water quality. Regularly spawning 

populations now occur only in Upper Klamath Lake, Clear Lake Reservoir, and 

Gerber Reservoir. However, populations in Upper Klamath Lake are 

characterized by low recruitment, reduced survivorship of adult fish, and 

reduced age-class diversity. Length-frequency analysis suggests that the last 

substantial recruitment to the spawning population occurred during the late 1990s. 

Current abundance of spawning individuals of both species in Upper Klamath 

Lake is estimated to be roughly 50 percent of 2001 abundances. Less information 

is available on Clear Lake Reservoir populations, which makes it difficult to 

accurately assess these populations. 

HABITAT REQUIREMENTS

Lost River and shortnose suckers have complex life histories that include 

stream/river, lake, marsh, and shoreline habitats. Both spawn during the spring 

over gravel substrates in habitats less than 1.3 meters (4 feet) deep in tributary 

 

1 Terms defined in the glossary (Appendix I) are indicated with bold formatting at the 

first instance of occurrence.
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streams and rivers. A smaller but significant number of Lost River sucker also 

spawn over gravel substrates at shoreline springs along the margins of Upper 

Klamath Lake. 

Larvae spend relatively little time in rivers or streams before drifting 

downstream to the lakes by mid-summer. Larval habitat is generally along the 

relatively shallow shoreline where emergent vegetation provides cover from 

predators, protection from currents and turbulence, and abundant food (including 

zooplankton, macroinvertebrates, and periphyton). Juvenile suckers utilize a 

wide variety of near and off-shore habitat including emergent wetlands and nonvegetated areas. They increasingly move off-shore into the lake as they grow. 

Adults occupy open water habitats. 

LIMITING FACTORS

A main factor cited at the time of listing as contributing to population 

declines was loss or degradation of spawning, rearing, and adult habitats. The rate 

of habitat loss has slowed during recent years; nevertheless, only about 25 percent 

of the original habitat remains. Reductions in habitat quality compound the 

effects of reduced habitat quantity and availability on Lost River sucker and 

shortnose sucker abundance. Current factors limiting species recovery also 

include high mortality of larvae and juveniles due to reduced rearing habitat, 

entrainment in water management structures, poor water quality and negative 

interactions with introduced species. Adult populations are limited by the 

negligible recruitment to the population, as well as high levels of stress and 

mortality associated with severely impaired water quality. As a whole the species 

are potentially limited by the lack of habitat connectivity.

RECOVERY GOAL

The goal of our recovery program is to arrest the decline and enhance Lost 

River sucker and shortnose sucker populations so that Endangered Species Act

protection is no longer necessary.

RECOVERY OBJECTIVES

Demographic-based and threats-based objectives will facilitate recovery 

and enable attainment of the recovery goal. Demographic-based objectives 

include increasing larval production, individual survival and recruitment to 
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spawning populations, and therefore abundance in spawning populations. The 

objectives of restoring spawning and nursery habitat, expanding reproduction, 

reducing the negative impacts from water quality on all life stages, clarifying the 

effects of other species on all life stages, reducing entrainment, and establishing 

auxiliary populations comprise the threats-based objectives. 

RECOVERY STRATEGY

The recovery strategy is intended to produce and document healthy, selfsustaining populations by reduction of mortality, restoration of habitat, including 

spawning, larval and juvenile habitats, and increasing connectivity between 

spawning and rearing habitats. It also involves ameliorating adverse effects of 

degraded water quality, disease, and non-native fish. The plan provides areas of 

emphasis and guidelines to direct recovery actions. Recent, 5-year status reviews 

for each species assigned a recovery priority number of 4C for both species 

(USFWS 2007a, b). However, shortnose sucker were inaccurately assigned given 

that they do not belong to a monotypic genus. Instead, the recovery priority 

number for Lost River and shortnose sucker should be 4C and 5C, respectively. 

The only difference being that Lost River suckers belong to a monotypic genus, 

whereas shortnose sucker are a species in a polytypic genus. As a result, Lost 

River sucker merit a higher priority number.

RECOVERY UNITS

Establishing recovery units is a useful tool for species that occur in 

multiple populations where varying ecological conditions, threats, and 

management challenges exist. Recovery goals are set for each unit, and progress 

toward recovery is measured within each unit. Recovery criteria must be met in 

all recovery units for both species before downlisting or delisting will be 

considered. The recovery units for both species are the Upper Klamath Lake Unit 

and the Lost River Basin Unit. Each recovery unit also includes several 

management units. These management units allow for tailored management 

objectives and actions for individual populations or sub-populations.

Upper Klamath Lake Unit (designated for each species separately)

includes all individuals residing in Upper Klamath Lake, its tributaries, or within 

any of the reservoirs along the Klamath River. This unit is comprised of four 

management units, depending on the species:
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• Upper Klamath Lake and tributaries – River Spawning Individuals

• Upper Klamath Lake – Shoreline Spring Spawning Individuals

• Keno Reservoir

• Populations below Keno Reservoir

Recovery of the species in all of these management units is not necessary 

to achieve recovery of the species overall. For example, although the populations 

of suckers below Keno Reservoir provide some redundancy to populations in the 

other more important management units, they are sink populations that likely will 

never be viable, and therefore will not be actively managed for recovery.

Lost River Basin Unit (designated for each species separately): includes 

all individuals residing in the reservoirs and flowing water in this sub-basin. Four 

specific management units have been designated:

• Clear Lake Reservoir and tributaries

• Tule Lake

• Gerber Reservoir and tributaries

• Lost River Proper

RECOVERY CRITERIA

The recovery criteria comprise a combination of measures that must be 

taken to directly ameliorate or eliminate threats to the species for each of the 

above recovery units and to achieve numerical demographic targets. These criteria

are described in detail in the ‘Downlisting Criteria’ and ‘Delisting Criteria’

sections of this document.

ACTIONS NEEDED

Actions needed to recover this species include the following (in no 

specific order):

Action 1: Restore or enhance spawning and nursery habitat

Action 2: Reduce negative impacts of poor water quality where necessary
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Action 3: Clarify and reduce the effects of introduced species on all life stages by 

conducting and applying scientific investigations

Action 4: Reduce the loss of individuals to entrainment

Action 5: Establish a redundancy and resiliency enhancement program

Action 6: Increase juvenile survival and recruitment to spawning populations

Action 7: Maintain and increase the number of recurring, successful spawning 

populations

Action 8: Establish a Klamath Basin Sucker Recovery Implementation Program

DATE OF RECOVERY

If actions are successfully implemented, Lost River sucker and shortnose 

sucker could recover in five to seven generations, based on the concept that a 

generation is the average time it takes for a female to become reproductive. This 

is typically seven years for Lost River sucker and five years for shortnose suckers. 

Therefore, we expect it will take roughly 30 to 50 years to achieve recovery for 

both species.

TOTAL ESTIMATED COST OF RECOVERY

We estimate that it will cost roughly $135 million to recover both of these 

species, as summarized below. Values in the table are given in thousands of 

dollars.

Fiscal 

Year

Action 

1

Action 

2

Action 

3

Action 

4

Action 

5

Action 

6

Action 

7

Action 

8

FY 1 0 0 0 50 160 110 500 60

FY 2 150 100 0 60 205 135 500 110

FY 3 500 215 0 500 155 260 500 125

FY 4 450 1,300 100 500 110 260 740 85

FY 5 1330 1,400 100 800 110 280 900 35

FY 6+ 39,415 34,988 2,350 1,990 18,650 2,690 20,850 2,050

Total 41,845 38,003 2,550 3,900 19,390 3,735 23,990 2,465
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IV. Table of Contents

I. DISCLAIMER -------------------------------------------------I

II. ACKNOWLEDGEMENTS--------------------------------III

III. EXECUTIVE SUMMARY ---------------------------------V

CURRENT SPECIES STATUS------------------------------------------------------------- V

HABITAT REQUIREMENTS -------------------------------------------------------------- V

LIMITING FACTORS--------------------------------------------------------------------- VI

RECOVERY GOAL----------------------------------------------------------------------- VI

RECOVERY OBJECTIVES --------------------------------------------------------------- VI

RECOVERY STRATEGY ---------------------------------------------------------------- VII

RECOVERY UNITS --------------------------------------------------------------------- VII

RECOVERY CRITERIA ---------------------------------------------------------------- VIII

ACTIONS NEEDED -------------------------------------------------------------------- VIII

DATE OF RECOVERY ------------------------------------------------------------------- IX

TOTAL ESTIMATED COST OF RECOVERY -------------------------------------------- IX

IV. TABLE OF CONTENTS-----------------------------------XI

V. LIST OF FIGURES --------------------------------------- XV

VI. LIST OF TABLES -------------------------------------- XVII

VII. BACKGROUND --------------------------------------------- 1

OVERVIEW ------------------------------------------------------------------------------- 1

SPECIES DESCRIPTION AND TAXONOMY---------------------------------------------- 2

DISTRIBUTION --------------------------------------------------------------------------- 3

HABITAT CHARACTERISTICS----------------------------------------------------------- 7

FIGURE 2 VICINTY MAP OF CLEAR LAKE RESERVOIR WATERSHED.LIFE 

HISTORY AND ECOLOGY -------------------------------------------------------12

POPULATION DEMOGRAPHY AND TRENDS ------------------------------------------16

1. Upper Klamath Lake --------------------------------------------------------18

2. Clear Lake Reservoir--------------------------------------------------------22

REASONS FOR LISTING AND CONTINUED THREATS --------------------------------24

3. Factor A. The present or threatened destruction, modification, or 

curtailment of its habitat or range -----------------------------------------25

4. Factor B: Overutilization for commercial, recreational, scientific, or 

educational purposes --------------------------------------------------------28
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5. Factor C: Disease or predation---------------------------------------------29

6. Factor D: Inadequacy of existing regulatory mechanisms-------------30

7. Factor E. Other natural or manmade factors affecting its continued 

existence ----------------------------------------------------------------------31

a) Water Quality---------------------------------------------------------------- 31

b) Entrainment ------------------------------------------------------------------ 32

c) Climate Change ------------------------------------------------------------- 33

PAST CONSERVATION EFFORTS-------------------------------------------------------34

VIII. RECOVERY PROGRAM --------------------------------39

RECOVERY PRIORITY NUMBER -------------------------------------------------------39

RECOVERY STRATEGY -----------------------------------------------------------------39

RECOVERY UNITS ----------------------------------------------------------------------40

1. Upper Klamath Lake Recovery Unit--------------------------------------41

2. Lost River Recovery Unit --------------------------------------------------42

RECOVERY GOAL, OBJECTIVES, AND CRITERIA ------------------------------------44

3. Recovery Goal ---------------------------------------------------------------44

4. Recovery Objectives --------------------------------------------------------44

a) Threat-based Objectives--------------------------------------------------- 44

b) Demographic-based Objectives ------------------------------------------ 44

5. Recovery Criteria ------------------------------------------------------------44

DOWNLISTING CRITERIA—LOST RIVER SUCKER AND SHORTNOSE SUCKER ---45

6. Factor A: The present destruction, modification, or curtailment of its 

habitat or range---------------------------------------------------------------46

7. Factor C: Disease or predation---------------------------------------------46

8. Factor D: Inadequacy of existing regulatory mechanisms-------------46

9. Factor E: Other natural or manmade factors affecting its continued 

existence ----------------------------------------------------------------------47

DELISTING CRITERIA—LOST RIVER SUCKER AND SHORTNOSE SUCKER --------47

10. Factor B: Overutilization for commercial, recreation, scientific, or 

educational purposes --------------------------------------------------------47

11. Factor E: Other natural or manmade factors affecting its continued 

existence ----------------------------------------------------------------------48

RECOVERY ACTIONS -------------------------------------------------------------------48

12. Recovery Action Outline ---------------------------------------------------49

13. Recovery Action Narrative -------------------------------------------------52

IMPLEMENTATION SCHEDULE---------------------------------------------------------63
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14. Definition of Action Durations --------------------------------------------64

15. Explanation of Acronyms in Implementation Table--------------------64

IX. LITERATURE CITED -------------------------------------71

X. PERSONAL COMMUNICATIONS CITED -----------83

XI. APPENDICES -----------------------------------------------85

I. Glossary-----------------------------------------------------------------------85

II. Lost River Sucker and Shortnose Sucker Demography----------------91

III. Summary of Comments on the Draft Revised Recovery Plan for the 

Lost River Sucker and Shortnose Sucker --------------------------------96
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V. List of Figures

Figure 1 Upper Klamath Basin. ----------------------------------------------------------- 4

Figure 2 Vicinty map of Clear Lake Reservoir Watershed.Life History and 

Ecology----------------------------------------------------------------------------12

Figure 3 Size at a given age for female shortnose sucker in the Clear Lake 

Reservoir System. Age determined from otolith examination of fish 

collected 1989 through 1993 (D. Markle, Oregon State University, 

unpubl. data 2010). Each symbol represents an individual female. ------17

Figure 4 Proportion of ages of Lost River sucker from Upper Klamath Lake 

collected during a 1970 creel survey (otoliths; ODFW, unpubl. data, 

Terwilliger et al. 2010) and fish die-offs which occurred during 1986, 

1995, 1996 and 1997 (opercles; Coleman et al. 1988, D. Hewitt, 

USGS, unpubl. data). Data from 1970 and 1986 were read by a single 

individual, while data from 1995 – 1997 were read by two 

individuals, and disagreements (24 percent of the fish) were averaged 

and rounded up. ------------------------------------------------------------------19

Figure 5 Realized change in populations proportional to 2001 for river 

spawning shortnose suckers (SNS) and 2002 for spring-spawning 

Lost River suckers (LRS) as determined by mark-recapture studies 

(Janney and Hewitt, unpubl. data). --------------------------------------------21

Figure 6 Shortnose sucker age distribution compiled from Clear Lake 

Reservoir fish sampled during (A) 1989 (Buettner and Scoppettone 

1991), and (B) 1993 (U.S. Geological Survey, unpubl. data).-------------24

Figure 7 Map showing historical Upper Klamath Lake wetlands and their 

current connectivity to the lake. Yellow points identify locations of 

current shoreline-spring spawning locations. --------------------------------28

Figure 8 Two recovery units have been delineated for both the Lost River 

sucker and the shortnose sucker. Within each recovery unit, multiple 

management units have also been designated. Both recovery units 

must have healthy, self-sustaining populations for recovery to be 

achieved, although viable populations in each management unit are 

not necessarily essential.--------------------------------------------------------43
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VI. List of Tables

Table 1 Basic information on the lakes and reservoirs of the upper Klamath 

Basin, adapted from Table 3-1 from The National Research Council 

of the National Academies (2004:96). One hectare is equivalent to 

approximately 2.47 acres, and 1 meter is equivalent to approximately 

3.3 feet. ----------------------------------------------------------------------------11

Table 2 Estimated survival and annual rate of population change (λ) for Upper 

Klamath Lake shoreline spring habitat spawning male and female 

Lost River sucker and for Williamson/Sprague spawning male and 

female shortnose sucker (Janney and Hewitt, U.S. Geological Survey, 

unpubl. data 2009). All estimates are provisional and are subject to 

change with the collection of more data or refinements to the analysis 

strategy. Standard errors of estimates and a detailed description of 

how these factors were calculated are presented in Appendix II.---------22

Table 3 A summary of some recent major restoration projects benefitting Lost 

River sucker and shortnose sucker populations. Many of these 

projects were cooperative efforts of many state and federal agencies, 

non-profit organizations, and private landowners. --------------------------35

Table 4 The Implementation schedule for the Lost River and shortnose 

Recovery Plan. Dollar estimates of costs to achieve recovery (in 

thousands of dollars) are given for the first five fiscal years (FY) and 

the total estimated costs. Totals include estimates for the first five 

fiscal years and estimates for an additional 30 years, assuming the 

time to recovery would be 35 years. If no funds are required during 

the first five fiscal years this is indicated with a dash (–). 

Implementation of lower priority actions may not occur within the 

first five fiscal years; only the total estimated cost is presented in 

these cases. Unless specifically noted, actions are intended to benefit 

both species. Actions or headings that have been broken down into 

sub-actions do not have costs estimated when it is assumed that 

estimates of the sub-actions will comprise estimates for the entire 

action or heading and have therefore been excluded from this table. ----66

Table 5 Mean and one standard error (SE) of estimates of the probability of 

survival, seniority, and annual rate of population change (λ) for Upper 

Klamath Lake shoreline spring habitat spawning male and female 

Lost River sucker. Subsequent estimates of Δt for males = 0.56 and 

for females = 0.75. Data provided by E. Janney and D. Hewitt, U.S. 

Geological Survey, Klamath Falls, Oregon. All estimates are 

provisional and are subject to change with the collection of more data 

or refinements to the analysis methods.---------------------------------------92
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Table 6 Mean and one standard error (SE) of estimates of the probability of 

survival, seniority, and annual rate of population change (λ) for 

Williamson/Sprague spawning male and female shortnose sucker. 

Subsequent estimates of Δt for males = 0.42 and for females = 0.49. 

Data provided by E. Janney and D. Hewitt, U.S. Geological Survey, 

Klamath Falls, Oregon. All estimates are provisional and are subject 

to change with the collection of more data or refinements to the 

analysis strategy. -----------------------------------------------------------------93
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VII. Background

OVERVIEW

We, the U.S. Fish and Wildlife Service (USFWS), listed Lost River sucker (Deltistes 

luxatus) and shortnose sucker (Chasmistes brevirostris) as endangered throughout their entire 

range on July 18, 1988 (USFWS 1988) under the Endangered Species Act of 1973, as 

amended. Both species are also listed as endangered by the States of Oregon and California. 

A recovery plan for both species was finalized on March 17, 1993 (USFWS 1993). A 

substantial amount of additional information has accumulated since then and it is appropriate 

to revise the plan and incorporate this new information into the recovery program. An 

independent review panel of 12 scientists was convened in 2004 to review research 

conducted since listing of the species and evaluate its relevance to the species’ status 

(Independent Science Review Panel [ISRP] 2005). Biological and status information relevant 

to their listing was also considered in 5-year status reviews for each species (USFWS 2007a, 

b). Both species were assigned a Recovery Priority Number of 4C (indicating a high threat of 

extinction, low recovery potential, monotypic2 genus, with conflict) in the 5-year status 

reviews. However, shortnose sucker were inaccurately assigned given that they do not belong 

to a monotypic genus. Instead, the recovery priority number for Lost River and shortnose 

sucker should be 4C and 5C, respectively. The only difference being that Lost River suckers 

belong to a monotypic genus, whereas shortnose sucker are a species in a polytypic genus. 

As a result, Lost River sucker merit a higher priority number.

Early accounts note that these species were abundant and an important food resource 

for Native Americans and early settlers (Speir 1930). The species ascended the Williamson 

River in the thousands and were “taken and dried in great numbers by the Klamath and 

Modoc Indians.” (Cope 1879:785). Bendire (1889) notes a similar spawning run up the Lost 

River emanating from Tule Lake. However, at the time of listing both species had declined 

dramatically, reducing spawning runs to a fraction of historical levels. Abundance, longevity, 

and frequency of spawning success and recruitment have probably all decreased in Upper 

Klamath Lake relative to pre-settlement conditions, and recent information indicates that 

populations continue to decline because of low recruitment (Janney et al. 2008).

 

2 Terms defined in the glossary (Appendix I) are indicated with bold formatting at the first instance of 

occurrence.
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Nevertheless, between 1999 and 2008, roughly 10,000 Lost River sucker were captured and 

tagged at shoreline-spring spawning sites, with another 15,000 handled as part of the 

spawning run up the Williamson River (Janney et al. 2009). During a similar time period, 

1995 – 2008, approximately 14,000 shortnose sucker were captured, predominantly 

associated with the Williamson River (Janney et al. 2009). We don’t know what proportion 

of the entire population these tagged individuals represent. Although current distribution has 

changed little since listing, important changes in demography have been observed. 

The following discussion summarizes characteristics of Lost River sucker and 

shortnose sucker biology, demography and distribution, population status, and threats that are 

most relevant to recovery. A substantial amount of additional information is available to the 

interested reader in Buettner and Scoppettone (1990, 1991), Scoppettone and Vinyard (1991), 

Markle and Cooperman (2002), National Research Council of the National Academies 

(National Research Council 2004), Independent Science Review Panel (2005), U.S. Fish and 

Wildlife Service (2007a, b), Janney et al. (2008), Barry et al. (2009), and associated 

literature.

SPECIES DESCRIPTION AND TAXONOMY

Both of these species are members of a group of suckers (Family Catostomidae), 

which predominantly utilize lake environments. Typically adults of this group, collectively 

known as “lake suckers,” are relatively large individuals (National Research Council 2004). 

Lake suckers differ morphologically from other suckers in having terminal or sub-terminal 

mouths. These species also generally possess numerous, branched gill rakers (Miller and 

Smith 1981). Both mouth position and gill raker structure suggest these species are adapted 

for feeding in a more forward manner on prey such as zooplankton rather than consuming 

prey from the substrate (Scoppettone and Vinyard 1991, National Research Council 2004).

The Lost River sucker was described as Chasmistes luxatus by Cope (1879) from 

specimens collected from Upper Klamath Lake. Later, Seale (1896) placed it in the new 

monotypic genus Deltistes, which reflects the distinctive triangular gill rakers (Scoppettone 

and Vinyard 1991). Its taxonomy remained uncertain until Miller and Smith (1967)

examined fossil material and confirmed that other diagnostic characteristics were consistent 

with extinct members of the genus (Andreasen 1975). It is now recognized as the only extant

member of the genus (Nelson et al. 2004). Lost River suckers are relatively large fish, up to 

0.8 meter (2.6 feet) long and 4.5 kilograms (9.9 pounds) in weight, distinguished by an 

elongate body and sub-terminal mouth with a deeply notched lower lip that are relatively more 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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papillose (Scoppettone and Vinyard 1991). They have dark backs and sides that fade to 

yellow or white on the belly. 

The shortnose sucker was described by Cope (1879) as Chasmistes brevirostris. This 

genus includes three extant species of lake suckers in the western U.S. It is generally 

distinguished by a smaller head than Lost River sucker also with an oblique, terminal mouth, 

and thin, but fleshy, lips. The lower lip is deeply notched, giving the appearance of two 

separate lobes. Coloration is very similar to Lost River sucker, with dark back and sides and 

a silvery or white belly. They are generally smaller than Lost River suckers, but can still

grow to about 0.65 meters (2.1 feet; Moyle 2002). Shortnose sucker are one of three extant 

species in the genus Chasmistes (Nelson et al. 2004), with the other two being the cui-ui 

sucker (Chasmistes cujus) in Pyramid Lake, Nevada and the June sucker (Chasmistes liorus) 

in Utah Lake, Utah (Cooke et al. 2005). 

Hybridization was identified at the time of listing as a threat. Data suggest that 

hybridization among four Klamath Basin suckers (Lost River sucker, shortnose sucker, 

Klamath largescale sucker [Catostomus snyderi] and Klamath smallscale sucker 

[Catostomus rimiculus]) does occur (Dowling 2005, Tranah and May 2006). Specifically, 

morphological and molecular genetics research indicate that hybridization occurs between 

shortnose sucker and Klamath largescale suckers throughout the range of shortnose sucker

(Markle et al. 2005, Tranah and May 2006). Increased hybridization resulting from human 

intervention can be cause for concern for imperiled species, and may even lead to extinction 

(Rhymer and Simberloff 1996). However, data suggest that hybridization among Klamath 

Basin suckers, especially shortnose sucker and Klamath largescale sucker, is consistent with 

a pattern of historical hybridization, which is not uncommon for the sucker family (Dowling 

and Secor 1997, Dowling 2005, Tranah and May 2006). Even in the presence of 

hybridization all species continue to maintain unique morphological traits, although 

intermediate forms do occur as well (Dowling 2005, Markle et al. 2005). Further studies are 

needed to determine the extent and causes of hybridization. 

DISTRIBUTION

Both Lost River sucker and shortnose sucker are endemic to the upper Klamath River 

Basin, including the Lost River and Lower Klamath Lake sub-basins (Figure 1). Historical 

distribution of these species is known primarily from incidental records by early explorers 

and newspaper reports, and so it is often difficult to precisely estimate historical distribution. 

We do know that the quantity of suitable stream/river, lake, and marshland habitats has been 

reduced by approximately 75 percent(USFWS 2007a, b). Currently the total area of lake 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

4

habitat available for Lost River sucker and shortnose sucker is about 32,000 hectares (79,000 

acres), of which approximately 80 percent is in Upper Klamath Lake, which covers 

approximately 26,000 hectares (64,000 acres).

Figure 1 Upper Klamath Basin.

At the time of listing, Lost River sucker and shortnose sucker were known from 

Upper Klamath Lake and its tributaries and outlet (Klamath Co., Oregon; Figure 1), 

including a “substantial population” of shortnose sucker in Copco Reservoir (Siskiyou Co., 

California), as well as collections of both species from Iron Gate Reservoir (Siskiyou Co., 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

5

California) and J.C. Boyle Reservoir (Klamath Co., Oregon). Remnants and/or highly 

hybridized populations were also documented to occur in the Lost River system (Klamath 

Co., Oregon, and Modoc and Siskiyou Co., California) including both species in Clear Lake

Reservoir (Modoc Co., California), but it was apparently presumed that Lost River sucker

populations in Sheepy Lake, Lower Klamath Lake, and Tule Lake (Siskiyou Co. California) 

had been “lost” (USFWS 1988). Although not stated explicitly, shortnose sucker within 

Gerber Reservoir (Klamath Co., Oregon) were likely part of the “highly hybridized 

populations” in the Lost River Basin referenced in the listing (USFWS 1988). At the date of 

this revision the overall distribution has not changed at the sub-basin scale, but occurrences 

of shortnose sucker and Lost River sucker within Tule Lake have been documented. 

Currently, Clear Lake Reservoir and Upper Klamath Lake and their tributaries support the 

largest populations. Populations in Klamath River below Keno Dam and in the Lost River 

drainage below Clear Lake Dam are comprised mostly of adults. These populations are 

probably functioning as sink populations, as they are not likely self-sustaining because of 

low recruitment due to the lack of access to spawning habitats (Moyle 2002, NRC 2004). All 

life stages of listed suckers have been found in Link River, the outlet of Upper Klamath 

Lake, in recent years (Bureau of Reclamation [BOR] 2000, Piaskowski 2003, PacifiCorp 

2004).

Fisheries surveys in Keno Reservoir have been conducted infrequently and have 

generally been short in duration (Oregon Department of Fish and Wildlife [ODFW]1996, 

Piaskowski 2003, PacifiCorp 2004). The only intensive monitoring effort was conducted by 

Terwilliger et al. (2004). Larvae and age-0 suckers were generally most abundant in the 

upper part of Keno Reservoir and decreased downstream. Based on recent sampling efforts 

conducted by the Bureau of Reclamation (2008 – 2010) juvenile, sub-adult and adult 

suckers may occur in higher numbers than previously thought (T. Tyler, Klamath Basin Area 

Office, Bureau of Reclamation, pers. comm. 2010). Several hundred adults from both 

species (predominantly shortnose sucker) were captured and tagged in Lake Ewauna near the 

confluence of the Link River (Kyger and Wilkens 2010).

