Appendix G

DETAILED DISCUSSION

O F I MPACT THRESHOLDS FOR

A QUATIC ORGANISMS
ENVIRONMENTAL IMPACT STATEMENT 213

APPENDIX G: DETAILED DISCUSSION OF 

IMPACT THRESHOLDS FOR AQUATIC ORGANISMS 

IMPACT CRITERIA AND METHODOLOGY 

Four separate sets of impact thresholds, ranging from negligible to major intensity, were defined to 

address potential impacts on the plankton, macroinvertebrates, and amphibians in the 91 study area lakes 

and native fish in downstream drainages. Because there is incomplete knowledge of the actual impacts 

that are occurring or could occur in the 91 lakes under all four alternatives, impact thresholds were 

developed using predictive factors that have been shown to affect the distribution and viability of these 

organisms. These factors were identified from a review of scientific literature and past research. In 

addition to predictive factors, data and professional knowledge supplied by National Park Service (NPS) 

and Washington Department of Fish and Wildlife (WDFW) staff involved in the preparation of this Draft 

Mountain Lakes Fishery Management Plan / Environmental Impact Statement (plan/EIS) were used to 

arrive at impact intensities, whenever possible. The assessments were done on a lake-by-lake basis, using 

impact thresholds based on both the predictive factors and actual knowledge of site conditions, to arrive at 

a final impact level for each lake and associated downstream drainage. 

The discussions below present more detail about the predictive factors that were used in the impact 

thresholds for four groups of aquatic organisms. 

PLANKTON 

The plankton community in lakes in the North Cascades National Park Service Complex (North Cascades 

Complex) is divided into two components: phytoplankton and zooplankton. Phytoplankton mainly 

include microscopic photosynthetic algae (such as diatoms and dinoflagellates), while zooplankton are 

non-insect invertebrate animals ranging in size from microscopic to as large as 0.25 inch in length that 

drift with the current. 

The direct and indirect effects of fish stocking on each of these community components differ. Stocked 

trout generally do not prey directly on phytoplankton but can indirectly cause significant changes in the 

abundance of individual species and overall community structure in mountain lakes because their 

presence indirectly results in altered nutrient cycling and food web dynamics (Brett et al. 1994; Drake and 

Naiman 2000; Elser et al. 1995; Leavitt et al. 1994). While changes in abundance and community 

structure can be substantial, total loss of phytoplankton species has generally not been observed. Shifts in 

community composition (referred to as “state changes”) tend to remain stable following fish removal, not 

returning to conditions that were present prior to fish stocking (Drake and Naiman 2000). Changes in the 

phytoplankton community caused by fish stocking resemble those that occur due to other natural events 

(e.g., catastrophic forest fires or volcanism). 

Because changes to the phytoplankton community due to fish stocking are similar to those that occur 

under natural conditions, and food web dynamics generally remain resilient, effects on the phytoplankton 

community from fish stocking were considered minimal for the purpose of evaluating impacts. Therefore, 

the focus was placed on impacts to zooplankton species, especially larger copepods, which can be 

demonstrably affected by predation and changes in food web dynamics resulting from fish introduction. 

Research has shown that, in some cases, fish introductions have been observed to result in the complete 

elimination of some zooplankton species, with large copepods and large cladoceran species appearing to 

be most vulnerable. For example, large copepods in high-altitude lakes in Alberta, Canada, were no 
A PPENDIXES

214 DRAFT MOUNTAIN LAKES FISHERY MANAGEMENT PLAN

longer present as a result of very high densities of reproducing trout in some mountain lakes and, in some 

cases, did not recover following fish removal (Parker et al. 1996, 2001). This level of effects was 

observed to occur only in smaller shallow lakes (Donald et al. 1994). Another recent study found that the 

average recovery time for zooplankton assemblages from the influence of stocked salmonids in Canadian 

lakes was 19 years (Donald et al. 2001). 

Failure of copepods to recover has been attributed to the presence of scuds, or large amphipods 

(Gammarus lacustris), that prey on dormant copepod eggs, thus eliminating the potential for population 

recovery (Parker et al. 1996). Cladoceran species in shallow lakes were also no longer present in some 

cases, but they are likely to recover (Parker et al. 2001). Large amphipod species may also be vulnerable 

to extirpation (complete disappearance of a species) resulting from intense predation. It should be noted 

that zooplankton species were not extirpated in deeper lakes, even lakes with extremely high stocking 

densities (exceeding 800 fish/acre), because the profundal (deep) zone provides a refuge area against 

predation. Lakes greater than 50 feet in depth appear to provide sufficient refuge habitat for the large 

copepod and cladoceran species that are most vulnerable to extirpation (Donald et al. 1994). Similarly, 

larger lakes with more overall refuge habitat can provide areas for escape from fish predation. A size of 

40 acres was selected for use in the impact thresholds (based on professional judgment and experience 

working in similar lakes) to help distinguish between impact levels. 

Based on the information described above and the professional knowledge and judgment of the NPS and 

WDFW staff involved in this plan/EIS, the following impact thresholds were defined for plankton (to be 

applied on a lake-by-lake basis): 

Major: Significant changes in community structure would potentially occur, and large copepod 

abundance would be reduced significantly such that they are undetectable. If fish were removed or died 

off, the community structure may not become comparable to currently fishless lakes. For this assessment, 

potentially major impacts to large zooplankton would be expected in a lake where the following 

predictive factors are found: 

• Lake depth less than ( < ) 50 feet , and 

• Lake area <40 acres, and 

• Fish density is very high (reproducing trout or multiple age classes at greater than [ > ] 

400 fish/acre) 

Moderate: Noticeable changes in community structure would potentially occur, and large copepod 

abundance would be greatly reduced. If fish were removed or died off, the relative abundance of large 

copepods would increase. For this assessment, potentially moderate impacts to large zooplankton would 

be expected in a lake where the following predictive factors are found: 

• Lake depth <50 feet, and 

• Lake area <40 acres, and

• Fish density is high (reproducing trout at >50 fish/acre). 

Minor: Minor changes in community structure would potentially occur. If fish were removed or died off, 

the community structure would become comparable to currently fishless lakes. For this assessment, minor 

impacts to the zooplankton community would be expected in a lake where the following predictive factors 

are found: 
Appendix G

ENVIRONMENTAL IMPACT STATEMENT 215

• Lake depth >50 feet, or 

• Lake area >40 acres, or 

• Fish density is low (stocked trout at <100 fish/acre or reproducing trout at <50 trout/acre). 

Negligible: Long-term adverse impacts would potentially be negligible even though these lakes have 

historically been stocked. Abundance and community structure would be expected to be influenced 

primarily by biogeographical and evolutionary processes. For this assessment, negligible impacts to the 

zooplankton community would be expected in a lake that was previously stocked but is currently fishless. 

Table G-1 (located at the back of this appendix) provides the analysis matrix used for the assessment of 

impacts on plankton, by alternative, for each of the 91 lakes in the study area. 

MACROINVE RTEBRATES 

Impacts on the macroinvertebrate community were evaluated by considering the effects of fish stocking 

on the primary prey species of fish: aquatic insect species with terrestrial adult forms. These include 

mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), and midges (Diptera). 

These species are considered to be primary prey because they are large, mobile, and most exposed to 

predation. Other macroinvertebrate species, such as snails and fingernail clams (mollusca), flatworms 

(Platyhelminthes), and nematodes frequent less exposed habitats and are less likely to be targeted by fish 

as prey. Populations of primary macroinvertebrate prey (Diptera, Ephemeroptera, Trichoptera, 

Plecoptera) are considered to exist at the drainage basin scale, due to the dispersal potential from 

individual lakes and streams (Bilton et al. 2001). Other species of macroinvertebrates, including terrestrial 

insects, snails, and nematodes, are generally minor prey species and not sensitive to predation at the 

population level but can be influenced by indirect effects on food web dynamics. The primary prey 

species are relatively resilient to fish predation at the population level in lake environments, with the 

exception of specific sensitive species such as phantom midges (Chaoborus spp.), which are highly 

sensitive to fish predation and can be extirpated by even low stocking densities. This is not an issue of 

concern, however, because the temperature regime in high-mountain lakes in the North Cascades 

Complex is too cold to support these sensitive species (Verschuren and Marnell 1997). 

Fish predation may result in significant changes in abundance and biomass of some macroinvertebrates, 

as well as behavioral and phenotypical changes (Chess et al. 1993; Knapp 1996; Luecke 1990; Walters 

and Vincent 1973). Because population boundaries usually extend beyond individual lakes, these effects 

are limited to the segments of the population exposed to fish predation. While some population segments 

may be depressed or even temporarily extirpated from a given lake environment, the affected species are 

usually capable of recolonizing these habitats quickly because they have high dispersal rates (Bilton et al. 

2001; Bohonak and Jenkins 2003). 

Recent studies by NPS staff of the biological integrity of benthic macroinvertebrate (BMI) communities 

in 32 lakes have substantially improved the identification of factors contributing to changes in the 

community. Primary predictive factors identified include, among others, fish density, reproductive status 

of the fish, quality of the bottom habitat, and area of the lake. Major changes to the benthic 

macroinvertebrate communities in the 32 lakes studied were associated with a loss of over 40% of the 

expected taxa in a lake. Other lakes containing high densities of reproducing fish also showed major 

changes in macroinvertebrate communities (density and/or diversity), although those lakes that contained 

substantial refuge habitat showed a lessened effect (NPS, R. Glesne, pers. comm., 2004). 
A PPENDIXES

216 DRAFT MOUNTAIN LAKES FISHERY MANAGEMENT PLAN

Based on the factors identified in the NPS BMI monitoring results, and actual monitoring data from 

several of the study area lakes, the following impact thresholds were defined for macroinvertebrates (to be 

applied on a lake-by-lake basis): 

Major: Major impacts include the absence of more than 40% of taxa expected to commonly occur in 

fishless lakes of similar environmental characteristics. Additionally, significant changes in dominant taxa 

and functional feeding group composition would also occur. Recolonization might not occur for an 

extended period of time without active intervention. Of the 91 lakes where the benthic community has not 

been studied, major impacts would be expected where the following predictive factors are present: 

• Fish density is high (stocked trout at >100 fish/acre or reproducing trout at >50 fish/acre), and 

• Lake area is <10 acres, often with limited habitat complexity.

Moderate: Moderate changes in community structure and functional group composition in a lake would 

potentially occur, relative to currently fishless but otherwise similar lakes. Populations eventually would 

recover from impacts if fish were removed. For lakes where the benthic community has not been studied, 

moderate impacts would be expected when the following predictive factors are present: 

• Fish density is high (stocked trout at >100 fish/acre or reproducing trout at >50 fish/acre), and 

• Lake area is more than 10 acres or lake area is less than or equal to ( ≤ ) 10 acres with high 

habitat complexity. 

