Biology and Management of Threatened and Endangered Western Trouts

Home , Gila trout, Paiute cutthroat trout, Trout Creek (Lake Tahoe)

August 1976 USDA Forest Service General Technical Report RM-28 Rocky Mountain Forest and Range Experiment Station Forest Service U.S. Department of Agriculture Fort Collins, Colorado 80521 Abstract

Behnke, R. J., and Mark Zarn. 1976. Biology and management of threatened and endangered western trouts. USDA For. Sew. Gen. Tech. Rep. RM-28, 45 p. Rocky Mt. For. and Range Exp. Stn., Fort Collins, Colo.

Discusses taxonomy, reasons for decline, life history and ecology, and sug- gestions for preservation and management of six closely related trouts native to western North America: Colorado River cutthroat, Salmo clarki pleuriticus; greenback trout, S. c. stomias; Lahontan cutthroat, S. c. henshawi; Paiute trout, S. c. seleniris; Gila trout, S. gilae; and Arizona native trout, S. apache. Meristic characters, distribution and status, habitat requirements and limiting factors, protective measures, and management recommendations are presented for each taxon.

Keywords: Native trout, Salrno clarki pleuriticus. Sali?zo ckurki stoi~zius. Sulnzo clarki herzshawi, Salmo clarki seleniris, Salrno gilue. Sulrno uprrchc. USDA Forest Service General Technical Report RM-28 August 1976

Biology and Management of Threatened and Endangered Western Trouts

R. J. Behnke Colorado State University

Mark Zarn Conservation Library Denver Public Library

Information reported here was prepared under contract by the Conservation Library of the Denver Public Library, through the Rocky Mountain Forest and Range Experiment Station. The report is printed as prepared by the authors; opinions are not necessarily those of the U.S. Forest Service. TABLE OF CONTENTS

I . GJ3NERAL MANAGEMENT GUIDELINES FOR RAE3 AND ENDANGJIRED WESTERN TROUTS Introduction ...... Taxonomy ...... Reasons for Decline ...... Life History and Ecology ...... Preservation. Restoration and Management Programs ...... Potential Role of Native Trout in Fisheries Management ...... Summary ...... Authorities ...... References ...... 11 . COLORADO RImR CUTTHROAT TROUT. Salmo clarki pleuriticus Typical Meristic Characteristics. * ...... Species Description ...... Distribution ...... Status and Population Trend ...... LifeHistory ...... Habitat Requirements and Limiting Factors ...... Protective Measures ...... Recommendations ...... Authorities ...... References ...... I11 . WNBACK CUTTHROAT TROUT. Salmo clarki s tomias Typical Meristic Characteristics...... Species Description ...... Distribution ...... Status and Population Trend ...... Life History ...... Habitat Requirements and Limiting Factors . . Protective Measures ...... Recommendations ...... Authorities ...... References ...... IV . LAHONTAN CUTTHROAT TROUT. Salmo clarki henshawi Typical Meristic Characteristics ...... Species Description ...... Distribution ...... Status and Population Trend ...... Life History ...... Habitat Requirements and Limiting Factors . . Protective Measures ...... Recommendations ...... Authorities ...... References ...... V . PAIUTE TROUT. SaLmo clarki seleniris Typical Meristic Characteristics ...... 32 Species Description ...... 32 Distribution ...... 33 Status and Population Trend ...... 33 Life History ...... 34 Habitat Requirements and Limiting Factors ...... 34 Protective Measures ...... 34 Recommendations ...... 34 Authorities ...... 35 References ...... 35 TABLE OF CONTENTS (CONT'D)

VI . GILA TROUT. Salmo ailae Typical Meristic Characteristics...... 36 Species Description ...... 36 Distribution ...... 38 Status and Population Trend ...... 39 Life History ...... 39 Habitat Requirements and Limiting Factors ...... 39 Protective Measures ...... Recommendations ...... Authorities ...... References ...... VII . ARIZONA NATIVE TROUT. Salmo apache Typical Meristic Characteristics . .... Species Description ...... Distribution ...... Status and Population Trend ...... Life History ...... Habitat Requirements and Limiting Factors Protective Measures ...... Recommendations ...... Authorities ...... References ...... BIOLOGY AND MANAGEMENT OF THREATENED AND ENDANGERED WESTERN TROUTS

occur with anadromous steelhead trout (5. gairdneri) does coexistence occur naturally This report discusses the biology and without hybridization. In all instances where management of six closely related trouts the rainbow trout has been established beyond native to western North America. All sharg its native range and stocked with Gila trout, many common ecological and genetic attributes; golden trout or any of the interior subspecies all have suffered catastrophic declines in of cutthroat trout, hybridization has invariably abundance due to essentially similar factors. resulted. The indiscriminate stocking of The folLowing section presents general in- untold millions of rainbow trout and several formation applicable to all of these trouts subspecies of cutthroat trout into virtually and relevant to any meaningful preservation, every habitable water throughout the West, and restoration and management efforts. Succeed- subsequent hybridization with the native trout ing chapters present more specific biological fauna, has been the primary cause for the and management considerations for each taxa. almost complete elimination of pure populations of most of the taxonomic categories of native trouts in the interior regions of the West.