Known areas of concentrated Lost River sucker spawning in the Williamson and 

Sprague Rivers include the lower Williamson River from river mile 6 to the confluence of

the Sprague River (river mile 11), lower Sprague River below Chiloquin Dam area, and in the 

Beatty Gap area of the upper Sprague River (river mile 75; Buettner and Scoppettone 1990, 

Tyler et al. 2004, Ellsworth et al. 2007). Other areas in the Sprague River watershed where 

Lost River sucker may spawn include the lower Sycan River and in the Sprague River near 

the Nine Mile area (Ellsworth et al. 2007). A smaller but significant number of Lost River 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

6

sucker also spawn over gravel at shoreline springs along the margins of Upper Klamath Lake

(Buettner and Scoppettone 1990, National Research Council 2004). Mark-recapture data 

indicate that the two stocks maintain a high degree of fidelity to spawning areas and seldom 

interbreed (Hayes et al. 2002, Barry et al. 2007a), although lack of genetic distinction 

suggests that some mixing may occur (Dowling 2005). Historically, suckers were known to 

spawn at many shoreline springs, including Harriman Springs and Barkley Spring 

(Andreasen 1975, National Research Council 2004). However, significant spawning 

aggregations currently occur at Sucker Springs, Cinder Flats, Silver Building Springs, and 

Ouxy Springs. Fewer individuals are also known to spawn at Boulder Springs. Spawning at 

these springs is very sensitive to lake levels; as levels decline much of the spawning habitat

quickly becomes unavailable.

Shortnose sucker from Upper Klamath Lake also currently spawn primarily in the 

lower Williamson and Sprague Rivers (Tyler et al. 2004, Ellsworth et al. 2007). However, 

the few adult shortnose sucker captured at shoreline spawning areas in Upper Klamath Lake

indicate that some shortnose sucker spawning is likely to still occur at these locations (Hayes 

et al. 2002, Barry et al. 2007a, b). A small number of suckers, approximately 80 individuals

and primarily shortnose suckers, were captured during spring sampling in 1996, 1999, and 

2000 in the Wood River and near the mouth of the Wood River in Agency Lake, presumably 

preparing to spawn (Peck 2000, BOR 2001). Investigations have not located suckers in Upper 

Klamath Lake tributaries other than the Williamson, Sprague, and Wood Rivers; although, 

some have reported much broader historical distribution of spawning among Upper Klamath 

Lake tributaries (Stine 1982).

A small group of Lost River sucker apparently resides in the Sprague River near 

Beatty. A few adult Lost River sucker were first encountered during the summer of 2001 

during fish survey work in the Sprague River (L. Dunsmoor, Klamath Tribes, pers. comm.

2007). In 2007 and 2008, we located small groups of adult Lost River sucker above the 

confluence of the Sycan River and below Beatty Gap and near the community of Sprague 

River (M. Buettner, U.S. Fish and Wildlife Service, pers. comm. 2009). Although a 

substantial fish survey effort was conducted on the Sprague River in 2007 by us and Oregon 

State University, no adult shortnose sucker were collected.

Historically, large sucker spawning migrations occurred from Tule Lake up the Lost 

River to near Olene and Big Springs near Bonanza (Bendire 1889, Howe 1969). Such 

migrations are currently blocked by Anderson Rose Dam. There is evidence, however, of 

resident populations of shortnose sucker in impounded portions of the Lost River (above 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

7

Malone, Lost River Diversion, and Harpold dams for example) and Clear Lake Reservoir

tributaries (Buettner and Scoppettone 1991, Perkins and Scoppettone 1996, Shively et al. 

2000). Populations of Lost River sucker and shortnose sucker residing in Clear Lake

Reservoir are known to spawn in Willow Creek (Buettner and Scoppettone 1991, Barry et al. 

2007a); however it is also possible, but currently unknown, if areas other than the Willow 

Creek drainage, including Fletcher, Bailey, and Boles Creek, are used for spawning. The 

Bureau of Land Management (Klamath Falls Resource Area) has been monitoring sucker 

spawning in the Gerber Reservoir tributaries from 1993-2011, and has documented spawning 

in Barnes Valley Creek, Long Branch Creek, Pitchlog Creek, and Ben Hall Creek (BLM 

Klamath Falls Resource Area, unpublished data). Surveys of spawning areas during the 

spring 2006 detected more than 1,700 suckers ascending Ben Hall Creek and Barnes Valley 

Creek (Barry et al. 2007a).

HABITAT CHARACTERISTICS

Upper Klamath Lake is a large natural lake that was modified with a control structure 

in 1919 (Table 1). The watershed encompasses about 9,800 square kilometers (3,800 square 

miles), ranges in elevation from 1,250 meters (4,100 feet) to over 2,700 meters (9,000 feet), 

and has an average annual precipitation of approximately 68 centimeters (27 inches; Boyd et 

al. 2002) . Its three major contributing drainages are the Sprague, Williamson, and Wood 

Rivers (Figure 1). The Williamson River flows into the lake from the north shortly after 

receiving the Sprague River, which is the larger of the two streams. The Wood River flows 

into a large embayment of the lake known as Agency Lake, also from the north. The lake 

itself is relatively shallow throughout, but the Eagle Ridge trench on the west side of the lake 

can reach depths of 12 meters (40 feet). Approximately 10,000 hectares (25,000 acres) of 

wetlands remain connected to the lake. The outlet river of Upper Klamath Lake, the Link 

River, flows a short distance before entering Lake Ewauna. This habitat functions primarily 

as a corridor for large numbers of larval and juvenile suckers entrained in the downstream 

flow moving through the Link River Dam (Gutermuth et al. 2000, Foster and Bennetts 2006, 

Tyler 2007). The river may also potentially permit movement of adults upstream toward 

spawning habitats during spring. Such movements are ultimately dependent on passage 

through the Link River Dam by means of a fish ladder (Piaskowski 2003). Only seven 

individuals were detected between 2005 – 2007 in the fish ladder (Korson et al. 2008), but 25

individuals were detected in the fish ladder in 2010 (T. Tyler, pers. comm. 2010). This 

increase may indicate an improved ability to detect such movements as the number of tagged 

fish increases.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

8

Lake Ewauna is a naturally occurring lake, but it has become functionally 

indistinguishable from a downstream impoundment, the Keno Reservoir. This reservoir 

experiences extremely poor water conditions annually (Sullivan et al. 2008, Kirk et al. 2010). 

Dissolved oxygen levels of less than 1 milligram/liter, which are well below levels generally 

recognized as harmful to fish, occur regularly (Kirk et al. 2010).

Clear Lake Reservoir (Figure 2), also a modified natural lake, was modified by a 

control structure in 1910, which increased the size of the lake (Table 1); although, it remains 

relatively shallow throughout. It is located in the upper reaches of the Lost River watershed, 

which covers 2,100 square-kilometers (700 square-miles) and ranges in elevation from 

approximately 1,400 meters to 1,900 meters (4,500 feet to 6,100 feet; BOR 1970). Annual 

precipitation is approximately 33 centimeters (13 inches). The lake has one major tributary, 

Willow Creek. Upstream stock ponds and diversions reduce inflows somewhat, and over half 

of the annual inflow is lost to seepage and evaporation (BOR 1970). During the 65-year 

period prior to 1970, annual net inflow fluctuated between 22,200 cubic decameters and 

460,000 cubic decameters (approximately 18,000 acre-feet to 370,000 acre-feet; BOR 1970). 

The lake has never reached its capacity of 555,000 cubic decameters (450,000 acre-feet), but 

averages approximately 2.4 meters (7.8 feet) in depth (BOR 1970, National Research 

Council 2004).

Hydrographs of both Clear Lake and Upper Klamath Lake exhibit patterns of a snowmelt driven system with highest inflows and levels during spring and early summer, but 

groundwater is also a significant contributor to Upper Klamath Lake (Risley et al. 2005, 

Gannett et al. 2007). However, Clear Lake Reservoir and Upper Klamath Lake are managed 

to store water for irrigation. Clear Lake Reservoir is highly sensitive to drought and 

downstream water delivery because of its small watershed, low precipitation, minimal 

groundwater input, and high evaporation rates (National Research Council 2004).

Water quality conditions in Upper Klamath Lake are driven by extensive nutrient 

loading. The lake was highly productive or eutrophic prior to settlement by Europeans in the 

mid-19th century, but it has become hypereutrophic from increased external loading 

(pumping of diked wetlands, farm/ranch run-off, and roads) that has enriched the naturally high

internal (lake sediments) loads (Snyder and Morace 1997, Boyd et al. 2002, Independent 

Multidisciplinary Science Team IMST 2003, Bradbury et al. 2004, Eilers et al. 2004, 

National Research Council 2004, Graham et al. 2005). Much of the nutrient load entering

Upper Klamath Lake comes from non-point sources (Boyd et al. 2002). Nevertheless, on 

average, approximately 60 percent of the biologically available phosphorus is derived from 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

9

internal loads, such as lake sediment, although it has been suggested that these internal loads 

have been enriched by modern land management practices (Eilers et al. 2001).

Sedimentation rates within Upper Klamath Lake dramatically increased during the 

20th century, and these “modern” sediments are higher in nitrogen and phosphorus than presettlement sediment (Eilers et al. 2001) and are a significant contributor to the internal source 

of nutrients. Because the system has a significant internal source of phosphorus, some 

authors express pessimism regarding prospects for remediation even if external sources are 

reduced (National Research Council 2004). However, Oregon Department of Environmental 

Quality believes that reduction in total phosphorus loading can improve water quality to the 

point that Total Maximum Daily Load standards can eventually be attained (Boyd et al. 

2002). Likewise, the Sprague River, the primary spawning habitat for suckers in Upper 

Klamath Lake and the largest tributary to the Williamson River, is listed as water quality 

impaired for nutrients, temperature, sediment, and dissolved oxygen under the section 303d 

of the Clean Water Act. 

Poor water quality in Upper Klamath Lake is particularly associated with high 

abundance of the blue-green algae Aphanizomenon flos-aquae. Core samples of bottom 

sediments indicate that Aphanizomenon flos-aquae was not present in Upper Klamath Lake 

prior to the 1900s (Bradbury et al. 2004, Eilers et al. 2004). Its appearance is believed to be 

associated with increases in productivity of the lake (National Research Council 2004). This 

algae now dominates the algal community from June to November, and, because of the high 

phosphorus concentrations and its ability to fix nitrogen, is able to reach seasonally high 

biomass levels that eventually produce highly degraded water quality (Boyd et al. 2002). 

Once the algal bloom subsides, decomposition of the massive amounts of Aphanizomenon 

flos-aquae biomass can lower dissolved oxygen to levels harmful or fatal to fish (Perkins et 

al. 2000a, Boyd et al. 2002, IMST 2003, National Research Council 2004, Wood et al. 2006). 

The processes that produce these conditions are complex and vary on many time scales:

daily, seasonally, and annually. In some years the massive bloom of blue-green algae 

experiences near catastrophic die-offs (crashes), which provides an abundant source of 

organic material for bacterial decomposition. During these periods of high levels of 

decomposition, the bacteria can deplete dissolved oxygen from the water column as they 

respire, and as a by-product of decomposition nitrogen is also released, which can then 

convert to toxic forms (un-ionized ammonia) when the pH is basic (greater than 7). There 

are many other factors, such as wind-driven mixing of the water column, that determine the 

severity and extent (whether it is localized or lake-wide) of these crashes. Additionally, other 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

10

cyanobacteria (Microcystis sp.) may produce toxins harmful to sucker liver tissue 

(Vanderkooi et al. 2010). 

Water quality data for Clear Lake Reservoir is limited (BOR 1994, Hicks 2001), but it 

appears to be less productive than Upper Klamath Lake, and does not experience similar 

algal blooms. Data collected during 1991 to 1995 near Clear Lake Dam and within the east 

and west lobes of the reservoir indicate that dissolved oxygen levels rarely declined below 4 

milligram/liter, and temperatures rarely exceeded 26 degrees Celsius (79 degrees Fahrenheit; 

Hicks 2001). Likewise, aquatic vegetation is much less abundant in Clear Lake Reservoir

than in Upper Klamath Lake (National Research Council 2004).
11

Table 1 Basic information on the lakes and reservoirs of the upper Klamath Basin, adapted from Table 3-1 from The National Research Council of the 

National Academies (2004:96). One hectare is equivalent to approximately 2.47 acres, and 1 meter is equivalent to approximately 3.3 feet.

Lake Name

Size before 1900 (hectares) Size since 1960 (hectares)

Volumea

(acre-feet)

Mean Depthb

Minimum Maximum Minimum Maximum (meters)

Lakes and reservoirs used for water storage and routing

Upper Klamathc 31,600 44,900 22,700 27,100 603,000 2.7

Lower Klamathd 34,400 38,100 1,900 1,900 < 20,000 < 1.2

Clear Lake Reservoird 6,100 6,100 3,400 10,400 527,000 6.1

Tule Laked 22,300 44,500 3,800 5,300 50,000 1.2

Gerber Reservoird n/a n/a 450 1,600 94,000 7.3

Reservoirs used for power production

Kenoe,f n/a n/a 1,000 1,000 18,500 2.1

J.C. Boylef n/a n/a 170 170 1,700 1.2

Copco No. 1f n/a n/a 400 400 46,900 14.3

Copco No. 2f n/a n/a 16 16 70 0.6

Iron Gatef n/a n/a 380 380 58,800 18.9

a At current maximum depth. Historic volumes are not readily available.

b Mean depths are typically lower than shown in the table, which are based here on current maximum volume.

c Including Agency Lake, from Table 2-1 of Welch and Burke 2001(2001). Current maximum elevation is 4143.3. Area and volume data from U.S. Fish and 

Wildlife Service (2002).

d From Bureau of Reclamation (2001, Table 4.1)

e Including Lake Ewauna. Keno has no turbines.

f

From Pacific Corp (2000), pp. 2-16 and 2-17.

Abbreviations: n/a, not applicable
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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Figure 2 Vicinty map of Clear Lake Reservoir Watershed.Life History and Ecology

Given the apparent similarities between the species, information on the life history

and ecology of the species presented here is presumed to be pertinent to both, unless 

specified.

Lost River sucker and shortnose sucker exhibit many adaptations characteristic of 

long-lived species, with maximum ages of up to 57 and 33 years respectively (Scoppettone 

1988, Buettner and Scoppettone 1990, 1991, Terwilliger et al. 2010). Juveniles grow rapidly 

until reaching sexual maturity sometime between four and nine years for Lost River sucker 

and four and six years for shortnose sucker (Perkins et al. 2000b). In ecological terms this is 

known as the generation time. Adults tend to have high survival rates enabling populations to 

outlive unfavorable periods, like droughts. Once achieving sexual maturation, Lost River 

sucker are expected to live on average 12.5 years (D. Hewitt, U.S. Geological Survey, pers. 

comm., 2011) based on methodology developed by Hoenig (1983). Similarly, shortnose 

sucker adults are estimated to live on average 7.4 years after having joined the adult 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

13

population. Thus, for those individuals surviving to adulthood, we expect an average total life 

span of 20 years for Lost River sucker and 12 years for shortnose sucker, based on the 

average time to maturity and average adult life spans. Females produce a large number of 

eggs, 44,000 to 236,000 for Lost River sucker and 18,000 to 72,000 for shortnose sucker per 

year, of which only a small percentage survive to become juveniles (National Research 

Council 2004). The vast majority of individuals spawn every year (D. Hewitt and S. Burdick, 

U.S. Geological Survey, pers. comm., 2010). Larger, older females often produce 

substantially more eggs and, therefore, can contribute relatively more to production than a 

recently matured female.

Spawning occurs from February through May over gravel substrates in habitats less 

than 1.3 meters (4.3 feet) in rivers and shoreline springs (Buettner and Scoppettone 1990). 

Females broadcast their eggs which are fertilized most commonly by two accompanying 

males, but the number may be as high as seven (Buettner and Scoppettone 1990). The 

fertilized eggs settle within the top few inches of the substrate until hatching, around one 

week later. Approximately 10 days after hatching, when larvae reach about 7 to 10 

millimeters (0.2 inches to 0.6 inches) total length and are still mostly transparent with a 

small yolk sac, they emerge out of the gravel (Coleman et al. 1988, Buettner and Scoppettone 

1990). 

Generally, larvae spend little time in rivers after swim-up, but quickly drift 

downstream to the lakes. In the Williamson River, larval movement away from the spawning 

grounds begins in April and is typically completed by July. Downstream movement mostly 

occurs at night near the water surface (Klamath Tribes 1996, Tyler et al. 2004, Ellsworth et 

al. 2010). The downstream drifting of the larvae that occurs during the daytime appears to be 

relatively distributed throughout the water column (Ellsworth et al. 2010). Once in the lake, 

larvae inhabit near-shore areas (Cooperman 2004, Cooperman and Markle 2004). Larvae 

density is generally higher within and adjacent to emergent vegetation than in areas devoid 

of vegetation (Klamath Tribes 1996, Cooperman and Markle 2004, Crandall et al. 2008). 

Emergent vegetation provides cover from predators and habitat for prey such as zooplankton, 

macroinvertebrates, and periphyton (Klamath Tribes 1996, Cooperman and Markle 2004, 

Crandall 2004). Such areas also may provide refuge from wind-blown current and 

turbulence, as well as areas of warmer water temperature which may facilitate larval growth 

(Crandall 2004, Cooperman et al. 2010). 

Larvae transform into juveniles by mid-July at about 25 millimeters (1 inch) total 

length. Juvenile suckers primarily use relatively shallow (less than approximately 1.2 meters
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

14

[3.9 feet]) vegetated areas, but may also begin to move into deeper, un-vegetated off-shore 

habitats (Buettner and Scoppettone 1990, Terwilliger et al. 2004, Hendrixson et al. 2007a, b, 

Burdick et al. 2008, Bottcher and Burdick 2010, Burdick and Brown 2010). One year old 

juveniles occupy shallow habitats during April and May, but may afterwards move into 

deeper areas along the western shore of Upper Klamath Lake until dissolved oxygen levels 

become reduced (Bottcher and Burdick 2010, Burdick and Vanderkooi 2010).

It is assumed that sub-adults (individuals which display all of the characteristics of 

adults with the exception of reproductive maturity) utilize habitats similar to adults (National 

Research Council 2004). Adult suckers inhabit water depths of 1 to 4.5 meters (3.3 – 14.8 

feet), but appear to prefer depths from 1.5 to 3.4 meters (4.9 – 11.2 feet; Peck 2000, Reiser et 

al. 2001, Banish et al. 2009). Adult Lost River sucker and shortnose sucker are widely 

distributed in Upper Klamath Lake during the fall and winter (USFWS 2002, National 

Research Council 2004) but in the spring, congregations form in the north-east quadrant of 

the lake prior to moving into tributaries or shoreline spawning areas for spawning (Janney et 

al. 2009). 

In general, lake suckers (including Lost River sucker and shortnose sucker) are 

relatively tolerant of degraded water quality conditions. They tolerate higher pH, 

temperature, un-ionized ammonia concentrations, and lower dissolved oxygen concentrations 

than many other fishes (Saiki et al. 1999, Meyer and Hansen 2002, National Research 

Council 2004). Nevertheless, water quality in Upper Klamath Lake and the Lost River often 

becomes poor enough to adversely affect both species, especially in summer (National 

Research Council 2004). Adults are primarily found in the northern portion of the lake above 

Bare Island during summer months (Peck 2000, Banish et al. 2009). Reasons for this summer 

distribution are probably related to better water quality near spring-fed Pelican Bay and the

Williamson River (Reiser et al. 2001, USFWS 2002, Banish et al. 2009). During the summer 

and early fall, Upper Klamath Lake water quality conditions periodically deteriorate to 

stressful and even lethal levels for suckers as a result of decomposition of massive algae 

blooms and resultant low levels of dissolved oxygen (Loftus 2001). A multiple-year radio 

telemetry study documented Lost River sucker and shortnose sucker concentrating in or near 

Pelican Bay (in the northwest corner of Upper Klamath Lake) during periods of poor water 

quality, presumably to seek areas of better water quality (Banish et al. 2009).

Fewer specifics are known about Clear Lake Reservoir Lost River sucker and 

shortnose sucker populations. Life-history characteristics of these populations are similar to 

those in Upper Klamath Lake, with some notable differences. Annual variability in the 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

15

number of individuals participating in spawning runs into Willow Creek can be attributed to 

spring time discharge; large runs occur during years of high flow. Likewise, spawning runs 

for both shortnose sucker and Lost River sucker are generally about one month earlier in 

Clear Lake Reservoir than river spawning fish from Upper Klamath Lake. This may be 

related to the small watershed supporting the lake, which effectively reduces the length of 

higher flows during the spring spawning period (Scoppettone et al. 1995). Barry et al. (2009)

found that growth rates of both species in Clear Lake Reservoir were substantially greater 

than observed in Upper Klamath Lake. Also, there is evidence of some juvenile and adult 

rearing in tributaries to Clear Lake Reservoir (Buettner and Scoppettone 1991, Perkins and 

Scoppettone 1996). Although, it is possible that some adults simply become stranded during 

the spawning season as flows in Willow Creek may recede rapidly. 

Lost River sucker and shortnose sucker have an evolutionary history with predatory 

species, including lamprey (Lampetra species), Klamath redband trout (Oncorhynchus 

mykiss sub-species), sculpin (Cottus species), and chubs (Cyprinidae), which may also 

compete with some life stages of suckers. In addition, approximately 20 fish species have 

been accidentally or deliberately introduced into the upper Klamath River basin, and 

comprised about 85 percent of fish biomass in Upper Klamath Lake when the suckers were 

listed (Scoppettone and Vinyard 1991, National Research Council 2004). The non-native fish 

species most likely to affect Lost River sucker and shortnose sucker are the fathead minnow 

(Pimephales promelas) and yellow perch (Perca flavescens). These fishes are believed to 

prey on young suckers and compete with them for food or space (Markle and Dunsmoor 

2007). For example, fathead minnows were first documented in the Klamath Basin in the 

1970s and are now the numerically dominant fish in Upper Klamath Lake (Andreasen 1975, 

Simon and Markle 1997). Additional exotic, predatory fishes found in sucker habitats, 

although typically in relatively low numbers, include bullheads (Ameiurus species), 

largemouth bass (Micropterus salmoides), crappie (Pomoxis species), green sunfish (Lepomis 

cyanellus), pumpkinseed (Lepomis gibbosus), and Sacramento perch (Archoplites 

interruptus; Koch et al. 1975, Logan and Markle 1993). Effects on suckers by these latter 

species are unknown.

Likewise, a number of pathogens or parasites have been identified from moribund

suckers in Upper Klamath Lake, including anchor worm (Lernaea species; a parasitic 

copepod), Trichodina species (an external ciliate protozoan), and the bacterium 

Flavobacterium columnare, which produces Columnaris or “gill rot” disease, among 

others (Holt 1997, Foott 2004, Foott et al. 2010). F. columnare can damage gills and 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

16

produce body lesions, and results in respiratory problems, internal salt concentration 

imbalances, or provide an entry route for lethal systemic pathogens (ISRP 2005).

Sufficient information on disease and parasites are lacking for Clear Lake Reservoir. 

During 1992, a year of extremely low water levels, adult suckers showed signs of stress and a 

high incidence of anchor worm and lamprey infestation compared to fish sampled during

1993 through 1995 when water levels were higher (BOR 1994). 

POPULATION DEMOGRAPHY AND TRENDS

In general, assessing the health of a population often includes estimation of how 

many individuals there are, what is the relative composition of the population by different 

groups, for example sexes or different age groups, and whether the numbers are increasing or 

decreasing (trend). With these tools, conclusions may be drawn not only on the current 

factors affecting the population, but often predictions can also be formulated about the future 

status of the population. Nevertheless, both demographic and overall population trend 

analysis are very sensitive to differences in methodology. For example, sampling gear, such 

as a specific type of net or trap, that poorly captures a specific size group may skew the 

resulting conclusions. 

To gather demographic data on the relative composition of age classes for fish it is 

typical to examine various hard structures, which often record growth patterns in the form of 

annual rings, similar to tree rings. Though a useful tool, hard structures still often yield 

imprecise measurements with some amount of error, and such data, especially for individuals 

older than 10 years, are therefore best considered as estimates of age and not necessarily 

exact measurements (D. Hewitt, pers. comm., 2010). The most reliable of these hard 

structures, often otoliths (ear stones) or opercles, require sacrificing the fish (Belk 1998, 

Terwilliger et al. 2010). Because hard structure estimates are imprecise and because sacrifice 

can detrimentally affect small populations, length is often used as a surrogate for age,

assuming that individuals continue to grow throughout their life. However, for lake suckers 

reduced growth rates often occur after sexual maturity (Figure 3) producing a poor

correlation between size and age for older fish (Belk 1998). For example, a 10-year old 

female shortnose sucker in Clear Lake Reservoir could measure anywhere from 

approximately 315 millimeters to 450 millimeters fork length (Figure 3). Nevertheless, given 

limited available data, below we discuss age structure of Lost River sucker and shortnose 

sucker populations within the context of length frequency as well as ages determined from 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

17

Figure 3 Size at a given age for female shortnose sucker in the Clear Lake Reservoir System. Age 

determined from otolith examination of fish collected 1989 through 1993 (D. Markle, Oregon State 

University, unpubl. data 2010). Each symbol represents an individual female.

hard structures extracted from dead fish. Likewise, because of difficulty in sampling all life 

stages, information presented here primarily reflects spawning or adult populations, but also 

includes some non-reproductive individuals collected during fish die-off events.

Additionally, a number of methods can be used to estimate the size of animal 

populations. Selection of an appropriate method must consider life history, habitat 

characteristics, effectiveness of capture methods, sensitivity of a species to handling, and 

required accuracy. Accurate estimates are most easily made in situations where the number 

of populations are relatively small and occupy a discrete, closed environment where the 

ability to count each individual is great. Accuracy decreases as habitat size and rarity 

increase because the probability of encountering each individual becomes increasingly small. 

Under such conditions, the error of an estimate can become unacceptably large, rendering the 

estimate effectively meaningless. 

250

300

350

400

450

500

2 4 6 8 10 12 14 16 18

Fork Length (millimeters)

Age (years)
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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1. Upper Klamath Lake

Accurately determining age class distribution is often a challenge because of sample 

size and methods (such as non-randomly selecting individuals). Because both species are 

long-lived, many age classes may be underrepresented while others may be very abundant in 

the sample which may skew conclusions. To account for this relatively large stratified 

random samples (across sexes and lengths) are required to determine accurate age class 

distributions (D. Markle, Oregon State University, pers. comm., 2010). Data produced from

otoliths of fish collected during an April 1970 creel survey conducted by the Oregon 

Department of Fish and Wildlife provide insight into historic Lost River sucker age class 

structure in Upper Klamath Lake (Terwilliger et al. 2010), even though the data are 

somewhat limited in scope. Seventy-four spawning Lost River sucker ranging in age from 

approximately 8 to 57 years old were analyzed (Figure 4). In more recent data derived from 

fish die-offs during 1995, and 1997, the distribution ages of examined Lost River sucker 

were predominantly limited to less than 10-year-old fish, although some older individuals 

were also part of the sample (Figure 4). Distribution of ages of shortnose sucker collected 

during the same fish die-offs exhibit similar patterns (D. Hewitt, unpubl. data). However, in 

each of these instances the non-random sample resulting from opportunistic sampling of

individuals from fish die-off events or creels limits our ability to make general conclusions 

about overall population age distributions during these periods.

At the time of listing, Upper Klamath Lake spawning populations of Lost River 

sucker, and presumably shortnose sucker, received little recruitment and were dominated by 

older individuals (Scoppettone and Vinyard 1991, Janney and Shively 2007, Janney et al. 