Minor: Minor changes in community structure in a lake would potentially occur, although populations 

would recover if fish were removed. For lakes where the benthic community has not been investigated, 

minor impacts would be expected where the following predictive factor is present: 

• Fish density is low (stocked trout at <100 fish/acre). 

Negligible: Community structure would be comparable to fishless lakes with similar physical/chemical 

characteristics. Abundance and community structure would be predominantly influenced by 

biogeographical and evolutionary processes. Negligible impacts to the macroinvertebrate community 

would be expected in a lake that was previously stocked but is currently fishless. 

Table G-2 (located at the back of this appendix) provides the analysis matrix used for the assessment of 

impacts, by alternative, on macroinvertebrates for each of the 91 lakes in the study area. 

AMPHIBIANS 

The amphibian community in mountain lakes is represented by a range of species that includes 

salamanders, newts, frogs, and toads. The aquatic amphibian community found in the study area consists 

of two subspecies of long-toed salamander (Ambystoma macrodactylum macrodactylum and A. m. 

columbianum), Northwestern salamander (A. gracile), rough-skinned newt (Taricha granulosa), 

Columbia spotted frog (Rana luteiventris), western toad (Bufo boreas), tailed frog (Ascaphus truei), and 

northern red-legged frog (Rana aurora). The latter four are listed species and are addressed in the 

“Affected Environment” chapter under the “Special Status Species” section of this plan/EIS. Due to their 

sensitivity to stocked trout, the long-toed salamander and Northwestern salamander were selected as the 

focus of the analysis of impacts on amphibians. 
Appendix G

ENVIRONMENTAL IMPACT STATEMENT 217

Amphibians are both directly and indirectly impacted by the presence of stocked fish populations in 

mountain lakes. Direct impacts include predation and competition for prey. Indirect impacts include 

changes in prey availability resulting from changes in food web dynamics and nutrient cycling 

attributable to fish introductions in historically fishless lakes. Direct and indirect impacts of the proposed 

alternatives on amphibians are evaluated at the population level for each amphibian species. 

The potential for adverse impacts on the salamander species varies with a number of factors, including the 

habitat requirements of each species, physical and chemical lake characteristics, the type (that is, stocked 

or reproducing), and density of stocked fish populations. The two species are generally not found in the 

same spawning and rearing habitats, but adult habitats are similar. In the adult stage, both species use 

animal burrows for migration and overwintering habitat, which in turn restricts their range to areas with 

sufficient soil depth for burrowing mammals (Semlitsch 1983). The differences in habitat preference and 

tendency for competition between the two species influence the extent of impacts from stocked trout on 

each species. 

Northwestern salamanders are restricted to the west side of the Cascade Crest and require dense, closedcanopy forest during their terrestrial adult phase and downed woody debris in the nearshore areas of 

ponds and lakes for spawning substrate (Hoffman et al. 2003; Dvornich et al. 1997; Aubry and Hall 1991; 

Petranka 1998). Dense old-growth forest habitat is particularly important to hibernating adults in the 

Cascade Mountains from Mount Hood, north (Aubry and Hall 1991). Because this species requires a long 

juvenile rearing stage of at least two years, and often reaches maturity in aquatic form, spawning and 

juvenile rearing habitat must be perennial. Because of this range of habitat preferences, suitable lakes and 

pods for Northwestern salamanders are usually large and deep and typically found below the treeline. The 

available evidence indicates that when in their preferred habitat, Northwestern salamanders usually 

dominate and out-compete long-toed salamanders to the point of exclusion (Hoffman et al. 2003; 

Hoffman 2003; Hoffman and Larson 1999). Trout populations have been documented to reduce the 

numbers of larvae and neotenic adults (adults that retain some juvenile characteristics) of Northwestern 

salamanders in individual lakes. However, populations of Northwestern salamanders are likely to coexist 

with stocked trout and remain viable, albeit at reduced densities. This is likely due to the large size of 

older larvae and neotenic adults in this species (relative to long-toed salamanders), and a stronger 

propensity for behavioral adaptations for avoiding predation. 

Because long-toed salamanders do not compete well with Northwestern salamanders in perennial bodies 

of water on the west side of the North Cascades, this species is usually found in lakes in open terrain 

above the treeline where its competitor is not present. However, these lake habitats will be within a 

relatively short distance of forested terrestrial habitat for adult salamanders. Lakes above the treeline lack 

the woody structure and debris required by Northwestern salamanders as spawning substrate. Long-toed 

salamander breeding sites on the east side of the Cascade Crest are still usually located in areas of open 

vegetation within a relatively short distance of forested terrestrial habitat, but they are more likely to 

occur in forested regions below treeline because Northwestern salamanders do not occur in this region. 

Long-toed salamanders are generally more sensitive to competition and predation by stocked trout and, 

therefore, are more likely to suffer adverse impacts. 

Three predictive factors appear to influence the extent of impacts: the productivity of the rearing lakes (as 

measured by total Kjeldahl nitrogen, or TKN), the density of stocked trout populations, and the Index of 

Connectivity (IOC). Based on available evidence, long-toed salamanders are at highest risk of extirpation 

in low-productivity lakes (TKN values <0.045 mg/l) with high-density populations of reproducing fish 

(>50 fish/acre), or high-density populations of stocked fish (>100 fish/acre) (Liss et al. 1995, 1999, 2002). 

A lower potential for extirpation exists in high-productivity lakes (TKN values greater than or equal to [≥] 

0.045 mg/l) with high-density fish populations. Lakes with low-density fish populations of stocked trout 
A PPENDIXES

218 DRAFT MOUNTAIN LAKES FISHERY MANAGEMENT PLAN

(≤100 fish/acre) do not appear to be at risk of extirpation, but the density of rearing salamander larvae 

may be reduced. 

A final factor to explain the variability of impacts from stocked trout on long-toed salamander larvae in 

lakes with otherwise suitable habitats is the IOC. The IOC was based on the density or number of 

potential long-toed salamander breeding ponds or lakes (lakes with suitable aquatic and terrestrial habitat) 

within a target lake’s basin (lakes/mile), number of known long-toed salamander populations within a 

radius of 3.75 miles (maximum likely colonization distance) of the target lake or pond, and the number of 

potential long-toed salamander breeding ponds or lakes within a 0.4-mile radius (maximum likely 

dispersal distance) of the target lake. These values were used to calculate the IOC, which represents the 

level of gene flow likely to occur between lake populations, likelihood of colonization events, and degree 

of isolation of a lake from the long-toed salamander metapopulation. IOC cannot exceed a value of 1.0, 

but it can be below a value of 0. Lakes with an IOC below 0 are considered to have very low potential for 

colonization or recolonization events in the short term and low levels of genetic interchange. The higher 

the IOC, the higher the connectivity, and the more likely it is that genetic exchange would occur. 

Based on the above information and the knowledge of the plan/EIS team experts about the presence of 

amphibians in study area lakes, the following thresholds were defined (to be applied on a lake-by-lake 

basis): 

Major: Populations of long-toed salamanders would be permanently altered from normal levels and 

possibly eliminated from a lake, with recolonization unlikely. For the impact assessment, potentially 

major impacts to long-toed salamanders would be expected where the following predictive factors are 

present: 

• Lake with suitable habitat (open terrain at the lake with forest nearby) is within the range of the 

long-toed salamander, and 

• TKN is ≥0.045 mg/L, fish density is high, and IOC is less than 0; 

OR 

• Lake with suitable habitat is within their range, and 

• TKN is <0.045 mg/L, fish density is high, and IOC is ≤0.3. 

Major impacts to Northwestern salamanders are unlikely in any lake due to larger larvae than long-toed 

salamanders and behavioral adaptations for avoiding predation. 

Moderate: Populations of long-toed salamanders would be present within their historic range, but density 

of larvae in a lake would potentially be smaller than in comparable fishless lakes, and populations may be 

eliminated on a temporary or local basis. Populations would deviate from normal levels. Potentially 

moderate impacts to long-toed salamanders would be expected where the following predictive factors are 

present: 

• Lake with suitable habitat is within their range, and 

• TKN is ≥0.045 mg/L, fish density is high, and IOC is ≥0; 

OR 

• Lake with suitable habitat is within their range, and 

• TKN is <0.045 mg/L, fish density is high, and IOC is between 0.4 and 0.6. 
Appendix G

ENVIRONMENTAL IMPACT STATEMENT 219

Moderate impacts to Northwestern salamanders may occur where a lake with dense, closed-canopy forest 

habitat is within their range, and fish density is high. 

Minor: Populations of long-toed salamanders likely would be present within their historic range, but 

density of larvae in a lake would potentially be slightly smaller than comparable fishless lakes. Minor 

impacts to long-toed salamanders would be expected where the following predictive factors are present: 

• Lake with suitable habitat is within their range, and 

• TKN is ≥0.045 mg/L, fish density is low, and IOC is ≤0.3. 

Minor impacts to Northwestern salamanders may occur where a lake with suitable forested habitat is 

within their range and fish density is low. 

Negligible: Populations likely would be present in any lake within their historic range, with larval density 

close to that of fishless lakes. For the impact assessment, negligible impacts to long-toed salamanders 

would be expected where the following predictive factors are present: 

• Lake with suitable habitat is within their range, and 

• TKN is ≥0.045 mg/L, fish density is low, and IOC is ≥0.4; 

OR 

• Lake with suitable habitat is within their range, and 

• TKN is <0.045 mg/L and fish density is low; 

OR 

• Lake with suitable habitat is within their range, and 

• TKN is <0.045 mg/L, fish density is high, and IOC is ≥0.7. 

Table G-3 summarizes the outcome of various combinations of the principal predictive factors for impacts 

on the long-toed salamander larvae. 

TABLE G-3: PRINCIPAL PREDICTIVE FACTORS 

FOR IMPACTS ON LONG-TOED SALAMANDER LARVAE

TKN ≥0.045 mg/L Fish Density 

Index of 

Connectivity Impact Level 

Yes High <0.0 Major 

No High <0.0 - 0.3 Major 

Yes High 0.0 - 1.0 Moderate 

No High 0.4 - 0.6 Moderate 

Yes Low <0.0 - 0.3 Minor 

No High 0.7 - 1.0 Negligible 

Yes Low 0.4 - 1.0 Negligible 

No Low <0.0 - 1.0 Negligible 
A PPENDIXES

220 DRAFT MOUNTAIN LAKES FISHERY MANAGEMENT PLAN

Table G-4 (located at the back of this appendix) provides the analysis matrix used for the assessment of 

impacts, by alternative, on amphibians for each of the 91 lakes in the study area. 

NATIVE FISH 

Impacts on native salmonids from downstream colonization by nonnative species can occur through 

competition for resources (such as prey species and spawning gravels), introgression (hybridization 

between nonnative trout and closely related native trout), and predation on juvenile native trout. 