Man still lacks complete knowledge of The presence of all degrees of hybridi- the evolutionary history which resulted in zation greatly confounds the work of correctly the diverse array of western North American identifying and evaluating the purity of exist- trouts of the genus Salmo. Earlier thought ing populations of native trout in most regions, considered that all western trouts either and the recognition of pure stocks of any of belonged to or recently derived from two the six trouts considered in this report is evolutionary lines or species: the rainbow not a simple matter. Although one can acquire trout, Salmo gairdneri, and the cutthroat sufficient familiarity with the subtle varia- trout, 2. clarki. Recent studies have demon- tions among the different species and sub- strated that the true situation is much more species of western trouts to distinguish the complex; several distinct groups including various taxa, the average field worker cannot the Gila trout (S-. gilae), Arizona native be expected to accurately differentiate the trout (5. apache), Mexican golden trout true native trout of a given area from hybrid (Salmo chrysogaster) , California golden trout populations. Taxonomic criteria exist for all (Salmo aguabonita) and redband trout (not the trouts in this report, but the sorting and officially named) do not fit the diagnosis of evaluation of specimens collected during survey either the rainbow trout or the cutthroat work to determine the status of a native trout trout and probably represent distinct evolu- and to locate pure populations remains an in- tionary lines of their own which sprang from volved process of detailed examination and a common ancestor to all western Salmo comparison of twr~ycharacters. (Behnke 1972b, Schreck and Behnke 1971, Miller 1972). So unless an agency is dealing with "certified" pure popqlations in a rare trout Despite such evolutionary diversity, all management program, it will ultimathll confront western trouts are closely related to the the problem of identification. Possibilities extent that they can interbreed freely with for additional refinement of information useful each other to produce fertile hybrids. Only in taxonomic identification exist; these in- in Pacific Coast rivers, where rainbow trout clude biochemical techniques such as protein and the coastal cutthroat, 5. c. clarki, electrophoresis and karyotype examination-- reside together and in the Salmon and Clear- the determination of chromosome number and water drainages of the Columbia River basin morphology. Yet the investigator should use of Idaho where resident interior cutthroat caution in utilizing these modern techniques to determine the relative purity of trout also favor the displacement of native trouts populations, for they require both a Icnowledge by more tolerant introduced species, notably of basic principles of taxonomy and a familiar- the brook trout (Salvelinus fontinalis) and ity with the natural range of variability of the brown trout (Salmo trutta). the trout under study. Often, if the extent of hybridization has reached a level where it Most pure native trout populations in can be detected by electrophoresis or altera- the interior regions of the West persist only tions in the chromosome compleaent, it will in small isolated headwater stream situations also show up in the form of changes in den- in essentially undisturbed habitat. tition, spotting pattern, scale counts and other morphological characters. LIFE HISTORY AND ECOLOGY The lack of reproductive isolation and the lack of clear-cut diagnostic features, All of our western trouts are highly has raised questions concerning the validity adaptable; they can live in a variety of of the recognized taxa of western trouts. environments ranging from small brooks to The most pertinent advice relevant to large rivers and lakes, and they feed on a management policies for any trout under con- broadrspectrum of organisms. This wide range sideration is to ignore or avoid questions of adaptability makes it highly misleading to concerning the validity of zoological nomen- base the ecological characteristics of an clature, while recognizing that each of these entire taxon on data taken from a population trouts is indeed an evolutionary reality. in a specific habitat. A11 trouts are oppor- That is, it has become an integral part of tunistic and eclectic in their diet, which the biological and evolutionary heritage of a essentially reflects the availability of food given geographical area as a result of its organisms in their particular environment. unique genetic programming under the natural Growth depends primarily on food availability, selection which has taken place during its size of prey, the degree of intraspecific and long isolation and divergence from ancestral interspecific competition, water temperatures, trout fauna. All of the six taxa of trout and the length of the growing season. Fecundity, discussed in this report fall within the in turn, depends on size. The life history province of the Endangered Species Act of and ecological traits of two neighboring popu- 1973 (P.L. 93-205) which defines a species to lations of the same subspecies living in dis- include "subspecies, smaller taxa or any tinctly different environments will differ population segment thereof ." Thus, the much more from each other than from those of validity of a species or subspecies should different trout species living in essentially not obstruct protective measures for a rare similar environments. One must be aware that trout; the major consideration ought to be different genotypes allow for a broad and that the trout represents a segment of a labile range of ecological options; to assume species indigenous to a particular geographi- that specific food habits, growth rate, cal area. fecundity or other characteristics of a given population under study represent genetic- Behnke (1972a) and Trojnar and Behnke ally "fixed" attributes of the taxon as a (1974) have discussed the rationale and prac- whole is a misconception. The significance of tical value of preserving the remaining this point in relation to restoration efforts genetic diversity of our native western trouts. which aim to expand the range of a rare trout is that waters with potential for reintroduction need not closely match the conditions of the waters of the potential donor population. With the condition that no non-native trouts are REASONS FOR DECLINE present, virtually any waters suitable for any trout species can serve as suitable habitat We mentioned that the hybridization for any of the six trouts treated in this re- caused by massive introduction of rainbow port. One notable exception in adaptability trout and subspecies of cutthroat trout into to environmental extremes exists in the waters in which they were not native has led Lahontan cutthroat trout, which can tolerate to the virtual elimination of pure populations tremendous ranges in alkalinity and flourish of the trouts under discussion in this report. in waters such as Walker Lake, Nevada, under Habitat loss and degradation as a result of conditions lethal to all other trouts. irrigation projects, mining, logging, road building and overgrazing have also taken their A11 of the non-domesticated western toll, particularly in the arid regions of the trouts of the genus Salmo spawn in the spring; West. These factors have not only greatly increasing water temperatures trigger repro- reduced the amount of suitable habitat, but duction. Most spawning activity begins when water temperatures reach 5.5 - 9.0~C. Eleva- Cutthroat trout, and perhaps Gila trout tion and latitude also influencathe onset of and Arizona trout as well, suffer from a high which may occur as early as March or vulnerability to angling. In a small Idaho April in some areas and extend well into June stream, 32 man-hours of fishing removed 50 per- and July in others. The necessity of gravel cent of the cutthroat trout and only 25 percent for nest construction and high oxygen tensions of the brook trout 15 cm and over in length for the developing embryos makes all of the (McPhee 1966). In New Mexico the native trout trouts under consideration essentially obliga- of the Rio Chiquito dominated the introduced tory stream spawners. Fry emerge from nests brown trout by 420 to 37 in samples made in in early to mid-summer, depending on when 1965-1966, when the stream was on private spawning occurs; length of the growing season land and closed to fishing (Little and McKirdy dictates size, which reaches 2.5 to 7.5 cm 1968). In 1969, two years after the U. S. by autumn. Fish six to eight years old may Forest Service had acquired the Land and attain a length of less than 25 cm in small opened the stream to angling, sampling revealed streams with restricted habitats and dense that the ratio had been drastically reversed-- but in large rivers and lakes 137 brown trout versus 37 cutthroat trout-- can be rapid with trout reaching due to the differential vulnerability of the several pounds in weight by the fourth or two species to anglingu Management programs fifth year. The last spawning run, in 4938, for native trout can benefit from this angling of the native cutthroat of Pyramid Lake, vulnerability, however, by establishing Nevada, revealed an average weight of 9.0 kg special regulation catch-and-release fisheries, for spawning fish, most of which were seven or by restricting size and bag limits, as to eight years old (Sumner 1940); trout of discussed below (see pages 7-8). the same subspecies living in headwater streams may not exceed 25 cm in length. PRESERVATION, RESTORATION AND Sexual maturity typically occurs at an MANAGEMENT PROGRAMS age of two to four years. In small s trearn populations mature trout may only be 15 to It often seems difficult to initiate 20 cm in length and spawn only 100-200 eggs. meaningful rare trout restoration programs, A generalization on fecundity, with wide but while real problems and obstacles exist, individual variation, is that females will workers can overcome them if they develop a spawn about 1000 eggs per 450 gms of body set of priorities and goals and recommend that weight. specific actions be carried out. It remains a relatively simple matter to transplant trout Present populations of these trout prob- from a remnant population into new waters-- ably cannot persist in waters where maxilnum either barren or where all other fish have temperatures consistently exceed 21-22' C. been eliminated--in order to establish a new But they may possess tolerance to survive, population. under stress, brief daily periods of higher temperatures (25.5 - 26.7' C.) if the waters The first step in most restoration pro- significantly cool at night. The pattern of grams for rare, native trout--that of identi- replacement of native trouts by introduced fication--involves a survey and inventory of brook, brown and rainbow trout throughout the waters where there is a likelihood of encoun- interior West indicates that the native trouts tering pure populations. Remote and isolated prefer and function best at lower temperatures headwater areas, particularly above barrier than do other species. With few exceptions, falls and without tributary lakes (which serve native cutthroat trout coexist with and as popular target areas for introductions of dominate introduced species only in cold, exotic trouts) , offer the greatest potential headwater situations. Thus, clearcutting and for native trout population reserves. When overgrazing, which remove vegetative cover trout in such waters appear to resemble the and warm the waters, will favor the replace- diagnosis of the native trout, collect 10-20 ment of native trouts by other forms. specimens from each isolated site and preserve them in 10 percent formalin. In the field, In Oregon, after clearcutting of a water- wrap specimens in formalin-soaked cloth and shed, water temperatures increased due to inject formalin into the body cavity with a lack of cover, and dissolved oxygen in the hypodermic syringe. Comparative examination spawning gravel decreased due to siltation. of these collections can begin to identify This did not significantly affect the coho salmon population, but the cutthroat trout -'/ McKirdy, H. J. Rio Chiquito population populatioa suffered a decline of two-thirds survey. Carson National Forest memorandum. in number during six years of a follow-up 22 August 1969. study (Ringler and Hall 1975). those populations most closely conforming to live fish. Note that some barren headwater the diagnosis of the taxon involved. Graduate streams, particularly at high elevations, research thesis projects through universities appear to provide suitable habitat for trout can offer relatively efficient and economical in summer, but lack pools and cover sufficient means of handling survey and identification to successfully carry the fish through a hard worlc. Once researchers establish the relative winter. In these situations the trout migrate purity, distribution and abundance of the from the area and will not maintain a permanent native forms, those populations judged to be population (Bjornn 1971). Habitat improvement uncontaminated by hybridization can be given in headwater areas is feasible when it involves special consideration in land use decisions creating pools and cover to provide support and environmental impact analysis, and serve for a permenent fish population (Gard 1961, as a source for specimens for introductions to 1972). increase their abundance. Many more streams exist which support Unnecessary delays and procrastination introduced trouts or hybrids above a natural typically begin at this stage, when specific barrier; they too offer good possibilities for native populations have been identified. establishment of native trout populations with Many believe that they must initiate life minimal effort and expense. No doubt exists history and habitat studies before any manage- that these streams can support the transplanted ment decisions or transplants can take place. trout after the complete elimination of all The objectives are to gather detailed data on other fish. Use antimycin or rotenone in age, growth, food habits, fecundity and other small streams to completely kill all fish, life history characteristics of the trout taking care to treat all possible refuge areas population, and on the biological, physical such as backwater areas of beaver ponds and and chemical parameters of the waters in which spring seeps. The National Park Service used they live, with the idea that once this know- this technique in Rocky Mountain National Park ledge becomes available intelligent and scien- in eliminating the brook trout from Hidden tific management can begin. If the life Valley to re-establish the greenback cutthroat history characteristics of trout were genetic- trout. ally fixed traits, and if the environmental parameters measured composed a true reflection If no natural barrier exists on an other- of the limits for survival, this would be a wise suitable stream, it is possible to con- logical course of action; but in fact they struct an artificial barrier or to blast one are not. Such information usually has little out of a rock substrate. Follow barrier con- meaning when predicting the success of a struction with chemical treatment above the transplant into new waters, except where basic stream, to eliminate unwanted fishes, before information is needed to maintain an abundance the introduction of native trout. Workers of trout and a desirable age structure in a used this technique to re-establish greenback population exposed to exploitation in a trout in Black Hollow Creek, Colorado, and special regulations fishery program. Gila trout in McKnight Creek, New Mexico.