2008). A 1986 survey of 190 Lost River sucker opercles from Upper Klamath Lake revealed 

an age distribution of individuals between 8 and 43 years (Scoppettone and Vinyard 1991). 

The majority of individuals were 16 to 30 years old, and only 9 were less than 16 years old. 

Similarly, ages, determined from opercles, of 19 shortnose sucker from Copco Reservoir in 

1987 ranged from 16 to 33 (mean = 23 years) suggesting that shortnose sucker populations 

were also comprised primarily of older individuals (Scoppettone and Vinyard 1991).
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

19

Figure 4 Proportion of ages of Lost River sucker from Upper Klamath Lake collected during a 1970 creel 

survey (otoliths; ODFW, unpubl. data, Terwilliger et al. 2010) and fish die-offs which occurred during 

1986, 1995, 1996 and 1997 (opercles; Coleman et al. 1988, D. Hewitt, USGS, unpubl. data). Data from 1970 

and 1986 were read by a single individual, while data from 1995 – 1997 were read by two individuals, and

disagreements (24 percent of the fish) were averaged and rounded up. 

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

1970 

N = 74

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

1986 

N = 191

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56

0.0

0.1

0.2

0.3

0.4

1995 

N = 279

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56

0.0

0.1

0.2

0.3

1996 

N = 484

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

1997 

N = 506

Age

Proportion
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

20

Recent size distribution trends reveal that spawning populations are comprised mostly 

of similarly-aged, older individuals. Lost River and shortnose sucker spawning populations

in Upper Klamath Lake transitioned from populations dominated by old, larger adult fish 

with little size diversity in the late 1980s and early to mid-1990s, to populations dominated 

by young, smaller adult fish and very few large individuals by the late 1990s (Janney et al. 

2008). This marked shift in size structure to smaller individuals can only be explained by 

substantial recruitment to these populations sometime during the mid-1990s in combination 

with adult mortality that accounts for the rapid decline in the frequency of large and 

presumably old individuals. However, since the late 1990s populations of both species have 

exhibited an increasing trend in length (5 to 12 millimeters increase in median fork length per 

year; Janney and Shively 2007, Janney et al. 2008). During this period, 1995 through 1997, 

significant fish die-offs of suckers in Upper Klamath Lake were documented each year. 

Over 7,000 dead suckers, ranging in age from 2 years old to 33 years old were collected 

during the late summer months of these three years (D. Hewitt, USGS, unpubl. data. 2010, 

Perkins et al. 2000a). Collections of dead suckers were comprised predominantly of adultsized suckers, with the exception of 1997, which included relatively smaller Lost River 

sucker (330 to 400 millimeters fork length) and shortnose sucker (290 to 330 millimeters fork 

length; Perkins et al. 2000a).

Between 1999 and 2008, roughly 10,000 Lost River sucker were captured and tagged 

at shoreline-spring spawning sites, with another 15,000 handled as part of the spawning run 

up the Williamson River (Janney et al. 2009). During a similar time period, 1995 – 2008, 

approximately 14,000 shortnose sucker were captured, predominantly associated with the 

Williamson River spawning runs (Janney et al. 2009). Nevertheless, the size of Upper 

Klamath Lake and the relative scarcity of Lost River sucker and shortnose sucker in the lake 

make it difficult to accurately estimate their abundance. Means to detect trends within these 

populations are therefore necessary to monitor population status.

Since 1995, more detailed demographic information has been compiled through an 

extensive mark-recapture program using Passive Integrated Transponder (PIT) tags in 

Upper Klamath Lake and more recently in Clear Lake Reservoir (Janney et al. 2008, Janney 

et al. 2009). This program is designed to monitor demography of adult spawning populations 

of Lost River sucker and shortnose sucker and detect trends in spawning population size and 

composition. One way ecologists determine population trend is by estimating annual 

survival, mortality, and recruitment rates, which can be used to estimate realized population 

change rates (represented as λ). When λ is greater than one the population is increasing, and 

when λ is less than one the population is decreasing. A λ equal to one indicates a stable 

population. When λ is known from a number of contiguous sample events, the realized 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

21

change in the size of a population proportional to some previous period can be estimated. A 

detailed description of these variables, their estimates, how they are calculated for Lost River 

sucker and shortnose sucker populations in Upper Klamath Lake, and challenges to provide 

statistical rigor to their estimates are presented in Appendix II. 

Mark-recapture studies in Upper Klamath Lake from 2002 to 2007 produce annual 

survival probabilities for shoreline spring-spawning Lost River sucker that range between 

0.80 and 0.95 (mean = 0.90; Table 2). Lost River sucker spring-spawning abundance in 2007 

is estimated to be 56 percent and 75 percent of 2002 abundances for males and females 

respectively (Figure 5), although the exact abundances are unknown and these values 

represent estimates of realized population change. Estimates of river-spawning shortnose 

sucker annual survival probabilities are even lower; from 2001 to 2007 annual survival 

probabilities of river-spawning shortnose sucker ranged between 0.68 and 0.94 (mean = 0.82; 

Table 2). The spawning population abundances in 2007 of male and female river-spawning 

shortnose sucker were 42 percent and 48 percent Figure 5, relative to 2001. Similar data are 

not currently available for Upper Klamath Lake Lost River sucker river-spawning fish or for 

Clear Lake Reservoir Lost River sucker and shortnose sucker populations. This information 

will be obtainable when the number of tagged fish is sufficiently large to provide precise, 

statistically rigorous estimates and enough annual samples are conducted.

Figure 5 Realized change in populations proportional to 2001 for river spawning shortnose suckers 

(SNS) and 2002 for spring-spawning Lost River suckers (LRS) as determined by mark-recapture studies 

(Janney and Hewitt, unpubl. data).
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

22

Table 2 Estimated survival and annual rate of population change (λ) for Upper Klamath Lake shoreline 

spring habitat spawning male and female Lost River sucker and for Williamson/Sprague spawning male 

and female shortnose sucker (Janney and Hewitt, U.S. Geological Survey, unpubl. data 2009). All 

estimates are provisional and are subject to change with the collection of more data or refinements to 

the analysis strategy. Standard errors of estimates and a detailed description of how these factors were 

calculated are presented in Appendix II.

Lost River Sucker Shortnose sucker

Male Female Male Female

Year Survival λ Survival λ Survival λ Survival λ

2001 NA NA NA NA 0.691 0.766 0.675 0.735

2002 0.795 0.820 0.863 0.892 0.771 0.855 0.894 0.974

2003 0.857 0.883 0.907 0.937 0.902 1.000 0.871 0.949

2004 0.923 0.952 0.951 0.983 0.679 0.753 0.675 0.735

2005 0.905 0.933 0.939 0.970 0.870 0.965 0.862 0.939

2006 0.899 0.927 0.935 0.966 0.795 0.882 0.923 1.005

2007 0.917 0.945 0.947 0.978 0.905 1.004 0.944 1.028

0.56a 0.75a 0.42b 0.48b

a The relative change in spawning population size compared to the first year, 2002. b The relative change in spawning population size compared to the first year, 2001.

2. Clear Lake Reservoir

Clear Lake Reservoir currently supports the largest known spawning populations of 

Lost River sucker and shortnose sucker in the Lost River system. Adults of both species 

occur in other portions of the drainage, but spawning is irregular or populations are

potentially hybridized with Klamath largescale suckers, as is the case for shortnose sucker in 

Gerber Reservoir. Less is known about shortnose sucker and Lost River sucker demography 

and trends in Clear Lake Reservoir than in Upper Klamath Lake because monitoring studies 

have been sporadic over the past 35 years, and studies similar to those conducted by Janney 

et al. (2008) in Upper Klamath Lake were not initiated in Clear Lake Reservoir until 2006 

(Barry et al. 2009). Early data suggested that Clear Lake Reservoir populations were in 

decline (Andreasen 1975, Koch et al. 1975); however, monitoring from 1989-2000 indicated

that populations are relatively stable with somewhat diverse age structures (Buettner and 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

23

Scoppettone 1991, BOR 1994, Scoppettone et al. 1995). Fifteen age classes were 

documented in the shortnose sucker population during 1989 (Figure 6-A) and nine during 

1993 (Figure 6-B). Similar data are not currently available for Lost River sucker since they 

are captured less frequently than shortnose sucker and appear to be less abundant in Clear 

Lake Reservoir. In general, growth rates for both sexes of both species appear to be 2 – 4 

times higher than Upper Klamath Lake counterparts (Barry et al. 2009, Janney et al. 2009), 

which may be partly attributable to at least some recurring recruitment and therefore 

relatively younger populations in Clear Lake Reservoir. Also, sex ratios of shortnose sucker 

are strongly skewed in favor of females over males, often 2:1. 

Combined, more than 10,000 Lost River sucker and shortnose sucker have been 

captured and tagged in Clear Lake Reservoir since 1993. These data reflect periods of 

recruitment failure and success similar to patterns in Upper Klamath Lake populations (Barry 

et al. 2009). Populations in the early- to mid-1990s showed little evidence of recruitment and 

consisted mostly of large fish, but apparent recruitment events occurred in the late-1990s and 

early-2000s. Length-frequencies from 2005 – 2009 reveal evidence of shortnose sucker

recruitment, but recruitment into the Lost River sucker population has been sparse over that

period. 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

24

Figure 6 Shortnose sucker age distribution compiled from Clear Lake Reservoir fish sampled during (A) 

1989 (Buettner and Scoppettone 1991), and (B) 1993 (U.S. Geological Survey, unpubl. data).

REASONS FOR LISTING AND CONTINUED THREATS

Reasons for listing as well as threats to the continued survival of Lost River sucker

and shortnose sucker are reviewed in a number of reports and peer reviewed articles 

(USFWS 1988, Markle and Cooperman 2002, National Research Council 2004, ISRP 2005, 

USFWS 2007a, b). The following discussion is a brief summary of the interacting influences 

of physical, chemical, and biological factors that continue to threaten current Lost River 

sucker and shortnose sucker status. 

0

0.1

0.2

0.3

1 3 5 7 9 11 13 15 17 19 21 23 25

Age

Proportion

N = 98

0

0.1

0.2

0.3

1 3 5 7 9 11 13 15 17 19 21 23 25

Age

Proportion

N = 64

(A)

(B)
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

25

In determining whether to list, delist, or reclassify (change from endangered to 

threatened status, or vice versa) a species under section 4(a) of the ESA, we evaluate five 

major categories of threats to the species: (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 following is a summary of factors that supported Lost River sucker

and shortnose sucker listing (USFWS 1988) and that were addressed in the 5-year status 

reviews (USFWS 2007a, b) for each species:

3. Factor A. The present or threatened destruction, 

modification, or curtailment of its habitat or range

Loss and alteration of habitats (including spawning and rearing habitats) were major 

factors leading to the listing of both species (USFWS 1988) and continue to be significant 

threats to recovery. As noted above, both species utilize the spectrum of aquatic habitats 

during some stage of the life cycle, including river or stream habitats, open-water lake 

habitats, and the wetlands areas along banks and shores. However, negative impacts and 

alterations to each of these different habitats have occurred, and continue to threaten the 

recovery of these species. Suitable habitat has drastically declined due to conversion of 

wetlands to agricultural use and construction of irrigation and hydroelectric facilities, both of 

which drained lakes and wetlands, created barriers preventing access to spawning habitat, 

and caused mortality by entraining fish. For example, approximately 61,000 hectares 

(150,700 acres) of sucker habitat was lost by lowering Tule and Lower Klamath lakes 

(National Research Council 2004).

Barriers that limit or prevent access to spawning habitat were identified as a threat 

when we listed Lost River sucker and shortnose sucker. Chiloquin Dam was cited as the most 

influential barrier because it restricted access to potentially 95 percent of historic river 

spawning habitat in the Sprague River (USFWS 1988). However, this dam was removed in 

2008, improving access to approximately 120 kilometers (75 miles) of river for spawning. 

At the time of this revision, data are insufficient to assess the actual realized benefit to 

spawners, but studies are ongoing. Nevertheless, many other large and small diversion 

structures remain throughout the range of these species including the Sprague River, 

although specific direct and indirect negative impacts are difficult to quantify (National 

Research Council 2004). For example, several large dams (such as the Link River Dam and 

Anderson Rose Dam) hinder or completely impede upstream movements. Likewise, suckers 

attempting to run up the Lost River are restricted to below the Anderson-Rose Dam, a short 

distance upstream from Tule Lake (Appendix C of USFWS 2002).
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

26

Another equally important barrier is limited hydrologic connection to spawning or 

rearing habitat often resulting from an interaction of irrigation diversions and climate. For 

example, low lake levels adversely affect Clear Lake Reservoir sucker populations by 

limiting access to Willow Creek, the only known spawning tributary (Buettner and 

Scoppettone 1991). Likewise, the amount of suitable shoreline spring spawning habitat in 

Upper Klamath Lake is significantly affected by even minor changes in lake elevation, but it 

is unknown exactly how such levels directly affect annual productivity. Several springspawning populations, including Tecumseh Springs, Big Springs, and Barkley Springs, have 

been lost or significantly altered, in part due to reduced connectivity (Andreasen 1975, 

USFWS 1988, National Research Council 2004). 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

27

Historically, wetlands comprised hundreds of thousands of hectares throughout the 

range of the species (Akins 1970, Bottorff 1989, Gearhart et al. 1995), some of which likely 

functioned as crucial habitat for larvae and juveniles. Other wetlands may have played vital 

roles in the quality and quantity of water. Loss of ecosystem functions such as these, due to 

alteration or separation of the habitat, is as detrimental as physical loss of the habitat. For 

example, increases in sediment input to the lake and occurrence of Aphanizomenon flosaquae coincide with modification of riparian and wetland areas associated with Upper 

Klamath Lake (Bradbury et al. 2004). In Upper Klamath Lake, approximately 70 percent of 

the original 20,400 hectares (50,400 acres) of wetlands surrounding Upper Klamath Lake, 

including the Wood River Valley (Figure 7), was diked, drained, or significantly altered

between 1889 and 1971 (Bottorff 1989, Gearhart et al. 1995). Additionally, of the 

approximately 10,174 hectares (25,141 acres) of wetlands still connected to Upper Klamath 

Lake, relatively little functions as rearing habitat for larvae and juveniles, partly due to lack 

of connectivity with current spawning areas and habitat alterations.

Certainly not all modification or curtailment of sucker habitat is solely from 

anthropogenic causes; climatic trends, resulting from both anthropogenic causes and natural 

variation, also play an important role. Since 1960, eight of the ten lowest inflows into Upper 

Klamath Lake occurred between 1991 and 2009 (Bureau of Reclamation, unpubl. data, 

2010). Upper Klamath Lake levels are affected by drought, because it is shallow (average 

depth in summer = 2.2 meters [7.1 feet]), and because during droughts larger irrigation 

diversions are needed to offset low soil moisture in agricultural fields. Affected by the same 

regional droughts, Clear Lake Reservoir is even more sensitive to droughts given the limited

local precipitation and bathymetry of the lake itself. Severe or prolonged droughts likely 

negatively impact all Lost River sucker and shortnose sucker life stages throughout their 

range (Cooperman and Markle 2004, Helser et al. 2004, Loftus and Reiser 2004).
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

28

Figure 7 Map showing historical Upper Klamath Lake wetlands and their current connectivity to the lake. 

Yellow points identify locations of current shoreline-spring spawning locations.

4. Factor B: Overutilization for commercial, recreational, 

scientific, or educational purposes

Overharvest contributed to declining population levels, particularly for Lost River 

sucker, prior to listing, but harvest of any kind has been restricted since 1987 (USFWS 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

29

2007a, b). Shortnose sucker were not targeted by recreational fishing prior to listing as were 

Lost River sucker, though they were occasionally caught because of the indiscriminant 

methods of capture. In 1985, shortnose sucker comprised only 3 percent of the sport fishery 

catch (Bienz and Ziller 1987). However, if one or both of these species recover sufficiently 

to be removed from the endangered species list, recreational harvest may again affect these 

species. Regulated collections of these species for scientific purposes continue, and although

not considered a current threat to population status, the demographic effects of these 

collections need to be regularly evaluated.

5. Factor C: Disease or predation

Non-native fishes were identified as a potential threat at the time of listing through 

predation or as sources of exotic diseases/parasites, although no direct evidence was cited. 

Since then, controlled experiments have demonstrated that adult fathead minnows prey on 

sucker larvae (Markle and Dunsmoor 2007). In Upper Klamath Lake, higher fathead minnow

abundances were associated with lower sucker survival rates (Markle and Dunsmoor 2007).

Likewise, as indirect evidence, higher larval sucker survival rates were also associated with 

greater water depth and shoreline vegetative cover, habitat which help larvae avoid predation 

(Markle and Dunsmoor 2007). These data suggest that predation by overly-abundant fathead 

minnows may be an important threat to larval sucker survival, and that loss of emergent 

wetland habitat may exacerbate this. Other non-native fishes may also pose a threat to Lost 

River sucker and shortnose sucker; however, little quantitative information exists to indicate 

their influence on sucker abundance and distribution. 

Although not mentioned at the time of listing as a threat, several species of birds prey 

on Lost River sucker and shortnose sucker, but the ultimate effect to the status of the species 

from these avian predators is currently unknown. Bald eagles have been observed perching 

in trees directly above Ouxy Springs, which is one of five areas where Lost River sucker 

spawn along the eastern shoreline of Upper Klamath Lake. In Clear Lake Reservoir, radiotags and Passive Integrated Transponders (PIT tags) of individuals of both species have been 

located on islands associated with nesting colonies of American white pelican (Pelecanus 

erythrorhynchus), double-crested cormorant (Phalacrocorax auritus), and great blue heron 

(Ardea herodias) (U.S. Geological Survey Klamath Falls Field Station, unpublished data). 

Predation on spawning adults increases mortality rates of this crucial life stage, and may alter 

behavior during this critical period. For example, predation on adults at spawning sites may 

limit the amount of time spent on the spawning ground. Throughout the range of the species 

there are numerous species of piscivorous birds, including terns, grebes, and mergansers, that 

may prey on juvenile and larvae suckers.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

30

Parasites were not identified as a threat at the time of listing, but information suggests 

they could be a threat to the suckers. Anchor worm parasitism on age-0 suckers appears to be 

highly variable from year to year in Upper Klamath Lake (ISRP 2005, Bottcher and Burdick 

2010). From 1994-1996, the percent of age-0 suckers parasitized by anchor worms ranged 

from 0 percent to 7 percent, but during 1997 through 2000 it increased to between 9 and 40 

percent. In 2008 only four percent of captured juvenile suckers were infected with parasites, 

but this jumped to 18 percent in 2009 (Bottcher and Burdick 2010). Parasites can lead to 

direct mortality, provide a route for pathogens to enter fish (since they create a wound), or 

can make fish more susceptible to predation (Robinson et al. 1998). We currently do not have 

enough information to accurately assess the degree to which parasites negatively impact

sucker survival and productivity.

Of recent interest are the effects of microcystin, an algal toxin that affects the liver. 

In a 2007 survey, 49 percent of a sample of juvenile suckers (n = 47) collected at 11 

shoreline sites exhibited indications of microcystin exposure (Vanderkooi et al. 2010). 

However, these data are preliminary and further investigations are required. For example, the 

means by which the toxin is introduced into the body remains unknown. One hypothesis is 

that the toxin is indirectly ingested when suckers consume midge larvae (Chironomidae), 

which feed on the algae.

6. Factor D: Inadequacy of existing regulatory mechanisms

Many federal and state regulations directly and indirectly affect the Lost River sucker 

and shortnose sucker, but the primary areas of regulatory authority are the Endangered 

Species Acts enacted by the Federal Government, and the States of Oregon and California. 

Both species are listed as endangered by each of these entities (California Department of Fish 

and Game [CDFG] USFWS 1988, 2010, ODFW 2010). In general, such authorities prohibit 

activities that will harm the species’ chances of survival and/or recovery. For example, the 

Federal Endangered Species Act broadly prohibits import, export, take (to harass, kill, 

capture, etc. [Section 3 of the Endangered Species Act]), and possession of endangered 

species. However, the term “take” as defined individually by the States of Oregon and 

California is somewhat narrower, but conveys the same intent to prohibit killing and/or 

possession of endangered species (Callens 2004, State of California 2009).

Under Section 7 of the Federal Endangered Species Act, federal agencies seeking to 

implement an action that may affect, either directly or through modification of critical 

habitat, the Lost River sucker or the shortnose sucker must consult with the U.S. Fish and 

Wildlife Service. In 2008, we issued a Biological Opinion addressing the effects of the 

Klamath Project, operated by the U.S. Department of Interior Bureau of Reclamation, on the 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

31

Lost River sucker and the shortnose sucker (USFWS 2008). At that time we concluded that 

the actions proposed by the Bureau of Reclamation to operate the Klamath Project were not 

“likely to jeopardize the continued existence of LRS [Lost River sucker] and SNS [shortnose 

sucker], and [are] not likely to destroy or adversely modify proposed critical habitat for these 

species” (USFWS 2008:159). The Bureau of Reclamation is currently working to develop a 

new proposed action, with input from the Service and the National Marine Fisheries Service, 

for the ongoing operations of the Klamath Project. We will then provide a joint biological 

opinion to the Bureau of Reclamation, in conjunction with the National Marine Fisheries 

Service, to ensure that the needs of the listed Coho (Oncorhynchus kisutch) are coordinated 

with the needs of listed suckers to avoid conflicting requirements under the Endangered 

Species Act. We anticipate the joint biological opinion will be completed by April 2013.

Other regulatory mechanisms relevant to these species also exist, including the 

National Environmental Policy Act, as amended, the Clean Water Act, and the PorterCologne Water Quality Control Act, which establishes a water quality control board for the 

state of California (State Water Resources Control Board 2009). A total maximum daily load 

and water quality management plan establishes water quality standards for Upper Klamath 

Lake and its tributaries (Boyd et al. 2002). Water quality management plans, including total 

maximum daily load, are being cooperatively developed by the States of Oregon and 

California for areas within the Klamath Basin, including Link River and the Lost River subbasin (Kirk et al. 2010).

Based on the protections provided by these current regulatory mechanisms, we do not 

consider the inadequacy of regulatory mechanisms to be a threat to either the Lost River or 

shortnose sucker.

7. Factor E. Other natural or manmade factors affecting its 

continued existence

a) Water Quality

Most water bodies currently occupied by Lost River sucker and shortnose sucker do 

not meet water quality standards for nutrients, dissolved oxygen, temperature, and pH set by 

the States of Oregon and California (Boyd et al. 2002, Kirk et al. 2010). These conditions 

(primarily in summer) have caused several incidents of mass adult mortality, which appears 

to be a consequence of inadequate amounts of dissolved oxygen. The occurrence of mass 

mortality of fish in Upper Klamath Lake is not new; however, it is believed that the increased 

dominance of Aphanizomenon flos-aquae in the system may lead to increased regularity of 

extreme events (National Research Council 2004). Although conditions are most severe in 

Upper Klamath Lake and Keno Reservoir, fish throughout the basin are vulnerable to water-
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

32

quality-related mortality (USFWS 2007a, b). Degraded water quality conditions may also 

weaken fish and increase their susceptibility to disease, parasites and predation (Holt 1997, 

Perkins et al. 2000a, ISRP 2005). 

As discussed under Factor C, new information indicates that adverse water quality 

events can increase the extent to which pathogens and parasites negatively impact sucker 

survival. Although fish die-offs that occurred in Upper Klamath Lake in the 1990s were 

likely a response to hypoxia (low levels of dissolved oxygen), disease outbreaks also 

probably contributed to mortality during these events (Perkins et al. 2000a, National 

Research Council 2004). 

Water quality remains one of the most important proximate factors threatening 

sucker existence; however, the uncertainty surrounding many of the potential ultimate 

factors (for example, the complex interactions of factors causing poor water quality), 

including wetland reduction, natural nutrient loads, non-point sources, and water 

management, also make it one of the most difficult threats to address.

b) Entrainment

Movement of fish into irrigation systems through unscreened diversions was 

identified as a threat to the suckers at the time of listing (USFWS 1988). At that time 

thousands of suckers, including some adults, were entrained into the A-Canal, the largest 

diversion in the upper basin located near the Link River Dam. Although some of these fish 

were salvaged, many likely died (National Research Council 2004). The impact of 

entrainment into the irrigation system of the Klamath Project was reduced by construction of 

screening facilities over the A-Canal; although larvae are still at risk. Under the present 

design, fish screened from entering the A-Canal are returned via pipeline to Upper Klamath 

Lake at a point that is near the river gates of the Link River Dam (Marine and Gorman 2005). 

Further investigations are needed to determine the overall effects and stress on transferred 

fish and if fish expelled through the pipeline remain in Upper Klamath Lake or are 

subsequently entrained by flows through the Link River Dam (USFWS 2007a, b).

Substantial entrainment occurs at the river gates of the Link River Dam (Marine and 

Lappe 2009). Currently these gates have no structures to prevent drawing fish downstream, 

but the East Side and West Side hydroelectric diversion facilities (operated by PacifiCorp) 

are currently shutdown between July 15 and November 15 to reduce entrainment when 

vulnerable life stages of listed suckers are present. During the late summer of 2006, over 

3,500 age-0 juvenile suckers were collected in the Link River just below the dam with 

intermittent sampling of a fraction of the channel (Tyler 2007). The Committee on 

Endangered and Threatened Fishes in the Klamath River Basin of the National Research 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

33

Council recommended screening to prevent downstream losses at Link River Dam (National 

Research Council 2004). Gutermuth et al. (2000) also documented tens of thousands of 

young suckers entrained at the PacifiCorp hydropower canals and turbines associated with 

the Link River Dam. Nonetheless, further research is required to better quantify the threats 

these structures pose to recovery.

Until recently, most suckers that pass through the gates at Link River Dam, or that 

survive passage through the hydroelectric facilities, were believed to be entirely lost from the 

breeding population. It was assumed that these fish either die in poor summer water quality 

conditions in Keno Reservoir, or pass further downstream into reservoirs along the Klamath 

River, from which upstream passage is blocked. However, recent surveys by the Bureau of 

Reclamation have detected a relatively small population residing in Lake Ewauna (see 

Distribution Section) indicating that some percentage of suckers do persist following passage 

through the Link River Dam gates or the hydroelectric facilities. A new fish ladder was also 

constructed at Link River Dam in 2004 through which adult suckers have been documented 

(using PIT tag readers) moving upstream through Link River. As of 2008, only seven 

individuals had been documented as passing through the ladder (Korson et al. 2008); 

however, at least 20 individuals were documented in the ladder during 2010 and 2011 (T. 

Tyler, pers. comm. 2010). Since only PIT-tagged individuals that swim close enough to the 

PIT-readers’ antennae (generally within a couple of feet) can be detected and the numbers of 

tagged suckers in Lake Ewauna are still extremely low, these values are probably 

underestimates of the total number using the ladder.

There are also significant unscreened diversion structures that divert water from Lake 

Ewauna, including the Lost River Diver Channel and Ady Canal, but we aren’t aware of any 

data indicating the amounts of entrainment through these structures. In addition to major 

diversion points, several hundred small, typically unscreened diversions in tributary streams 

and rivers and the lakes proper may also affect Lost River sucker and shortnose sucker. In 

2001, the Bureau of Reclamation reported 193 diversions within the Klamath Project that 

were “directly connected to endangered sucker habitat below Upper Klamath Lake,” with

only three of these diversions equipped with fish screens (Bureau of Reclamation 2001: 2). 