Native fish communities in watersheds below mountain lakes can be affected if salmonids stocked in 

mountain lakes establish populations in outlet streams. The extent of potential adverse impacts on native 

fish depends upon the species and strain stocked in a given mountain lake and the native species in the 

downstream areas of the watershed exposed to colonization. There is incomplete information regarding 

actual impacts currently occurring, or that could occur, for all 91 lakes under all alternatives; therefore, 

impact thresholds were developed using predictive factors based on the types of species stocked and the 

watershed locations (since certain species are native only to either the east or west side of the Cascades). 

Relevant literature and the professional experience of biologists on the plan/EIS team were used to relate 

the presence of certain nonnative fish to a likely level of impact. In addition to this predictive approach, 

actual knowledge of impacts (colonization and/or hybridization) occurring in certain drainages (as 

provided by WDFW staff involved in the preparation of this plan/EIS) was used to characterize impact 

levels whenever possible (see “Table G-5: Assessment of Impacts on Native Fish”). After the record of 

decision on this plan/EIS is made and a monitoring program is implemented, more specific biologically 

based factors would be developed and used in making future adaptive management decisions that would 

affect lake stocking. 

The predictive factors used in this analysis focus on the potential for colonization and/or hybridization of 

downstream drainages. Colonization of downstream habitats by stocked mountain lake trout has been 

widely documented, but colonization success varies by species. For example, brook trout stocked in 

mountain lakes have successfully transited 80% gradient stream reaches and, in one case, a 60-foot 

waterfall to colonize tributaries with a gradient as high as a 23%. Downstream colonization over distances 

up to 68 miles has been documented (Adams et al. 2001). In contrast, Mt. Whitney rainbows and 

California golden trout have been widely stocked in high-elevation lakes in Washington, but successful 

colonization of downstream habitats by these species has never been documented in Washington State 

(WDFW, B. Pfeifer, pers. comm., 2002; WDFW, M. Downen, pers. comm., 2002). Various strains of 

cutthroat and rainbow trout have also been broadly stocked to high-elevation lakes and have had variable 

success with colonization of downstream habitats. 

Because of the low potential of establishing populations in watersheds below mountain lakes, Ross Lake 

rainbows, Mt. Whitney rainbows, or California golden trout stocked in mountain lakes are unlikely to 

adversely affect native salmonids on the west side of the Cascade Crest. Also, the stocking of coastal 

cutthroat trout in a west-side lake would not create adverse effects, since these species are native to westside watersheds. 

Westslope cutthroat trout, however, are not native to stream basins on the west side of the Cascades and 

have the potential to compete with native trout, char, and salmon for resources and to hybridize with 

coastal rainbows and coastal cutthroat trout (WDFW, M. Downen, pers. comm., 2002, 2003). The Twin 

Lakes strain of westslope cutthroat trout has been widely stocked on the west side of the Cascades, with 

many reproducing populations established in both mountain lakes and streams. The zone of hybridization 

is likely to be restricted to reaches of streams where both westslope cutthroat and native trout can 

reproduce. Westslope cutthroat trout generally reproduce later in the year and in colder water 
Appendix G

ENVIRONMENTAL IMPACT STATEMENT 221

temperatures than coastal cutthroat and rainbow trout, which restricts the potential for introgression. 

Brook trout cannot hybridize with native rainbow or cutthroat trout, but can compete with native trout for 

available resources in headwater streams and tributaries (Adams et al. 2001). Brook trout are capable of 

hybridizing with bull trout, which are currently listed as threatened under the Endangered Species Act. A 

high percentage of the hybrids produced are thought to be sterile, giving the smaller but numerically 

superior brook trout a competitive advantage. A few lakes in the study area west of the Cascade Crest 

contain reproducing populations of rainbow trout strains, which are more closely related to native strains 

of rainbow trout and less likely to impact native trout than westslope cutthroat trout. 

In the Lake Chelan / Stehekin River basin, Twin Lakes westslope cutthroat trout are stocked in many of 

the mountain lakes. Although this strain of westslope cutthroat may not be genetically identical to 

westslope cutthroats that are native to east-side streams, it is closely related and unlikely to have 

substantial impacts to native trout. Rainbow trout that were adapted to headwater stream and mountain 

lake environments (perhaps from Packwood Lake, Washington) were stocked into Rainbow Lake in the 

1930s before the establishment of the Washington Game Department (currently the Washington 

Department of Fish and Wildlife). These stocked trout established a reproducing population of rainbow 

trout on the east side of the Cascade Crest. Reproducing populations of rainbow trout or populations of 

cutthroat/rainbow hybrids also exist in approximately three other lakes in the study area east of the 

Cascade Crest. Stocked rainbow trout have been documented to replace, through competition or 

hybridization, native populations of westslope cutthroat trout throughout its native range (Behnke 1992). 

In general, the greatest threat to native fish in downstream drainages would occur from the presence of 

reproducing brook trout in a west-side lake with outlets to streams containing native char, or from 

rainbow or rainbow/cutthroat hybrids in an east-side lake, where native westslope cutthroat trout could 

occur in downstream reaches. These impacts would be considered major if both colonization and 

hybridization occur as a result of downstream dispersal. 

Based on the above information, including the knowledge of WDFW biologists familiar with streams in 

the study area, the following impact thresholds were defined for native fish populations (to be applied on 

a lake-by-lake basis): 

Major: There would be measurable evidence of colonization, and where interbreeding is possible, 

hybridization with native fish. Native species deviate from normal population levels or abundance, and/or 

genotypes are permanently altered. On a local basis, native species may be eliminated or become hybrid 

swarms. For this assessment, potentially major impacts would be expected when a surface outlet connects 

to a downstream basin AND the following additional predictive factors are found: 

• Inventories demonstrate colonization and hybridization of the outlet stream from downstream 

dispersal of nonnative stocked fish has occurred, 

AND 

• Reproducing brook trout are present in a west-side lake, or

• Reproducing rainbow trout or rainbow/cutthroat hybrids are present in an east-side lake.

Moderate: Although individuals of nonnative species stocked into a lake could occasionally disperse 

downstream and rear in streams, there would be no measurable evidence of colonization or hybridization 

with native fish. All native species would be indefinitely viable. For this assessment, potentially moderate 

impacts would be expected when a surface outlet connects to a downstream basin AND the following 

additional predictive factors are found: 
A PPENDIXES

222 DRAFT MOUNTAIN LAKES FISHERY MANAGEMENT PLAN

• Inventories demonstrate that colonization and/or hybridization of the outlet stream has not 

occurred from populations of nonnative stocked fish that have a long history of high levels of 

reproduction, 

AND 

• Reproducing brook trout are present in a west-side lake, or 

• Reproducing rainbow trout or rainbow/cutthroat hybrids are present in an east-side lake.

Minor: Relatively small numbers of individuals could potentially be affected through intraspecies 

hybridization. Outbreeding depression may occur in vicinity of outlet stream, but effects would be 

localized. All native species would be indefinitely viable. For this assessment, potentially minor impacts 

would be expected when a surface outlet connects to a downstream basin AND one of the following 

additional predictive factors is found: 

• Reproducing strains or subspecies of rainbow or cutthroat trout not native to the basin are present 

in a west-side lake, 

OR 

• Mt. Whitney rainbow trout are stocked in an east-side lake. 

Negligible: If present in a lake with an outlet, fish are either native to the basin or are unlikely to colonize 

downstream areas if one or more of the following predictive factors applies: 

• Ross Lake or Mt. Whitney rainbow trout, coastal cutthroat trout, or California golden trout are 

present in a west-side lake, 

OR· 

• Westslope cutthroat trout are present in an east-side lake, 

OR 

• The lake is fishless. 
ENVIRONMENTAL IMPACT STATEMENT 

TABLE G-1: ASSESSMENT OF IMPACTS ON PLANKTON

Management Action Fish Den

Lake Name 

NPS Lake 

Code Zone 

Elevation 

(ft) 

Surface 

Area 

(acres) 

Maximum 

Depth 

(ft) 

Water Temp 

(°C) 