If a survey determines that pure popula- Another viable possibility in any rare tions of a native trout are rare and restricted trout reintroduction program is the establish- to a few isolated stocks, then first priority ment of populations in newly constructed lakes should be to effect transplants into new to establish a unique fishery under special waters within their native range, before regulations. Christmas Tree Lake on the natural or man-caused catastrophes can further Apache Indian Reservation, Arizona, stocked decimate the remnant stocks. After the estab- with Arizona native trout, serves as an lishment of populations in new waters, life example of this method. Lake populations history studies and environmental analyses offer an abundant and easily obtainable source can include both donor and recipient popula- of eggs for propagation, and can greatly tions and their environments. Such information facilitate new introductions. would have greater predictive value since it would offer more insight into the range of Some difficulties may exist in establish- adaptive responses of the trout under study. ing a new population from transplants of a few adult fish into a new environment, par- Naturally barren waters above barriers, ticularly in small headwater streams without which prevent mixing with introduced trouts, deep pools above a barrier. The natural ten- constitute ideal sites for establishing new dency of a displaced fish is to return to the populations. Such locations still exist, place of its origin, and most may soon migrate though they are rare. The expense and efforts downstream over the barrier. Trout movement of effecting a transplant of this nature in- is also more pronounced during periods of low volves only the collection and transport of or decreasing temperatures (Bjornn 1971). Once natural reproduction has occurred in the new construction of pools over the only adequate the success of the intsoduction deposits of spawning gravel in the stream. should be assured, barring some catastrophe. Diagnosis of specific problems in the stream leads to a prescription of, treatment methods Particularly in arid regions where streams and their sequence. Implement first those characteristically display intermittent summer treatments which have the greatest positive flows and lack suitable pools and cover, stream effect for the least expenditure of money and improvement devices can promote increased effort. A logical concluding step, but one abundance of trout by creating trout habitat that may be overlooked, consists of following where none previously existed. Stream improve- treatment with an orderly program of inspection ment devices often require a considerable and maintenance (White and Brynildson 1967). investment of money, time and labor, but the in the 1930's of such devices in Do not fail to consider either the Diamond Creek, New Mexico, by Civilian Con- fertility of the water or the year-round servation Corps personnel may have saved the carrying capacity of a stream which otherwise Gila trout in this stream from extinction appears to have potential for improvement. during subsequent drought years when virtually Habitat manipulation aimed at increasing the entire population was restricted to the cover in a stream will prove of little value pools created by the small dams. in providing more trout either if production is limited by a lack of nutrients or if the Successful stream habitat management carrying capacity of the stream is drastically improves living conditions in the waters and reduced at some season, as by freezing in increases survival, growth and reproduction winter or flooding in spring, thereby negating of trout. Good trout habitat provides shelter any effects of increased summer production from predators, fertile water, adequate living (White and Brynildson 1967). space, proper water temperature, and gravel in the streambed for spawning. Proper stream Protecting natural stream habitat best management, especially when it involves the guarantees the perpetuation of native trout construction of in-stream improvement devices, populations. The most significant habitat in is both relatively expensive and relatively small to moderate-sized streams consists of complicated, and remains a job for professionals undercut banks, which in turn depend on exten- who are both well-versed in fundamental trout sive vegetative cover of the exposed bank ecology and familiar with habitat management (Wesche 1973). Livestock overgrazing presents techniques. Every stream has its individual the greatesk threat to the integrity of head- problems and characteristics, and to proceed water stream habitat quality in the West. with habitat alteration projects to "improve" Grazing livestock may destroy the vegetative a stream without a thorough knowledge of cover and cave in overhanging banks, thereby available methods, the physical, chemical and eliminating the most important trout habitat. biological parameters of the waters in question, Loss of streambank vegetation leads to increased and the ecological characteristics of the water temperatures, erosion and silting, elimi- resident fish population, can do more harm nation of spawning sites and reduction of food than good. A habitat improvement team should supplies in the stream, all of which drastically consist of biologists skilled in habitat degrade trout habitat. development, technicians familiar with survey- ing and mapping techniques, and foremen Guidelines have been developed to minimize experienced in carpentry and mechanics (White damage to streams from logging, road building and Brynildson 1967). Space does not permit and mining operations; if they are conscien- a thorough discuss ion of habitat improvement tiously followed, good trout populations can techniques here; several excellent papers be maintained in watersheds subject to these exist to familiarize personnel with this uses. The major multiple-use problem yet to topic (see: Boreman 1974, Packer 1957, be adequately treated on National Resource Lands, Jester and McKirdy 1966, Gee 1952, Hunt 1969, however, is the impact of livestock grazing on White and Brynildson 1967, Jackson 1974). aquatic habitat. This problem is particularly acute in arid regions, where livestock often A survey of streams in an area to locate tend to concentrate in riparian vegetation along those having potential for improvement con- stream banks. Their impact on trout habitat stitutes the first step in an orderly manage- can be devastating. ment sequence. Examination of streams should proceed on an individual basis and take into Although lack of riparian vegetation, caved- account the characteristics of the entire in banks, erosion, and siltation are readily stream course, and not just those sections visible results of overgrazing, quantitative obviously in need of management. In this data documenting such damage are not abundant. way many problems can be avoided, such as Gunderson (1968) reported on the fish populations in comparable grazed and ungrazed sec- Dr. Platts' research should provide a tions of Rock Creek, Montana. In 1964, factual basis for multiple use management and 126.6 kg/ha of wild brown trout occurred in more harmonious coexistence of livestock and the grazed section and 167.8 kg/ha in the trout populations. It would be a mistake, ungrazed section. Trout above 30 cm in however, to delay attempts to reverse stream length were more than three times as abundant habitat deterioration 10 years while awaiting in the ungrazed section. The major habitat the outcome of the study. As a starting point, differences between the grazed and the ungrazed a recommendation in the Bureau of Land Manage- sections concerned riparian vegetation, bank ment's environmental impact statement on stability and average stream channel depth. grazing in Nevada (USDI Bureau of Land Manage- The grazed segment of the stream consisted of ment 1974) sho~lldbe implemented, namely that a spread-out channel with mainly shallow costs for protecting critical environments, riffle areas; it lacked deep pools and undercut such as streams and riparian vegetation, be banks. By 1970 the differences between the assumed by the interests causing the damage. two stream segments were even greater. Biomass If a rare trout restoration program is to be of wild brown trout had declined to 71 kg/ha successful where the habitat is exposed to in the grazed section, while it increased in grazing, an integral part of the program must the ungrazed part of the study area to consist of strict grazing controls and water- 238.9 kg/ha. Interestingly, investigators shed protection. found moFe mountain whitefish (Prosopium williamsoni) in the grazed than in the For background information on the actual ungrazed section. The mountain whitefish, or potential impact of various land-use often accused of being a serious competitor practices on trout streams, see: Burns 1970, with trout, more likely is just better Cordone 1956, Cordone and Kelley 1960, Elser adapted than trout to utilize disturbed 1968, Megahan and Kidd 1972, Mullan 1975, habitat. In the natural, ungrazed section of Platts 1974, U.S. Forest Service 1975, White the stream, whitefish comprised only 10 percent 1975, Gibbons and Salo 1973, and Grove 1976. of the total fish biomass, whereas in the altered grazed habitat they made up 35 percent The U. S. Forest Service, Region VI, of the total fish biomass (Marcuson 1970). Portland, Oregon, is currently developing a fish habitat management policy which will The need for more precise data on the include guidelines on: relationships of livestock density and grazing techniques to soil, climate, vegetation and I. Fish habitat protection and restoration impacts on stream environments and fish A. Timber management and road con- populations must be considered as the highest s truction research priority to provide a sound basis for B . Livestock grazing management decisions which will resolve the C. Mining conflicts between livestock grazing and fish 11. Fish habitat enhancement habitat quality. The section on timber management and The Intermountain Forest and Range road construction has been completed. The Experiment Station of the U. S. Forest Service section on livestock grazing is in draft at Boise, Idaho has initiated a 10-year study form, scheduled for completion by July 1976. titled "The effects of livestock grazing in Other sections have not yet been started. high mountain meadows on aquatic environments, The Oregon chapter of the American Fisheries streamside environments and fisheries," under Society passed a resolution endorsing this the direction of Dr. William Platts, who has habitat management policy and urging its studied livestock impacts on treams for many adoption on a nationwide basis (American years. In an earlier report^^ he raised Fisheries SocietyNewsletter, March-April, significant questions on the efficacy of rest- 1975). rotation grazing management for restoring streambank vegetation and rehabilitating unstable banks. Platts observed that, while POTENTIAL ROLE OF NATIVE TROUT IN one year of rest may be sufficient to restore FISHERIES MANAGEMENT pasture grass, it may not be sufficient time to enable previously overgrazed streambank At first glance, the idea of promoting shrubs to recover. angling for a rare trout while the goal of the program is to increase its abundance may appear contradictory. Actually, though, the g~latts,W. and C. Roundtree. 1972. Bear major hope for increasing the abundance of a Valley Creek, Idaho. Aquatic environment and rare trout lies in re-establishing it in. fishery study. USDA Forest Service, unpubl. waters, within its native range, where it has rept. 4E p. been extirpated or hybridized. In all likelihood, such sites are now public fishing waters. four times--8100 after institution of special State game and fish agencies funded, by angler regulations versus 1800 before--and the catch- license fees may be understandably reluctant per-man-hour increased by six times, from 0.8 to close public fishing waters in order to to 4.8, when comparing data of 1973 with that re-establisl~a native trout population which of 1968 in one five-mile stream section would be fully protected from angling. No (Bjornn 1975). With the 33-cm minimum size rare or endangered trout has become so through limit, anglers kept many fewer cutthroat, but overfishing; the fear that fishermen might because of the greatly increased average size, ,%terminate a population is simply not based the total weight of cutthroat trout creeled in fact. Properly publicized, native trout has probably not changed greatly. Angler can be used in unique, quality fisheries with response to the native cutthroat fishery has virtually no expense, if populations reproduce generally been quite supportive and by 1974, *aturally. Fishermen of ten place a higher the stream enjoyed the same intensity of use recreational value on the opportunity to fish that it had prior to the institution of for a native trout than for a hatchery trout. special regulations, when heavy stocking of catchable rainbow trout supported the fishery. Special regulations for native cutthroat And so by protection from excessive exploita- in Idaho test streams include a catch-and- tion, a more valuable fishery based solely on release fishery and a 33-cm minimum size natural reproduction of a native trout has limit. The abundance, average size and replaced a more expensive catchable trout catch-per-hour of trout in the stream have fishery and the vulnerability of the cutthroat all increased under these regulations (Ball trout to repeated catching has resulted in a 1971, Bjornn and Thurow 1974, Bogander et a1 greatly increased catch rate. 1974). The National Park Service initiated a catch-and-release fishery on the Yellowstone Basically, the design of a special regu- River in Yellowstone National Park in 1973 lations fishery assumes that a natural trout after comparisons had shown that 309 cutthroat population will undergo a "stockpiling" effect trout sampled in a closed section averaged if smaller trout are protected from fishing 44.7 cm, against 36.1 cm for 378 trout from exploitation and allowed to survive to a the open-fishing area. The catch-per-hour larger size. Most detailed studies of wild under the special regulations increased by trout populations in streams have shown that two- to four-fold over the previous four special regulations designed to produce more years; most fishermen were enthusiastic over and larger trout by restricting the catch do the change (Jack Dean, personal communication not work (Allen 1951; Hunt 1966, 1970; Latta to Robert Behnke). 1973; Klein 1974). But most of these studies concerned brook trout (Salvelinus fontinalis) The research of Dr. Ted Bjornn, leader and brown trout (Salmo trutta). In these of the Idaho Cooperative Fishery Unit, has species, the lack of response to restricted provided the best evidence of the potential catch results from the fact that habitat of native cutthroat trout to produce a high characteristics and food supply govern natural quality fishery under special regulations. mortality rates and age-size structure of the In 1971 investigators attempted to restore populations. Typically, the above studies the abundance of the native trout in several demonstrated that the overwhelming majority of miles of the upper St. Joe River, Idaho, by production and biomass--from 70 to 90 percent-- cessation of hatchery rainbow trout stocking remained tied up in the 0 and I age groups and institution of an artificial lure fishery (trout of sub-catchable size) and that about with a minimum size limit of 33 cm. Studies 98 percent of all trout hatched died from from 1968 to 1970 had revealed that the cut- natural causes before they reached catchable throat was suffering heavy angling exploita- size, typically in age group II+. Under cir- tion. Cutthroat trout caught by fishermen cumstances where all age groups compete for a averaged only slightly over 17.8 cm; only 2.5 common food supply, and where sub-catchable percent of the population exceeded 25 cm and trout constitute the bulk of the biomass, only 0.1 percent exceeded 33 cm. The results attempts to change the age and size structure of this management program have proved very of the population either by protecting it encouraging. Rainbow trout have virtually from angling or conversely, to promote angling disappeared from the unstocked area. Cut- in the hopes of stimulating growth in the throat trout increased from three- to six-fold fishes that remain, will have little effect in abundance in areas under special regulation, on the population as a whole. This is because and without stocking. Average size of fish such a small segment of the total population caught by anglers increased 5 cm in the first is exposed to removal by angling, and because two years. The proportion of fish longer mortality is compensatory. That is, reduced than 25 cm increased by 1000 percent; those angling mortality results in increased natural over 33 cm increased by 3000 percent. The mortality; therefore the annual survival rate number of cutthroat caught increased by over of trout of any year class remains approximately the same whether the fish are protected or size. Virtually all fish in a small stream unprotected from angling. may die of old age before reaching a length of 25 cm. Most streams holding pure populations Why, then, have the cutthroat trout popu- of rare, native trout are too small and lations mentioned above apparently responded remote from civilization to attract more than to special protective regulations and exhibited negligible fishing pressure; special angling a "stockpiling" effect? Three major factors restrictions are not justified under such cir- are likely involved. cums tances . The Province of Alberta, Canada, has instituted management regulations for 1. In all of these areas investigators small streams containing cutthroat trout which speculate, but have not conclusively demon- consists of closing the streams in alternate strated, that the spawning and rearing areas years to allow a buildup of larger trout exist apart from the main fishing areas. This (Radford 1975) . reduces or eliminates the intraspecific competition between the younger, sub -catchable age groups, and the older, larger trout. SUMMARY