The Bureau also noted there are at least 24 large diversions outside of the Klamath Project 

Service area that have the potential of entraining suckers. The influence on sucker abundance 

and recovery of these diversions is unknown.

c) Climate Change

Climate variability, such as fluctuations between wet and dry periods, is part of 

natural processes; however, climatic models suggest that much of the recent trends in climate 

is driven by anthropogenic causes (Barnett et al. 2008). Since the 1950's, western North 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

34

America generally has exhibited trends toward less snowfall, earlier snowmelt, and earlier 

peak spring runoff, much of which cannot be attributed to natural fluctuations (Hamlet et al. 

2005, Stewart et al. 2005, Knowles et al. 2006). Furthermore, models indicate that these 

trends are likely to continue into the future (Barnett et al. 2008). More specifically, a suite of 

climate models predict that over the next 100 years the mean flow of the Sprague River will 

increase during winter months but decrease during the spawning period (Markstrom et al. 

2012, Risley et al. 2012), a pattern which is likely to be exhibited throughout the upper 

Klamath Basin.

It is difficult to accurately predict how such climatic changes will affect the Lost River 

sucker and shortnose sucker. These species are adapted to weather periodic droughts 

(Dicken and Dicken 1985, Negrini 2002), but given the current reduced state of the species, 

they may be negatively impacted if there is an increase in the intensity or frequency of 

droughts or a substantial shift in the timing of snowmelt and runoff. Likewise, detrimental 

changes in refugia availability or community composition may also accompany climate 

change (Dahm et al. 2003, Magoulick and Kobza 2003).

PAST CONSERVATION EFFORTS

Although the current population status of Lost River sucker and shortnose sucker

indicates that they continue to be endangered and at risk of extinction, we, together with

many other entities, have accomplished much to reduce threats to these species over the last 

15 years. In most instances, considerable time is necessary to determine the efficacy of 

recovery actions. For example, actions to increase reproduction and recruitment into adult 

populations require at least five years for shortnose sucker and nine years for Lost River 

sucker to be properly assessed. Similarly, it will take time for incremental improvements in 

habitat to be manifested by healthy populations.

We have worked with other agencies and stakeholders to recover the endangered 

suckers since 1994. Approximately 300 on-the-ground restoration projects, including 90 

wetland, 130 riparian, 45 in-stream, 25 upland, and 15 fish passage projects have been 

funded and implemented in the Upper Klamath Basin that directly or indirectly benefit Lost 

River sucker and shortnose sucker. Many of the projects included elements of more than one 

category of restoration project type taking a holistic or ecosystem approach based on the 

assumption that restoration of natural ecosystem functioning will ultimately benefit multiple

species, including listed suckers. These projects have had significant cost share from multiple 

sources, including Federal programs such as the Service’s Partners for Fish and Wildlife, 

Jobs in the Woods, and the Oregon Resources Conservation Act Program, as well as state 

and private grant programs and contributions from landowners. For example, PacifiCorp has 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

35

seasonally shutdown the East Side and West Side Hydroelectric diversion facilities at Link 

River Dam to reduce entrainment of vulnerable sucker life stages and provided funding to 

promote restoration activities. PacifiCorp is also currently developing a Habitat Conservation 

Plan (HCP) that will identify actions to be taken by the company for the protection and 

recovery of listed species within the Klamath Basin, including both sucker species.

Major sucker recovery oriented projects completed include: screening of irrigation 

diversions, eliminating barriers to fish passage, and restoration of rearing and spawning 

habitat (Table 3). For example, restoration of the Williamson River Delta by The Nature 

Conservancy, with substantial support from PacifiCorp and other organizations, has provided 

approximately 2,500 hectares (~6, 000 acres) that can serve as rearing habitat for the largest 

spawning populations of both species, although much of the area is deeper than it was 

historically due to subsidence. Following restoration, larvae quickly moved into the restored 

area (Crandall et al. 2008) and exhibited evidence that conditions were favorable for rearing, 

such as sufficient growth and feeding (Erdman and Hendrixson 2009). A related project 

supporting recovery of these species is the removal of Chiloquin Dam in 2008. 

Approximately 120 kilometers (75 miles) of potential spawning and migration corridor has 

been made available. These two projects should provide an enormous benefit to the river 

spawning populations of both species in Upper Klamath Lake, although it is too early to 

assess the exact results of these projects. Additionally, screening of the A-canal in 2002 is a 

significant accomplishment towards reducing entrainment of fish greater than 30 millimeters 

(1.2 inches) into the irrigation systems of the Klamath Project. Prior to placement of the 

screen, tens of thousands to hundreds of thousands of juveniles were estimated to be

entrained into the irrigation canals at this point each year (Gutermuth et al. 2000, Bennetts et 

al. 2004). A dramatic decline of suckers captured as part of end-of-year salvage efforts in the 

A-canal (from nearly 6,000 before screening to only 3 in 2004) indicated that the screen was 

functioning successfully (Kyger and Wilkens 2011). This enabled the U.S. Bureau of 

Reclamation to reduce end-of-year salvage in certain areas, and redirect resources to other 

areas of effort.

Table 3 A summary of some recent major restoration projects benefitting Lost River sucker and 

shortnose sucker populations. Many of these projects were cooperative efforts of many state and 

federal agencies, non-profit organizations, and private landowners. 

Project Year 

Completed Potential Benefits
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

36

Project Year 

Completed Potential Benefits

Reducing Entrainment

A-canal Screen 2002 Retain more larvae and juveniles in Upper 

Klamath Lake by limiting entrainment into 

the canal

Clear Lake Dam Screen 2003 Retain more larvae, juveniles, and adults in 

Clear Lake Reservoir by limiting entrainment 

into the canal

Modoc Irr. Dis. 

Williamson River Div.

Screen

2007 Reduce larval mortality due to entrainment

Geary Canal Screen 2009 Retain more larvae and juveniles in Upper 

Klamath Lake by limiting entrainment into 

the canal

Eliminating Barriers

Link River Dam fish 

ladder

2004 Restore connectivity of sucker populations in 

Upper Klamath Lake and Lake Ewauna by 

allowing for adult passage upstream, which 

may then contribute to spawning populations.

Chiloquin Dam 2008 Opening 120 km (75 mi) of historic 

migration, rearing, and spawning habitats in 

the Sprague River

Providing Habitat

Williamson River Delta 

Restoration

2008 Provide ~2,500 hectares (6,000 acres) of 

potential rearing habitat for larvae and 

juvenile suckers in Upper Klamath Lake

In addition to these major accomplishments, many other smaller projects have been 

completed. Since Lost River sucker and shortnose sucker listing, private landowners, the 

Oregon Department of Fish and Wildlife, Bureau of Reclamation, Natural Resources 

Conservation Service, the U.S. Fish and Wildlife Service, and others have built or funded 

construction of many new fish screens in the upper basin. As a result, the threat of 

entrainment is now lower than at the time of listing. Needs for additional screening and 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

37

passage for suckers are now coordinated in the upper basin through a working group led by

Bureau of Reclamation (BOR 2007). 

In 2004, a report by the National Research Council of the National Academies 

concluded that water issues must be dealt with in an integrated and comprehensive way to 

achieve lasting resolution in the Klamath Basin (National Research Council 2004). 

Representatives of the States of California and Oregon, the President’s Klamath River Basin 

Working Group, and the Environmental Protection Agency have signed the Klamath River 

Watershed Coordination Agreement. The respective agencies agreed to place a high priority 

on their Klamath Basin activities, and to coordinate and communicate with one-another and 

with tribal governments, local governments, private groups and individuals to resolve water 

quantity/quality problems in the basin. For example, water quality management plans were 

developed which provide targets and guidance on improvements for water quality in the 

Sprague River and Upper Klamath Lake, and many wetland and riparian restoration projects 

are now designed to address Total Maximum Daily Load issues.

In 2004, Oregon State University Agricultural Extension Service and the Klamath 

Watershed Council (now Klamath Watershed Partnership) began a series of monthly 

meetings with rural landowners in the Sprague River Valley to discuss watershed restoration 

goals. With the help of the Service, Natural Resources Conservation Service and the Klamath 

Soil & Water Conservation District, this effort has effectively connected landowners with 

appropriate state and federal resource conservation programs. As a result, landowners 

holding more than 70 percent of the private lands within the Sprague River Valley are 

partnering with local, state and/or federal agencies on land conservation and natural resource 

actions, some of which may benefit listed suckers. The efforts of the Klamath Watershed 

Partnership have brought additional fiscal partners (for example, Oregon Department of 

Agriculture, Klamath County, and Oregon Watershed Enhancement Board) into the 

conservation partnership. These partnership-forming actions will continue and build on 

themselves and enable more restoration to be done in the future. 

The tributaries in the Wood River Valley supply a large portion of the inflow to 

Upper Klamath Lake. This valley also supports much of the livestock grazing in the Upper 

Basin and is responsible for approximately 30 percent of the external phosphorus loading to 

the lake. Because of this, it was identified by Oregon Department of Environmental Quality

as a priority water quality impaired area. The Klamath Basin Rangeland Trust has been 

active in the Wood River Valley encouraging landowners to adopt sustainable land and water 

management practices. Since 2002, the number of landowners who partner with this 

organization on conservation and restoration activities has increased to include a significant 

portion of the agricultural lands in the watershed. 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

38

The above discussion underscores that landowners and agencies are involved in

activities that improve sucker habitat and support sucker recovery. The high rate of 

participation in federal and state conservation programs by ranchers and farmers in the 

Sprague and Wood River valleys suggests that essential elements of habitat recovery on 

private land (such as voluntary participation and adequate funding) should allow for effective 

recovery actions to occur. 

Klamath River Basin stakeholders, including the States of Oregon and California, the 

Karuk, Klamath, and Yurok Tribes, several counties, 26 parties associated with the Klamath 

Reclamation Project or irrigators above Upper Klamath Lake, and 7 other conservation 

organizations, signed the Klamath Basin Restoration Agreement (KBRA) in early 2010. This

agreement “is intended to result in effective and durable solutions which: (i) restore and 

sustain natural production and provide for Full Participation in Harvest Opportunities of fish 

species throughout the Klamath Basin; (ii) establish reliable water and power supplies which 

sustain agricultural uses and communities and National Wildlife Refuges; (iii) contribute to 

the public welfare and the sustainability of all Klamath Basin communities...”(KBRA 

2010:4). Although further events such as legislation and funding authorizations must occur 

prior to full implementation, we believe that implementation of this agreement will produce

substantial progress toward the recovery of Lost River sucker and shortnose sucker.

Despite the progress in many important areas, there is still a need for additional 

habitat restoration in the Upper Klamath Basin. Many programs, including our Partners for 

Fish and Wildlife Program, the National Resource Conservation Service Wetlands Reserve 

Program, and organizations such the National Fish and Wildlife Foundation and the Oregon 

Watershed Enhancement Board, among others, can play an important role in achieving 

suitable and sustainable habitat conducive for the recovery of these species.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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VIII. Recovery Program

This section describes the Lost River sucker and shortnose sucker recovery program 

by outlining a strategy, identifying where recovery will occur (recovery units), defining the 

recovery goal and objectives, and delineating criteria to down list Lost River sucker and 

shortnose sucker to threatened and to remove them from the list of threatened and 

endangered species (delist the species).

RECOVERY PRIORITY NUMBER

Recent 5-yr status reviews of each species assigned a recovery priority number of 4C 

to each species (USFWS 2007a, b). However, this was an inaccurate assignment for the 

shortnose sucker. Instead, the recovery priority numbers for Lost River sucker and shortnose 

sucker should be 4C and 5C, respectively. These priority numbers indicate that both species 

have a high degree of threat and a low potential for recovery. However, given that Lost 

River suckers belong to a monotypic genus (Deltistes) while shortnose sucker belong to a 

polytypic genus (Chasmistes), the recovery priority for Lost River sucker is slightly higher. 

The “C” in the recovery priority number indicates that conflict exists with “construction or 

other development projects or other forms of economic activity” (USFWS 1983:43104).

RECOVERY STRATEGY

The most pressing threat to these species is the lack of both resiliency and 

redundancy due to severe reduction of viable populations range wide. Of the few 

populations that do remain from historic distributions, most are restricted and many lack the 

ability to successfully reproduce. Reproducing populations are only known to exist in Upper 

Klamath Lake, Clear Lake Reservoir, and Gerber Reservoir (shortnose sucker only). This 

condition means that a threat to any single reproducing population becomes a threat to the 

entire species. Populations in Upper Klamath Lake are able to spawn, but are threatened by a 

uniformly aged population, due to relatively few or no individuals progressing from larvae to 

spawning adults. The actual causes of this lack of recruitment are complex and poorly 

understood, but include loss of spawning and nursery habitat, degradation of juvenile and 

adult habitat, loss of individuals to sink populations or mortality, and, potentially, negative 

interactions with introduced and/or predatory species. The limited amount of information on 

populations in Clear Lake Reservoir prevent rigorous assessment of status and trends, but 

many characteristics of the lake (such as susceptibility to drought and only one major

spawning stream) raise concerns of potential stochastic loss of the populations. Similar 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

40

threats face the shortnose population in Gerber Reservoir, with the added complexity of 

hybridization with Klamath largescale sucker.

In general, the strategy to recover these species is to ameliorate negative impacts on 

viable populations throughout the species’ range in order to restore natural population 

dynamics in the upper Klamath Basin systems, primarily populations of Upper Klamath Lake

and Clear Lake Reservoir. This will include efforts to prevent extinction through 

establishment of viable auxiliary populations, determine the specific threats to and needs of 

distinct portions or populations of the species (see Recovery Units in this document), reduce 

threats to the extent possible through restoration or manipulation, and promote the growth of 

populations. We believe that with successful implementation of actions associated with the 

specific objectives enumerated below, Lost River sucker and shortnose sucker populations 

will obtain healthy, self-sustaining demographic characteristics and age structure; however, 

should these measures fail, as indicated by continued population declines, a program to 

enhance redundancy and resiliency through controlled propagation may be needed to prevent 

extinction in the near-term. It is our policy to use controlled propagation as part of a recovery 

strategy “only when other measures employed to maintain or improve a listed species’ status 

in the wild have failed, are determined to be likely to fail, are shown to be ineffective in 

overcoming existing factors limiting recovery, or would be insufficient to achieve full 

recovery” (USFWS and National Oceanic and Atmospheric Administration 2000:56920). 

Given the potential difficulties and drawbacks of intensive hatchery rearing (Belk et al. 2008, 

Rasmussen et al. 2009) this option is considered a last resort to guard the species from 

imminent extinction. Artificial propagation programs have likely contributed to continued 

persistence of several related species, though, none of the programs has been sufficiently 

successful to achieve delisting; see Andersen et al. (2007) for a summary of the importance 

of rearing programs to recovery of the endangered June sucker (Chasmistes liorus). 

RECOVERY UNITS

Given differences in population dynamics, life history and genetics between 

populations in the Klamath River Basin and the Lost River Sub-basin, each species is 

classified into two recovery units (Upper Klamath Lake and Lost River), which are further 

divided into management units. Such divisions are intended to insure conservation of unique 

genetic and life history traits (for example, shoreline-spring spawning), or allow for recovery 

actions or criteria specific to a population. Recovery units are not regulatory in nature, but 

indicate areas that are each individually necessary for long-term sustainability of the entire 

listed species and thus serve to facilitate species recovery. When recovery units are 

delineated by the Service as part of a recovery plan for a listed entity, it is the policy of the 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

41

Service that the recovery units "should collectively cover the entire range of the species. 

However, this does not mean that each individual or population within the recovery unit must 

be conserved; only that the boundaries around recovery units should be sufficiently broad to 

include all current populations" (National Marine Fisheries Service and U.S. Fish and 

Wildlife Service 2010: 5.1-12).Management units are designated solely to permit us to 

compartmentalize distinct portions of recovery units to enable application of unique and 

specific management approaches. Designation of the management units does not imply an 

inherent recovery value of the individuals within those units. The management unit structure 

allows us to tailor management plans and actions to the needs of populations within those 

management units. This serves to promote efficiency and focus on recovery implementation. 

However, each management unit may not be necessary for the conservation of the species, as 

is the case for each recovery unit. It is recognized that Lost River sucker and shortnose 

sucker are different species and likely to occupy somewhat different niches in the ecosystem; 

nevertheless, ecological similarities between the species are also quite strong. Therefore, 

recovery units and management units are designated separately for each species, but unit 

boundaries, recovery actions and recovery criteria will be considered the same unless 

specifically stated. Currently, we believe that to achieve delisting for each species, both

recovery units for each species must possess healthy, viable populations. 

1. Upper Klamath Lake Recovery Unit

This recovery unit includes individuals residing in Upper Klamath Lake, its 

tributaries, the Link River, Keno Reservoir, and reservoirs located along the Klamath River 

to Iron Gate Reservoir. Management units are designated as follows:

• Upper Klamath Lake-River: Individuals residing in Upper Klamath Lake and areas 

associated with tributary spawning (current and future), 

• Upper Klamath Lake-Spring: Individuals residing in Upper Klamath Lake associated 

with shoreline spring spawning locations (current and future); this management unit 

applies only to Lost River sucker because shortnose sucker do not spawn at shoreline 

springs, 

• Keno Reservoir: Individuals residing between Link River Dam and Keno Dam 

(including Link River, Lake Ewauna, and Keno Reservoir), and

• Klamath River: Individuals residing in flowing water or reservoirs between Keno 

Dam and Iron Gate Dam.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

42

Overlap between the Upper Klamath Lake – River and Upper Klamath Lake – Spring 

management units is significant with the primary distinction being spawning location; 

however, this difference in life history is important to recognize and manage separately.

2. Lost River Recovery Unit

This recovery unit includes individuals residing in lakes, sumps, reservoirs, or

flowing waters found in the Lost River sub-basin in the following management units:

• Clear Lake Reservoir: Individuals residing in Clear Lake Reservoir and tributaries,

• Tule Lake: Individuals residing in Tule Lake, and the Lost River downstream from 

the Anderson-Rose Diversion Dam,

• Gerber Reservoir: Individuals residing in Gerber Reservoir and tributaries; this 

includes only shortnose sucker because Lost River sucker do not occur here, and

• Lost River: Individuals residing in Lost River proper downstream of Clear Lake Dam 

to Anderson Rose Dam, including Miller Creek downstream of Gerber Dam.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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Figure 8 Two recovery units have been delineated for both the Lost River sucker and the shortnose 

sucker. Within each recovery unit, multiple management units have also been designated. Both recovery 

units must have healthy, self-sustaining populations for recovery to be achieved, although viable 

populations in each management unit are not necessarily essential. 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

44

RECOVERY GOAL, OBJECTIVES, AND CRITERIA 

3. Recovery Goal

The ultimate goal of the recovery program is to arrest the decline and enhance Lost 

River sucker and shortnose sucker populations so that ESA protection is no longer necessary.

To obtain this goal it is necessary to produce naturally self-sustaining populations, which 

possess healthy long-term demographic traits and trends. 

4. Recovery Objectives

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

objectives are identified (in no specific order):

a) Threat-based Objectives

i. Restore or enhance spawning and nursery habitat in Upper Klamath 

Lake and Clear Lake Reservoir systems.

ii. Reduce negative impacts of poor water quality

iii. Clarify and reduce the effects of non-native organisms on all life 

stages

iv. Reduce the loss of individuals to entrainment

v. Establish a redundancy and resiliency enhancement program

b) Demographic-based Objectives

i. Maintain or increase larval production

ii. Increase juvenile survival and recruitment to spawning populations

iii. Protect existing and increase the number of recurring, successful

spawning populations. 

5. Recovery Criteria

An endangered species is defined in the Endangered Species 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 and 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

45

endangered. 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 Endangered Species Act. 

Recovery criteria are conditions that, when met, are likely to indicate that a species 

may warrant downlisting or delisting. Thus, recovery criteria are mileposts that measure 

progress toward recovery. Recovery criteria are provided below for each listed species 

covered in this draft recovery plan. Because the appropriateness of downlisting or delisting 

is assessed by evaluating the five threat factors identified in the Endangered Species Act, the 

recovery criteria below pertain to and are organized by these factors. These recovery criteria 

are our best assessment at this time of what needs to be completed so that the species may be 

downlisted to threatened status or 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 downlisting or 

delisting is warranted although not all recovery criteria are met. Conversely, it is possible 

that the recovery criteria could be met and a status review may indicate that downlisting or 

delisting is not warranted; for example, a new threat may emerge that is not addressed by the 

recovery criteria below and that causes the species to remain threatened or endangered.

DOWNLISTING CRITERIA—LOST RIVER SUCKER AND SHORTNOSE

SUCKER

Recovery occurs when threats outlined in the Reasons for Listing and Continued 

Threats sections have been ameliorated based on the criteria enumerated below. Recovery in 

this case is not defined in terms of absolute numbers of individuals but by the achievement of 

natural, self-sustaining demography, as determined through monitoring. Similarities in 

shortnose sucker and Lost River sucker life history, demographics and ecology, makes it 

possible to identify similar criteria for each species; however, species specific criteria are 

noted when necessary. Reproduction and recruitment are apparently occurring within Clear 

Lake Reservoir, but population trends are unknown. This general lack of information 

concerning all management units in the Lost River recovery unit, but specifically Clear Lake

Reservoir, preclude establishment of specific demographic criteria; however, sufficient 

monitoring plans to better quantify the status of Clear Lake Reservoir populations through 

time must be developed and implemented in order for downlisting to occur.

The following enumerates recovery criteria in the context of threats identified in the 

listing rule and the above objectives. Unless stated explicitly, criteria are applicable to both 

species, both recovery units, and all management units.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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6. Factor A: The present destruction, modification, or 

curtailment of its habitat or range 

In order to downlist shortnose sucker and Lost River sucker to threatened status, 

threats to the species due to degraded or limited habitat must be reduced. This will have been 

accomplished if the following have occurred:

A.1 Current spawning and rearing habitat is maintained and improved access ensures

annual use.

A.2 A range-wide Spawning and Rearing Enhancement Plan has been developed and 

implemented. This plan shall identify and prioritize areas of potential spawning and 

rearing habitat for enhancement and/or restoration, including areas which are 

degraded or unavailable due to lack of connectivity or passage.

A.3 Connectivity and access is assured to habitats that provide refuge to suckers to avoid 

poor water quality (particularly Pelican Bay) during the months of July, August, and 

September – Upper Klamath Lake Recovery Unit.

A.4 Natural vegetated wetland areas are restored, including in-stream, wetland, and 

riparian areas around the mouth of Willow Creek where it meets Clear Lake

Reservoir and throughout its drainage – Clear Lake Reservoir Management Unit.

7. Factor C: Disease or predation 

Little is known about effects of predation or disease on Lost River sucker or 

shortnose sucker populations. In order to safely enable downlisting of Lost River sucker and 

shortnose sucker to threatened status, the effects of predation, disease, and parasites must be 

clarified and, if necessary, minimized. This will have been accomplished if the following has 

occurred: 

C.1 Newly identified or clarified effects of predation and disease are minimized through 

implementation of recommendations from ongoing scientific research which clarifies 

the interaction of Lost River sucker and shortnose sucker with predators and 

pathogens.

8. Factor D: Inadequacy of existing regulatory mechanisms 

Because we do not consider the inadequacy of regulatory mechanisms to be a threat 

to either the Lost River or shortnose sucker, recovery criteria under this factor are not 

necessary.
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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9. Factor E: Other natural or manmade factors affecting its 

continued existence 

In order to safely downlist Lost River sucker and shortnose sucker to threatened 

status, the species must be protected from other natural or manmade factors known to affect 

their continued existence. This will have been accomplished if the following has occurred:

E.1 An Entrainment Reduction Plan has been developed and implemented. This plan 

shall identify and prioritize screening of diversions throughout upper Klamath Basin, 

including the Klamath Project, and propose strategies for efficient reduction of 

entrainment.

E.2 Establishment of two additional recurring and successful spring-spawning 

populations in the Upper Klamath Lake-Spring Management Unit – Lost River sucker 

specific.

E.3 Development and implementation of a plan to assess, monitor, and improve juvenile

and sub-adult vital rates and demography, including threats and negative impact 

reduction. This plan shall also designate specific demographic or vital rate targets, 

and strategies for achieving these targets, important for downlisting and delisting.

E.4 The effects of detrimental water quality have been minimized through 

implementation of recommendations from ongoing scientific research which clarifies 

the relationship of these factors with sucker mortality – Upper Klamath Lake

Recovery Unit.

DELISTING CRITERIA—LOST RIVER SUCKER AND SHORTNOSE 

SUCKER

In order to safely delist Lost River and shortnose sucker the following additional 

criteria must be met: 

10. Factor B: Overutilization for commercial, recreation, 

scientific, or educational purposes 

Overutilization was a factor affecting Lost River sucker abundance until 1987 when 

recreational fishing was no longer permitted. While this contributed to declining population 

levels prior to listing, it has ceased and is not currently known to be a threat. However, given 

the potential recreational use once these species are delisted the following criteria are made 

for delisting:
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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B.1 The States of Oregon and California and the Klamath Tribes, collaboratively or 

separately, should prepare and finalize population management plan(s) for the Lost 

River sucker.

11. Factor E: Other natural or manmade factors affecting its 

continued existence 

E.5 After 25 years, the average annual rate of population change is greater than one and 

the number of spawning individuals is greater than what was present in the baseline 

years for the Upper Klamath Lake River and Upper Klamath Lake Spring 

Management Units. See Appendix II for descriptions and estimation procedures of 

these measures. Twenty-five years equates to approximately two average adult life 

spans for Lost River sucker and three for shortnose sucker, and will enable 

assessment of the populations’ response to cyclical threats, such as periodic die-offs 

and drought. 2002 and 2001 will serve as the baseline years for Lost River sucker 

and shortnose sucker, respectively, since these are the first years in which estimates

of this type are statistically valid for each species.

RECOVERY ACTIONS

The actions identified below are those that, in our opinion, are necessary to bring 

about the recovery of Lost River sucker and shortnose sucker and ensure their 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. 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. In our view, populations within Upper Klamath Lake are generally 

a higher priority than other populations, because of the importance and status of the 

populations to the overall stability of the species. Also, we believe that the lack of survival 

of juveniles is currently a significant limiting factor for these species. Given these 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

49

perspectives, we generally assign higher priorities to actions that will clarify and improve the 

ecology of suckers within Upper Klamath Lake, especially for juveniles. Likewise, many 

significant actions have occurred since publication of the original recovery plan for these 

species (USFWS 1993; see also the Past Conservation Section within this document). For 

this reason, many of the highest priority actions include research and the subsequent 

implementation of appropriate actions in accord with the new findings, while other, perhaps 

more tangible, actions have been assigned lower priorities. 

The following Recovery Action Outline provides a summary of recovery actions, 

whereas the Recovery Action Narrative provides greater detail of the actions necessary to 

achieve full Lost River sucker and shortnose sucker recovery. Throughout the Recovery 

Action Outline and the Recovery Action Narrative the priorities of each action are specified 

within parentheses at the end of the description.