Fish 

Status 

Fish 

Density 

Reproducing 

Trout Alternative A Alternative B Alternati

Azure MP-09-01 W 4,055 91.6 344.5 8.5 FL N N Fishless Fishless Fishless Battalion MLY-02-01 E 5,340 6.3 15.6 12.2 M H Y Fish-high density Fishless Fishless Beara MC-12-01 W 5,795 25.7 151.9 11.4 R H Y Fish-high density Fish-low density Fishless Berdeena M-08-01 W 5,000 126.7 215.0 9.3 M H Y Fish-high density Fish-low density Fishless Berdeen, Lower M-07-01 W 4,460 7.5 36.1 9.7 R H Y Fish-high density Fishless Fishless Berdeen, Upper M-09-01 W 5,050 9.5 — — R H Y Fish-high density Fishless Fishless Blum (Largest/Middle, No. 3) M-11-01 W 5,030 12.9 — 11.0 M H Y Fish-high density Fishless Fishless Blum (Lower/West, No. 4) LS-07-01 W 4,940 6.4 25.9 12.9 R VH Y Fish-high density Fish-low density Fishless Blum (Small/North, No. 2) MC-01-01 W 5,620 0.9 10.0 19.5 FL N N Fishless Fishless Fishless Blum (Vista/Northwest, No. 1) MC-02-01 W 5,900 2.7 35.0 11.0 FL N N Fishless Fishless Fishless Bouck, Lower DD-04-01 W 3,850 10.8 63.2 11.2 R H Y Fish-high density Fish-low density Fish-low deBouck, Upper DD-05-01 W 5,030 5.5 29.0 10.5 S L N Fish-low density Fishless Fishless Bowen MR-12-01 E 6,495 1.5 13.1 — S L N Fish-low density Fishless Fishless Coon MM-10-01 E 2,172 11.3 19.0 16.6 S L N Fish-low density Fish-low density Fish-low deCopperb MC-06-01 W 5,263 12.9 67.2 10.3 S L N Fish-low density Fishless Fishless Dagger MR-04-01 E 5,508 8.2 15.9 12.3 R H Y Fish-high density Fishless Fishless Dee Dee, Upper MR-15-01 E 6,303 12.2 89.2 7.4 M H Y Fish-high density Fishless Fishless Dee Dee/Tamarack, Lower MR-15-02 E 6,260 0.8 9.8 7.1 S L N Fish-low density Fishless Fishless Despair, Lower M-14-01 W 4,820 1.7 — — FL N N Fishless Fishless Fishless Despair, Upper M-13-01 W 5,100 2.1 — — FL N N Fishless Fishless Fishless Diobsud No. 1 LS-01-01 W 4,220 1.0 11.2 14.1 R H Y Fish-high density Fishless Fishless Diobsud No. 2, Lower LS-02-01 W 4,220 3.1 17.2 13.7 M H Y Fish-high density Fishless Fishless Diobsud No. 3, Upper LS-03-01 W 4,420 3.9 17.1 14.8 S L N Fish-low density Fishless Fishless Doubtful CP-01-01 E 5,385 30.2 68.2 10.9 R H Y Fish-high density Fish-low density Fishless Doug's Tarn M-21-01 W 3,951 5.0 10.2 11.2 R H Y Fish-high density Fish-low density Fishless East, Lower MC-14-02 W 5,460 8.0 — 15.6 FL N N Fishless Fishless Fishless East, Upper MC-14-01 W 5,595 6.2 — — FL N N Fishless Fishless Fishless Firn MP-02-01 W 5,472 5.7 37.7 12.6 M L N Fish-low density Fish-low density Fishless Greena M-04-01 W 4,261 80.0 153.2 8.7 R H Y Fish-high density Fishless Fishless Green Bench LS-04-01 W 4,870 3.9 21.5 10.5 FL N N Fishless Fishless Fishless Hanginga,c MC-08-01 W 4,522 88.8 — — R H Y Fish-high density Fishless Fishless Hiddena SB-01-01 W 5,733 61.7 258.2 7.2 M L N Fish-low density Fish-low density Fishless Hidden Lake Tarn EP-14-01 W 5,830 4.9 42.7 12.8 S L N Fish-low density Fishless Fishless Hi-Yu M-01-01 W 3,830 3.6 18.0 16.4 S L N Fish-low density Fishless Fishless Hozomeena HM-02-01 W 2,823 97.4 66.7 17.4 R VH Y Fish-high density Fishless Fishless Ipsoot LS-06-01 W 4,460 8.9 50.8 19.7 R L Y Fish-low density Fish-low density Fishless Jeanita DD-01-01 W 4,904 1.4 8.0 12.7 R L N Fish-low density Fish-low density Fishless Kettling MR-05-01 E 5,375 9.9 23.0 11.4 R H Y Fish-high density Fishless Fishless Kwahnesum MC-07-01 W 5,102 16.4 104.3 12.3 S L N Fish-low density Fishless Fishless McAlester MR-10-01 E 5,507 13.2 23.0 13.0 R H Y Fish-high density Fishless Fishless Middle, Lower MC-16-02 W 5,595 2.9 8.0 7.9 FL N N Fishless Fishless Fishless Middle, Upper MC-16-01 W 5,700 4.5 25.9 3.4 FL N N Fishless Fishless Fishless Monograma M-23-01 W 4,873 29.1 122.0 12.3 M H Y Fish-high density Fish-low density Fishless Monogram Tarn M-23-11 W 4,860 — — — S L N Fish-low density Fishless Fishless Nert M-05-01 W 4,556 3.6 29.5 15.8 S L N Fish-low density Fishless Fishless 
TABLE G-1: ASSESSMENT OF IMPACTS ON PLANKTON (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT 

Management Action Fish Den

Lake Name 

NPS Lake 

Code Zone 

Elevation 

(ft) 

Surface 

Area 

(acres) 

Maximum 

Depth 

(ft) 

Water Temp 

(°C) 

Fish 

Status 

Fish 

Density 

Reproducing 

Trout Alternative A Alternative B Alternati

Noisy Creek, Upper LS-14-01 W 3,660 0.3 — — FL N N Fishless Fishless Fishless No Name PM-01-01 W 3,843 7.5 31.2 7.6 S L N Fish-low density Fish-low density Fishless Panther Potholes, Lower RD-05-02 W 3,375 0.5 17.2 17.4 S L N Fish-low density Fishless Fishless Panther Potholes, Upper RD-05-01 W 3,380 0.2 9.4 17.8 FL N N Fishless Fishless Fishless Pegasus EP-10-01 W 5,620 10.9 — — FL N N Fishless Fishless Fishless Pond SE of Kettling Lakes MR-09-01 E 5,945 4.7 16.1 — S L N Fish-low density Fish-low density Fish-low deQuill, Lower M-24-02 W 4,510 1.0 18.0 S L N Fish-low density Fishless Fishless Quill, Upper M-24-01 W 4,510 1.2 10.0 20.0 S L N Fish-low density Fishless Fishless Rainbow MR-14-01 E 5,630 15.5 107.6 13.1 R H Y Fish-high density Fish-low density Fish-low deRainbow, Upper (North) MR-13-01 E 5,900 0.6 7.2 15.7 FL N N Fishless Fishless Fishless Rainbow, Upper (South) MR-13-02 E 5,865 3.6 24.1 10.6 S L N Fish-low density Fishless Fishless Rainbow, Upper (West) MM-11-01 E 6,473 3.5 27.6 13.4 S L N Fish-low density Fishless Fishless Redoubt MC-11-01 W 5,300 18.4 45.9 9.3 FL N N Fishless Fishless Fishless Reveille, Lower MC-21-02 W 4,995 4.4 9.8 13.8 FL N N Fishless Fishless Fishless Reveille, Upper MC-21-01 W 4,995 3.4 16.4 8.0 FL N N Fishless Fishless Fishless Ridley HM-03-01 W 3,140 10.9 35.1 18.2 S L N Fish-low density Fish-low density Fish-low deSky EP-13-01 W 5,380 1.9 — — FL N N Fishless Fishless Fishless Skymo PM-03-01 W 5,277 10.8 20.0 11.1 M H Y Fish-high density Fish-low density Fishless Sourdough PM-12-01 W 4,623 27.6 107.0 14.7 M VH Y Fish-high density Fishless Fishless Sourpuss ML-01-01 W 4,835 2.0 3.9 7.8 FL N N Fishless Fishless Fishless Stiletto MR-01-01 E 6,795 9.9 85.3 6.1 S L N Fish-low density Fishless Fishless Stouta EP-09-02 W 5,215 25.2 175.5 5.4 M L Y Fish-low density Fish-low density Fishless Stout, Lower EP-09-01 W 5,190 1.0 8.2 13.2 R L Y Fish-low density Fish-low density Fishless Sweet Pea ML-02-01 W 5,540 10.3 92.0 6.5 S L N Fish-low density Fish-low density Fishless Talus Tarn M-06-01 W 5,355 1.5 11.8 11.7 FL N N Fishless Fishless Fishless Tapto, Lower MC-17-03 W 5,700 0.4 — — FL N N Fishless Fishless Fishless Tapto, Middle MC-17-02 W 5,730 1.2 18.0 12.9 FL N N Fishless Fishless Fishless Tapto, Upper MC-17-01 W 5,750 10.2 43.0 — FL N N Fishless Fishless Fishless Tapto, West MC-17-04 W 5,660 2.3 14.1 11.7 FL N N Fishless Fishless Fishless Thornton, Lower M-20-01 W 4,486 55.1 108.3 12.2 M L N Fish-low density Fish-low density Fishless Thornton, Middle M-19-01 W 4,700 11.9 78.7 8.2 S L N Fish-low density Fish-low density Fishless Thunder RD-02-01 W 1,350 6.8 24.6 15.3 FL N N Fishless Fishless Fishless Tiny MC-15-01 W 6,100 0.3 6.0 17.0 FL N N Fishless Fishless Fishless Torment ML-03-01 W 6,560 3.6 49.9 8.0 S L N Fish-low density Fishless Fishless Trappera GM-01-01 E 4,165 147.2 160.8 14.1 R H Y Fish-high density Fish-low density Fishless Triplet, Lower SM-02-01 E 6,331 2.2 7.2 17.5 R H Y Fish-high density Fish-low density Fish-low deTriplet, Upper SM-02-02 E 6,551 2.3 12.5 19.7 R H Y Fish-high density Fishless Fishless Triumph M-17-01 W 3,685 4.3 20.5 17.1 S L N Fish-low density Fish-low density Fishless Unnamed FP-01-01 W 5,140 13.5 — — FL N N Fishless Fishless Fishless Unnamed MR-11-01 E 6,111 2.9 28.9 14.6 S L N Fish-low density Fish-low density Fish-low deUnnamed MR-16-01 E 6,230 1.9 6.6 — R L N Fish-low density Fish-low density Fish-low deVulcan ML-04-01 W 5,180 8.2 25.2 10.7 FL N N Fishless Fishless Fishless Wilcox/Lillie, Upper EP-06-01 W 5,136 10.5 65.0 14.5 R H Y Fish-high density Fishless Fishless Wilcox/Sandie, Lower EP-05-01 W 5,120 5.4 19.7 13.5 R H Y Fish-high density Fish-low density Fishless Wild MC-27-01 W 4,880 12.7 28.9 10.1 FL N N Fishless Fishless Fishless Willow HM-04-01 W 2,853 16.9 26.9 19.5 S L N Fish-low density Fish-low density Fish-low de
TABLE G-1: ASSESSMENT OF IMPACTS ON PLANKTON (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT Notes: Zone: E = East side of Cascade Crest  W = West side of Cascade Crest Fish Status: S = Stocked  S* = Stocked with reproducing fish. Limited reproduction in the past – needs verification. 

 R = Reproducing  M = Mixed reproducing and stocked  NF = No fish (historically stocked)  FL = No fish (historically fishless) Fish Density: H = High fish density (> 100 trout/acre for stocked fish or > 50 trout/acre for reproducing fish)  L = Low fish density (< 100 trout/acre for stocked fish or < 50 trout/acre for reproducing fish)  N = No fish present  VH = Very High fish density (> 400 trout/acre of reproducing fish or stocked fish with multiple year-classes approximating age structure of reproducing fish) 

Reproducing Trout: N = No  Y = Yes Management Action Fish Densities: Level of Impact:  For impact thresholds, refer to “Table 31: Summary of Impact Thresholds—Aquatic Organisms” in the “Environmental Consequences” chapter. 

a. The feasibility of complete removal of fish in these lakes would need to be evaluated. b In August 2004, a large fish kill was observed in Copper Lake, possibly due to disease. Further surveys are needed to confirm that the lake is fishless. 

c. Remove all reproducing fish from Hanging Lake pending agreement with British Columbia. 
ENVIRONMENTAL IMPACT STATEMENT 

TABLE G-2: ASSESSMENT OF IMPACTS ON MACROINVERTEBRATES

 Management Action Fish Densities 

Lake Name 

NPS Lake 

Code Zone 

Elevation 

(ft) 

Surface 

Area 

(acres) 

Max. Depth 

(ft) 

Water Temp 

(°C) 