2. The vulnerability of the cutthroat Steps in a native trout management pro- trout to angling results in a higher catch- gram may consist of: per -man-hour from cutthroat trout than from other species. No one knows how many times a 1. Survey of waters to collect specimens trout might be caught and released in any from suspected pure populations and to locate given fishery, but Webster and Little (1947) potential sites for re-introduction. reported that 200 rainbow trout stocked in an enclosed section of stream yielded a catch 2. Taxonomic study sf collections to (when released) of 601 in 54 days--each trout identify pure populations. was caught an average of three times. All studies to date have revealed virtually no 3. Protection and possible improvelnent (under five percent) mortality in trout re-. of habitat. leased from artificial flies and lures. 4. Introduction into barren or chemically 3. In the studies on brook trout cited treated waters isolated by some barrier against above, virtually no trout survived to age contamination by non-native trouts. class IV or V. In most cutthroat trout populations, maximum ages of VI or VII appear 5. Establishment of special regulation rather commonly. Subsequent survival of older fisheries where applicable. age groups results in a higher ratio of catchable-size to smaller sizes in cutthroat trout populations when compared to populations of typically short-lived brook trout. 1. Robert Behnke A higher annual survival of older age Dept. of Fishery and Wildlife Biology groups (age I1 and older) indicates a decrease Colorado State University in natural mortality. Where angling mortality Fort Collins, CO 80521 becomes high in such a situation, it may exceed natural mortality and depress the popu- (trout taxonomy; evaluation of relative lation below the carrying capacity of the purity of populations; restoration environment. Temporary protection from angling, projects) or a lowering of the creel limi't in such instances, would result in higher annual sur- 2. Allen Binns vival and an increase in numbers. Habitat Management Biologist Wyoming Game and Fish Department Stream modification to produce more shelter Box 342 and deeper water can increase the proportion of Lander, WY 52520 older to younger trout, food utilization, biomass and angler catch. Hunt (1969) demonstrated (state-federal cooperative restoration the efficacy of stream modification in Lawrence projects including surveys, habitat Creek, Wisconsin. improvement, construction of barriers)

Generally, special regulations work best 3. Ted Bjornn, Leader for a trophy fishery and require moderate to Idaho Cooperative Fishery Unit large rivers or lakes where food and space College of Forestry and Wildlife Management permit rapid growth and attainment of a large University of Idaho Moscow, ID 83843 (experience with special regulations to 11. James Mullan establish fisheries based on native trout) U. S. Fish and Wildlife Service Vernal, UT 4. Robert Borovicka Bureau of Land Management (restoration projects? extermination of 729 N. E. Oregon Street non-native fishes, land-use impacts) Portland, OR 97208

12. , William Platts (state-federal cooperative projects to U. S. Forest Service improve trout habitat by dams and other Boise Research Work Unit structures and by protection from 316 E. Myrtle Street overgrazing) Boise, ID 83706

5. Jack Dean (land-use impacts on streams and aquatic Fish Management Biologist life) U. S. Fish and Wildlife Service Yellowstone National Park, WY 82190 13. Max Rollefson Wyoming Department of Game and Fish (special regulation fisheries, native Box 483 trout management) Jackson, WY 63001 (habitat improvement to increase spawning 6. Paul Jeppson and nursery areas for native cutthroat Idaho Fish and Game Department trout) 600 S. Walnut, Box 25 Boise, ID 83707 REFERENCES (state-federal cooperative projects to improve trout habitat by dams and other structures, and protection from over- Allen, K. R. grazing) 1951. The Horokiwi stream: a study of a trout population. New Zealand Marine Dept., 7. Douglas Jester Fish. Bull. 10. Department of Range and Wildlife New Mexico State University Ball, K. Las Cruces, NM 88003 1971. Evaluation of catch-and-release regulations on cutthroat trout in the North (rare trout restoration projects, stream Fork of the Clearwater River. Idaho Fish improvements ) and Game Dept., Job Completion Report F-59-R-2. 37 p. 8. James Johnson U.S. Fish and Wildlife Service Behnke, R. J. Albuquerque, New Mexico 1972a. The rationale of preserving genetic diversity. Proc. West. Assoc. of State (livestock grazing impacts on streams) Game and Fish Comm. 52:559-561.

9. J. R. Kimball U. S. Forest Service 1972b. The systematics of salmonid fishes 4438 Federal Building in recently glaciated lakes. Jour. Fish. 125 S. State Street Res. Bd. Canada 29(6):639-671. Salt Lake City, UT 84111 Bjornn, T. C. (improvement of trout habitat through con- 1971. Trout and salmon movements in two trol of overgrazing; improvement devices) Idaho streams as related to temperature, food, streamflow, cover and population 10. Henry McKirdy density. Trans. Am. Fish. Soc. 100(3): U. S . Forest Service 423 -438. Federal Building Missoula, MT 59801 1975. The St. Joe River cutthroat fishery-- (stream improvement devices, native trout a case history of angler preference. Proc. management) West. Assoc. State Game and Fish Comm. In press. , M. A. Brusven, M. Molnau, F. J. Gee, M. A. Watts and R. L. Wallace. 1952. Fish stream improvement handbook. 1974. Sediment in streams and its effect USDA Forest Service. 21 p. on aquatic life. Water Resources Res. Inst., Univ. Idaho, Moscow. Gibbons, Dave R., and Ernest 0. Salo. 1973. An annotated bibliography of the and R. F. Thurow. effects of logging on fish of the western 1974. Life history of St. Joe River cutthroat United States and Canada. USDA For. Serv. trout. Idaho Fish and Game Dept ., Job General Tech. Rep. PNW-10, 145 p. Pacific Perf. Rept. F-60-R-5. 23 p. Northwest For. and Range Exp. Stn., Port- land, Ore. Boreman, J. 1974. Effects of stream improvement on Griffith, J. S. juvenile rainbow trout in Cayuga Inlet, 1972. Comparative behavior and habitat New York. Trans. Am. Fish. Soc. 103(3): utilization of brook trout (Salvelinus 637-641. fontinalis) and cutthroat trout (Salmo clarki) in small streams in northern Idaho. Burns, J. E. Jour. Fish. Res. Bd. Canada '29:265-273. 1970. The importance of streamside vegetation to trout and salmon in British Columbia. Brit. Col. Fish and Wildl. Branch, Fish. 1974. Utilization of invertebrate drift by Tech. Circ. 1. 12 p. brook trout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in small Cordone, A. J. streams in Idaho. Trans. Am. Fish. Soc. 1956. Effects of logging on fish production. 103:440-447. Calif. Fish and Game Dept., Inland Fish. Admin. Rept. 56-7. 98 p. Grove, A. (ed.) 1976. Stream management of salmonids. Supplement to Trout Magazine, 17(1):31 p. and D. W. Kelley. 1961. The influence of inornanic- sediments on the aquatic life of streams. Calif. Gunderson, D. R. Fish and Game 47:189-228. 1968. Floodplain use related to stream morphology and fish populations. Jour. Wildl. Mgmt. 32:507-514. Corning, R. V., R. F. Raleigh, G. D. Schuder and A. Wood (ed. ) . Herrington, R. B. and D. K. Dunham. 1975. Symposium on stream channelmodifi- 1967. A technique for sampling general fish cation proceedings. Published by Stream habitat characteristics of streams. U. S. channel modification symposium, Box 312, Forest Service, Intermountain For. and Grottoes, Vir. 172 p. Range Exp. Sta., Res. Pap. 41. 12 p.