12. Recovery Action Outline

1. Restore or enhance spawning and nursery habitat in the Upper Klamath Lake and Lost 

River Recovery Units

1.1. Develop and implement a range-wide Spawning and Rearing Enhancement Plan (2)

1.2. Conduct and apply research on how to best manage lake levels to protect spawning 

habitat (1)

1.2.1. Assess the effects of Upper Klamath Lake elevations on shoreline-spring 

spawning and production (1) – Lost River sucker specific

1.2.2. Assess the effects of Clear Lake Reservoir elevations on spawning access and 

production (2)

1.2.3. Improve our ability to assess and forecast hydrologic conditions in the upper 

Klamath Basin (2)

1.3. Reestablish stream and river connectivity (2)

1.3.1. Improve access to Willow Creek from Clear Lake Reservoir (2)

1.3.2. Improve passage for upstream migrants through Link River (2)

1.4. Conserve and restore wetland and riparian areas (2)

1.4.1. Determine the importance of in-stream rearing habitats for larvae and 

juveniles in the Sprague River (2)
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1.4.2. Improve in-stream, wetland, and riparian habitat in Willow Creek (3)

1.5. Improve habitat quantity and quality of eastern shoreline springs in Upper Klamath 

Lake (2) – Lost River sucker specific

1.6. Identify and assess the feasibility of potential habitat improvements for suckers in 

Lake Ewauna / Keno Reservoir (3)

2. Reduce negative impacts of poor water quality

2.1. Ensure continued connectivity and access to refugial areas (2)

2.2. Conduct and apply research on the dynamics of algal cycles within Upper Klamath 

Lake and their effects on sucker populations (1)

2.2.1. Conduct comparisons of algal community composition and ecology among 

sites where these species currently occur (2)

2.2.2. Clarify ecology of Aphanizomenon flos-aquae (2)

2.2.3. Determine the effects of the algal toxin microcystin on suckers in Upper 

Klamath Lake and implement appropriate management actions, if necessary

(1)

2.3. Conserve and restore riparian and wetland areas along the Wood, Williamson, and 

Sprague Rivers, and Upper Klamath Lake to improve water quality (1)

3. Clarify and reduce the effects of introduced species on all life stages by conducting and 

applying scientific investigations (2)

4. Reduce the loss of individuals to entrainment

4.1. Develop and implement an Entrainment Reduction Plan (1)

4.2. Assure the efficacy of A-canal bypass (1)

4.3. Improve the efficacy of the Link River Dam fish ladder (3)

5. Establish a redundancy and resiliency enhancement program

5.1. Develop and implement a Genetics Assessment and Management Plan (1)

5.2. Prepare emergency response protocols for Upper Klamath Lake, Clear Lake

Reservoir, Gerber Reservoir, and Tule Lake populations (1)
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5.3. Establish at least two auxiliary populations (1)

5.4. Develop a controlled propagation program (1)

6. Increase juvenile survival and recruitment to spawning populations

6.1. Develop and implement a plan to assess, monitor, and improve juvenile and subadult vital rates and demography (1)

6.2. Improve understanding of juvenile life history and ecology through study of Clear 

Lake Reservoir populations (2)

7. Maintain and increase the number of recurring, successful spawning populations

7.1. Increase the number of spawning sub-populations in Upper Klamath Lake (3)

7.1.1. Establish a spawning population in the Harriman Springs area (3) – Lost River 

sucker specific

7.1.2. Establish a spawning population in the Barkley Springs area (3) – Lost River 

sucker specific

7.1.3. Establish an additional river-spawning population in the Upper Klamath Lake 

system (3)

7.2. Facilitate successful spawning for the Tule Lake population (1)

7.3. Continue monitoring of adult populations (1)

7.4. Determine the status of shortnose sucker in Gerber Reservoir (3)

8. Establish a Klamath Sucker Recovery Program

8.1. Formally establish the Klamath Sucker Recovery Program (1)

8.2. Conduct outreach with public / stakeholder groups (3)

8.3. Facilitate information exchange and synthesis through establishment or utilization of 

an information sharing process (3)

8.4. Periodically assess the effectiveness of and adjust recovery actions and priorities (1)

8.4.1. Implementation (compliance) assessment (1)

8.4.2. Cause and effect monitoring (1)
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13. Recovery Action Narrative

The following step-down narrative further clarifies the actions needed to achieve 

recovery, with recovery priorities within the parentheses:

1. Restore or enhance spawning and nursery habitat in the Upper Klamath Lake and 

Lost River Recovery Units

The relationship between spawning and nursery habitat with healthy population 

demography is critical. Given the extensive losses of habitat in general, including loss of 

connectivity, it is vital that such habitats be restored to functionality.

1.1. Develop and implement a range wide Spawning and Rearing Enhancement Plan 

(2)

Production of larvae is restricted to a few populations, and although substantial 

production does occur in Upper Klamath Lake, the lack of larval production from 

many other populations is a significant threat to the species. A plan should be 

developed to enhance spawning and rearing range wide with emphasis on those areas 

that currently lack substantial spawning production. This plan should include, but not 

be limited to, the most efficient and effective means for restoring spawning and 

rearing habitat, and evaluation and prioritization of restoration efforts of spawning 

and rearing habitat throughout the range of these species. This plan should also 

address potential improvements to currently used spawning areas as well as potential 

sites for spawning expansion. Likewise, measures for assessing the effectiveness of 

efforts should be developed.

1.2. Conduct and apply research on how to best manage lake levels to protect 

spawning habitat (1)

The primary populations of these species occur in bodies of water that are managed 

to provide water for irrigation. Additional information is needed to better understand 

relationships between lake level and the functionality of spawning habitat. If it is 

determined that management of lake levels can reduce the risk of extinction or 

improve the recovery of these species, actions should be taken through collaboration 

with agencies and other interested parties to develop and implement appropriate 

activities to achieve desired outcomes. 

1.2.1. Assess the effects of Upper Klamath Lake elevations on shoreline-spring 

spawning and production (1) – Lost River sucker specific

Much of the seasonal and annual fluctuations in Upper Klamath Lake are 

driven by the complex interaction among irrigation demand, climate, and 
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downstream flows to provide habitat for threatened Coho. Lake levels within 

Upper Klamath Lake are likely very important to spawning at the springs 

located on the east shoreline of the lake, as well as to the inundated wetlands 

utilized as rearing habitats. Water levels can affect the development of these 

wetland habitats and subsequent connectivity. Likewise, areas may become 

separated from the lake if levels are too low. These issues should be 

researched and strategies to reduce the impacts of lake level management 

should be developed and implemented.

1.2.2. Assess the effects of Clear Lake Reservoir elevations on spawning access 

and production (2)

Water elevations within Clear Lake Reservoir currently may affect the access 

to the only known spawning site given the location of the mouth of Willow 

Creek. These issues should be researched and strategies to reduce the impacts 

of lake level management should be developed and implemented. Likewise, 

the sensitivity of rearing habitat to water elevations within this system should 

be clarified.

1.2.3. Improve our ability to assess and forecast hydrologic conditions in the 

upper Klamath Basin (2)

In large degree our ability to manage and reduce negative impacts on sucker 

populations by low lake elevations is dependent on the accuracy of forecasts 

of hydrologic conditions (for example, seasonal inflow estimates). We need to 

improve the tools necessary for making such assessments and forecasts, 

including refinement of statistical methods, and better regional coverage and 

collection of important data (for example, groundwater and snow pack 

assessments).

1.3. Reestablish stream and river connectivity (2)

Lost River sucker and shortnose sucker spawn in rivers and streams and grow to 

adulthood in lakes; this requires connectivity between habitats for spawning adults 

ascending the rivers and drifting larvae moving to wetland habitats surrounding the 

lakes. Likewise, barriers often preclude entire populations from being able to access 

suitable spawning habitat, as in the case of populations in Keno Reservoir and Tule 

Lake. Efforts to restore connectivity to promote spawning and rearing should occur 

based on recommendations from the Spawning and Rearing Enhancement Plan.

1.3.1. Improve access to Willow Creek from Clear Lake Reservoir (2)
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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Currently the arrangement of the mouth of Willow Creek with the forebay of 

Clear Lake Dam may limit access of adults to spawning sites during dry years 

or increase entrainment rates of out-migrating larvae. The threats posed by 

this arrangement should be determined and ameliorated, if necessary.

1.3.2. Improve passage for upstream migrants through Link River (2)

To promote use of the Link River Dam fish ladder, the suitability of the Link 

River for upstream sucker passage should be assessed and improved 

accordingly, if necessary.

1.4. Conserve and restore wetland and riparian areas (2)

Programs should be implemented to restore historical wetlands associated with 

known or potential spawning areas and to provide suitable rearing habitat for larvae 

and juveniles, through such programs as our Partners for Fish and Wildlife Program, 

the National Resource Conservation Service’s Wetlands Reserve Program, or 

organizations such as National Fish and Wildlife Foundation or the Oregon 

Watershed Enhancement Board, as well as any others that may be appropriate.

1.4.1. Determine the importance of in-stream rearing habitats for larvae and 

juveniles in the Sprague River (2)

It is unclear if historic nursery and rearing areas included areas within the 

rivers, such as side channel or backwater. Studies should be conducted to 

better assess this possibility and the potential benefits to populations.

1.4.2. Improve in-stream, wetland, and riparian habitat in Willow Creek (3)

Efforts to improve spawning and rearing habitat associated with Willow Creek 

and tributaries should be carried out.

1.5. Improve habitat quantity and quality of eastern shoreline springs in Upper 

Klamath Lake (2) – Lost River sucker specific

Many eastern shoreline springs have been degraded by alterations to the surrounding 

area. Efforts to improve both the quality and quantity of these sites should be 

undertaken, such as substrate improvements or reasonable expansion of the sites.

Given that these areas are indispensable and sensitive to perturbations extreme care 

should be used when planning and completing these actions.

1.6. Identify and assess the feasibility of potential habitat improvements for suckers 

in Lake Ewauna / Keno Reservoir (3)

Plans to improve water quality within Lake Ewauna / Keno Reservoir are being 

addressed cooperatively through the Total Maximum Daily Load analysis by the 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

55

States of Oregon and California; additionally, improvements to habitat may further 

promote sucker recovery. These habitat improvements should be undertaken based 

on recommendations in the Spawning and Rearing Enhancement Plan. 

2. Reduce negative impacts of poor water quality

Most water bodies currently occupied by Lost River sucker and shortnose sucker do not 

meet water quality standards for nutrients, dissolved oxygen, temperature, and pH. This is 

mostly attributed to nutrient loading. Upper Klamath Lake has become hypereutrophic, 

and summer time conditions are characterized by an overabundance of the blue-green 

alga, Aphanizomenon flos-aquae. Poor water quality may affect fish by creating lethal 

conditions or by weakening fish thereby increasing their susceptibility to disease and 

parasites. Lost River sucker and shortnose sucker are able to tolerate relatively harsh 

conditions, but periodic die-offs show that they are susceptible to poor water quality that 

occurs primarily during summer. Actions to reduce these effects by providing sufficient 

habitat that provides refuge and minimizing the occurrence of poor water quality events 

should occur. 

2.1. Ensure continued connectivity and access to refugial areas (2)

Pelican Bay, located in the northwestern quadrant of Upper Klamath Lake, has been 

identified as an area utilized by sucker to avoid extreme poor water quality within 

Upper Klamath Lake. Steps should be taken to assure connectivity to this area as 

well as any others that may be determined to be important for the suckers during the 

critical period between July and September. Likewise, identification of other areas 

that provide refuge to any life stages of suckers from poor water quality events 

should occur. Connectivity and access to these areas should be assured during the 

periods when poor water quality events are probable.

2.2. Conduct and apply research on the dynamics of algal cycles within Upper 

Klamath Lake and their effects on sucker populations (1)

Additional information is needed to quantitatively determine relationships between 

water quality (especially as a result of algal population cycles) and sucker mortality 

or susceptibility to disease and parasites. Once such relationships are better 

understood, the next step will be to develop and implement actions, which may 

include management, restoration, and manipulation, to reduce the negative effects to 

suckers. However, it is problematic to specifically identify such actions until more 

information becomes available.

2.2.1. Conduct comparisons of algal community composition and ecology 

among sites where these species currently occur (2)
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Comparisons of algal community composition and ecology among sites where 

these species currently occur may provide insight into the how algal 

community dynamics are affecting suckers within Upper Klamath Lake.

2.2.2. Clarify ecology of Aphanizomenon flos-aquae (2)

The mechanism(s) by which Aphanizomenon flos-aquae maintains dominance

in the Upper Klamath Lake ecosystem is essentially unknown. Studies to 

better understand the ecology of this alga, with a focus to reduce its 

abundance, should be undertaken. However, implementation of actions must 

also attempt to maintain a healthy algal community, and not simply eliminate 

Aphanizomenon flos-aquae, which may then be replaced with another equally 

detrimental or worse species.

2.2.3. Determine the effects of the algal toxin microcystin on suckers in Upper 

Klamath Lake and implement appropriate management actions, if 

necessary (1)

Additional research on the interactions of suckers with microcystin, including 

the effects on individuals, the pathways for ingestion, and how these may 

ultimately affect the health of populations within Upper Klamath Lake, should 

occur. Efforts should also include ways to minimize these negative effects, if 

warranted.

2.3. Conserve and restore riparian and wetland areas along the Wood, Williamson, 

and Sprague Rivers, and Upper Klamath Lake to improve water quality (1)

Although, conservation and restoration of these areas has already been proposed for 

nursery and rearing habitats, it is also important that these actions occur to promote 

healthier water quality. As areas for each of these purposes may be slightly different 

in structure and/or location, this action is included here as well.

3. Clarify and reduce the effects of introduced species on all life stages by conducting 

and applying scientific investigations (2)

Approximately 85 percent of the fish biomass in Upper Klamath Lake when the suckers 

were listed was comprised of non-native species. The fathead minnow and yellow perch 

are most likely to affect Lost River sucker and shortnose sucker through predation on and 

competition for food and space with young suckers. Nevertheless, there is little 

quantitative information to indicate their actual influence on sucker abundance, 

distribution, and status. Additional work is needed to clarify these relationships and their 

effects on the trends, distribution and demography of suckers. Observational and 

controlled experiments should be conducted to determine the negative effects of non-
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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native species on suckers, and strategies to efficiently reduce or minimize such effects 

should be developed and implemented

4. Reduce loss of individuals to entrainment

Entrainment of individuals, especially larvae and juveniles, can remove significant 

numbers of individuals from populations. It is critical that a reduction in the number of 

individuals lost to entrainment occur.

4.1. Develop and implement an Entrainment Reduction Plan (1)

To facilitate efficient and effective entrainment reduction, an Entrainment Reduction 

Plan should be prepared. It is anticipated that entrainment resulting from action of 

Federal Agencies will be addressed through consultation (Section 7 of the ESA); 

therefore, this plan will evaluate and prioritize entrainment reductions measures 

throughout the range of these species, with emphasis on diversions outside of the 

Klamath Irrigation Project. 

4.2. Assure the efficacy of A-canal bypass (1)

Under present design, a screen prevents fish from entering the A-Canal and being 

removed from the population into irrigation facilities. These fish are delivered via 

pipeline to Upper Klamath Lake at a point that is near the Link River Dam. The 

screen appears to reduce fish movement into A-Canal but little is known about where 

fish go that are delivered into Upper Klamath Lake. Investigations are needed to 

determine if these fish remain in Upper Klamath Lake or pass downstream into Lake 

Ewauna. 

4.3. Improve the efficacy of the Link River Dam fish ladder (3)

Limited use of the Link River fish ladder has been documented. Improvements must 

be made to assure utility of these structures. Functionality of the Link River Dam 

fish ladder should be improved by design and implementation of operational 

protocols.

5. Establish a redundancy and resiliency enhancement program

The purpose of this program will be to support and enhance efforts to improve in situ

conditions through creation or maintenance of populations that provide redundancy and 

potentially produce individuals for augmentation to increase resiliency of the most 

important populations for the species, Upper Klamath Lake and Clear Lake Reservoir. 

This program will proactively prepare for contingencies that may arise if numbers 

become so low that action is required. This program may include two similar but distinct 

parts, auxiliary populations and controlled propagation, both of which may be utilized to 

maintain a stock of individuals to prevent extinction or loss of significant diversity, or to 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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produce individuals to augment existing “wild” populations or to facilitate research. We 

recognize that augmentation simply treats the “symptoms”, in other words, the declining 

populations, and does not ultimately fix the cause of those declines, but we assert that this 

can be a very useful tool, even though substantial time and planning will be required to 

develop this program, and construction of new facilities may be necessary. 

5.1. Develop and implement a Genetics Assessment and Management Plan (1)

Although some clarification of sucker genetics has occurred within the past decade 

(See Dowling 2005 and Tranah and May 2006), there is still no single document that 

completely synthesizes our current understanding of the genetics of these species and 

identifies specific needs and plans for moving forward. A Genetics Assessment and 

Management Plan should be developed to 1) determine genetic diversity within and 

among recovery units and management units and 2) prescribe objectives and 

protocols for preserving and protecting genetic diversity within natural populations, 

and propagation efforts. This plan will also address the effects of hybridization to the 

species. Because actions 5.3 and 5.4 depend on this plan, this action was also given a 

Recovery Priority of 1.

5.2. Prepare emergency response protocols for Upper Klamath Lake, Clear Lake

Reservoir, Gerber Reservoir, and Tule Lake populations (1)

Given the vulnerability of these areas to potential catastrophe, such as widespread 

fish die-offs or severe drought, site specific protocols to detect and respond to an 

emergency in each of these locations should be developed and revised periodically.

5.3. Establish at least two auxiliary populations (1)

Species that are concentrated into a few populations are inherently at risk to 

demographic and environmental stochasticity and catastrophic events (such as 

disease outbreaks). One method to reduce this risk is to establish separate distinct 

populations that can serve as a source of individuals should abundance in other 

populations decline severely. At least two auxiliary sites for each species outside of 

Upper Klamath Lake, Clear Lake Reservoir, and Gerber Reservoir (for shortnose 

sucker only) should be established and maintained. Potential sites for the 

establishment of auxiliary populations should be identified using quantifiable 

evaluations and qualitative assessment of feasibility. Criteria should include 

suitability (for example, water quality, food resources, and drought risk, to name a 

few) as well as the potential for reproduction and/or rearing. Tule Lake is the only 

known water body where significant sucker populations currently occur that will 

likely be able to persist into the future, outside of Upper Klamath Lake, Clear Lake

Reservoir, and Gerber Reservoir. Therefore, this system will be given preference 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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when assessing the feasibility of managing populations there as auxiliary

populations. However, should other equally suitable and/or successful areas be 

identified, the establishment of auxiliary populations in those areas should not be 

preempted by the current importance of Tule Lake. Small numbers of mostly adult 

Lost River sucker and shortnose sucker are also scattered elsewhere throughout the 

upper Klamath River basin. These populations are supported by fish moving 

downstream from Upper Klamath Lake and Clear Lake Reservoir. Although 

reproduction is low or does not occur in these populations, these fish currently serve 

as auxiliary populations that provide redundancy to Upper Klamath Lake and Clear 

Lake Reservoir populations, and may potentially provide stock for augmentation, 

should this be necessary. It is important to note, however, that many of the dams 

located along the Klamath River have been proposed for removal in the Klamath 

Basin Restoration Agreement (KBRA 2010). While the populations located in the 

reservoirs behind these dams are currently important as auxiliary populations, the 

inability of these Klamath River mainstem reservoir populations downstream of 

Keno Dam to contribute directly to long-term recovery means that protection of 

these populations should not preclude removal of the dams. Nevertheless, efforts to 

capitalize upon these populations prior to dam removal should occur.

Recommendations from the Genetics Assessment and Management Plan for 

preserving and protecting genetic diversity should be adhered to. Monitoring plans 

for each auxiliary population should be developed and implemented, including 

protocol for utilizing auxiliary populations as a source population to augment other 

areas (such as capture and transport methods, timing, target individuals, and number 

of individuals to be extracted, etc.).

5.4. Develop a controlled propagation program (1)

The declining demographic health of Lost River sucker and shortnose sucker

populations documented in Upper Klamath Lake since 2001 suggests that a 

controlled propagation program may also be necessary to prevent extinction. This 

program may involve various methods, including but not limited to in situ rearing of 

larvae and/or juveniles in semi-natural environments, such cages or ponds, or more 

intensive (traditional) hatchery methods. The selected option(s) should be 

implemented if populations in any Recovery Unit decline below 25 percent of the

early 2000s (See Appendix II for discussion on how to estimate this realized 

population change). Demographic monitoring will provide information for tracking 

trends and informing managers about the urgency of creating a hatchery program and 

the effectiveness of augmentation efforts if initiated. 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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6. Increase juvenile survival and recruitment to spawning populations

Relatively little is known about the ecology and demography of these species as 

juveniles. Studies should be implemented to better understand the manner and magnitude 

to which individuals of this age class are affected by the various biotic and abiotic 

factors.

6.1. Develop and implement a plan to assess, monitor, and improve juvenile and 

sub-adult vital rates and demography (1)

Understanding the ultimate and proximate causes of the apparent high rate of juvenile 

mortality is of critical importance. Research with an emphasis on decreasing juvenile 

mortality and increasing recruitment into spawning populations should be 

collaboratively planned and implemented range wide.

6.2. Improve understanding of juvenile life history and ecology through study of 

Clear Lake Reservoir populations (2)

A clearer understanding of the ecology and life history of populations within Clear 

Lake Reservoir is important to understand the overall status of the species and 

specifically the dynamics within this reservoir, but this information may also provide 

insight into ways to improve populations in Upper Klamath Lake through 

comparison of ecology and life history. Studies to clarify the ecology of populations 

within Clear Lake Reservoir should therefore be conducted.

7. Maintain and increase the number of recurring, successful spawning populations

When populations or sub-populations of species are temporally or spatially distinct, this

can provide a measure of security against potential catastrophic loss for the overall group. 

This is known as redundancy and is relevant to spawning groups of the same species. 

The number of total spawning aggregations has decreased dramatically for both Lost 

River sucker and shortnose sucker. Successful establishment of additional spawning 

aggregations will likely increase the species’ ability to overcome many threats. 

7.1. Increase the number of spawning sub-populations in Upper Klamath Lake (3)

At least two additional spawning sub-populations should be established within Upper 

Klamath Lake. This should include at least one population which spawns at springs 

near the shoreline of the lake.

7.1.1. Establish a spawning population in the Harriman Springs area (3) – Lost 

River sucker specific
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A distinct self-perpetuating spawning population should be established in the 

Harriman Springs area. This may include individuals that use the spring area 

or habitat within Fourmile Creek.

7.1.2. Establish a spawning population in the Barkley Springs area (3) – Lost 

River sucker specific

A distinct self-perpetuating spawning population should be established in 

Barkley Springs.

7.1.3. Establish an additional river-spawning population in the Upper Klamath 

Lake system (3)

A distinct self-perpetuating spawning population should be established within 

the Upper Klamath Lake. This population should be in addition to 

improvement made in the Williamson and Sprague Rivers. Feasibility 

assessments of potential sites should be part of the Spawning and Rearing 

Enhancement Plan.

7.2. Facilitate successful spawning for the Tule Lake population (1)

Habitat within Tule Lake is able to sustain populations of both Lost River and 

shortnose sucker; however, spawning habitat is limiting. Attempts to perform 

spawning migrations by adult suckers in this system have been observed. Currently 

there are no plans to restore passage through Anderson-Rose Dam for spawning 

migrations. However, there may be alternative means to restore successful 

spawning. With the addition of successful spawning of this population the threat of 

extinction of these species from stochastic events would be significantly reduced. 

Details to accomplish this should be included in the Spawning and Rearing 

Enhancement Plan, and implementation should occur as collaboration with the Tule 

Lake National Wildlife Refuge, Bureau of Reclamation, and other interested parties.

7.3. Continue monitoring of adult populations (1)

Continued monitoring of population status and trends is imperative as we continue to 

assess the threats to each population and the species overall. Such monitoring trends 

will enable us to determine if threats are being appropriately addressed, or if further 

actions are necessary to protect the species. Monitoring of adult populations, 

especially in Upper Klamath Lake and Clear Lake Reservoir, should continue. Such 

monitoring may include demographic characteristics (for example, age composition 

of spawning populations), spawning occurrence and success, and responses to poor 

water quality events, but at a minimum should include the data necessary to assess 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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trends within the population. Plans to monitor and protect these populations should 

also account for potential impacts due to climate change.

7.4. Determine the status of shortnose sucker in Gerber Reservoir (3)

Little information exists on the status of shortnose sucker within Gerber Reservoir, 

but this information will be important to fully understand the status of the species 

within the Lost River Recovery Unit. This recovery action will utilize techniques 

similar to those used for other listed Klamath sucker populations to better understand 

trends and structure of the population. For example, if shortnose sucker in Gerber 

Reservoir are found to be a stable, self-sustaining population, they may be used as a 

model to determine what a stable age-class distribution looks like.

8. Establish a Klamath Sucker Recovery Program

A program comprised of interested parties and entities to implement recovery actions 

should be initiated. This recovery implementation program will consist of several 

focused “teams” and coordinate public outreach, scientific collaboration, and assessment 

of current program direction. Because the efficiency and effectiveness of many other 

recovery actions depends on portions of this action, many of the sub-actions named here 

have been assigned a Recovery Priority of 1.

8.1. Formally establish the Klamath Sucker Recovery Program (1)

The Recovery Implementation Program will be a coordinated effort among federal, 

state, tribal, academic, private, and other stakeholders to implement the recovery 

plan. This will include various teams, as necessary, to address specific issues 

concerning the recovery of these species. These teams will be vital in developing the 

various specific plans identified as important, including genetics management, 

emergency response, and spawning and rearing enhancement plans, as well as 

individual management plans for each of the management units.

8.2. Conduct outreach with public / stakeholder groups (3)

Those responsible for implementing recovery should inform interested parties of 

proposed and completed actions regularly through various means. A stakeholder 

group, including participants during the process to revise this recovery plan, should 

be maintained and consulted. 

8.3. Facilitate information exchange and synthesis through establishment or 

utilization of an information sharing process (3)

A team should be created to regularly review and assess activities to ascertain the 

effectiveness of research and management. This team should facilitate the sharing of 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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information among organizations implementing recovery actions and research, as 

well as other interested parties. 

8.4. Periodically assess the effectiveness of and adjust recovery actions and priorities

(1)

Effectiveness monitoring is an essential part of any recovery program. We plan to 

assess the effectiveness of actions regularly through the efforts of the recovery 

implementation program.

8.4.1. Implementation (compliance) assessment (1)

We will periodically solicit internal and external expert review of the recovery 

implementation program to promote the highest quality of work and provide 

suggestions for future recovery actions. The goal will be to determine if 

recovery actions are being implemented as laid out in the recovery plan.

8.4.2. Cause and effect monitoring (1)

Given the level of uncertainty associated with some threats, many of the 

actions described in this plan call for development and implementation of 

scientific research to further clarify the situation. As the impacts of threats are 

reduced or eliminated the expectation is that beneficial responses will be seen 

in the status and trends of populations. It is vital that we understand the effect 

of implemented actions in order to sufficiently assess the success of those 

actions. This includes assessment of the effectiveness of restoration efforts, 

reduction of entrainment, and research to reduce impacts from poor water 

quality and non-native species.

IMPLEMENTATION SCHEDULE

Implementing recovery actions will require multiple partners and a diversity of 

approaches. Decisions about when and how to implement recovery actions will be a 

collaborative process with Federal, State, Tribal, and private partners and stakeholders. The 

Implementation Schedule (Table 4) shown below is a guide for meeting the recovery goals 

identified in this revised plan for Lost River sucker and shortnose sucker. It indicates action 

priorities, action numbers, action descriptions, duration of actions, and proposed parties 

responsible for actions (either funding or implementing), as well as estimated costs. It is 

important to note that most actions contribute toward recovery of both species. Parties with

authority, responsibility, or expressed interest to implement a specific recovery action are 

identified in this schedule. However, the listing of party in the Implementation Schedule does 

not require the identified party to implement the action(s) or secure funding for implementing 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

64

the action(s). For the sake of brevity in the Implementation Schedule, annual costs are 

estimated for the first five years, and an estimated total cost to achieve full recovery is 

provided.