Fish 

Status 

Fish 

Density Alternative A Alternative B Alternative C 

Azure MP-09-01 W 4,055 91.6 344.5 8.5 FL N Fishless Fishless Fishless Battalion MLY-02-01 E 5,340 6.3 15.6 12.2 M H Fish-high density Fishless Fishless Beara MC-12-01 W 5,795 25.7 151.9 11.4 R H Fish-high density Fish-low density Fishless Berdeena M-08-01 W 5,000 126.7 215.0 9.3 M H Fish-high density Fish-low density Fishless Berdeen, Lower M-07-01 W 4,460 7.5 36.1 9.7 R H Fish-high density Fishless Fishless Berdeen, Upper M-09-01 W 5,050 9.5 — — R H Fish-high density Fishless Fishless Blum (Largest/Middle, No. 3) M-11-01 W 5,030 12.9 — 11.0 M H Fish-high density Fishless Fishless Blum (Lower/West, No. 4) LS-07-01 W 4,940 6.4 25.9 12.9 R VH Fish-high density Fish-low density Fishless Blum (Small/North, No. 2) MC-01-01 W 5,620 0.9 10.0 19.5 FL N Fishless Fishless Fishless Blum (Vista/Northwest, No. 1) MC-02-01 W 5,900 2.7 35.0 11.0 FL N Fishless Fishless Fishless Bouck, Lower DD-04-01 W 3,850 10.8 63.2 11.2 R H Fish-high density Fish-low density Fish-low density Bouck, Upper DD-05-01 W 5,030 5.5 29.0 10.5 S L Fish-low density Fishless Fishless Bowan MR-12-01 E 6,495 1.5 13.1 — S L Fish-low density Fishless Fishless Coon MM-10-01 E 2,172 11.3 19.0 16.6 S L Fish-low density Fish-low density Fish-low density Copperb MC-06-01 W 5,263 12.9 67.2 10.3 S L Fish-low density Fishless Fishless Dagger MR-04-01 E 5,508 8.2 15.9 12.3 R H Fish-high density Fishless Fishless Dee Dee, Upper MR-15-01 E 6,303 12.2 89.2 7.4 M H Fish-high density Fishless Fishless Dee Dee/Tamarack, Lower MR-15-02 E 6,260 0.8 9.8 7.1 S L Fish-low density Fishless Fishless Despair, Lower M-14-01 W 4,820 1.7 — — FL N Fishless Fishless Fishless Despair, Upper M-13-01 W 5,100 2.1 — — FL N Fishless Fishless Fishless Diobsud No. 1 LS-01-01 W 4,220 1.0 11.2 14.1 R H Fish-high density Fishless Fishless Diobsud No. 2, Lower LS-02-01 W 4,220 3.1 17.2 13.7 M H Fish-high density Fishless Fishless Diobsud No. 3, Upper LS-03-01 W 4,420 3.9 17.1 14.8 S L Fish-low density Fishless Fishless Doubtful CP-01-01 E 5,385 30.2 68.2 10.9 R H Fish-high density Fish-low density Fishless Doug's Tarn M-21-01 W 3,951 5.0 10.2 11.2 R H Fish-high density Fish-low density Fishless East, Lower MC-14-02 W 5,460 8.0 — 15.6 FL N Fishless Fishless Fishless East, Upper MC-14-01 W 5,595 6.2 — — FL N Fishless Fishless Fishless Firn MP-02-01 W 5,472 5.7 37.7 12.6 M L Fish-low density Fish-low density Fishless Greena M-04-01 W 4,261 80.0 153.2 8.7 R H Fish-high density Fishless Fishless Green Bench LS-04-01 W 4,870 3.9 21.5 10.5 FL N Fishless Fishless Fishless Hanginga,c MC-08-01 W 4,522 88.8 — — R H Fish-high density Fishless Fishless Hiddena SB-01-01 W 5,733 61.7 258.2 7.2 M L Fish-low density Fish-low density Fishless Hidden Lake Tarn EP-14-01 W 5,830 4.9 42.7 12.8 S L Fish-low density Fishless Fishless Hi-Yu M-01-01 W 3,830 3.6 18.0 16.4 S L Fish-low density Fishless Fishless Hozomeena HM-02-01 W 2,823 97.4 66.7 17.4 R VH Fish-high density Fishless Fishless Ipsoot LS-06-01 W 4,460 8.9 50.8 19.7 R L Fish-low density Fish-low density Fishless Jeanita DD-01-01 W 4,904 1.4 8.0 12.7 R L Fish-low density Fish-low density Fishless Kettling MR-05-01 E 5,375 9.9 23.0 11.4 R H Fish-high density Fishless Fishless Kwahnesum MC-07-01 W 5,102 16.4 104.3 12.3 S L Fish-low density Fishless Fishless McAlester MR-10-01 E 5,507 13.2 23.0 13.0 R H Fish-high density Fishless Fishless= Middle, Lower MC-16-02 W 5,595 2.9 8.0 7.9 FL N Fishless Fishless Fishless Middle, Upper MC-16-01 W 5,700 4.5 25.9 3.4 FL N Fishless Fishless Fishless 
TABLE G-2: ASSESSMENT OF IMPACTS ON MACROINVERTEBRATES (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT 

 Management Action Fish Densities 

Lake Name 

NPS Lake 

Code Zone 

Elevation 

(ft) 

Surface 

Area 

(acres) 

Max. Depth 

(ft) 

Water Temp 

(°C) 

Fish 

Status 

Fish 

Density Alternative A Alternative B Alternative C 

Monograma M-23-01 W 4,873 29.1 122.0 12.3 M H Fish-high density Fish-low density Fishless Monogram Tarn M-23-11 W 4,860 — — — S L Fish-low density Fishless Fishless Nert M-05-01 W 4,556 3.6 29.5 15.8 S L Fish-low density Fishless Fishless Noisy Creek, Upper LS-14-01 W 3,660 0.3 — — FL N Fishless Fishless Fishless No Name PM-01-01 W 3,843 7.5 31.2 7.6 S L Fish-low density Fish-low density Fishless Panther Potholes, Lower RD-05-02 W 3,375 0.5 17.2 17.4 S L Fish-low density Fishless Fishless Panther Potholes, Upper RD-05-01 W 3,380 0.2 9.4 17.8 FL N Fishless Fishless Fishless Pegasus EP-10-01 W 5,620 10.9 — — FL N Fishless Fishless Fishless Pond SE of Kettling Lakes MR-09-01 E 5,945 4.7 16.1 — S L Fish-low density Fish-low density Fish-low density Quill, Lower M-24-02 W 4,510 1.0 18.0 S L Fish-low density Fishless Fishless Quill, Upper M-24-01 W 4,510 1.2 10.0 20.0 S L Fish-low density Fishless Fishless Rainbow MR-14-01 E 5,630 15.5 107.6 13.1 R H Fish-high density Fish-low density Fish-low density Rainbow, Upper (North) MR-13-01 E 5,900 0.6 7.2 15.7 FL N Fishless Fishless Fishless Rainbow, Upper (South) MR-13-02 E 5,865 3.6 24.1 10.6 S L Fish-low density Fishless Fishless Rainbow, Upper (West) MM-11-01 E 6,473 3.5 27.6 13.4 S L Fish-low density Fishless Fishless Redoubt MC-11-01 W 5,300 18.4 45.9 9.3 FL N Fishless Fishless Fishless Reveille, Lower MC-21-02 W 4,995 4.4 9.8 13.8 FL N Fishless Fishless Fishless Reveille, Upper MC-21-01 W 4,995 3.4 16.4 8.0 FL N Fishless Fishless Fishless Ridley HM-03-01 W 3,140 10.9 35.1 18.2 S L Fish-low density Fish-low density Fish-low density Sky EP-13-01 W 5,380 1.9 — — FL N Fishless Fishless Fishless Skymo PM-03-01 W 5,277 10.8 20.0 11.1 M H Fish-high density Fish-low density Fishless Sourdough PM-12-01 W 4,623 27.6 107.0 14.7 M VH Fish-high density Fishless Fishless Sourpuss ML-01-01 W 4,835 2.0 3.9 7.8 FL N Fishless Fishless Fishless Stiletto MR-01-01 E 6,795 9.9 85.3 6.1 S L Fish-low density Fishless Fishless Stouta EP-09-02 W 5,215 25.2 175.5 5.4 M L Fish-low density Fish-low density Fishless Stout, Lower EP-09-01 W 5,190 1.0 8.2 13.2 R L Fish-low density Fish-low density Fishless Sweet Pea ML-02-01 W 5,540 10.3 92.0 6.5 S L Fish-low density Fish-low density Fishless Talus Tarn M-06-01 W 5,355 1.5 11.8 11.7 FL N Fishless Fishless Fishless Tapto, Lower MC-17-03 W 5,700 0.4 — — FL N Fishless Fishless Fishless Tapto, Middle MC-17-02 W 5,730 1.2 18.0 12.9 FL N Fishless Fishless Fishless Tapto, Upper MC-17-01 W 5,750 10.2 43.0 — FL N Fishless Fishless Fishless Tapto, West MC-17-04 W 5,660 2.3 14.1 11.7 FL N Fishless Fishless Fishless Thornton, Lower M-20-01 W 4,486 55.1 108.3 12.2 M L Fish-low density Fish-low density Fishless Thornton, Middle M-19-01 W 4,700 11.9 78.7 8.2 S L Fish-low density Fish-low density Fishless Thunder RD-02-01 W 1,350 6.8 24.6 15.3 FL N Fishless Fishless Fishless Tiny MC-15-01 W 6,100 0.3 6.0 17.0 FL N Fishless Fishless Fishless Torment ML-03-01 W 6,560 3.6 49.9 8.0 S L Fish-low density Fishless Fishless Trappera GM-01-01 E 4,165 147.2 160.8 14.1 R H Fish-high density Fish-low density Fishless Triplet, Lower SM-02-01 E 6,331 2.2 7.2 17.5 R H Fish-high density Fish-low density Fish-low density Triplet, Upper SM-02-02 E 6,551 2.3 12.5 19.7 R H Fish-high density Fishless Fishless Triumph M-17-01 W 3,685 4.3 20.5 17.1 S L Fish-low density Fish-low density Fishless Unnamed FP-01-01 W 5,140 13.5 — — FL N Fishless Fishless Fishless Unnamed MR-11-01 E 6,111 2.9 28.9 14.6 S L Fish-low density Fish-low density Fish-low density 
TABLE G-2: ASSESSMENT OF IMPACTS ON MACROINVERTEBRATES E (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT 

 Management Action Fish Densities 

Lake Name 

NPS Lake 

Code Zone 

Elevation 

(ft) 

Surface 

Area 

(acres) 

Max. Depth 

(ft) 

Water Temp 

(°C) 

Fish 

Status 

Fish 

Density Alternative A Alternative B Alternative C 

Unnamed MR-16-01 E 6,230 1.9 6.6 — R L Fish-low density Fish-low density Fish-low density Vulcan ML-04-01 W 5,180 8.2 25.2 10.7 FL N Fishless Fishless Fishless Wilcox/Lillie, Upper EP-06-01 W 5,136 10.5 65.0 14.5 R H Fish-high density Fishless Fishless Wilcox/Sandie, Lower EP-05-01 W 5,120 5.4 19.7 13.5 R H Fish-high density Fish-low density Fishless Wild MC-27-01 W 4,880 12.7 28.9 10.1 FL N Fishless Fishless Fishless Willow HM-04-01 W 2,853 16.9 26.9 19.5 S L Fish-low density Fish-low density Fish-low density 

Notes: Zone: E = East side of Cascade Crest  W = West side of Cascade Crest Fish Status: S = Stocked  S* = Stocked with reproducing fish. Limited reproduction in the past – needs verification. 