Dunham, D. K., and A. Collotzi. Hogander, G., T. C. Bjornn and S. Pettit. 1975. The transect method of stream habitat 1974. Evaluation of catch-and-release regu- inventory: guidelines and application. lations on cutthroat trout in the North U.S. For. Ser Intermt. Reg., Ogden, Utah. Fork of the Clearwater River. Idaho Fish 98 p. and Game Dept., Job Perf. Rept. F-59-R-5. 17 p. Elser, A. A. 1968. Fish populations in a trout stream in Hunt, R. L. relation to major habitat zones and channel 1966. Production and angler harvest of wild alterations. Trans. Am. Fish. Soc. 97: brook trout in Lawrence Creek, Wisconsin. 389-397. Wisconsin Conserv. Dept., Tech. Bull. 35:52 p. Gard, R. 1961. Creation of trout habitat by construct- ing small dams. Jour. Wildl. Mgmt. 25: 1969. Effects of habitat alteration on pro- 384-390. duction, standing crops and yield of brook trout in Lawrence Creek, Wisconsin. In P . S . Larkin (ed .) , Symposium on salmon 1972. Persistence of headwater check dams and trout in streams . H. R. McMillan in a small stream. Jour. Wildl. Mgmt. Lectures in Fisheries, Univ. of British 36:1363-1367. Columbia, Vancouver. p. 281-312. Mullan, J. W. 1970. A compendium of research onangling 1975. Fisheries habitat plan for the Uintah regulations for brook trout conducted at and Ouray Indian Reservation as affected Lawrence Creek, Wisconsin. Wisc. Cons. by the Uinta and Opalco Units of the Cen- Dept., Res. Rept. 54:37 p. tral Utah Project. U. S. Fish and Wildlife Service, Salt Lake City, Utah. 132 p. ~~~kson,Bonnie J. 1974. Stream bed stabilization in Enfield Packer, P. E. Creek, New York. N. Y. Fish and Game 1957. Management of forest watersheds and Jour. 21: 32-46. improvement of fish habitat. Trans. Am. Fish. Soc. 87:392-397. Jester, D. B. and H. J. Mcurdy. 1966. Evaluation of trout stream improve- Platts, W. S. ments in New Mexico. Proc. West. Assoc. 1974. Geomorphic and aquatic conditions in- State Game and Fish Comm. 46:316-333. fluencing salmonids and stream classification. U. S. Forest Service, SEAM publica- King, W. (ed. ) tion, Billings, Montana. 199 p. (mimeo.). 1975. Wild trout management. Trout Unlimited, Denver, Colo. 103 p. Radford, D. S. 1975. The harvest of fish from Dutch Creek, Klein, W. D. a mountain stream open to angling on 1974. Special regulations and elimination alternate years. Alberta Dept. of Recrea- of stocking: influence on fishermen and tion, Parks and Wildlife, Fish Mgmt. Rept. the trout population at the Cache la 15:54 p. Poudre River, Colorado. Colo. Div. Wildl., Tech. Publ. 30:57 p. Ringler, N. H. and J. D. Hall. 1975. Effects of logging on water temperature Latta, W. C. and dissolved oxygen in spawning beds. 1973. The effects of a flies-only regulation Trans. Am. Fish. Soc. 104:117-121. upon trout in the Pigeon River, Otsego County, Michigan. Mich. Dept. Nat. Res., Schreck, C. B. and R. 3. Behnke. Fish. Div., Fish. Res. Rept. 1807. 28 p. 1971. Trouts of the upper Kern River basin, California, with reference to systematics Little, R. G. and H. J. McKirdy. and evolution of western North American- 1968. Statewide fisheries investigations. -Salmo. Jour. Fish. Res. Bd. Canada 28: Rancho del Rio Grande grant, Carson National 987-998. Forest. New Mexico Dept. Game and Fish. Job compl. rept. F-22-R-7 and F-22-R-8. Stalnaker, C. B., and J. L. Arnette (ed.) 14 p. 1976. Methodologies for the determination of stream resource flow requirements. U.S. MacPhee, C. Fish and Wildlife Serv., Office of Biol. 1966. Influence of differential angling mor- Serv., Western Water Allocation. 199 p. tality and stream gradient on fish abundance in a trout-sculpin biotope. Trans. Am. Fish. Sumner, F. SOC. 95:381-387. 1940. The decline of the Pyramid Lake fishery. Trans. Am. Fish. Soc. 69:216-224. Marcuson, P. 1970. South-central Montana fisheries study. Trojnar, J. R. and R. J. Behnke. Rock Creek floodplain study. Montana Dept. 1974. Management implications of ecological of Fish and Game. Job Progr. Rept. F-20-R-14, segregation between two introduced popula- Job IIa. 4 p. tions of cutthroat trout in a small Colo- rado Lake. Trans. Amer. Fish. Soc. 103: Megahan, W. F. and W. J. Kidd. 423 -430. 1972. Effects of logging and logging roads on erosion and sediment disposition from USDA Forest Service. steep terrain. Jour. Forestry 80:136-141. 1975. Symposium on trout habitat research and management proceedings. USDA, USPS, Miller, R. R. Southeast For. Exp. Stn., Asheville, NC 1972. Classification of the native trouts of 110 p. Arizona with the description of a new species, Salmo apache. Copeia 3:401-422. USDIBureau of Land Management. 1974. Effects of livestock grazing on wild- 1974. Relationships of discharge reductions life, watershed, recreation and other re- to available trout habitat for recommending source values in Nevada. Bureau of Land suitable streamflow. Water Resources Management, Nevada State Office, Reno. Res. Inst., Univ. of Wyoming, Laramie. 71 p.

Webster, D. A. and G. S. Little. White, R. J. 1947. Angling experiments by the fly tyers' 1973. Stream channel suitability for cold- club at Cornell University. Trans. Am. water fish. Proc. 28th Ann. Mtg. Soil Fish. Soc. 64:63-70. Cons. Serv. (Plants, Animals and Man): 61-79. Wesche, T. A. 1973. Parametric determination of minimum and D. M. Brynildson. streamflow for trout. Water Resources 1.967. Guidelines for management- of trout Res. Inst., Univ. of Wyoming, Laramie. stream habitat in Wisconsin. Wisc. Div. 102 p. Cons., Tech. Bull. 39:65 p. COLORADO RIVER CUTTHROAT --Salmo clarki pleuriticus