We estimate that Lost River sucker and shortnose sucker recovery can occur in five to 

seven generations. In ecological terms, a generation is the average time it takes for females to 

become reproductive; this is approximately seven years for Lost River sucker and five years 

for shortnose sucker (Perkins et al. 2000b). Therefore, we may expect recovery of these 

species to occur in between 30 – 50 years, depending on our ability to reverse current trends

and eliminate threats. This time frame also includes the estimated time required to reverse 

current trends, and the time required to establish and document increased abundances and 

stable population dynamics.

14. Definition of Action Durations

Continual (C): An action that will be implemented on a routine basis once begun.

Ongoing (O): An action that is currently being implemented and will continue until 

no longer necessary.

Periodic (P): An action that recurs periodically, for example every five years, so 

long as the species are listed.

To Be Determined (TBD): The action duration is not known at this time or 

implementation of the action is dependent on the 

outcome of other recovery actions.

15. Explanation of Acronyms in Implementation Table

BOR Bureau of Reclamation

CDFG California Department of Fish and Game

FWS U.S. Fish and Wildlife Service

KBNWR Klamath Basin National Wildlife Refuge Complex, U.S. Fish and 

Wildlife Service

KT Klamath Tribes

NRCS Natural Resources Conservation Service

ODFW Oregon Department of Fish and Wildlife
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

65

RI Research Institutions

Team Klamath Basin Recovery Implementation Team
66

Table 4 The Implementation schedule for the Lost River and shortnose Recovery Plan. Dollar estimates of costs to achieve recovery (in thousands of dollars) 

are given for the first five fiscal years (FY) and the total estimated costs. Totals include estimates for the first five fiscal years and estimates for an additional 

30 years, assuming the time to recovery would be 35 years. If no funds are required during the first five fiscal years this is indicated with a dash (–). 

Implementation of lower priority actions may not occur within the first five fiscal years; only the total estimated cost is presented in these cases. Unless 

specifically noted, actions are intended to benefit both species. Actions or headings that have been broken down into sub-actions do not have costs 

estimated when it is assumed that estimates of the sub-actions will comprise estimates for the entire action or heading and have therefore been excluded 

from this table.

Action number and description Priority Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Comments

FY1 FY2 FY3 FY4 FY5 Total

1.1 Develop and implement a range-wide 

Spawning and Rearing Enhancement Plan

2 Team 15 – – 50 – – 125

$25K every 5th year 

for reassessment of 

the plan developed in 

FY3

1.2

Conduct and apply research on how to 

best manage lake levels to protect 

spawning habitat

1 Team C – – – – – –

Costs for this action 

are broken out in the 

sub-actions listed 

below.

1.2.1

Assess the effects of Upper Klamath Lake 

elevations on shoreline-spring spawning 

and production – Lost River sucker 

specific

2 BOR, FWS 5 – – 200 200 150 800 Costs for assessment 

and implementation

1.2.2

Assess the effects of Clear Lake Reservoir 

elevations on spawning access and 

production

1 BOR, FWS,

KBNWR

4 – – 50 50 50 200

1.2.3

Improve our ability to assess and forecast 

hydrologic conditions in the upper 

Klamath Basin

2 BOR, FWS, 

NRCS

15 – 40 100 100 100 660
67

Action number and description Priority Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Comments

FY1 FY2 FY3 FY4 FY5 Total

1.3 Reestablish stream and river connectivity 2 Team C – – – – – –

Costs for this action 

are broken out in the 

sub-actions listed 

below.

1.3.1 Improve access to Willow Creek from 

Clear Lake Reservoir

2 BOR, FWS,

KBNWR

4 – 30 50 50 30 160

1.3.2 Improve passage for upstream migrants 

through Link River

2 BOR, FWS, 

KT

9 – – – – – 2,075

1.4 Conserve and restore wetland and riparian 

areas3 2 25 – – – – 950 36,415

1.4.1

Determine the importance of in-stream 

rearing habitats for larvae and juveniles in 

the Sprague River

2 FWS, KT 6 – – – – – 625

1.4.2 Improve in-stream, wetland, and riparian

habitat in Willow Creek

3 FWS 4 – – – – – 400

1.5

Improve habitat quantity and quality of 

eastern shoreline springs in Upper 

Klamath Lake – Lost River sucker 

specific

2 BOR, FWS, 

KT

13 – 80 50 50 50 310

1.6

Identify and assess the feasibility of 

potential habitat improvements for 

suckers in Lake Ewauna / Keno Reservoir

3 BOR, FWS 2 – – – – – 75

 

3 Some riparian or wetland restoration actions may receive funding under other programs, such as the Klamath Basin Restoration Agreement or Clean Water 

Act compliance, but given that funding is not guaranteed, cost estimates presented here assume that other programs do not contribute funding to this action. Estimates 

for these actions were adapted from Klamath Basin Restoration Agreement estimates.
68

Action number and description Priority Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Comments

FY1 FY2 FY3 FY4 FY5 Total

2.1 Ensure continued connectivity and access 

to refugial areas

2 BOR, FWS P – – 75 – – 225

2.2

Conduct and apply research on the 

dynamics of algal cycles within Upper 

Klamath Lake and their effects on sucker 

populations

1 BOR, FWS, 

KT, RI

10 – – – 50 150 1,400

2.2.1

Conduct comparisons of algal community 

composition and ecology among sites 

where these species currently occur

2 BOR, FWS, 

RI

6 – – 20 100 100 495

2.2.2 Clarify the ecology of Aphanizomenon 

flos-aquae

2 FWS, KT, 

RI

9 – – 20 100 100 995

2.2.3

Determine the effects of the algal toxin 

microcystin on suckers in Upper Klamath 

Lake and implement appropriate 

management actions, if necessary

1 FWS, KT, 

RI

10 – 100 100 100 100 1,000

2.3

Conserve and restore riparian and wetland 

areas along the Wood, Williamson, and 

Sprague Rivers, and Upper Klamath Lake

to improve water quality

1 26 – – – 950 950 33,888

3

Clarify and reduce the effects of 

introduced species on all life stages by 

conducting and applying scientific 

investigations

2 FWS, KT, 

RI

15 – – – 100 100 2,550

4.1 Develop and implement an Entrainment 

Reduction Plan

1 Team 12 50 60 400 400 400 3,060

4.2 Assure the efficacy of A-canal bypass 1 BOR 5 – – 100 100 400 800
69

Action number and description Priority Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Comments

FY1 FY2 FY3 FY4 FY5 Total

4.3 Improve the efficacy of the Link River 

Dam fish ladder

3 BOR 4 – – – – – 40

5.1 Develop and implement a Genetics 

Assessment and Management Plan

1 Team, RI 10 – 75 75 75 75 700

5.2

Prepare emergency response protocols for 

Upper Klamath Lake, Clear Lake

Reservoir, Gerber Reservoir, and Tule 

Lake populations

1 Team 2 60 30 – – – 90

5.3 Establish at least two auxiliary

populations

1 FWS C 100 100 80 35 35 1,850

5.4 Develop a controlled propagation 

program

1 FWS C – – – – – 16,750

Implementation of 

this action will only 

occur, if necessary; 

therefore, start time is 

unknown.

6.1

Develop and implement a plan to assess, 

monitor, and improve juvenile and subadult vital rates and demography

1 Team, RI 15 50 75 200 200 200 3,075

6.2

Improve understanding of juvenile life 

history and ecology through study of 

Clear Lake Reservoir populations

2 BOR, RI 10 60 60 60 60 80 660

7.1.1

Establish a spawning population in the 

Harriman Springs Area – Lost River 

sucker specific

3 FWS, KT 15 – – – – – 600

7.1.2

Establish a spawning population in the 

Barkley Springs Area – Lost River sucker 

specific

3 FWS, KT 15 – – – – – 1,600
70

Action number and description Priority Responsible 

Parties

Duration 

(years)

Fiscal Year Cost Estimates

(thousands of dollars)

Comments

FY1 FY2 FY3 FY4 FY5 Total

7.1.3

Establish an additional river-spawning 

population in the Upper Klamath Lake 

system

3 FWS, KT 15 – – – – – 600

7.2 Facilitate successful spawning for the 

Tule Lake population

1 BOR, FWS 11 – – – 40 200 2,690

7.3 Continue monitoring of adult populations 1 BOR, FWS, 

RI

O 500 500 500 500 500 17,500

Costs based on 

current levels of 

monitoring.

7.4 Determine the status of shortnose sucker 

in Gerber Reservoir

3 BLM, BOR, 

FWS, RI

O – – – 200 200 1,000

8.1 Formally establish the Klamath Sucker 

Recovery Program

1 Team O – – – – – –

Costs for this action 

are included in the 

estimates of all the 

other recovery 

actions.

8.2 Conduct outreach with public / 

stakeholder groups

3 Team C – 50 50 10 10 420

8.3

Facilitate information exchange and 

synthesis through establishment or 

utilization of an information sharing 

process

3 Team C 60 60 25 25 25 945

8.4.1 Implementation (compliance) assessment 1 Team P – – – 50 – 550

Includes costs every 

fourth year once 

initiated

8.4.2 Cause and effect monitoring 1 Team P – – 50 – – 550

Includes costs every 

fourth year once 

initiated
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

71

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in a desert stream, and management implications for two endangered fishes. North 

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variables to larval and juvenile Lost River and shortnose suckers. Environmental 

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and Cyprinids in western North America. Transactions of the American Fisheries 

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Scoppettone, G., S. Shea, and M. Buettner. 1995. Information on population dynamics and 

life history of shortnose suckers (Chasmistes brevirostris) and Lost River suckers 

(Deltistes luxatus) in Tule and Clear Lakes. Reno Field Station, Northwest Biological 

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Scoppettone, G. and C. L. Vinyard. 1991. Life history and management of four lacustrine 

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distribution of fishes in the Lost River, Oregon. U.S. Geological Survey, Klamath 

Falls, Oregon.

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(Pimephales promelas) in Upper Klamath Lake, Oregon. Western North American 

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wetlands adjacent to Upper Klamath and Agency Lakes, Oregon: Water Resources 

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State Water Resources Control Board. 2009. Porter-Cologne water quality control act. 

California Environmental Protection Agency, State of Californina, Sacramento, 

California.

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timing across western North America. Journal of Climate 18:1136-1155.

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J. Vaughn. 2008. Klamath River water quality and acoustic doppler current profiler 

data from Link River Dam to Keno Dam, 2007: Open File Report 2008-1185. U.S. 

Geological Survey, Reston, Virginia.

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growth of endangered Lost River and shortnose suckers in Upper Klamath Lake, 

Oregon. Environmental Biology of Fishes 89:239-252.

Terwilliger, M., D. C. Simon, and D. F. Markle. 2004. Larval and juvenile ecology of Upper 

Klamath Lake: 1998-2003. Unpublished report submitted to the Bureau of 

Reclamation, U.S. Department of Interior, Klamath Falls, Oregon.

Tranah, G. J. and B. May. 2006. Patterns of intra- and interspecies genetic diversity in 

Klamath River Basin suckers. Transactions of the American Fisheries Society 

135:306-316.

Tyler, T. J. 2007. Link River 2006 screw trap assessment. Klamath Basin Area Office, U.S. 

Bureau of Reclamation, U.S. Department of Interior, Klamath Falls, Oregon.

Tyler, T. J., E. C. Janney, H. A. Hendrixson, and R. S. Shively. 2004. Monitoring of Lost 

River and shortnose suckers in the lower Williamson River. Unpublished report 

submitted to the Bureau of Reclamation, U.S. Department of Interior, Klamath Falls, 

Oregon.

USFWS. 1983. Endangered and threatened species lisitng and recovery priority. Federal 

Register 48:43098-43105.

USFWS. 1988. Final Rule: Endangered and threatened wildlife and plants: determination of 

endangered status for the shortnose sucker and Lost River sucker. Federal Register 

53:27130-27134.

USFWS. 1993. Lost River and shortnose recovery plan. U.S. Fish and Wildlife Service, U.S. 

Department of Interior, Portland, Oregon.

USFWS. 2002. Biological/conference opinion regarding the effects of the U.S. Bureau of 

Reclamation's proposed 10-year operation plan for the Klamath Project and its effect 

on the endangered Lost River sucker (Deltistes luxatus), endangered shortnose sucker 

(Chasmistes brevirostris), threatened Bald Eagle (Haliaeetus leucocephalus), and 

proposed critical habitat for the Lost River and shortnose suckers.in Klamath Falls 

Fish and Wildlife Office, U.S. Fish and Wildlife Service, U.S. Department of Interior, 

editor., Klamath Falls, Oregon.
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USFWS. 2007a. Lost River sucker (Deltistes luxatus) 5-year review: Summary and 

evaluation. U.S. Department of Interior, Klamath Falls, Oregon.

USFWS. 2007b. Shortnose sucker (Chasmistes brevirostris) 5-year review: Summary and 

evaluation. U.S. Department of Interior, Klamath Falls, Oregon.

USFWS. 2008. Biological/conference opinion regarding the effects of the U.S. Bureau of 

Reclamation's proposed 10-year operation plan (April 1, 2008 - March 31, 2018) for 

the Klamath Project and its effects on the endangered Lost River and shortnose 

suckers. Klamath Falls Fish and Wildlife Office, U.S. Fish and Wildlife Service, U.S. 

Department of Interior, Klamath Falls, Oregon.

USFWS. 2011. Draft revised recovery plan for the Lost River sucker (Deltistes luxatus) and 

shortnose sucker (Chasmistes brevirostris). U.S. Fish and Wildlife Service, Pacific 

Southwest Region, Sacramento, California.

USFWS and National Oceanic and Atmospheric Administration. 2000. Policy regarding 

controlled propagation of species listed under the endangered species act. Federal 

Register 65:56916-56922.

Vanderkooi, S. P., S. M. Burdick, K. R. Echols, C. A. Ottinger, B. H. Rosen, and T. M. 

Wood. 2010. Algal toxins in Upper Klamath Lake, Oregon: Linking water quality to 

juvenile sucker health. Fact-sheet 2009-3111. U.S. Geological Survey.

Welch, E. B. and T. Burke. 2001. Interim summary report: Relationship between lake 

elevation and water quality in Upper Klamath Lake, Oregon. Unpublished report 

submitted to the Bureau of Indian Affairs, U.S. Department of Interior, Portland, 

Oregon.

White, G. C. and K. P. Burnham. 1999. Program MARK: survival rate estimation from both 

live and dead encounters. Bird Study 46 (Supplement):S120-S139.

Wood, T. M., G. R. Hoilman, and M. K. Lindenberg. 2006. Water-quality conditions in 

Upper Klamath Lake, Oregon, 2002-04: Scientific Investigations Report 2006-5209. 

U.S. Geological Survey, Reston.
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X. Personal Communications Cited

Hewitt, D.A. 2010. Fishery Biologist, Western Fisheries Research Center, U.S. Geological 

Survey, U.S. Department of Interior, Klamath Falls, Oregon. Email to Josh Rasmussen, 

U.S. Fish and Wildlife Service, Klamath Fall, Oregon, dated 20 December 2010.

Hewitt, D.A. and S.M. Burdick. 2010. Fishery Biologists, Western Fisheries Research 

Center, U.S. Geological Survey, U.S. Department of the Interior, Klamath Falls, Oregon. 

Email to Josh Rasmussen, U.S. Fish and Wildlife Service, Klamath Falls, Oregon, dated 

02 December 2010. 

Markle, Douglas. 2010. Professor, Department of Fisheries and Wildlife, Oregon State 

University, Corvallis, Oregon. Email to Josh Rasmussen, U.S. Fish and Wildlife Service, 

Klamath Falls, Oregon, dated 06 December 2010.

Tyler, T. 2010. Fishery Biologist, Klamath Basin Area Office, Bureau of Reclamation, U.S. 

Department of Interior, Klamath Falls, Oregon. Email to Josh Rasmussen (among 

others), U.S. Fish and Wildlife Service, Klamath Falls, Oregon, dated 10 September 

2010.
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XI. Appendices

I. Glossary

Acre-feet – a unit of volume of water in irrigation: the amount covering one acre to a 

depth of one foot, equal to 43,560 cubic feet.

Age cohort – in this instance, all the individuals of a given species in a specific area that are 

approximately the same age.

Age-0 – this term refers to individuals that have lived less than one year, but is most 

often used in reference to juveniles.

Algal Bloom – the sudden development of conspicuous masses of organisms, such as algae, 

on the surface of a body of water.

Anthropogenic – caused or influenced by humans.

Bathymetry – the measurement of the depth of bodies of water, such as a lake.

Biomass – the amount of living matter in a given habitat, expressed either as the weight 

of organisms per unit area or as the volume of organisms per unit volume of 

habitat.

Copepod – any of numerous tiny marine or freshwater crustaceans of the order (or 

subclass) Copepoda, some abundant in plankton and others parasitic on fish. 

Cyanobacteria – also known as blue-green algae, a widely distributed group of 

predominantly photosynthetic, single celled organisms, occurring singly or in 

colonies in diverse habitats: some species can fix atmospheric nitrogen.

Demographic Stochasticity – chance events affecting survival and reproduction of 

individuals in small populations, skewed sex ratios for example.

Demography – the science of vital statistics of populations, including births, deaths, and 

distribution of age classes, etc.

Ecology – the branch of biology dealing with the relations and interactions between 

organisms and their environment, including other organisms.
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Emergent Vegetation – erect, rooted herbaceous plants that may be temporarily to 

permanently flooded at the base but do not tolerate prolonged inundation of 

the entire plant.

Endemic – native to or confined to a certain region or locale.

Entrainment – in this case, when organisms, especially larval or juvenile suckers, are pulled 

along with the force of moving water. This may be through natural features, 

such as a river corridor or into irrigation canals or other similar structures,

such as dams and hydroelectric facilities.

Environmental Stochasticity – random variation in physical environments, including 

temperature or precipitation.

Eutrophic – characterized by an abundant accumulation of nutrients that support a dense 

growth of algae and other organisms.

Exotic – of foreign origin or character; not native; introduced from abroad.

Extant – still in existence; not destroyed, lost, or extinct.

Fork Length – a length measurement in fish stretching from the tip of the snout to the fork 

between the two lobes of the tail fin.

Geometric Mean – the mean of n positive numbers obtained by taking the nth root of the 

product of the numbers. For example, the geometric mean of 3 and 12 is 6. 

This calculation is more appropriate for values which may be exponential in 

nature such as population growth.

Gill rakers – projections off of the gill arch of fish into the throat, which are often used to 

filter food particles from passing water.

Hypereutrophic – characterized by an over-abundant accumulation of nutrients that support a 

dense growth of algae and other organisms.

Hypoxia – a condition where water, as in a lake or pond, exhibit low levels of dissolved 

oxygen.

In situ – situated in the original or natural place or position.

Juvenile – individuals which have developed the full complement of fin rays and no 

longer receive sustenance from a yolk but that have not reached sexual 

maturity.
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Life-History – those traits and characteristics relating to the reproductive cycle of a species, 

including size and age at maturity, number of offspring per reproductive 

event, and number of reproductive bouts.

Macroinvertebrates – organisms lacking a backbone that are large enough to be seen with the 

naked eye, for example, aquatic insect larvae and snails.

Mark-Recapture – also known as capture-recapture, a sampling technique whereby 

organisms are captured, marked, released, and subsequently recaptured to 

provide information on such things as growth, dispersal, and survival rates.

Monotypic – having only one representative, as is a genus with a single species.

Moribund – approaching death; about to die.

Morphologically – referring to the form and structure of an organism. 

Non-Point Sources– In this case, refers to pollution affecting a water body from diffuse 

sources, such as agricultural runoff.

Oblique– in this case, referring to a mouth that is slightly slanting or sloping relative to 

the axis of the body.

Opercle – the hard, bony flaps covering and protecting the gills of fish (singular –

operculum).

Otolith – small, calcareous structures or stones that are found in the inner ear.

Papillose – in this instance small, nipple-like bumps or projections on the lips.

Passive integrated transponder (PIT) tags – PIT tags are used during mark-recapture studies 

to mark individuals so as to enable identification with subsequent recapture. 

Slightly bigger than a grain of rice and injected internally under the skin, each 

tag has a unique alphanumeric code that can be detected using an electronic 

scanner.

Periphyton – tiny organisms, such as algae or protozoans, which live on submerged objects, 

including vegetation and rocks.

Polytypic – having more than one representative, as is a genus with a more than one 

species.
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Proximate factor – in a series of events the cause or factor that is very near or immediately 

preceding the end result.

Quantitative – of or pertaining to the describing or measuring of a specific quantity.

Qualitative – pertaining to or concerning certain qualities or characteristics of an object.

Realized population change – the actual change of abundance population between successive 

samples or time steps. 

Recruitment – the act or process when a juvenile becomes part of the adult population.

Redundancy – in conservation biology, the condition of having multiple populations that 

provide security from the risk of extinction of the species given the low 

probability that all populations will be negatively affected by a single 

catastrophic event.

Resiliency – in conservation biology, the ability of a population to recover from reduced 

abundance due to a disturbance.

River mile – a measure of distance in mile along a river from its mouth. River mile 

numbers begin at zero and increase moving upstream.

Sink population – a population in a low-quality habitat in which the birth rate is generally 

lower than the death rate and population density is maintained by immigrants 

from “source populations,” which are generally more robust.

Sub-Adult – an individual that has survived to at least one year of age, but has yet to 

become sexually mature and recruit into the spawning population.

Sub-Basin – a distinct watershed that is part of a larger watershed or basin.

Sub-Terminal Mouth – a mouth that is intermediate of the terminal mouth (positioned 

pointing forward on fish) and inferior (positioned pointing downward).

Swim-Up – a period when larvae abandon the gravel in which they have sheltered since 

hatching and enter the flow of the river. In western lake suckers this typically 

occurs around 7 – 14 days after hatching.

Taxonomy – the classification of organisms in an ordered system that indicates natural 

relationships.
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Total length – a measurement of individual length from the tip of the snout to the tip of the 

tail fin.

Terminal mouth – in fish, a mouth positioned to be directed forward.

Ultimate factor – in a series of events the factor that is the fundamental cause of the end 

result.

Zooplankton – the aggregate of animal and animal-like organisms in the plankton.
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II. Lost River Sucker and Shortnose Sucker Demography

An on-going demographic sampling program for Upper Klamath Lake Lost River 

sucker and shortnose sucker was initiated in 1995 by USGS using mark-recapture methods 

based on passive integrated transponder (PIT) tags in all suckers captured in nets or fish 

ladders. PIT tags are small, permanent chips with a unique code to identify each individual, 

which are read using electronic, external readers, either hand-held units or arrays of antennae 

installed at strategic locations. A tagged fish is detected when near a reader (typically within 

a few inches), and over time individual data translate into population trends of such 

parameters as probability of surviving from year to year or being recaptured (detected) 

during a particular sample event. In addition to the use of PIT tags, yearly data on weight and 

length are collected on a sub-sample of individuals. For Lost River sucker and shortnose 

sucker, PIT-readers are deployed during the spring time near spawning sites. Between 1999 

and 2008 3,780 female Lost River sucker and 5,728 male Lost River sucker were captured, 

tagged, and released at Upper Klamath Lake shoreline spring spawning areas (Janney et al. 

2009). In the Williamson and Sprague Rivers, between 2000 and 2008, 8,901 female and 

6,157 male Lost River sucker were tagged and released, and between 1995 and 2008, 8,743 

female and 5,553 male shortnose suckers were captured, tagged and released. 

One method of analyzing mark-recapture data uses a model developed by Pradel 

(1996) and implemented in program MARK (White and Burnham 1999). For example, if an 

individual fish was captured only during the third and fourth events of a four-event sampling 

effort, the individual capture history would be 0011, with “1” representing captured and “0” 

representing not captured. This approach permits estimation of survival probabilities. The 

reverse-time analog of this example capture history would be 1100 and enables estimation of 

the probability that an individual present in a population in year t was also present in the 

previous year (year t-1). This parameter is known as seniority (γ), and is the inverse of 

recruitment. Using estimates of annual survival (Φ) and annual seniority (γ), an annual rate of 

change in a population (λ) can be estimated: 

+1

Φ =

t

t

t γ

λ (see also Janney et al. 2009). 
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Table 5 Mean and one standard error (SE) of estimates of the probability of survival, seniority, and 

annual rate of population change (λ) for Upper Klamath Lake shoreline spring habitat spawning male and 

female Lost River sucker. Subsequent estimates of Δt for males = 0.56 and for females = 0.75. Data 

provided by E. Janney and D. Hewitt, U.S. Geological Survey, Klamath Falls, Oregon. All estimates are 

provisional and are subject to change with the collection of more data or refinements to the analysis 

methods.

Males

Year Survival SE Seniority SE λ SE ∆t

2002 0.795 0.021 0.97 0.006 0.820 0.022 NA

2003 0.857 0.020 0.97 0.006 0.883 0.021 0.724

2004 0.923 0.016 0.97 0.006 0.952 0.018 0.689

2005 0.905 0.010 0.97 0.006 0.933 0.012 0.643

2006 0.899 0.006 0.97 0.006 0.927 0.009 0.596

2007 0.917 0.005 0.97 0.006 0.945 0.008 0.563

Females

Year Survival SE Seniority SE λ SE ∆t

2002 0.863 0.016 0.968 0.011 0.892 0.019 NA

2003 0.907 0.014 0.968 0.011 0.937 0.018 0.836

2004 0.951 0.011 0.968 0.011 0.983 0.016 0.822

2005 0.939 0.007 0.968 0.011 0.97 0.013 0.797

2006 0.935 0.004 0.968 0.011 0.966 0.012 0.770

2007 0.947 0.004 0.968 0.011 0.978 0.012 0.753

Annual estimates of λ provide insight into the rate of growth and the stability of adult 

spawning populations by indicating whether a population decreased (λ < 1), remained stable 

(λ = 1), or increased (λ > 1). The long-term dynamics of a population can be summarized 

using a quantity known as ∆t, which is simply the cumulative product of the λ estimates over 

a time period of interest (Anthony et al. 2006). This quantity represents the percent change in 

population size from the beginning of the period to the end. Values of ∆t greater than 1.0 

indicate increases in population size relative to the baseline. For example, a ∆t of 7 indicates 

that populations are seven times greater than the reference year. 
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For Upper Klamath Lake sucker populations, seniority and, therefore, λ is currently 

only estimable for shoreline-spawning Lost River sucker and river-spawning shortnose 

sucker populations. Data are insufficient to provide reliable estimates for river-spawning Lost 

River sucker in Upper Klamath Lake or populations in Clear Lake Reservoir. Over the time 

period beginning in 2002 and ending in 2007, the adult spawning population of male Lost 

River sucker at the springs is estimated to have decreased to 56 percent of the starting 

population size (an estimated 44 percent reduction; Table 5). As shown in Table 5 and Table 

6, estimated values of ∆t for the populations of Lost River sucker and shortnose sucker in 

Upper Klamath Lake range from 0.42 to 0.75, indicating significant reductions in population 

size for both sexes of both species.