 R = Reproducing  M = Mixed reproducing and stocked  NF = No fish (historically stocked)  FL = No fish (historically fishless) Fish Density: VH = Very high density of reproducing trout (> 220 fish/acre), typically brook trout.  H = Reproducing trout at >100 fish/acre, or reported high density trout population with poor condition index or high reproductive rate.  M = Reproducing population with documented density of 50 to 100 fish/acre or reported reproducing population with good numbers, size, growth, and condition factor.  L = Stocked population < 100 fish/acre or reproducing population < 50 fish.  N = No fish present. Impacts:  See table 31 for impact thresholds. a. The feasibility of complete removal of fish in these lakes would need to be evaluated. b. In August 2004, a large fish kill was observed in Copper Lake, possibly due to disease. Further surveys are needed to confirm that the lake is fishless. 

c. Remove all reproducing fish from Hanging Lake pending agreement with British Columbia. 
ENVIRONMENTAL IMPACT STATEMENT 

TABLE G-4: ASSESSMENT OF IMPACTS ON AMPHIBIANS

Management Action Fish Densities 

Lake Name 

NPS Lake 

Code Zone 

Index of 

Connectivity 

Within Range 

of Distribution 

LTS NWS 

Fish 

Density TKN > 0.045 mg/L Alternative A Alternative B Alternative C Alt

Azure MP-09-01 W — — N — Fishless Fishless Fishless FishlesBattalion MLY-02-01 E 0.0 X H N Fish-high density Fishless Fishless FishlesBeara MC-12-01 W — — H N Fish-high density Fish-low density Fishless FishlesBerdeena M-08-01 W — — H — Fish-high density Fish-low density Fishless FishlesBerdeen, Lower M-07-01 W 0.4 X H N Fish-high density Fishless Fishless FishlesBerdeen, Upper M-09-01 W — — H — Fish-high density Fishless Fishless FishlesBlum (Largest/Middle, No. 3) M-11-01 W 0.3 X H U Fish-high density Fishless Fishless FishlesBlum (Lower/West, No. 4) LS-07-01 W 0.2 X VH N Fish-high density Fish-low density Fishless FishlesBlum (Small/North, No. 2) MC-01-01 W 0.3 X N Y Fishless Fishless Fishless FishlesBlum (Vista/Northwest, No. 1) 

MC-02-01 W 0.3 X N N Fishless Fishless Fishless Fishles

Bouck, Lower DD-04-01 W — — X H — Fish-high density Fish-low density Fish-low density FishlesBouck, Upper DD-05-01 W 0.2 X L Y Fish-low density Fishless Fishless FishlesBowan MR-12-01 E 0.4 X L Y Fish-low density Fishless Fishless FishlesCoon MM-10-01 E -0.2 X L Y Fish-low density Fish-low density Fish-low density FishlesCopperb MC-06-01 W -1.4 X L N Fish-low density Fishless Fishless FishlesDagger MR-04-01 E 0.5 X H Y Fish-high density Fishless Fishless FishlesDee Dee, Upper MR-15-01 E 0.2 X H N Fish-high density Fishless Fishless FishlesDee Dee/Tamarack, Lower MR-15-02 E 0.2 X L N Fish-low density Fishless Fishless FishlesDespair, Lower M-14-01 W — — N — Fishless Fishless Fishless FishlesDespair, Upper M-13-01 W — — N — Fishless Fishless Fishless FishlesDiobsud No. 1 LS-01-01 W 0.4 — X H Y Fish-high density Fishless Fishless FishlesDiobsud No. 2, Lower LS-02-01 W 0.5 X H Y Fish-high density Fishless Fishless FishlesDiobsud No. 3, Upper LS-03-01 W 0.5 X L Y Fish-low density Fishless Fishless FishlesDoubtful CP-01-01 E — — H N Fish-high density Fish-low density Fishless FishlesDoug's Tarn M-21-01 W — — H N Fish-high density Fish-low density Fishless FishlesEast, Lower MC-14-02 W — — N — Fishless Fishless Fishless FishlesEast, Upper MC-14-01 W — — N — Fishless Fishless Fishless FishlesFirn MP-02-01 W — — L — Fish-low density Fish-low density Fishless FishlesGreena M-04-01 W 0.4 X H U Fish-high density Fishless Fishless FishlesGreen Bench LS-04-01 W — — N — Fishless Fishless Fishless FishlesHanginga,c MC-08-01 W NA X H U Fish-high density Fishless Fishless FishlesHiddena SB-01-01 W — — L — Fish-low density Fish-low density Fishless FishlesHidden Lake Tarn EP-14-01 W — — L — Fish-low density Fishless Fishless FishlesHi-Yu M-01-01 W 0.2 X L Y Fish-low density Fishless Fishless FishlesHozomeena HM-02-01 W — — X VH Y Fish-high density Fishless Fishless FishlesIpsoot LS-06-01 W 0.3 X L U Fish-low density Fish-low density Fishless FishlesJeanita DD-01-01 W -0.5 X L Y Fish-low density Fish-low density Fishless FishlesKettling MR-05-01 E 0.5 X H Y Fish-high density Fishless Fishless FishlesKwahnesum MC-07-01 W -0.9 X L Y Fish-low density Fishless Fishless FishlesMcAlester MR-10-01 E 0.7 X H Y Fish-high density Fishless Fishless FishlesMiddle, Lower MC-16-02 W — N — Fishless Fishless Fishless Fishles
TABLE G-4: ASSESSMENT OF IMPACTS ON AMPHIBIANS (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT 

Management Action Fish Densities 

Lake Name 

NPS Lake 

Code Zone 

Index of 

Connectivity 

Within Range 

of Distribution 

LTS NWS 

Fish 

Density TKN > 0.045 mg/L Alternative A Alternative B Alternative C Alt

Middle, Upper MC-16-01 W — N — Fishless Fishless Fishless FishlesMonograma M-23-01 W 0.9 X H N Fish-high density Fish-low density Fishless FishlesMonogram Tarn M-23-11 W 0.8 X L U Fish-low density Fishless Fishless FishlesNert M-05-01 W 0.2 X L Y Fish-low density Fishless Fishless FishlesNoisy Creek, Upper LS-14-01 W — X N — Fishless Fishless Fishless FishlesNo Name PM-01-01 W — L N Fish-low density Fish-low density Fishless FishlesPanther Potholes, Lower RD-05-02 W — X L Y Fish-low density Fishless Fishless FishlesPanther Potholes, Upper RD-05-01 W — X N Y Fishless Fishless Fishless FishlesPegasus EP-10-01 W — N — Fishless Fishless Fishless FishlesPond SE of Kettling Lakes MR-09-01 E 0.7 X L N Fish-low density Fish-low density Fish-low density FishlesQuill, Lower M-24-02 W 0.0 X L U Fish-low density Fishless Fishless FishlesQuill, Upper M-24-01 W 0.0 X L U Fish-low density Fishless Fishless FishlesRainbow MR-14-01 E 0.5 X H Y Fish-high density Fish-low density Fish-low density FishlesRainbow, Upper (North) MR-13-01 E 0.4 X N Y Fishless Fishless Fishless FishlesRainbow, Upper (South) MR-13-02 E 0.4 X L N Fish-low density Fishless Fishless FishlesRainbow, Upper (West) MM-11-01 E — L N Fish-low density Fishless Fishless FishlesRedoubt MC-11-01 W — N Y Fishless Fishless Fishless FishlesReveille, Lower MC-21-02 W — N N Fishless Fishless Fishless FishlesReveille, Upper MC-21-01 W — N N Fishless Fishless Fishless FishlesRidley HM-03-01 W — X L Y Fish-low density Fish-low density Fish-low density FishlesSky EP-13-01 W — N — Fishless Fishless Fishless FishlesSkymo PM-03-01 W 0.5 X H N Fish-high density Fish-low density Fishless FishlesSourdough PM-12-01 W -0.5 X VH U Fish-high density Fishless Fishless FishlesSourpuss ML-01-01 W — N N Fishless Fishless Fishless FishlesStiletto MR-01-01 E — L Y Fish-low density Fishless Fishless FishlesStouta EP-09-02 W — L — Fish-low density Fish-low density Fishless FishlesStout, Lower EP-09-01 W — L N Fish-low density Fish-low density Fishless FishlesSweet Pea ML-02-01 W — L N Fish-low density Fish-low density Fishless FishlesTalus Tarn M-06-01 W 0.2 X N N Fishless Fishless Fishless FishlesTapto, Lower MC-17-03 W — N — Fishless Fishless Fishless FishlesTapto, Middle MC-17-02 W — N N Fishless Fishless Fishless FishlesTapto, Upper MC-17-01 W — N N Fishless Fishless Fishless FishlesTapto, West MC-17-04 W — N N Fishless Fishless Fishless FishlesThornton, Lower M-20-01 W -0.3 X L Y Fish-low density Fish-low density Fishless FishlesThornton, Middle M-19-01 W — L N Fish-low density Fish-low density Fishless FishlesThunder RD-02-01 W — X N Y Fishless Fishless Fishless FishlesTiny MC-15-01 W — N — Fishless Fishless Fishless FishlesTorment ML-03-01 W — L N Fish-low density Fishless Fishless FishlesTrappera GM-01-01 E — H N Fish-high density Fish-low density Fishless FishlesTriplet, Lower SM-02-01 E -0.2 X H Y Fish-high density Fish-low density Fish-low density FishlesTriplet, Upper SM-02-02 E — H N Fish-high density Fishless Fishless FishlesTriumph M-17-01 W 0.0 X L U Fish-low density Fish-low density Fishless FishlesUnnamed FP-01-01 W — N — Fishless Fishless Fishless Fishles
TABLE G-4: ASSESSMENT OF IMPACTS ON AMPHIBIANS (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT 

Management Action Fish Densities 

Lake Name 

NPS Lake 

Code Zone 

Index of 

Connectivity 

Within Range 

of Distribution 

LTS NWS 

Fish 

Density TKN > 0.045 mg/L Alternative A Alternative B Alternative C Alt

Unnamed MR-11-01 E 0.4 X L Y Fish-low density Fish-low density Fish-low density FishlesUnnamed MR-16-01 E 0.2 X L Y Fish-low density Fish-low density Fish-low density FishlesVulcan ML-04-01 W — N N Fishless Fishless Fishless FishlesWilcox/Lillie, Upper EP-06-01 W — H N Fish-high density Fishless Fishless FishlesWilcox/Sandie, Lower EP-05-01 W — H N Fish-high density Fish-low density Fishless FishlesWild MC-27-01 W — N N Fishless Fishless Fishless FishlesWillow HM-04-01 W — X L Y Fish-low density Fish-low density Fish-low density Fishles

Notes: Zone: E = East side of Cascade Crest  W = West side of Cascade Crest Index of Connectivity: An Index of Connectivity (IOC) based on weighted calculations of potential salamander breeding lake (lakes within range of salamander distribution and having appropriate habbreeding Lakes within 6 km (maximum colonization distance) of target lake, and number of potential salamander lakes with 0.6 km (maximum dispersal distance) of target lake. Lakes with an IOC = 0.7–0.9 

0–0.3 have poor connectivity, and lakes with an IOC of < 0.0 can be considered isolated. Dash (-) indicates outside the range of long-toed salamanders (LTS) and TKN not determined.