TYPICAL MERISTIC CHARACTERS --Salmo clarki pleuriticus, native to the upper Colorado River basin is, with the green- Scale counts back trout of the Arkansas and South Platte lateral series drainages on the other side of the Continental (two rows above lateral Divide, among the most colorful of all the line) 170-20M- recognized forms of cutthroat trout. The and above lateral line highly variable coloration consists typically (origin of dorsal fin of a poorly defined pink or red band along the to lateral line) 38-48 brassy yellow sides. The ventral region may be suffused with crimson in mature males. Vertebrae 60-63 (mean 61-62) Character variability between populations of differing geographical areas exists due to Gillrakers 17-21 long physical isolation of major habitat areas in the Colorado and Green River basins. For Pyloric caecae 25-45 example, cutthroat trouts native to the upper (mean 30-40) Green River basin (La Barge Creek, north) display small to moderate-sized spots, typically Basibranchial teeth 1-20 smaller than the pupil of the eye, concentrated mainly on the caudal peduncle and, anteriorly, -/-~axonomic data from Behzke (1974, above the lateral line. Significantly larger 1975), Wernsman (1973)-/ spots occur on cutthroats from the Little Snake River drainage (a tributary to the Yampa SPECIES DESCRIPTION River); these may approach a size more typical of the greenback trout. All degrees of inter- No meristic characters unique to g. 2. mediacy in spotting occur, but one should pleuriticus exist which can serve to authori- expect pure or essentially pure populations tatively assign a specimen to. this taxon. to share a high degree of uniformity within Hybridization resulting from the introduction any geographical area where they have had the of rainbow trout and other subspecies of opportunity to freely intercommunicate. Baxter cutthroat trout into the Colorado River basin and Simon (1970) and Baxter (1972) present further complicates the recognition of pure photographs of the large-spotted form of the Populations. In general, the mean values of Colorado River cutthroat, probably taken of at least ten specimens are needed to determine specimens from the Little Snake River drainage the degree of purity of a population in of Wyoming. The illustration in this report is question. based on a specimen from Rock Creek, Wyoming, Map 1. Indigenous distribution of Salrno clarki pleuriticus. and &aracterizes the spotting pattern of the brook trout have frequently displaced it in native trout of the upper Green River system. smaller tributaries, but the major factor push- ing pure populations of the Colorado River cutthroat towards extinction has been hybridization DISTRIBUTION with rainbow trout and non-native cutthroat trout used in stocking programs in Colorado, The original distribution of 2. 5. Utah, and Wyoming. leuriticus extended from the headwaters of fhe Colorado River basin downstream to the Miller (1972) included S. 5. pleuriticus Dirty Devil River, Utah, on the west and to in his list of threatened freshwater fishes of the San Juan drainage of Colorado, New Mexico the United States. The Utah Fish Committee of and Arizona on the east. But due to the the American Fisheries Society's Bonneville and turbidity of the water, most areas Chapter lists it as endangered (Holden et al. of the Colorado and Green Rivers did not com- 1974). The Colorado Division of Wildlife p-ise trout habitat until after the construc- lists 5. 2. pleuriticus as threatened. tion of mainstream dams (Behnke 1974, Wernsman 1973). Resultant isolation of the various We recommend that 5. & pleuriticus be tributaries caused much of the variability recognized as threatened by the U.S. Depart- inherent in &. 5. pleuriticus. ment of Interior.

Only two populations of the many examined appear to be wholly pure. They occur in an isolated section of Rock Creek, tributary to La Barge Creek, and in North Beaver Creek, an isolated tributary in the Piney Creek drainage; both populations exist in Sublette County, Wyoming. A possibly pure population discovered in 1970 and described by Wernsman (1973) from the very headwaters of the Colorado River in Rocky Mountain National Park can probably now be considered extinct for all practical pur- LIFE HISTORY poses. Extensive sampling of the area in 1974 and 1975 turned up only three cutthroat trout No published life history data exist for in a multitude of brook trout. this trout save that concerning the lacustrine- specialized and slightly hybridized population Numerous populations, however, remain of Trapper's Lake, Colorado (Snyder and Tanner phenotypically good representatives of S, c. 1960, Drummond 1966), which has little value in pleuriticus even though they show some evidence relation to knowledge of the life history and of hybridization. Although coloration and ecology of 2. 5 pleuriticus throughout its spotting patterns remain typical, closer range. All of the general information concerning examination reveals a slight hybrid influence life history and ecology appearing in Chapter I in the form of the absence of basibranchial can be applied to &. 2. pleuriticus. teeth, a greater range of variability in meristic characters, and a shift in the mean A significant attribute of the Colorado values of some characters. Such populations, River cutthroat in the Green River drainage of while not wholly pure, still merit special Wyoming lies in the fact that several "good" recognition in management and land use decisions representative populations of this subspecies affecting their well-being (Belmke 1974, 1975, exist in several badly degraded streams of the 1976; Wernsman 1973). foothills region. Many of these streams might be characterized as submarginal trout habitat, since they have suffered from the effects of STATUS AND POPULATION TReND overgrazing and irrigation dewatering, which have led in turn to erosion, warm temperatures Although cutthroat trout exist in good and turbidity. In spite of habitat degradation numbers in small lakes and streams in the and the introduction of rainbow trout and non- Colorado River basin of Colorado, Utah, and native forms of cutthroat trout, the native Wyoming, pure populations of 2. c. pleuriticus populations have resisted hybridization and are indeed rare throughout its range. displacement to a surprising degree. The only explanation appears to be that these local pop- Habitat alteration and the introduction ulations are hardy and adapted to the present Of non-native trouts have caused the precipitous conditions to such an extent that natural decline of the Colorado River cutthroat. Brown selection strongly favors maintenance of the trout and rainbow trout have completely re- native genotype. These factors--environmental PLaced &. c. pleuriticus in larger rivers, and degradation and the introduction of non-native trouts--under which many predominantly 2. 5 the dewatering impact of the project on the pleuriticus still survive, have almost invar- trout population. iably caused the extermination of other subspecies of interior cutthroat trout (Behnke Another Bureau of Reclamation project, 1975). the Meek's Cabin Reservoir in the Utah-Wyoming border area, flooded a natural barrier on the HABITAT K3QUIREMENTS Ah9 LIMITING FACTORS Little West Fork of the Black Fork River and an artificial barrier was constructed to pre- All western trouts of the genus Salmo vent hybridization of the essentially pure possess essentially similar habitat requirements -S. 2. pleuriticus population with rainbow A broad-based ecological variability allows trout. populations to thrive in small streams, large rivers or lakes. Wile several lakes in the According to 1973 and 1974 annual reports Colorado River basin originally contained on fisheries management in Rocky Mountain -S. 2. pleuriticus whose basic life history National Park, prepared by James Mullan of attributes may have differed slightly from the U. S. Fish and Wildlife Service, Vernal, stream or river populations, the basic require- Utah, plans exist for reintroduction of g. 5. ments in terms of temperature, oxygen, and pleuriticus into the Colorado River drainage substrate for reproduction and survival are in $he Park. quite similar for all 5. 2. pleuriticus . Any factors leading to loss of cover, siltation and warming of the waters will have detrimental RECOMMENDATIONS impacts on cutthroat trout. But the most significant factor limiting the perpetuation Although the original range of 5. 2. of pure populations remains the hybridization pleuriticus covers a large area in Wyoming, resulting from the introduction of rainbow Utah, Colorado and New Mexico, only in the trout and exotic subspecies of cutthroat trout. Green River basin of Wyoming has a concerted effort been made to survey waters for native trout populations, evaluate their relative PROTECTIVE MEASURES purity and institute protective and r,estorative measures. The efforts of the Wyoming' Fish and The Wyoming Game and Fish Department has Game Department should be emulated in Colorado, hired a habitat management biologist, Dr. Utah and New Mexico in order to authoritatively Allen Binns, to direct protection, enhancement determine its status and to develop programs and restoration of native trout populations in to protect and perpetuate this trout throughout Wyoming. The Department is conducting several its range. projects in the Green River drainage, some in cooperation with the Bureau of Land Management Populations which are virtually pure and and the U. S. Forest Service. Projects include judged to be good taxonomic representatives stream improvement, spawning enhancement, should be given special recognition in relation barrier construction, transplanting and experi- to habitat protection or enhancement projects. mental propagation. Dr. Binns reported on this work at the Colorado-Wyoming Chapter of Habitat improvement and transplants into the American Fisheries Society meeting in barren or chemically treated streams and lakes April 1975. Robert Behnke has examined several can effect the increased abundance of pure hundred specimens and has evaluated the rela- populations. Habitat managers should consider tive purity of many samples of Green River special regulation fisheries programs both to basin cutthroat trout, collected during surveys offer anglers the opportunity to fish for a made by Wyoming personnel (Behnke 1975). rare and beautiful native trout and to generate interest and support among the public for The Bureau of Land Management, Colorado restoration programs. State Office, has fenced a section of Northwater Creek, a tributary to Parachute Creek in the These recommendations assume added sig- oil shale country of northwest Colorado, to nificance in view of the fact that g. 2. protect a good representative population of pleuriticus is native to all of the oil shale S. 2. pleuriticus from livestock overgrazing. region and much of the potential coal strip Gother virtually pure population of 5. 2. mine areas of Colorado, Utah and Wyoming. A pleuriticus occurs in Cunningham Creek, which 1975 report prepared for the Office of Biologi- has been affected by diversions from the cal Services of the U. S. Fish and Wildlife Frying Pan-Ar-kansas Project of the Bureau of Service (Thorne Ecological Institute, 1975), Reclamation. A cooperative agreement between gave the highest research priority to threat- the Colorado Division of Wildlife and the ened and endangered species. Bureau of Reclamation is designed to mitigate AUTHORITIES 1975. Report on recent collections of cut- 1, Robert Behnke throat trout from the Green River basin, Dept. of Fishery and Wildlife Biology Wyoming. Wyoming Game and Fish Department. Colorado State University 12 p. (mimeo) Fort Collins, CO 80521

(systematic investigations, evaluation of 1976. Report on collections of cutthroat purity, restoration projects) trout from Parachute Creek drainage, Garfield County, Colorado. Prepared for 2. Allen Binns BLM, Grand Junction. 7 p. Wyoming Game and Fish Department Box 342 Drummond, R. A. Lander, WY 82520 1966. Reproduction and harvest of cutthroat trout at Trapper's Lake, Colorado. Colo- (protective and restoration projects in rado Department of Game, Fish and Parks, the Green River basin) Spec. Rept. 10:26 p.