Table 6 Mean and one standard error (SE) of estimates of the probability of survival, seniority, and 

annual rate of population change (λ) for Williamson/Sprague spawning male and female shortnose 

sucker. Subsequent estimates of Δt for males = 0.42 and for females = 0.49. Data provided by E. Janney 

and D. Hewitt, U.S. Geological Survey, Klamath Falls, Oregon. All estimates are provisional and are 

subject to change with the collection of more data or refinements to the analysis strategy.

Males

Year Survival SE Seniority SE λ SE ∆t

2001 0.691 0.069 0.902 0.019 0.766 0.078 NA

2002 0.771 0.079 0.902 0.019 0.855 0.090 0.655

2003 0.902 0.081 0.902 0.019 1.000 0.092 0.655

2004 0.679 0.043 0.902 0.019 0.753 0.050 0.493

2005 0.870 0.030 0.902 0.019 0.965 0.039 0.476

2006 0.795 0.022 0.902 0.019 0.882 0.030 0.420

2007 0.905 0.014 0.902 0.019 1.004 0.026 0.421

Females

Year Survival SE Seniority SE λ SE ∆t

2001 0.675 0.052 0.918 0.014 0.735 0.058 NA

2002 0.894 0.063 0.918 0.014 0.974 0.071 0.716

2003 0.871 0.056 0.918 0.014 0.949 0.062 0.679

2004 0.675 0.028 0.918 0.014 0.735 0.032 0.499

2005 0.862 0.019 0.918 0.014 0.939 0.025 0.469

2006 0.923 0.012 0.918 0.014 1.005 0.02 0.471

2007 0.944 0.008 0.918 0.014 1.028 0.018 0.484
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Three important caveats pertain to the seniority and λ estimates provided by the 

capture-recapture models. First, estimates of λ apply only to the populations or segments of 

populations being sampled, in this case adult spawning populations, and are not necessarily 

representative of the entire population. This means that changes in juvenile and sub-adult 

abundance are not reflected in our estimates of λ until those individuals join the spawning 

aggregations.

Second, estimates of seniority are based on a data set that includes only physical 

captures of fish during spring sampling with trammel nets. Detections of PIT-tagged fish on 

remote antennas are critical to estimating survival probabilities, but they cannot be used to 

estimate seniority because they induce bias in seniority, and thus λ. The model for estimating 

seniority requires that both tagged and untagged fish have the same probability of being 

encountered, but untagged individuals have a zero probability of being captured with antenna 

detections, and therefore physical captures of both tagged and untagged fish are required. 

The exclusion of remote detections from models for estimating seniority means that the 

amount of data available to estimate seniority is far less than that available to models for 

estimating survival. As a result, estimation problems and model selection indicate that the 

most appropriate models are ones in which seniority is constant through time. Thus, 

estimates of seniority are an average across years. For shoreline-spawning Lost River sucker, 

estimates of seniority from all models varied little through time, so this has little effect on 

inferences about Lost River sucker population dynamics. However, estimates of seniority for 

shortnose sucker are more variable and in some years appear to be indistinguishable from 1.0 

based on the available data. Models with estimates so near 1.0 (termed “boundary” estimates) 

are eliminated in generating the model-averaged estimates presented here, as they may 

indicate other estimation problems. If in reality no recruitment occurred in years with 

boundary estimates, the seniority estimate presented here may be too low, thus indicating 

more recruitment than actually occurred. The overall effect is that the ∆t presented for 

shortnose sucker may be as much as 10-15 percent higher than the actual value, providing a 

picture of shortnose sucker population dynamics that is overly optimistic. Data collection in 

future years may help to resolve this, but for now the γ, λ, and ∆t values for shortnose sucker

should be considered best case estimates in terms of population status.

The third caveat relates to the calculation of the standard errors for the annual λ

estimates. Ideally, estimates of survival and seniority would be generated from a single 

model or several models from the same dataset as the standard error for the resulting λ

estimates would be corrected for the covariance between these two parameters. Because the 

remote detections must be excluded from estimation of seniority, separate models are used to 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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estimate seniority and survival and the two estimates are combined post-hoc to generate an 

estimate of λ. The delta method is then used to calculate standard errors for the λ estimates, 

but the covariance between survival and seniority is ignored. The effect of this approach on 

the standard errors is expected to be small, but the standard errors for λ may be too small.
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III. Summary of Comments on the Draft Revised Recovery Plan for the 

Lost River Sucker and Shortnose Sucker

In October 2011, we released the Draft Revised Recovery Plan for Lost River Sucker 

(Deltistes luxatus) and Shortnose Sucker (Chasmistes brevirostris) – First Revision (USFWS 

2011) for review and comment by Federal agencies, the States of Oregon and California, 

members of the public and stakeholder groups (76 FR 64372; October 18, 2011), and three 

scientific peer reviewers. Over 70 copies of the draft plan were distributed (either in hard 

copy or in CD form) for review during the comment period. In addition, the draft plan was 

made available online through the Service’s website. Fifteen letters commenting on the draft 

plan were received. Comments were received from six private organizations, stakeholder 

groups, or individuals; one state agency; three federal agencies; and two scientific peer 

reviewers. Comments from the peer reviewers are indicated by an asterisk (*) at the end of 

the comment.

We thank all individuals who took the time to provide comments to improve this 

plan. Many of the comments were editorial or informational in nature, and we have 

incorporated those comments into the plan where appropriate. A summary of the substantive 

comments received, along with our responses is included below. Commenter text provided 

here is not necessarily verbatim from submitted comments, but may have been summarized 

to provide clarity, brevity, or to combine similar comments from multiple sources.

Issue 1 Background Information

Comment: Have there been measurable improvements to the species since listing?

Response: Section 4(a) of the Endangered Species Act of 1973, as amended, requires the 

Service to determine the status of a species by evaluating five major categories 

of threats to the species: (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. At this time, analyses of 

Lost River sucker and shortnose sucker indicate that they continue to be

endangered and at risk of extinction. That being said, several significant threats 

to the species have been removed or minimized since listing in 1988 which 

represent a significant improvement in the baseline of the species (for 

examples, see the discussion under “Past Conservation Efforts”). Furthermore, 

our understanding of population dynamics and range wide status has greatly 

improved since the listing of these species. However, only once in the last 
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decade has production and survival been sufficient to generate a significant 

contribution to the adult populations of both species in Upper Klamath Lake. 

This lack of recruitment, coupled with an aging adult population, has produced 

a fairly constant decline in the number of spawning adults over the last decade.

Comment: Sevenmile Creek should be added to the list of Upper Klamath Lake Tributaries 

where suckers have been identified since larvae were found in the Agency 

Ranch diversion.

Response: We have not revised the text of the plan in this regard since information 

regarding this assertion is currently limited and the source of the fish referred to 

in this comment is not clear. The fish, likely juveniles and not larvae, may have 

come upstream from the Agency Lake. Consequently, we are unable at this 

time to confirm that spawning occurs in Sevenmile Creek or that the habitat is 

utilized to any biologically significant extent.

Comment: The importance of access to Pelican Bay should be clarified.

Response: Based on available data it was believed that extremely low lake levels could 

significantly restrict access to Pelican Bay because of a shallow entry area at 

the mouth. However, very recent data suggest this is not the case (T. Tyler, 

Fish Biologist, Bureau of Reclamation, pers. comm.). Although these data are 

still being assessed for accuracy, we believe access restrictions under normal 

operating conditions are improbable. Consequently, this recovery action 

(Action 2.1) was clarified to indicate that it is important to ensure access to all 

areas that may provide refugia to the species so that the species can better avoid 

areas with poor water quality.

Comment: More detail should be given about the reasoning behind Link River ladder.

Response: We refer the reader to the Environmental Assessment of the Link River Fish 

Passage Project for details on the reasoning for this project (Bureau of 

Reclamation. 2002. Environmental Assessment: Link River Fish Passage 

Project. Klamath Basin Area Office, Bureau of Reclamation, U.S. Department 

of Interior, Klamath Falls, OR).

Comment: The trend of converting wetlands to agricultural use ended decades ago. In fact 

more agricultural land is now being removed and turned back into wetlands. 

This should be clearly noted. Development of irrigation and hydroelectric 

facilities ended over 75 years ago. This should now be considered as part of the 
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baseline. Additionally, entrainment and passage issues have been significantly 

reduced.

Response: The fact that habitat loss has slowed and very significant wetland restoration 

projects that benefit suckers have been implemented in recent years is noted in 

appropriate sections in the document (see Section VII Background – Past 

Conservation Efforts). Nevertheless, as presented in our analysis of the threats 

posed to the species by the present or threatened destruction, modification, or 

curtailment of its habitat or range (see Section VII Background – Reasons for 

Listing and Continued Threats – 3. Factor A), the amount of habitat that was 

destroyed, modified and curtailed in the past 100 years was so high that this 

continues to endanger the existence of these species.

Comment: Treatment of this critical issue [Upper Klamath Lake oxygen levels] is overly 

simplistic. For example, algal biomass alone does not cause anoxia as under 

“normal” conditions wind generated aeration can moderate the consequences of 

the biological oxygen demand. If you are going to discuss the issue, please give 

it the appropriate coverage needed to avoid unintended consequences.*

Response: While we agree it is important to detail these critical processes as best as 

possible, the complexity and scope of these processes prevent a complete 

detailed treatment within this document. Nonetheless, we included additional 

text to provide more coverage of the topic (see Section VII Background –

Habitat characteristics).

Comment: We request that the Service consider any new information that comes from the 

U.S. Geological Survey work currently underway and incorporate any new and 

relevant information into the Revised Recovery Plan. Again, we stress the 

serious uncertainties about whether the phosphorus load reductions required 

under Oregon Department of Environmental Quality's 2002 Upper Klamath 

Lake Total Maximum Daily Loads can be achieved.

Response: We regularly evaluate the applicability of new information as it becomes 

available. Organization of a Recovery Implementation Program will further 

enable improved incorporation of relevant information into the implementation 

of the actions to recover these species.

Issue 2: Comments on the Klamath Project and associated Biological Opinions

Comment: The Plan should better address the threat to habitat availability resulting from 

the 2010 NMFS Coho salmon biological opinion for the Klamath Project.
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Response: The Bureau of Reclamation is currently working to develop a new proposed 

action, with input from the Service and the National Marine Fisheries Service 

(NMFS), for the ongoing operations of The Klamath Project. The Bureau of 

Reclamation will then consult with the Service and NMFS during the course of 

which the Service and NMFS intend to develop joint biological opinion to 

ensure the needs of listed Coho are coordinated with the needs of listed suckers

so they do not result in conflicting requirements under the Endangered Species

Act. Text has been added to Section VII Background – Reasons for Listing and 

Continued Threats – 6. Factor D: Inadequacy of existing regulatory 

mechanisms.

Comment: Endangered Species Act regulation of irrigation deliveries removes the impact

of the Klamath Project to the species since water withdrawals to the Klamath 

Project occur only after the Service has deemed that the action will not result in 

harm to the listed species. Research should focus on the need for real time 

system flexibility.

Response: The Service's 2008 Biological Opinion on the Klamath Project ensures that 

project operation "is not likely to jeopardize the continued existence of [the 

suckers] or result in the destruction or adverse modification of habitat of such 

species..." (Endangered Species Act 1973, as amended). This does not mean 

that operation of the Klamath Project does not "impact" the species. We 

recognize the need for “real time” flexibility and are working with the Bureau 

of Reclamation and the National Marine Fisheries Service to build this into 

future operations of the Project.

Comment: Besides concerns about pelican predation on these endangered fish when water 

depths are too shallow, more realistic minimal lake levels need to be addressed 

and evaluated in a new Klamath Project Biological Opinion so as not to 

continue to further diminish and degrade the area’s water quality and the best 

habitats that still remain.

Response: The Bureau of Reclamation is currently working to develop a new proposed 

action, with input from the Service and the National Marine Fisheries Service 

(NMFS), for the ongoing operations of The Klamath Project. The Bureau of 

Reclamation will then consult with the Service and NMFS during the course of 

which the Service and NMFS intend to develop joint biological opinions to 

ensure the needs of listed Coho are coordinated with listed suckers so they do 

not result in conflicting requirements under the Endangered Species Act.
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Furthermore, the connection between Upper Klamath Lake water elevations and 

water quality have yet to be resolved (National Research Council 2004, Morace 

2007).

Comment: Specific criteria addressing long-term management of Upper Klamath Lake 

water level / water quality assurances should be included in the recovery plan, 

including threats-based downlisting criteria.*

Response: Water surface elevations and water quality are important to sucker welfare in 

Upper Klamath Lake as well as other water bodies across the range of the 

species. Several criteria within the plan reflect this. First, Recovery Criterion 

A.1indicates that recovery cannot be achieved unless the current spawning and 

rearing habitat is maintained and access is improved to ensure annual use. This 

is solidly linked with water levels, as is Recovery Criterion A.3, which relates 

to the need for sucker access to refuge habitats to avoid poor water quality.

Comment: The plan should better address the benefits to the species if the Wood River 

wetlands, Barnes and Agency Ranches, and the Upper Klamath National 

Wildlife Refuges were managed differently.

Response: We agree these areas have the potential to provide benefits to suckers. 

Assessment of the potential contributions to sucker recovery from these areas 

will be incorporated when implementing Actions 1.4 (Conserve and restore 

wetland and riparian areas) and 2.3 (Conserve and restore riparian and wetland 

areas along the Wood, Williamson, and Sprague Rivers, and Upper Klamath 

Lake to improve water quality).

Issue 3: Recovery action implementation

Comment: The focus of Sucker recovery should adopt a watershed-wide approach while 

recognizing that the landscape has been altered, and in most instances, is 

unlikely to change.

Response: The actions presented in this recovery plan promote a watershed approach by 

addressing needs throughout the range of the species and specific populations. 

The plan also recognizes, in what it requires for recovery, that a large portion of 

the species range has been permanently altered. For example, proposed 

recovery actions that foster a watershed approach include habitat improvements 

and conservation throughout the range of the species (see Actions 1.4.1, 1.4.2, 

1.5, 1.6, and 2.3). When completed, each of those actions will contribute to 

improvements to sucker habitat throughout the landscape.
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Comment: Add a new recovery action to determine the status of Gerber Reservoir 

Populations, and assess the utility of this water body for establishing an 

auxiliary population of Lost River sucker there.

Response: Per the commenter’s recommendation, we now include a recovery action 

(Action 7.4) to determine the status of the shortnose sucker within Gerber 

Reservoir. In implementing Action 5.3, the Service will assess the utility of 

various locations for auxiliary populations for both species.

Comment: The recovery plan needs to better view the restoration of marshes in, and in 

proximity to, the Klamath Basin NWR system as integral to the recovery of the 

marshland ecosystem of the endangered suckers.

Response: Recovery Action 1 seeks to "restore or enhance spawning and nursery habitat in 

the Upper Klamath Lake and Lost River Basin Recovery Units." The potential 

for restoration of marshes in, and in proximity to, the Klamath Basin NWR 

system will be considered in detail as the Spawning and Rearing enhancement 

plan (Action 1.1) is developed.

Comment: More information should be provided on the action to require screening.

Response Actions in recovery plans are recommendations, not requirements, and no 

Action in this recovery plan requires screening. Action 4 does focus on 

reducing loss of individuals to entrainment. However, fish screens are one of a 

number of mechanisms to reduce entrainment. Furthermore, the choice to use a 

given entrainment reduction tool at any single location may be site-specific. 

Given that, additional details regarding entrainment reduction, including the 

installation of fish screens, will be developed as part of the Entrainment 

Reduction Plan (Action 4.1) and provided by a Recovery Implementation 

Team. We intend for this team to include federal, state, tribal, local, and private 

stakeholders and provide a collaborative process for evaluating and 

implementing entrainment reduction measures. This approach also allows for 

flexibility over the lifetime of the recovery plan which will be particularly 

important as future research and technological innovation introduce new tools 

that will further reduce entrainment. 

Comment: Private stakeholders should be involved in any action affecting their territory, 

including development of the several plans such as the Entrainment Reduction 

Plan, individual site management plans, and assessment of data or information.

Response: Input from all concerned stakeholders is integral to developing and 

implementing the more detailed plans described in this document. We will seek 
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and encourage participation and input from all stakeholders to ensure a

collaborative process in implementing this plan.

Comment: The plan should also consider issues proposed and addressed in the Klamath 

Basin Restoration Agreement.

Response: We recognize the importance of many of the actions in the Klamath Basin 

Restoration Agreement (KBRA) to the recovery of suckers in a portion of their 

range (note that the KBRA does not cover the Lost River system). However, it 

is premature to consider the actions of the KBRA until it is authorized by 

Congress. If the KBRA is authorized, we anticipate that the KBRA’s fisheries 

management program will incorporate sucker recovery needs and be consistent 

with the Revised Recovery Plan.

Comment: Presenting the best science available in a real time situation makes for betterinformed decisions; therefore, Action 8.3.2 [8.4.2 in the final plan] should not 

be an every fourth year occurrence but an ongoing part of the recovery plan.

Response: We always strive to utilize the best available science and regularly assess the 

success of actions. However, Action 8.4 and Action 8.4.2 (formerly Action 

8.3.2 in the draft plan) are actions to assess the effectiveness of other recovery 

actions on Lost River and shortnose sucker recovery. Given that, sufficient 

time is needed after implementation of individual recovery actions to assess 

whether or not the species has responded positively to implementation of those 

actions. Consequently a periodic approach to cause and effect monitoring is 

more appropriate than a continuous approach. We have modified the narratives 

and names of sub-actions within Action 8.4 to make this clearer.

Comment: What does “auxiliary populations” mean? Where would they occur? There are 

few if any potential sites. Does this require self-sustaining populations or 

refugial populations? 

Response: We refer to the narrative for Action 5.3 (Recovery Action Narrative – establish 

at least two auxiliary populations) which provides a detailed explanation of the 

reasoning for and development of the proposed recovery action. 

Comment: The landscape of the region is altered from pre-European settlement conditions. 

This is not going to change. Significant efforts, presumably in a strategic 

manner have been made on the restoration of wetlands. Perhaps there are other 

areas that might be more important to focus on.
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Response: We agree that significant efforts have been made to restore wetlands. Based on 

the Service’s policy for assigning recovery priorities, we have categorized most 

recovery actions pertaining to habitat restoration as Priority 2 actions. We have 

also categorized a number of non-wetland-related recovery actions as Priority 1 

actions (see for example, Actions 2.2.3 and 4 which relate to water quality and 

entrainment, respectively). Still, while lack of wetland habitat is not 

necessarily the most pressing threat to the species, improvements can be made. 

Comment: Several specific areas provide the best opportunities for establishing auxiliary 

populations, including Tule Lake, Keno Reservoir, Gerber Reservoir, Indian 

Tom Lake, and the Lost River.

Response: As stated in Action 5, auxiliary populations “may be utilized to maintain a 

stock of individuals to prevent extinction or loss of significant diversity, to 

produce individuals to augment existing ‘wild’ populations or to facilitate 

research.” Tule Lake currently provides many of the benefits of an auxiliary 

site. Therefore, this system will be given preference when assessing the 

feasibility of managing the populations there as auxiliary populations. 

However, should other equally suitable and/or successful areas be identified, 

the establishment of auxiliary populations in those areas should not be 

preempted by the current importance of Tule Lake. All other potential areas for 

auxiliary populations, including Keno Reservoir, Gerber Reservoir (specifically 

for Lost River sucker), or the Lost River, will be assessed individually by the 

Recovery Implementation Program to determine the utility of such water bodies 

for promoting recovery.

Comment: Auxiliary populations would be wonderful, but the devil is in the details. If the 

auxiliary populations would reside within any of the already occupied lakes 

(Upper Klamath Lake, Clear Lake Reservoir, or Tule Lake), then I fail to see 

the point. If you have alternative lakes in mind, they should be specified to 

allow for evaluation of their potential for success.*

Response: Language was added to the Recovery Action Narrative (Action 5.3) to clarify 

that auxiliary populations will be established outside of Upper Klamath Lake, 

Clear Lake Reservoir, and Gerber Reservoir (for shortnose sucker only). 

However, despite the fact the Tule Lake is occupied by both species its utility 

as an auxiliary site can be improved and solidified (see Recovery Action 7.2 for 

example). The amount of detail to properly evaluate and assess specific 

potential auxiliary populations is beyond the scope of this document. For this 

reason we do not provide a list of potential sites in the Recovery Plan.
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Comment: The Service needs to be doing more age sampling to assess age-class structure

of and recruitment into the adult segment of populations.

Response: Extensive monitoring (primarily funded by the Bureau of Reclamation) is 

conducted annually by the Klamath Falls Field Station of the Western Fisheries 

Research Center of the U.S. Geological Survey. This work monitors age-class 

structure (albeit indirectly through size distribution) and recruitment for 

populations of both species in Upper Klamath Lake and Clear Lake Reservoir. 

As discussed in Section VII Background – Population Demography and Trends, 

ageing these species utilizing hard structures is infeasible given that use of 

otoliths is lethal and sample sizes need to be relatively large; however, we 

believe that the current level of monitoring, utilizing size as a surrogate for age,

is sufficient to provide the information needed to understand the status and 

trends of these populations into the future.

Comment: Water quality in Upper Klamath Lake is bad, and is going to stay that way for 

the foreseeable future. As such, provision of access to the best available water 

quality refugia in UKL should be a top priority.

Response: We agree that poor water quality in Upper Klamath Lake is a threat to the 

populations of listed suckers in that water body. To reflect this we have added 

Upper Klamath Lake to Recovery Action 2.3, which calls for conservation and 

restoration of riparian and wetland areas around and within Upper Klamath 

Lake for the express purpose of improving water quality. This action has been 

given a priority of 1.

Comment: Providing access to refugia addresses the symptoms of the water quality 

problem, but not the cause (i.e. nutrient loading). The Service should more 

explicitly state their intentions in providing refugia, especially when a single 

site is focused on (Pelican Bay), which may negatively impact individuals when 

they are so crowded.*

Response: Given the complexity of the water quality problem, it likely will take several 

years to understand and improve water quality. Therefore, it is important to 

ensure individuals are able to avoid the impacts from impaired water quality 

until this threat is addressed. The focus on Pelican Bay does not exclude efforts 

to protect other areas should they be needed, but data suggest that Pelican Bay 

is extremely important, and at this time there is little evidence that other areas 

are utilized to such an extent (Banish 2009).
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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Comment: The 2007 ISRP report suggests there was at least some level of connectivity 

between the sub-basins which may aid in increasing genetic diversity. The draft 

recovery plan does not provide reference to improving connectivity between the 

two recovery units.

Response: Recovery Action 5.1 describes the need to develop and implement a Genetics 

Assessment and Management Plan (Action 5.1) which will more fully address 

the specifics of such issues as the potential for interbasin gene flow.

Comment: Should Gerber be included in Action 1.2 (conduct and apply research on how to 

best manage lake levels to protect spawning habitat)?

Response: Currently, there is no information to indicate that spawning is limited by lake 

levels in Gerber Reservoir.

Comment: Given the downward trends, more emphasis is needed on recovery actions that 

will secure and stabilize current populations in the very short-term.

Response: Securing and stabilizing current populations as soon as possible is certainly a 

very important part of recovering these species. Several recovery actions have 

been included in the plan to specifically address this need. Action 5 (Develop a 

redundancy and resiliency enhancement program) includes actions to develop a 

controlled propagation program (Action 5.4) and establish at least two auxiliary 

populations (Action 5.3) for each of these species. This action also calls for 

preparation of emergency response protocols for important populations (Action 

5.2). In addition to Action 5, specific actions within Action 7 will serve to 

secure or stabilize populations (see Recovery Action Narrative – Action 7).

Comment: The plan should address whether there are plans to restore connectivity through 

Anderson Rose Dam.

Response: Information was included in the document to clarify that currently there are no 

specific plans to restore passage through Anderson-Rose Dam (Recovery 

Action Narrative 7.2 – facilitate successful spawning for the Tule Lake 

population). However, the recovery action to reestablish stream and river 

connectivity (Action 1.3) emphasizes in general the importance of restoring 

stream connectivity to the recovery of the species. Furthermore, Action 1.1 

(Develop and implement a range-wide Spawning and Rearing Enhancement 

Plan) must address how best to restore spawning to populations within the Lost 

River system. In so doing, the Spawning and Rearing Enhancement Plan will 

necessarily address barriers throughout the system, including Anderson Rose 

Dam. 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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Comment: Consideration should be given to conducting restoration on several sites 

connected or associated with Upper Klamath Lake, including Fourmile Canal 

through Thomasson Creek, Threemile Creek, Fourmile Creek, Sevenmile 

Creek, Crooked Creek, Odessa Springs, and Barkley Springs, to improve water 

quality, improve refugia, and potentially provide spawning habitat.

Response: The Recovery Implementation Program is identified in Recovery Action 8 as a 

coordinated effort among Federal, State, private, Tribal, and other stakeholders 

to facilitate the implementation of the recovery plan. This program will consist 

of various teams with specific roles including the consideration of potential 

restoration projects, such as those identified in this comment, to determine their 

ability to effectively contribute to sucker recovery. 

Comment: Why can't the details of the several proposed plans to be developed be included 

in this document?

Response: Each of the proposed plans (for example, the Spawning and Rearing 

Enhancement Plan or the Genetics Assessment and Management Plan) will 

contain specific detailed information concerning management that takes into 

account the overarching approach for recovery as described in this recovery 

plan. Along those lines, the recovery plan is intended to be a relatively broad 

outline of the approach to achieve recovery, while allowing for flexibility in 

adaptive recovery implementation. 

Comment: Research addressing the threat from hybridization may fit well with the 

development of a Genetics Assessment and Management Plan (Recovery 

Action 5.1). If addressing hybridization is not to be included in the recovery 

actions, additional explanation of why it is not a threat should be added to the 

background section of the plan.*

Response: The level of threat posed to the suckers from hybridization still needs to be 

clarified. Development of the Genetics Assessment and Management Plan 

(Recovery Action 5.1) will address this issue and enable managers to better 

understand the overall role of hybridization to the status of these species.

Comment: The original recovery plan (1993) also included an action to develop a genetics 

management plan. Discuss the progress made on the genetics assessment and 

management plan since 1993.

Response: Additional text has been incorporated into the narrative for Recovery Action 

5.1 to describe the progress that has been made since 1993.
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Comment: How does the service assess when to implement and "abandon" certain 

recovery actions? 

Response: Decisions about when and how to implement certain recovery actions will be a 

collaborative process with Federal, State, Tribal, and private stakeholders. 

Organization and implementation of the proposed Recovery Implementation 

Program will be vital to the task of assessing the success of implemented 

actions. 

Comment: Who will pay for enhancements of Link River dam as specified in Action 4.3, 

including the study to determine the need and feasibility?

Response: Decisions about the need and feasibility of funding certain recovery actions will 

be made through a collaborative process with Federal, State, Tribal, local, and 

private stakeholders. As a guidance document, the recovery plan does not 

require the implementation of proposed recovery actions nor does it secure or 

authorize funding for recovery actions. 

Comment: Providing new/enhanced spawning locations will not benefit the populations 

since all individuals will ultimately be affected by the same lake wide/regional 

water quality and climatic factors.*

Response: We disagree that providing new/enhanced spawning populations (as specified 

in Actions 1.1 – develop and implement a range-wide Spawning and Rearing 

Enhancement Plan and 7.1 – increase the number of spawning sub-populations 

in Upper Klamath Lake, including sub-actions) will not benefit the species. 