Fish Density: H or High = > 50 trout/acre of reproducing trout or > 100 trout/acre of stocked trout; L or Low = < 50 trout/acre of reproducing trout or ≤ 100 trout/acre of stocked trout, with a total fish density 

Within Range of Distribution: X - lake is within distribution range of long-toed salamander (LTS) or Northwestern salamander (NWS) and has suitable aquatic and terrestrial habitat for all life stages. TKN ≥ 0.045 mg/l: (Total Kjeldahl Nitrogen) Y =Yes, TKN ≥0.045 mg/L; N = No, TKN <0.045 mg/L. U = unknown concentration. Dash = outside range of salamanders. 

Fishless: Initial management action would result in a fishless lake. Depending upon the results of further evaluation, the lake may be stocked with a low density of trout. 

Level of Impact: See table 31 for impact thresholds. Where a (1) follows a Negligible impact determination, additional evaluation or management actions may result in a Minor impact. Where a (1) follows 

of an absence of data for one or more factors (e.g., IOC is unknown), and additional evaluation or management actions may result in a reduction of the impact by one level (e.g., reduce Major to Moderate). 

a. The feasibility of complete fish removal in these lakes would need to be evaluated. b. In August 2004, a large fish kill was observed in Copper Lake, possibly due to disease. Further surveys are needed to confirm that the lake is fishless. c. Remove all reproducing fish from Hanging Lake pending agreement with British Columbia. 
ENVIRONMENTAL IMPACT STATEMENT 

TABLE G-5: ASSESSMENT OF IMPACTS ON NATIVE FISH 

Trout Present, 

Historically Present, or Scheduled for Stocking in Lake Management Action 

Drainage 

Basin 

NPS Lake 

Code Lake Name 

Side of 

Cascade 

Crest 

Surface 

Inlet or 

Outlet 

Brook Trout 

Westslope 

Cutthroat 

Coastal 

Cutthroat 

Yellowstone 

Cutthroat 

Rainbow/ 

Cutthroat 

Hybrids

Rainbow 

Trout 

Mt. Whitney 

Rainbow 

Ross Lake 

Rainbow 

Rainbow 

Subspecies Alternative A Alternative B Alternati

Skagit MP-09-01 Azure W Yes Fishless Fishless Fishless Stehekin MLY-02-01 Battalion E Yes X X Fish-high density Fishless Fishless Chilliwack MC-12-01 Beara W Yes X * Fish-high density fish-low density Fishless Skagit M-08-01 Berdeena W Yes X X Fish-high density Fish –low density Fishless Skagit M-07-01 Berdeen, Lower W Yes X Fish-high density Fishless Fishless Skagit M-09-01 Berdeen, Upper W Yes X Fish-high density Fishless Fishless Baker M-11-01 Blum (Largest/Middle, 

No. 3) 

W Yes X * Fish-high density Fishless Fishless 

Baker LS-07-01 Blum (Lower/West, No. 4) W Yes X X Fish-high density Fish-low density Fishless Baker MC-01-01 Blum (Small/North, No. 2) W No Fishless Fishless Fishless Baker MC-02-01 Blum (Vista/Northwest, 

No. 1) 

W No Fishless Fishless Fishless 

Skagit DD-04-01 Bouck, Lower W Yes X X Fish-high density Fish-low density Fish-low deSkagit DD-05-01 Bouck, Upper W Yes X Fish-low density Fishless Fishless Stehekin MR-12-01 Bowan E Yes X Fish-low density Fishless Fishless Stehekin MM-10-01 Coon E Yes X Fish-low density Fish-low density Fish-low deChilliwack MC-06-01 Copperb W Yes X * Fish-low density Fishless Fishless Stehekin MR-04-01 Dagger E Yes X Fish-high density Fishless Fishless Stehekin MR-15-01 Dee Dee, Upper E Yes X * Fish-high density Fishless Fishless Stehekin MR-15-02 Dee Dee/Tamarack, Lower E Yes X Fish-low density Fishless Fishless Skagit M-14-01 Despair, Lower W Yes Fishless Fishless Fishless Skagit M-13-01 Despair, Upper W Yes Fishless Fishless Fishless Skagit LS-01-01 Diobsud No. 1 W Yes X Fish-high density Fishless Fishless Skagit LS-02-01 Diobsud No. 2, Lower W Yes X * Fish-high density Fishless Fishless Skagit LS-03-01 Diobsud No. 3, Upper W Yes X Fish-low density Fishless Fishless Stehekin CP-01-01 Doubtful E Yes X X X Fish-high density Fish-low density Fishless Skagit M-21-01 Doug's Tarn W Yes X Fish-high density Fish-low density Fishless Ross MC-14-02 East, Lower W Yes Fishless Fishless Fishless Ross MC-14-01 East, Upper W Yes Fishless Fishless Fishless Ross MP-02-01 Firn W Yes X * Fish-low density Fish-low density Fishless Skagit M-04-01 Greena W Yes X X X * Fish-high density Fishless Fishless Skagit LS-04-01 Green Bench W No Fishless Fishless Fishless Chilliwack MC-08-01 Hanginga,c W Yes X Fish-high density Fishless Fishless Skagit SB-01-01 Hiddena W Yes X X X Fish-low density Fish-low density Fishless Skagit EP-14-01 Hidden Lake Tarn W Yes X Fish-low density Fishless Fishless Skagit M-01-01 Hi-Yu W No X Fish-low density Fishless Fishless Ross HM-02-01 Hozomeena W Yes X Fish-high density Fishless Fishless Baker LS-06-01 Ipsoot W No X Fish-low density Fish-low density Fishless Skagit DD-01-01 Jeanita W Yes X Fish-low density Fish-low density Fishless 
TABLE G-5: ASSESSMENT OF IMPACTS ON NATIVE FISH (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT 

Trout Present, 

Historically Present, or Scheduled for Stocking in Lake Management Action 

Drainage 

Basin 

NPS Lake 

Code Lake Name 

Side of 

Cascade 

Crest 

Surface 

Inlet or 

Outlet 

Brook Trout 

Westslope 

Cutthroat 

Coastal 

Cutthroat 

Yellowstone 

Cutthroat 

Rainbow/ 

Cutthroat 

Hybrids

Rainbow 

Trout 

Mt. Whitney 

Rainbow 

Ross Lake 

Rainbow 

Rainbow 

Subspecies Alternative A Alternative B Alternati

Stehekin MR-05-01 Kettling E Yes X X X X Fish-high density Fishless Fishless Chilliwack MC-07-01 Kwahnesum W Yes X Fish-low density Fishless Fishless Stehekin MR-10-01 McAlester E Yes Fish-high density Fishless Fishless Ross MC-16-02 Middle, Lower W Yes Fishless Fishless Fishless Ross MC-16-01 Middle, Upper W Yes Fishless Fishless Fishless Skagit M-23-01 Monograma W Yes X X Fish-high density Fish-low density Fishless Skagit M-23-11 Monogram Tarn W No X Fish-low density Fishless Fishless Baker M-05-01 Nert W Yes X Fish-low density Fishless Fishless Baker LS-14-01 Noisy Creek, Upper W No Fishless Fishless Fishless Ross PM-01-01 No Name W Yes X Fish-low density Fish-low density Fishless Skagit RD-05-02 Panther Potholes, Lower W No X Fish-low density Fishless Fishless Skagit RD-05-01 Panther Potholes, Upper W No Fishless Fishless Fishless Skagit EP-10-01 Pegasus W Yes Fishless Fishless Fishless Stehekin MR-09-01 Pond SE of Kettling Lakes E No X Fish-low density Fish-low density Fish-low deSkagit M-24-02 Quill, Lower W No X X Fish-low density Fishless Fishless Skagit M-24-01 Quill, Upper W No X X Fish-low density Fishless Fishless Stehekin MR-14-01 Rainbow E Yes X X Fish-high density Fish-low density Fish-low deStehekin MR-13-01 Rainbow, Upper (North) E Yes Fishless Fishless Fishless Stehekin MR-13-02 Rainbow, Upper (South) E Yes X Fish-low density Fishless Fishless Stehekin MM-11-01 Rainbow, Upper (West) E Yes X Fish-low density Fishless Fishless Chilliwack MC-11-01 Redoubt W Yes Fishless Fishless Fishless Chilliwack MC-21-02 Reveille, Lower W Yes Fishless Fishless Fishless Chilliwack MC-21-01 Reveille, Upper W Yes Fishless Fishless Fishless Ross HM-03-01 Ridley W Yes X X Fish-low density Fish-low density Fish-low deSkagit EP-13-01 Sky W Yes Fishless Fishless Fishless Ross PM-03-01 Skymo W Yes X X Fish-high density Fish-low density Fishless Ross PM-12-01 Sourdough W Yes X X Fish-high density Fishless Fishless Ross ML-01-01 Sourpuss W Yes Fishless Fishless Fishless Stehekin MR-01-01 Stiletto E Yes X Fish-low density Fishless Fishless Skagit EP-09-02 Stouta W Yes X X Fish-low density Fish-low density Fishless Skagit EP-09-01 Stout, Lower W Yes X * Fish-low density Fish-low density Fishless Ross ML-02-01 Sweet Pea W Yes X Fish-low density Fish-low density Fishless Skagit M-06-01 Talus Tarn W Yes X Fishless Fishless Fishless Chilliwack MC-17-03 Tapto, Lower W Yes Fishless Fishless Fishless Chilliwack MC-17-02 Tapto, Middle W Yes Fishless Fishless Fishless Chilliwack MC-17-01 Tapto, Upper W Yes Fishless Fishless Fishless Chilliwack MC-17-04 Tapto, West W Yes Fishless Fishless Fishless Skagit M-20-01 Thornton, Lower W Yes X X Fish-low density Fish-low density Fishless Skagit M-19-01 Thornton, Middle W Yes X X Fish-low density Fish-low density Fishless Skagit RD-02-01 Thunder W No Fishless Fishless Fishless 
TABLE G-5: ASSESSMENT OF IMPACTS ON NATIVE FISH (CONTINUED)