Holden, P. B., W. White, G. Somerville, D. Duff, 3. James Johnson R. Gervais and S. Gloss. U.S. Fish and Wildlife Service 1974. Threatened fish of Utah. Proc. Utah Albuquerque, New Mexico Acad. Science, Arts and Letters 51 (pt. 2): 46-65. (formerly in charge of BLM efforts in Colorado to protect threatened and Miller, R. R. endangered fishes) 1972. Threatened freshwater fishes of the United States. Trans. Am. Fish. Soc. 4. James Mullan lOl(2): 239-252. U. S. Fish and Wildlife Service Vernal, UT Snyder, G. R. and H. A. Tanner. 1960. Cutthroat trout reproduction in the (general trout management and habitat inlets to Trapper's Lake. Colorado Dept. requirements in Xocky Mountain region of Game, Fish and Parks, Tech. Bull. 7: and fisheries management activities in 86 p. Rocky Mountain National Park) Thorne Ecological Institute. 1975. Wildlife and oil shale, a problem REFERENCES analysis and research program. U. S. Fish and Wildlife Service, Office of Baxter, G. T. Biological Services. Vol. I. 112 p. 1972. The cutthroat, a fish with native roots. Wyo. Wildl. 36 (5): 16-19. Wernsman, G. 1973. The native trouts of Colorado. M.S. and J. R. Simon. Thesis, Colorado St. Univ., Ft. Collins. 1970. Wyoming fishes. Wyoming Game and 57 p* Fish D&. ,-~ull. 4. 168 .- Behnke, R. J. 1970. Rare and endangered species report: the native cutthroat trout of the Colorado- Green River basin, Salmo clarki pleuriticus . Colorado Cooperative Fishery Unit. 7 p. (mimeo) - 1974. Status report: Saho clarki pleuriticus. Prepared for Region 11, U. S. Fish and Wildlife Service. Albuauer- we, N.M. 6 p. (mimeo) WYOMING NEBRASKA

Laramie

NEW MEXICO

0 25 50 75 I I I Kilometers

Map 2. Indigenous distribution of Salmo clarki stomias. GREENBACK CUTTHROAT ---Salmo clarki stomias

TYPICAL MERISTIC CHARACTERS SPECIES DESCRIPTION

Scale counts Taxonomic criteria for 5. c. stomias lateral series remain tentative due to the extreme rareness (two rows above lateral of pure populations and to the scarcity of line) 175-220+ ancient museum specimens. Even so, scale (mean values counts made from available specimens consist- 185-216) ently exhibit the highest values of any cut- and above lateral line throat trout, or any trout in the genus u. (origin of dorsal fin It may be assumed that extremely high scale to lateral line) 42-60 counts are characteristic of pure populations (mean values of 2. 5. stomias, with some suggestion that 45-55) those populations native to the South Platte basin may show slightly higher counts than Vertebrae 59-63 those native to the Arkansas drainage. The (mean values greenback cutthroat displays typically lower 60-62) numbers of pyloric caecae and vertebrae than most other subspecies of S. clarki, but much Pyloric caecae overlap occurs in these characters. (mean values 29-35) ---Salmo clarki stomias undoubtedly derived via an ancient headwater transfer from waters Basibranchial teeth Present, but of the Colorado River basin to the South highly variable Platte River drainage, and for this reason shares many similarities with the Colorado River cutthroat, &. c. pleuriticus. The strik- -/-~axonomic data from Bebgke (1973, ing spotting pattern and intense coloration 1976), Wernsman (1973)J which can develop in mature fish is the most diagnostic field character of the greenback trout. &. 2. stomias typically displays the largest and most pronounced spots of any cutthroat trout. Round to oblong in shape, they appear concentrated posteriorly on the caudal peduncle area. Coloration, similar to 2. 5. pleuriticus, tends toward blood-red over the lower sides and ventral region, especially in mature males. Although a genetic basis exists LIFE HISTORY to express characteristic color patterns, the actual manifestation of color intensity and Little specific life history data exist pattern depends also on age, sex and diet. for the greenback cutthroat. While S_. c. For example, a lake environment with crusta- stomias appears to lack t'he resiliency and ceans available for food will induce a more adaptability which it needs to coexist with intense expression of color than a small introduced trouts, the mechanisms by which it s tream environment. is displaced in relation to spawning behavior, temperature, habitat and food preferences, or other factors, remain unknown. DISTRIBUTION Some life history data have been collected The original distribution of 2. c. stomias on two slightly hybridized populations which included the headwaters of the South Platt and can be considered "goodn,representative green- Arkansas River basins in Colorado and a small back trout populations . Bulkley (1959) gatherel area in southeastern Wyoming, but permanent information on age and growth, food habits and trout habitat did not extend much beyond the movement of the greenback population in the foothills region. The advent of white man's headwaters of the Big Thompson River in Forest clvllization rapidly pushed the greenback trout Cqyon of Rocky Mountain National Park. Nelson back to headwater areas, replacing it in the (1972) studied the unexploited population of larger streams with brown trout, and with brook Island Lake, a reservoir in the City of Boulder trout in smaller tributaries. Further introduc- watershed, and provided data on age, growth tions into headwater streams and lakes displaced and fecundity. Jordan (1891) and Juday (1907) or hybridized the native greenback trout to the made observations on size and food habits of point of virtual extinction. greenback trout in Twin Lakes, Colorado. None of these reports indfcate any unique life history attributes of s. & stomias. That is, STATUS AND POPULATION TREND the data and observations are typical of any trout living under similar circumstances and When the white man came to Colorado, the offer little in~ightinto whatever subtle greenback trout was the only game fish found differences in ecoLogy exist for the greenback in the Arkansas and South Platte river systems trout which make it so vulnerable to displace- of the state. Rapid development brought about ment and extrnction. irrigation diversions and stream dewatering, mining pollution, logging, grazing, widespread Early literature (Jordan 1891, Juday 1907, introduction of non-native trouts, and caused Hallock 1877, Anon. 1878, Land 1913) indicates a precipitous decline of native trout popula- that 5. 5. stomias was originally abundant but tions. Greene (1937) believed they were not noted for its large size. It reached a extinct. Although cutthroat trout remain maximum weight of about 2.3 kg; other subspecies common in high elevation lakes and streams of of cutthroat trout were known to attain weights the South Platte and Arkansas River basins, of 4.5 to 9 kg ar more. virtually none of the populations so far examined resemble the native greenback trout (Wernsman 1973) but instead have resulted HABITAT REQUIREMENTS AND LIMITING FACTORS from introductions of various non-native races and crosses of cutthroat trout, usually with While no factual evidence exists to spe- traces of rainbow trout hybridization. This cifically define gre'enback trout habitat circumstantial evidence suggests that the requirements and limiting factors, circum- greenback trout may be the most vulnerable of stantial evidence suggests that all of those all the western trouts to extinction. factors relating to habitat alteration and Analysis of all specimens examined to introduction of non-native trouts which have 1970 suggested only two pure populations. caused declines in other native interior trouts, One of these occurs in Como Creek, an isolated have 'had a particularly debilitating effect on tributary to North Boulder Creek, Boulder -S. 2. stomias. The most obvious factor pre- County, Colorado; the other is found in the venting successful restoration of the green- very headwaters of the South Poudre River back trout into its original habrtat is the above a barrier falls in Larimer County, presence of non-native trouts. Certainly Colorado. Due to its extreme rareness, 2. 2. reintroduction programs for greenback trout stomias has been listed as endangered by the cannot achieve success unless the proposed U. S. Department of the Interior.. site is completely barren of all non-native trouts and thoroughly protected from A more complete discussion on the status re-invasion. of the green back cutthroat was written by Behnke (1976). PROTECTIVE MEASURES in Caddis Lake, immediately below Fay Lakes, where James Mullan discovered them in 1972. The U. S. Department of the Interior Since 1971 the City of Boulder has granted recognizes 2. c. stomias as an permission to the Colorado Division of Wildlife endangered species. to obtain spawn from a good representative greenback population in Island Lake and up to In a cooperative venture undertaken by 100,000 eggs per year have been taken and the U. S. Forest Service, the Colorado propagated. The Division of Wildlife stocks ~~~~erativeFishery Unit and the Colorado these trout into several mountain lakes in Division of Wildlife in 1967, construction of northeastern Colorado as part of its fishery a fish barrier and elimination of the brook management program. trout population above it created a sanctuary for the greenback trout in upper Black Hollow creek, a tributary to the Poudre River in RECOMMENDATIONS Larimer County, Colorado. A self-reproducing of greenback trout was established The greatest hope for expanding the by introducing adult greenbacks from Como distribution and abundance of 2. 5. stomias is creek (Gagnon 1973). But in 1973, Dale Wills, by reintroducing it, within its native range, U. S . Forest Service (personal communication into suitable habitat barren of exotic trouts. to Robert Behnke) , found two brook trout Here, ironically, the 1973 Endangered Species above the barrier. A survey conducted in Act actually hinders management of the green- August, 1975 by Rolf Nitman, Colorado Division back trout. While the intent of the Act is of Wildlife, found the brook trout now to be commendable, its prohibition of the "taking" the dominant trout in the creek. or any form of harassment of an endangered species would mean closing to angling any Restoration efforts on a larger scale stream into which greenback trout are intro- took place in October 1973 when brook trout duced. Virtually all potential sites for were eliminated with antimycin above a natural greenback reintroduction are currently open barrier in Hidden Valley Creek, Rocky Mountain to fishing. Public agencies are not enthusi- National Park. Complete eradication of brook astic to initiate restoration projects for an trout from this creek was made especially endangered trout which would result in closing difficult due to the presence of about 15 acres public angling waters. of beaver ponds and associated backwaters (Mullan 1973). A sampling of Hidden Valley The simplest and most direct solution to Creek on August 27, 1975 by James Mullan, this problem would be for the U. S. Department U. S. Fish and Wildlife Service, and Dave of the Interior to change the status of 2. 5. Stevens, U. S. National Park Service, found s tomias from "endangered" to "threatened. " A no brook trout, and documented the presence of "threatened" status, while still affording adults from the 1973 transplant as well as protection under the Endangered Species Act, fish from natural reproduction in 1974 and would not prohibit angling, thereby allowing 1975. But another transplant of Como Creek this trout to be incorporated into fisheries trout into a barren headwater section of the management programs and encouraging the re- North Big Thompson River in Rocky Mountain sumption of active restoration projects. This National Park in 1971 failed, evidently be- rare and beautiful trout has potential for cause all the fish migrated downstream over a inclusion in special regulation fisheries, barrier during the winter months. A dense which can stimulate public support for brook trout population below the barrier makes restoration programs, but first it must be it doubtful that the greenback population will removed from the endangered species list. sustain itself there. In October 1975 the National Park Service treated Bear Lake with Well-organized surveys of isolated head- antimycin to eliminate the brook trout popu- water areas of the South Platte and Arkansas lation, and on November 4 introduced greenback River drainages could find and identify other cutthroat taken from Como Creek. pure or virtually pure greenback populations, as well as determine potential sites for Other transplant programs have used reintroductions. virtually pure greenback populations. A 1959 transplant in Rocky Mountain National Park As with 2. 5. pleuriticus , it is not took greenback trout from the headwaters of likely that many pure populations of 2. 5. the Big Thompson River in Forest Canyon and stomias remain, but good representative popu- stocked them into Fay Lakes in the park. The lations, similar to those in Forest Canyon population did not establish itself there, and Island Lake, should be identified for but descendants of the original introduction special recognition in relation to perpetua- have maintained a self-reproducing population tion and protection efforts. AUTHORITIES Gagnon, J. G. 1973. The greenback. Trout 14 (4) :12-28, 30. Greenback Trout Recovery Team Greene, W. S. David Langlois 1937. Colorado trout. Denver Mus. Nat. Colorado Division of Wildlife Hist., Popular Ser. 2, 48 p.