New/enhanced spawning locations will potentially provide species resiliency to 

recover from any detrimental conditions because more individuals theoretically 

will be in the system. Water quality conditions in Upper Klamath Lake can be 

quite localized and having higher numbers of individuals will provide a greater 

chance for the population to spread throughout the system to avoid harmful 

conditions. It will also provide redundancy perhaps by dispersing individuals 

throughout the lake. This will be beneficial given that detrimental conditions 

often tend to be patchy in their distribution and dispersal throughout the lake 

will decrease the likelihood that any single event affecting lake conditions 

would have a disproportionate impact to the species. Furthermore, establishing 

these additional populations may enable the Service to also potentially address 

threats that are not related to water quality, such as entrainment. One hypothesis 

is that individuals rearing on the west side of Upper Klamath Lake may not be

as vulnerable to the lake currents and gyre which sweep larval and juvenile 

suckers towards the A-canal and Link River dam.
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Comment: Given that the removal of Chiloquin Dam was an enormous undertaking that 

included efforts from many groups and organizations within the community, we 

should assign a task to determine the effect to the species of the removal of 

Chiloquin Dam with a top priority.*

Response: Federal, Tribal, and private groups are performing ongoing research to assess 

the effects of the removal of Chiloquin Dam on the sucker populations. The 

Bureau of Reclamation has funded several studies to better assess benefits from 

this action. Much of this research is conducted as part of the ongoing 

monitoring of adult populations by the U.S. Geological Survey and will be part 

of Action 7.3 of the plan.

Comment: What algal specific management actions might actually exist as proposed in 

Action 2.2.3 (Determine the effects of the algal toxin microcystin on suckers in 

Upper Klamath Lake and implement appropriate management actions)? If you 

can’t articulate a range of potential actions based on current knowledge, then I 

doubt you’re going to create one via more study. This task seems like a red‐

herring to me, and should be a low priority.*

Response: The intent of this overall action (Action 2.2 – conduct and apply research on the 

dynamics of algal cycles within Upper Klamath Lake and their effects on 

sucker populations) is to explore all possible remedies (both direct and indirect) 

to reduce the effects of algal dynamics to suckers, including the algal toxin 

microcystin. It is still unclear how microcystin toxins may ultimately affect 

listed sucker population dynamics, if at all, but emerging evidence suggests this 

threat merits deeper and immediate inspection. Developing specific 

management actions will be impracticable until the dynamics of the interaction 

between suckers and the toxin are better understood.

Comment: For every action that you undertake, an appropriate amount of “post‐treatment” 

effectiveness evaluation must occur. In any place where an action is not linked 

to effectiveness evaluation the omission must be corrected.

Response: Implementation of post-treatment monitoring for all actions will be evaluated 

through implementation monitoring and cause and effect monitoring (Actions 

8.4.1 and 8.4.2) as coordinated by the Klamath Sucker Recovery Program. 

Comment: It would be a huge benefit to the Klamath Basin and its sucker populations to 

engage in a study of anticipated future climate and to incorporate the 

projections into sucker management plans.*
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Response: We agree that this is an important component of future needs. The narrative for 

Action 7.3 has been revised to reflect this need.

Comment: I fail to see why “pumping up the number of larvae entering the lake,” has any 

hope of improving the status of the suckers.*

Response: Production of larvae is restricted to a few viable populations, and although 

significant production does occur in Upper Klamath Lake, the plan is intended 

to promote healthy, stable larval production throughout the range of the species. 

The text has been revised in the Recovery Action Narrative for Action 1.1 to 

clarify this point.

Comment: It may be appropriate to include a recovery action to work directly with 

landowners within the watershed to implement best management practices to 

reduce the nutrient loading from non‐point sources. Such an action seems 

especially important in the Wood River system that contributes such a high 

proportion of nutrients to the system.*

Response: Action 8 and sub-actions calls for the establishment of a Klamath Basin Sucker 

Recovery Implementation Program, which will include a substantial effort to 

conduct outreach and coordinate with all stakeholders. As part of this process, 

the group will determine the best approach for utilizing best management 

practices as part of recovery plan implementation.

Comment: PacifiCorp’s current mitigation funding and the proposed funding and activities 

contained in PacifiCorp’s Habitat Conservation Plan will help to achieve the 

objectives (i) Restore or enhance spawning and nursery habitat in Upper 

Klamath Lake and Clear Lake Reservoir systems, and (iv) Reduce the loss of 

individuals to entrainment.

Response: We commend PacifiCorp’s significant effort to develop a Habitat Conservation 

Plan (currently in draft form at this writing – 2012) that will include actions and 

funding to promote recovery of suckers, as well as previous commitments. The 

text in the plan (in the section on ‘Past Conservation Efforts’) has been revised 

to better recognize PacifiCorp’s contributions.

Issue 4: Recovery action priorities 

GENERAL COMMENT
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Comment: A number of commenters generally commented on the categorization of relative 

priorities for specific recovery actions. In particular, commenters asked for a 

number of actions to be reprioritized. 

Response: As stated in Section VIII Recovery Program – Recovery Actions, the policy of 

the U.S. Fish and Wildlife Service is to prioritize recovery actions in the 

following manner, 1) actions that are taken to prevent extinction or to prevent 

species from declining irreversibly, 2) actions that are taken to prevent a 

significant decline in species population/habitat or some other significant 

negative impact short of extinction, and 3) all other actions necessary to provide 

for full recovery of a species. Our responses to the comments below reflect our

reasoning in assigning specific priorities to recovery actions in relation to this 

policy.

SPECIFIC COMMENTS 

Comment: The action to clarify and reduce the effects of introduced species on all life 

stages by conducting and applying scientific investigations (Action 3) needs to 

be a priority one issue. Including the effects on vegetation in the research on 

lake levels may be beneficial in identifying methods to reduce the predatory 

effects of fathead minnow and yellow perch.*

Response: We agree that this is a very important action that could benefit recovery in a 

significant way. Given the Service’s policy restated at the beginning of this

section, we believe we have appropriately assigned the priority for this recovery 

action. If the investigations proposed in this action reveal this threat is more 

pressing than currently believed we will revisit the priority of this action.

Comment: Action 2.3 (conserve and restore riparian and wetland areas along the Wood, 

Williamson, and Sprague Rivers) should be lowered to a priority 3 until it is 

determined to be required by a lack of results from other enacted actions.

Response: Most researchers agree that impaired water quality is one of the greatest threats 

facing these species. Action 2.3 is given this highest priority because without 

implementation of actions intended to improve water quality through restoration 

of riparian and wetlands areas along the Wood, Williamson, and Sprague 

Rivers, we believe the species could decline irreversibly.

Comment: Action 5.4 (develop a controlled propagation program) should be lowered to a 

priority 3 until it is determined to be required by a lack of results from other 

enacted actions.

Response: The continued downward trend in Upper Klamath Lake populations suggests 

these extremely important populations are at a high risk of extinction and a 
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controlled propagation program should be developed before numbers become 

irreversibly low and genetic representation is lost. Because such programs take 

time to fund and develop, we have determined it is imperative to retain this 

action as a priority one (1).

Comment: Action 1.2.2 (assess the effects of Clear Lake Reservoir elevations on spawning 

access and production) should be made a priority 1 item.

Response: Upon reconsideration of the status of the populations of both species in Clear 

Lake Reservoir and the threats presented in this system, we agree that 

understanding the population dynamics of the species related to water elevations 

is of the highest priority. We have altered the priority of this proposed action to 

protect spawning areas to a value of one (1).

Comment: Recovery Action 7.2 (Facilitate successful spawning for the Tule Lake 

population) is given a priority ranking of 3. This seems inconsistent with the 

prioritization of the other recovery actions. The establishment of auxiliary 

populations is given a priority 1. It appears that facilitating spawning in the Tule 

Lake population would qualify it for classification as an auxiliary population. 

Given the potential need for redundancy and rearing of additional individuals, 

raising the priority ranking of recovery Action 7.2 should be considered.*

Response: We agree this is a very important action that could potentially benefit the 

recovery of the species in a significant way. As stated in the Recovery Action 

Narrative, “with the addition of successful spawning of this population (Tule 

Lake) the threat of extinction of these species from stochastic events would be 

significantly reduced.” Therefore, upon reconsideration we have re-categorized 

the priority of Action 7.2 as priority.

Comment: Improving the upstream passage through Link River (Action 4.3) should be 

given a priority of 2.

Response: Although we agree this is an important action, we do not believe it meets the 

requirements for a priority two (2) action. Given that Lake Ewauna is extremely 

degraded and the numbers of listed suckers inhabiting this water body are very 

low, we do not believe that improving passage through the Link River will 

prevent a significant decline in the populations. This action will be most useful 

as larger numbers of listed suckers begin to spread throughout their historic 

range.

Comment: Outreach to the public and stakeholder groups should be a high priority.
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Response: We recognize that outreach to the public and stakeholder groups is an essential 

component of successfully implementing this plan. However, outreach does 

not fall within the definitions of Priority 1 or 2 recovery actions, as defined by 

the Service. Given these definitions, outreach has been assigned to priority 

three (3). Still, outreach will be a major component of the Klamath Sucker 

Recovery Program.

Comment: UKL shore‐line spawning Lost River sucker are at high risk of extirpation and 

there are credible data linking lake elevation management to sucker welfare. 

Lake elevation is under the direct human control. As such, the action to assess 

the effects of Upper Klamath Lake elevations on shoreline-spring spawning and 

production (Action 1.2.1) should be a top priority.*

Response: We have altered the plan and the recovery action to assess the effects of Upper 

Klamath Lake elevations on shoreline-spring spawning and production (1.2.1). 

This recovery action has been reprioritized as Priority 1 due to the uniqueness 

of the spring-spawning life history strategy and the continued lack of 

recruitment to the populations overall within Upper Klamath Lake.

Comment: Research on the algal dynamics should be given a lower priority so as not to 

distract from actions providing immediate tangible results.*

Response: Given the predominance of evidence indicating that Aphanizomenon flos-aquae

drives much of the impaired water quality dynamics and the recent evidence 

suggesting that microcystin exposure may be affecting specific life stages of 

suckers in Upper Klamath Lake, we find this research merits immediate 

attention to prevent irreversible decline. Therefore, we believe the current 

ranking of Action 2.2 (Conduct and apply research on the dynamics of algal 

cycles within Upper Klamath Lake and their effects on sucker populations, 

along with associated sub-actions) as a Priority 1 Action is appropriate.

Comment: Having a plan in place which details the resources which can and would be 

mobilized in a worst‐case scenario, should be a top priority.

Response: The recovery action to develop emergency response protocols (Action 5.2) has 

been reprioritized as Priority 1 based on the potential of this action to be useful 

in preventing the extinction or irreversible decline of critically important 

populations.
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Comment: Figuring out what allows for the more consistent recruitment in Clear Lake 

Reservoir would be a huge gain for the sucker recovery and should be a top 

priority.*

Response: We agree this (Action 6.2 – improve understanding of juvenile life history and 

ecology through study of Clear Lake Reservoir populations) is a very important 

action that could potentially benefit recovery of the species in a significant way. 

However, it is the policy of the U.S. Fish and Wildlife Service is to prioritize 

recovery actions in the following manner, 1) actions that are taken to prevent 

extinction or to prevent species from declining irreversibly, 2) actions taken to 

prevent a significant decline in the species population/habitat or some other 

significant impact short of extinction, 3) all other recovery actions. Based on 

our policy, we believe this action is appropriately prioritized as a level two (2) 

priority.

Comment: Elevation of Clear Lake Reservoir is under direct human control, and therefore 

can be rapidly manipulated to provide for the stabilization and recovery of 

sucker populations. As such, this action (Action 1.2.1) should be a top 

priority.*

Response: The assignment of recovery action priorities is based on the Service’s policy 

which is restated at the beginning of this section. In this case, assessment of the 

effects of Clear Lake Reservoir elevations on spawning access and production 

(Action 1.2.2) is an important action that can help prevent substantial declines 

in population abundance, but is not an action that would be taken to 

immediately prevent the extinction of the species. Therefore, the priority was 

left as a value of 2.

Comment: Facilitating information exchange and synthesis (Action 8.2) should be a low 

priority action since it is already occurring smoothly within the various 

researchers of the basin.*

Response: Action 8.2 was reprioritized and given a priority value of three (3) based on the 

current high level of information exchange that currently exists among 

researchers and stakeholders, and because it does not meet the definition of 

Priority 1 or 2 recovery actions. 

Comment: The Recovery Plan should provide a prioritized list of conservation actions, and 

associated costs of implementing such actions.
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Response: Table 4 of the recovery plan provides the proposed Implementation Schedule of 

the recovery actions with associated estimated costs (see Section VII Recovery 

Program – Implementation Schedule of the document).

Issue 5 Recovery Criteria

Comment: Why was 5 cubic feet per second used as criteria for screening in criterion E.2?

This criterion should be consistent with Oregon law.

Response: This criterion has been removed. However, actions to reduce entrainment will 

still be an important part of the species’ conservation. Entrainment reduction 

will be addressed through the development and implementation of the 

Entrainment Reduction Plan (Action 4.1).

Comment: It unclear what the reference to “multiple well represented age-classes” in 

action E.8 means in quantitative terms.

Response: Criterion E.8 in the draft plan (criterion E.6 in the final plan) does not provide 

quantitative values for the number of individuals in different age-classes 

because the historical data are very limited, and self-sustaining populations may 

be represented by several alternative age-class structures.

Comment: Provide more specificity on how this criterion E.7 would be defined.

Response: Criterion E.7 in the draft plan (criterion E.5 in the final plan) specifies that the 

average annual rate of population change needs to be greater than one and the 

number of spawning individuals need to be greater than what was present in the 

baseline years for the Upper Klamath Lake River and Upper Klamath Lake 

Spring management units. See Appendix II for greater detail on how the values 

used for this criterion are defined.

Comment: A criterion to assess recovery based on age class structure is needed.

Response: Criterion E.8 in the draft plan and E.6 in the final plan assess recovery, in part, 

based on evidence of multiple, well-represented age-classes being present in the 

population.

Comment: Achievement of action E.5 (development and implementation of a plan to 

assess, monitor, and improve juvenile and sub-adult vital rates and 

demography) will be extremely difficult and expensive to achieve, as exhibited 

by 20 years of juvenile studies conducted by Oregon State University and 

Bureau of Reclamation.
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Response: We agree that this criterion (E.5 in the draft plan and E.8 in the final plan) is 

complex and difficult to implement, but most researchers agree that addressing 

the lack of recruitment of juveniles to the adult populations is critical to the 

recovery of these species.

Comment: Should you specify Barkley Springs and Harriman Springs as required areas 

under the criteria?

Response: The commenter is likely referring to draft Recovery Criterion E.4 (E.2 in the 

final plan), which calls for the “establishment of two additional recurring and 

successful spring-spawning populations in the Upper Klamath Lake-Spring 

Management Unit” for Lost River sucker. Although Barkley Springs and 

Harriman Springs are historically important spawning sites for the suckers and 

re-established spawning populations in these areas may be part of the recovery 

process (see Section VII Recovery Program – Recovery Action Narrative for 

actions 7.1.1 and 7.1.2), we believe this criterion can also be achieved if

spawning populations in other locations within the Upper Klamath Lake-Spring 

Management Unit are established.

Comment: The downlisting criteria are insufficient at this time. Only demonstrated 

improvements and assurance in both water quality and quantity should the 

status of the suckers be changed to threatened or delisted altogether.

Response: Criterion E.4 (E.6 of the draft plan) was revised to reflect the need to minimize 

the effects of detrimental water quality in general, and not just those specific to 

algal bloom dynamics, although algal bloom dynamics dominate in Upper 

Klamath Lake.

Comment: The [delisting] criteria should be clarified to explain the meaning of “selfsustaining”. Self-sustaining could include an “i.e.” statement that includes 

diverse age structure, successful reproduction, and recruitment, etc.

Response: The criterion referred to by this comment (criterion E.8 in the draft) was 

removed from the final Recovery Plan. This criterion was redundant with the 

other demographic criterion in the plan (criterion E.5 in the final Recovery 

Plan).

Comment: It seems like 5 consecutive years as part of an objective to assess re-established 

spawning populations is an arbitrary selection of time.
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Response: We have revised the text (see Section VII Recovery Program – Recovery Goals, 

Objectives, and Criteria – Recovery Objective b.iii) to clarify that the objective 

is to re-establish spawning populations.

Comment: The NRC committee members said that they did not know how many suckers 

there were in the Klamath waters. So you have no baseline.

Response: It is unclear what the context of the comment is referring to, specifically the 

reference to a baseline, nor what the commenter would like the Service to 

consider when finalizing the Plan. Without additional information, we are 

unable to respond to this comment further. 

Issue 6: Data needs

Comment: Need to identify funding to pay for work in the Lost River basin since Klamath 

Basin Restoration Agreement does not cover this area.

Response: Recovery plans are guides for meeting recovery goals. While plans identify 

parties with authority, responsibility, or expressed interest to implement 

specific recovery actions, they do not require the identified party to implement 

the action(s) or secure funding for implementing the action(s). However, as the 

comment suggests, identification of funding for recovery implementation in 

each recovery unit is needed, especially given that the Klamath Basin 

Restoration Agreement has not been enacted.

Comment: The benefits of previous restoration actions need to be included in the 

information provided in the plan.

Response: In most instances, considerable time is necessary to determine the efficacy of 

restoration actions. For example, Chiloquin Dam was removed in 2008, and 

although active research to determine the benefits of this extremely significant 

restoration project are ongoing, more time is required to be able to discern if 

any distinct patterns of increased recruitment to the adult population are 

occurring. Valid assessment of large and small restoration activities requires

ample time for populations to respond and exhibit trends that can be detected 

with statistically valid measures. In the case of these listed suckers this process 

could take up to 10 years. Since most of the major restoration projects to 

benefit listed suckers have only recently been completed, more time is 

necessary to be able to detect benefits.

Issue 6: Description of threats
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Comment: More discussion of the potential interactions between anadromous fishes and 

suckers, both direct and indirect, should be included.

Response: Sucker populations in areas where anadromous fish are likely to return already 

interact with a large salmonid (Redband trout, Oncorhynchus mykiss), and are 

presumably adapted to such interactions with other similar species. It is

therefore unlikely that anadromous fish, should they return to areas inhabited 

by listed suckers, will significantly impact suckers. For this reason we find it 

unnecessary to include more detail in the recovery plan. 

Comment: More discussion of the threats to the species from climate change should be 

provided, including information on modeling runs.

Response: We have reviewed the best available data on climate change as it pertains to 

these listed species and have included that information in the threats analysis 

(see Section VII Background – Reasons for Listing and Continued Threats 7.c).

Comment: I find it curious, and troubling, that amongst the numerous potential 

contributing factors to the current poor recruitment within the sucker 

populations, degraded water quality is not mentioned. I think there is sufficient 

information to validate the position that elevated pH, low DO, etc., are indeed 

harmful to young suckers.*

Response: We agree with the assertion that water quality is a significant threat 

contributing to the poor recruitment of sucker populations within Upper 

Klamath Lake, and believe the case supporting this has been made explicitly 

throughout the document (see for example, the Factor E threats analysis which 

states that “water quality remains one of the most important proximate factors 

threatening sucker existence...”). More generally though, the Plan captures the 

impacts from poor water quality in the phrase "degradation of habitat," which 

includes impaired water quality. 

Comment: Do data exist on entrainment at Lost River Diversion Channel and Ady Canal, 

and should these be discussed as part of Factor E?

Response: We are not aware of any data that specifically addresses entrainment through 

the Lost River Diversion Channel or the Ady Canal. The potential threats from 

these structures are classified within Factor E.

Comment: Research has demonstrated that, at least for the shore spawning Lost River 

Sucker, export out of Upper Klamath Lake is a likely cause of their persistent 

poor recruitment. The definition of entrainment in the document does not 
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reflect this. This definition should be modified to account for export via natural 

features (not limited to man‐made structures) or a new term should be added to 

address this issue.*

Response: The definition of entrainment was clarified in the glossary.

Comment: Given that current knowledge of sucker abundance far exceeds the estimated 

12,000 at the time of listing, why are the species still listed?

Response: This early estimate was probably inaccurate because statistical assumptions 

necessary for modeling population size likely were not met. Nevertheless, 

after review of available data, a special committee of the National Research 

Council concluded that: “For purposes of [Endangered Species Act] actions, 

the critical facts, which are known with a high degree of certainty, are that the 

fish are much less abundant than they originally were and that they are not 

showing an increase in overall abundance” (NRC 2004:203). In addition, data 

that have only become available since approximately 2009 indicate the 

populations continue to decline in Upper Klamath Lake each year (see the 

section on Background – Population Demography and Trends of the recovery 

plan). Furthermore, as discussed in the Reasons for Listing and Continued 

Protection section, both species continue to face threats that necessitate listing. 

Comment: Declines in the populations of suckers resulted from unrestricted fishing 

policies of Oregon Department of Fish and Wildlife, since the operation of the 

Klamath Project for decades prior to the declines did not produce such 

significant declines.

Response: These species were listed due to several factors, as cited in the listing rule

(USFWS 1988). Overharvest contributed to declining population levels prior to 

listing; however, this threat was unlikely to be the strongest factor limiting 

sucker populations for three reasons: 1) generally only Lost River suckers were 

targeted, but both species experienced declines, 2) populations of these species 

have declined in places where fishing was not an issue, and 3) restriction of 

angler harvest should have produced a rebound of numbers in the last 15 years 

if it was the primary limiting threat.

Comment: Why have the recent conservation actions such as the 2001 water shutoff and 

removal of the Chiloquin Dam not resulted in a significant increase in the 

sucker populations.

Response: Although these actions removed significant threats, there are still several 

complex threats, such as water quality, that are impacting the populations in 
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Upper Klamath Lake. Each of the actions mentioned in the comment have 

benefitted the suckers but in different ways (one was preventative and the other 

proactive) and on different time frames. Ensuring water for the suckers in 2001 

likely prevented extreme population declines over the short-term. Removing 

the Chiloquin Dam has improved access to miles of potential spawning habitat 

which will provide a long-term benefit to the species. We are hopeful that we 

will see benefits to the species, but given that these species require 

approximately 4-7 years for individuals to become part of the spawning 

population and contribute to population growth, more time is needed to see any 

significant improvements. 

Comment: The draft recovery plan is lacking any reference to endocrine (e.g., 

reproduction) or immune disruption due to contaminants. It seems highly likely 

that there is some level of impact from agriculture in the region, the discharge 

of sewage and the runoff from urban areas. An accumulating body of literature 

suggests that this threat deserves greater attention.

Response: The commenter provides no references, nor are we aware of any references that 

indicate that this type of contaminant is an issue for the three primary 

populations of these species, Upper Klamath Lake, Clear Lake Reservoir, and 

Gerber Reservoir.

Comment: Given the Service’s expressed concern for habitat and water quality 

improvement, the Recovery Plan needs to better discuss if the Service now 

again supports its previous conclusions that sufficient lake levels have not been 

provided in Upper Klamath Lake and Clear Lake necessary to expand marsh 

refugia and maintain adequate water quality on which the endangered fish and 

other organisms are dependent on.

Response: The Recovery Plan does address the importance of lake levels to spawning 

habitat (page 6) and access to Willow Creek from Clear Lake Reservoir (page 

25). Furthermore, recovery action 1.2 specifically identifies the need for further 

research on how to manage lake levels to protect spawning habitat for the listed 

suckers, and the connection between Upper Klamath Lake water elevations and 

water quality have yet to be resolved (National Research Council 2004, Morace 

2007).
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Issue 7: General Structure of the Recovery Program

Comment: Tule Lake is included in Lost River Sub-basin Unit but has been managed as an 

auxiliary population for UKL Unit based on transfer of salvaged suckers in 

2010.

Response: Current knowledge of water flow through the Klamath Project indicates that it 

is more likely that fish in Tule Lake originated from Upper Klamath Lake than 

the Lost River system. We recognize the need to develop a formal management 

plan for fish in Tule Lake and therefore included the specific action item in 

Recovery Action 8.1 – Formally establish the Klamath Sucker Recovery 

Program.

Comment: The recovery program should not be "hooked" to the success of the Klamath 

Basin Restoration Agreement.

Response: The recovery plan is independent of the Klamath Basin Restoration Agreement, 

although the two plans overlap in many areas of emphasis and action. Should 

the Klamath Basin Restoration Agreement become enacted, much of that 

program will benefit and promote recovery efforts; however, the recovery plan 

will proceed regardless of the status of the Klamath Basin Restoration 

Agreement.

Comment: The need for caution in implementing a captive rearing/propagation program 

exists, but there may also be danger in waiting too long and thereby negating 

potential benefits to starting such a propagation program before the species 

declines further.*

Response: We agree and for this purpose this recovery action has been assigned a priority 

(1).

Comment: The focus of the recovery program to create more wetlands, fix water quality of 

the naturally phosphorus loaded Klamath Basin waters, and water levels 

management is contrary to everything said by the National Research Council

scientists.

Response: The National Research Council Committee on Endangered and Threatened 

Fishes in the Klamath Basin (NRC 2004) presented six general 

recommendations for recovery of the suckers which included, among many 

other things:

 restoration of wetland vegetation in the Williamson River estuary and 

northern portions of Upper Klamath Lake;
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 more intensive studies addressing water quality including mechanisms 

for internal loading of phosphorus etc.; and

 use of the U.S. Fish and Wildlife Service’s full authority to control the 

actions of federal agencies that impair habitat on federally managed 

lands...

See National Research Council (NRC 2004) pages 11 - 13. Based on these 

similarities, we believe that the Recovery Plan is consistent with the NRC 

report.

Comment: What happens to the Upper Klamath Lake – Klamath River management unit 

when the 4 downstream dams on the river are removed? Isn’t this area 

considered a “sink” due to lack of access to spawning habitat? Will a free 

flowing Klamath River provide habitat for the complete life histories of both 

species? Can this unit meet any recovery objectives? These individuals have a 

low recovery value and may utilize much needed funds from other, more 

important areas.

Response: Management areas are different than recovery units. Management units are 

designated within recovery units solely to compartmentalize distinct portions of 

recovery units so that unique and specific management approaches can be 

applied to these areas. Designation of management units does not imply an 

inherent recovery value of the individuals within that area – this occurs at the 

recovery unit level.

Comment: Specification of a Recovery Unit encompassing the reservoirs along the 

mainstem of the Klamath River may prejudice the Klamath Basin Restoration 

Agreement.

Response: When recovery units are identified in a recovery plan for a listed entity it is the 

policy of the Service that recovery units "should collectively cover the entire 

range of the species.” (NMFS and USFWS, 2010; Section 5.1.7.1) We do not 

anticipate that this designation will prejudice authorization or implementation 

of the KBRA.

Issue 8: Time to recovery

Comment: Even under the best of circumstances, water quality in Upper Klamath Lake

will not stabilize at non‐harmful levels for upwards of 100 years. Given that the 

Upper Klamath Lake sucker populations must be secure in order for the species 
Revised Lost River Sucker and Shortnose Sucker Recovery Plan

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to be down‐listed, and poor water quality is a primary threat, I fail to see how 

the Service can advance the claim of a 30‐50 year recovery period.*

Response: In determining whether a species can be downlisted or delisted, the Service 

carefully assesses the best scientific and commercial data available regarding 

the past, present, and future threats to a species. It is plausible that the 

implementation of recovery actions described in this plan would reduce threats 

and provide sufficient improvements to suckers to the extent that delisting 

could be considered within the time frame presented in the plan.