ENVIRONMENTAL IMPACT STATEMENT 

Trout Present, 

Historically Present, or Scheduled for Stocking in Lake Management Action 

Drainage 

Basin 

NPS Lake 

Code Lake Name 

Side of 

Cascade 

Crest 

Surface 

Inlet or 

Outlet 

Brook Trout 

Westslope 

Cutthroat 

Coastal 

Cutthroat 

Yellowstone 

Cutthroat 

Rainbow/ 

Cutthroat 

Hybrids

Rainbow 

Trout 

Mt. Whitney 

Rainbow 

Ross Lake 

Rainbow 

Rainbow 

Subspecies Alternative A Alternative B Alternati

Ross MC-15-01 Tiny W Yes Fishless Fishless Fishless Ross ML-03-01 Torment W Yes X Fish-low density Fishless Fishless Stehekin GM-01-01 Trappera E Yes X * Fish-low density Fish-low density Fishless Stehekin SM-02-01 Triplet, Lower E Yes X X Fish-high density Fish-low density Fish-low deStehekin SM-02-02 Triplet, Upper E Yes X Fish-high density Fishless Fishless Skagit M-17-01 Triumph W Yes X Fish-low density Fish-low density Fishless Skagit FP-01-01 Unnamed W Yes Fishless Fishless Fishless Stehekin MR-11-01 Unnamed E Yes X Fish-low density Fish-low density Fish-low deStehekin MR-16-01 Unnamed E Yes X * Fish-low density Fish-low density Fish-low deSkagit ML-04-01 Vulcan W Yes Fishless Fishless Fishless Skagit EP-06-01 Wilcox/Lillie, Upper W Yes X X X Fish-high density Fishless Fishless Skagit EP-05-01 Wilcox/Sandie, Lower W Yes X X X Fish-high density Fish-low density Fishless Skagit MC-27-01 Wild W Yes Fishless Fishless Fishless Ross HM-04-01 Willow W Yes X Fish-low density Fish-low density Fish-low de

Notes:Trout Present or Scheduled for Stocking in Lake: There are 9 columns for the 9 species, subspecies, or strains of trout reproducing, stocked, or currently scheduled to be stocked in mountain lakes. M

evaluation, stocking nonreproductive trout at low densities to replace or supplement current populations of trout. These lakes are indicated with an asterisk (*) under the column for Mt. Whitney Rainbow, w

Level of Impact: Refer to table 31 in the “Environmental Consequences” chapter. a. The feasibility of complete removal of fish in these lakes would need to be evaluated. b. In August 2004, a large fish kill was observed in Copper Lake, possibly due to disease. Further surveys are needed to confirm that the lake is fishless. 

c. Remove all reproducing fish from Hanging Lake pending agreement with British Columbia. 
Appendix G

ENVIRONMENTAL IMPACT STATEMENT 247

REFERENCES 

CITED IN APPENDIX G 

Adams, S.B., C.F. Frissell, and B.E. Reiman 

2001 “Geography of invasion in mountain streams: Consequences of headwater lake fish introductions.” 

Ecosystems 4(4):296-307. 

Aubry, K.B. and P.A. Hall 

1991 “Terrestrial amphibian communities in the southern Washington Cascade Range.” Wildlife and 

vegetation of unmanaged Douglas-fir forests. L.F. Ruggiero, K.B. Aubry, A.B. Carey, M.H. Huff 

eds. U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, General 

Technical Report PNW-GTR-285, Portland, OR. 

Behnke, R.J. 

1992 Native trout of western North America. Monograph 6. American Fisheries Society, Bethesda, MD. 

Bilton, D.T., J.R. Freeland, and B. Okamura 

2001 “Dispersal in freshwater invertebrates.” Annual review of Ecology and Systematics 32:159-181. 

Bohonak, A.J., and D.G. Jenkins 

2003 Ecological and evolutionary significance of dispersal by freshwater invertebrates. Ecol. Letters 6: 

783-796. 

Brett, M.T., K. Wiackowski, F.S. Lubnow, A. Mueller-Solger, J.J. Elser, and C.R. Goldman 

1994 “Species-dependent effects of zooplankton on planktonic ecosystem processes in Castle Lake, 

California.” Ecology 76:2243-2254. 

Chess, D.W., F. Gibson, A.T. Scholz, and R.J. White 

1993 “The introduction of lahontan cutthroat trout into a previously fishless lake: feeding habits and 

effects upon the zooplankton and benthic community.” Journal of Freshwater Ecology 8:215-225. 

Donald, D.B, R.D. Vinebrooke, R.S. Anderson, J. Syrgiannis, and M.D. Graham 

2001 “Recovery of zooplankton assemblages in mountain lakes from the effects of introduced sport 

fish.” Canadian Journal of Fisheries and Aquatic Sciences 58:1822-1830. 

Donald, D.B., R.S. Anderson, and D.W. Mayhood 

1994 “Coexistence of fish and large Hesperodiaptomus species (Crustacea: Calanoida) in subalpine and 

alpine lakes.” Canadian Journal of Zoology 72:259-261. 

Drake, D.C. and R.J. Naiman 

2000 “An evaluation of restoration efforts in fishless lakes stocked with exotic trout.” Conservation 

Biology 14(6):1807-1820. 

Dvornich, K.M., K.R. McAllister, and K.B. Aubry 

1997 Amphibians and reptiles of Washington State: Location data and predicted distributions, Volume 2 

in Washington State Gap Analysis - Final Report, (K.M. Cassidy, C.E. Grue, M.R. Smith and 

K.M. Dvornich, eds.), Washington Cooperative Fish and Wildlife Research Unit, University of 

Washington, Seattle. 146 pp. 

Elser, J.J., C. Luecke, M.T. Brett, and C.R. Goldman 

1995 “Effects of food web compensation after manipulation of rainbow trout in an oligotrophic lake.” 

Ecology 76:52-69. 
A PPENDIXES

248 DRAFT MOUNTAIN LAKES FISHERY MANAGEMENT PLAN

Hoffman, R.L. and G.L. Larson 

1999 “Ambystoma gracile (northwestern salamander). Predation and Cannibalism.” Natural History 

notes in Herpetological Review 30(3):159. 

Hoffman, R.L., G.L. Larson, and B.J. Brokes 

2003 “Habitat segregation of Ambystoma gracile and Ambystoma macrodactylum in mountain ponds 

and lakes, Mount Rainier National Park, Washington, USA.” Journal of Herpetology 37(1):24-34. 

Knapp R.A. 

1996 “Non-Native Trout in Natural Lakes of the Sierra Nevada: An Analysis of Their Distribution and 

Impacts on Native Aquatic Biota”. Chapter 8 in, Sierra Nevada Ecosystem Project: Final Report 

to Congress, Vol. II, Assessments and scientific basis for management options. University of 

California, Davis, Centers for Water and Wildland Resources. 

Leavitt, P.R., D.E. Schindler, A.J. Paul, A.K. Hardie, and D.W. Schindler 

1994 “Fossil pigment records of phytoplankton in trout-stocked alpine lakes.” Canadian Journal of 

Fisheries and Aquatic Sciences 51:2411-2423. 

Liss, W.J., G.L. Larson, E.K. Deimling, R. Gresswell, R. Hoffman, M. Kiss, G. Lomnicky, C.D. McIntire, R. Truitt, 

and T. Tyler 

1995 Ecological Effects of Stocked Trout in Naturally Fishless High Mountain Lakes: North Cascades 

National Park Service Complex, WA, USA. Technical Report NPS/PNROSU/NRTR-95-03. USDI 

National Park Service, Pacific Northwest Region, Science and Technology. Seattle, WA. 285 pp. 

Liss, W.J., G.L. Larson, and R.L. Hoffman, eds. 

2002 Ecological Impact of Introduced Trout on Native Aquatic Communities in Mountain Lakes: 

Phase III Final Report. Prepared for the USDI National Park Service, Pacific Northwest Region, 

North Cascades National Park Service Complex by USGS Forest and Rangeland Ecosystem 

Science Center. Corvallis, OR. 102 pp. 

Liss, W.J., G.L. Larson, T.J. Tyler, L. Ganio, R. Hoffman, E.A. Deimling, G. Lomnicky, C.D. McIntire, and 

R. Truitt 

1999 Ecological Effects of Stocked Trout in Naturally Fishless High Mountain Lakes: North Cascades 

National Park Service Complex, WA, USA: Phase II. Technical Report NPS/CCSSOOSU/NRTR98/01. USDI National Park Service, Pacific Northwest Region, Science and Technology. Seattle, 

WA. 133 pp. 

Luecke, C. 

1990 “Changes in abundance and distribution of benthic macroinvertebrates after introduction of 

cutthroat trout into a previously fishless lake.” Transactions of the American Fisheries Society

119:1010-1021. 

Marnell, L.F. 

1997 “Herpetofauna of Glacier National Park.” Northwestern Naturalist 78:17-33. 

Parker, B.R., D.W. Schindler, D.B. Donald, and R.S. Anderson 

2001 “The effects of stocking and removal of a nonnative salmonid on the plankton of an alpine lake.” 

Ecosystems 2001(4):334-345. 

Parker, B.R., F.M. Wilhelm, and D.W. Schindler 

1996 “Recovery of Hesperodiaptomus arcticus populations from diapausing eggs following elimination 

by stocked salmonids.” Canadian Journal of Zoology 74:1292-1297. 

Petranka, J.W. 

1998 Salamanders of the United States and Canada. Smithsonian Institution Press, Washington, DC. 
Appendix G

ENVIRONMENTAL IMPACT STATEMENT 249

Semlitsch, R.D. 

1983 “Burrowing ability and behavior of salamanders of the genus Ambystoma.” Canadian Journal of 

Zoology 61: 616-620. 

Verschuren, D., and L.F. Marnell 

1997 Fossil zooplankton and the historical status of Westslope cutthroat trout in a headwater lake of 

Glacier National Park. Trans. Amer. Fish. Soc. 126(1): 21-34. 

Walters, C.J. and R.E. Vincent 

1973 “Potential productivity of an alpine lake as indicated by removal and reintroduction of fish.” 

Transactions of the American Fisheries Society 102:675-697.