Richard Moore Halloclc, C. U.S. Forest Service 1877. The sportsman's gazeteer and general guide. New York. 688 p. Dave Stevens National Park Service Johnson, J. E. 1976. Status of endangered and threatened James Mullan fish species in Colorado. USDI, BLM, U.S. Fish and Wildlife Service Tech. Note 280. 23 p.

Robert Behnke Jordan, D. S. Colorado State University 1891. Report on explorations in Colorado (consultant) and Utah during the summer of 1889, with am account of the fishes found in each river basin examined. Bull. U. S. Fish. Comm. 9:l-40.

Juday, C. 1907. A study of Twin Lakes, Colorado, with special consideration to the foods of the Anonymous. trouts. Bull. U. S. Bur. Fish. 26:147-178. 1878. Trout in the Rocky Mountains. Forest and Stream 9(25) :468-469. Land, S. E. 1913. The black-spotted mountain trout Behnke, R. J. (Salmo stomias and related species). 1973. The greenback cutthroat trout, Salmo Trans. Am. Fish. Soc. 42:183-189. --clarki stomias. Status report prepared for U. S. Fish and Wildlife Service, Mullan, J. W. Region 11, Albuquerque, N. M. 11 p. 1973. Considerations in perpetuation of greenback cutthroat trout (Saho clarki Behnke, B. J. stomias). Spec. Rept. Fish. Mgmt. Program, 1976. Summary of information on the status Rocky Mountain Nat. Park. U. S..Fish and of the greenback cutthroat trout, Salmo Wildlife Service, Vernal, Utah. 26 p. --clarki stomias. Prepared for U.S. Fish and Wildlife Service, Salt Lake City Area Nelson, W. C. Office. 30- p. 1972. An unexploited population of greenback trout. Colo. Div. of Wildlife, Ft. Collins. Bulkley, R. V. 13 p. (mirneo) 1959. Report on 1958 fishing studies by the Bureau of Sport Fisheries and Wildlife in Wernsman, G. Rocky Mountain National Park. Rocky 1973. Systematics of native Colorado trout. Mountain Sport Fisheries Investigations, M. S . thesis, Colorado State Univ., Ft. Admin. Rept. 38 p. Collins. 57 p. LAHONTAN CUTTHROAT --Salmo clarki henshawi

TYPICAL MERISTIC CHARACTERS The number of pyloric caecae is also higher in the Lahontan cutthroat than in other subspecies Scale counts of 5. clarki. lateral series (two rows above lateral When Lake Lahontan desiccated 5000 to line) 150-180 8000 years ago, the separation of its major (125-150)~~ tributaries effectively isolated the fish and above lateral line fauna of the Carson, Walker, Truckee and (origin of dorsal fin Humboldt river systems from each other. One to lateral line) 33-42 would expect a high degree of genetic variability among the populations of the different Vertebrae 61-63 drainages under such circumstances, but in fact, all specimens examined from pure popu- Gillrakers lations in the Truckee, Carson and Walker drainages conform to the diagnosis given above (Behnke 1960). However, the native Pylor ic caecae 40-7 54- cutthroat of the Humboldt River system of Nevada differentiates recognizably from cut- Basibranchial teeth , Numerous and throats in the other tributaries to ancient well developed Lake Lahontan. It displays fewer scales in SPECIES DESCRIPTION the lateral series and a lower number of gillrakers. The Humboldt cutthroat trout may The Lahontan cutthroat trout achieved its represent an undescribed subspecies which great differentiation from all other subspecies probably separated from g. 2. henshawi much of Salmo clarki due to its long physical iso- earlier than the final desiccation of Lake lation in the Lahontan basin with the result- Lahontan, and probably differentiated in ant evolutionary selection for lacustrine response to evolutionary stimuli to adapt to specialization in pluvial Lake Lahontan, once fluvial conditions in order to utilize the the size of present-day Lake Erie. The number vast Humboldt River system (Behnke 1960, 1968, of gillrakers, higher than in any other west- 1972b). ern North American trout, further substantiates the ancient lacustrine evolutionary heritage Jordan and Evermanu (1898) described of 2. 2. henshawi; *th few exceptions, other --Salmo clarki tahoensis from Lake Tahoe taxa of trout possess only 17-21 gillrakers. under the assumption that: two different cutthroat trouts, differentiated by size, a Typical values of trout native to the inhabited Lake Tahoe. However, the type Humboidt River system of Nevada. Sacrame

50 100 Kilometers ...... :.... . ,.:.:.:.>...... _.,.. So/mo c/arki henshowi

Map 3. Indigenous distribution of Salmo clarki henshawi and Salmo clarki seleniris

24 of 2. 2. tahoensis is identical to Currently the only lakes which harbor S. c. henshawi and the observed size difference pure stocks of 2. 2. henshawi are Summit Lake, zrobably resulted from the presence of both Nevada, and Independence Lake, California. By older fish which had repeatedly spawned, and 1959 the only other known populations conform- younger fish spawning for the first tine, in ing to the diagnosis of 2. 2. henshawi occurred the spawning runs. Behnke (1960) considexs in Dog Creek of the Walker River drainage of S. 5 tahoensis a synonym of 2. 5. henshabi. California, the very headwaters' of the East -sa1mo evermanni, a name also used to describe Carson River above a falls, and one of its 5. 5 henshawi, was based on an introduced tributaries, Murray Canyon Creek (Behnke 1960). ~op~lationof Lahontan cutthroats in the Behnke discovered a small, apparently pure .pper Santa Ana River, California (Benson and population in Pole Creek, tributary to the ~~hnke1961). The trout named Salmo regalis Truckee River, in 1961, but ten years later from Lake Tahoe, and 2. smaragdus from Pyramid extensive electro-fishing disclosed only Lake, are considered to be based on introduced brook trout, and the native cutthroat of Pole trout, 2. gairdneri (Behnke 1972~). Creek is now presumed extinct. More recently, apparently pure 2. 2. henshawi populations Thus, a primordial cutthroat invaded the have been discovered in Golden Canyon Creek Lahontan basin, probably from the Columbia (an East Carson River tributary), By-Day Creek River basin, and gave rise to a large lacust~ine and East Fork Desert Creek (in the Walker fish, 2. 2. henshawi, from which an River drainagz), and Macklin Creek (tributary early separation led to the development of to the Yuba River in the Sacramento River the cutthroat trout endemic to the Humboldt basin). The Macklin Creek population is River drainage. Except for populat,ions in- probably the result of an early transplant habiting Lake Tahoe, Pyramid Lake, Walker from the Truckee River. A transplant from Lake and a few smaller lakes, the Lahontan Macklin Creek .into a barren, isolated section cutthroat was forced to become a stream trout of East Fork Creek of the Yuba River drainage by the desiccation of Lake Lahontan. This in 1970 and 1971 has established a smll ultimate division between lake and stream population there (California Department of with its associated evolutionary Fish and Game, Threatened Trout Committee programming, did not result in taxonomic notes; Stephen Nicola, personal communication differentiation (except for that exhibited by to R. Behnke). the Humboldt cutthroat), but it is significant for subsequent discussions concerning life Both California and Nevada annually history, habitat, and the reasons for the propagate millions of "2. 2. henshawi", but catastrophic declines in abundance suffered the great majority of these hatchery fish come by this trout. from the Heenan Lake stock which originated from a transplant of 2. 2. henshawi from the The spotting pattern of the Lahontan Carson River--a fluvial, not a lacustrine cutthroat constitutes its most diagnostic population--into Blue Lake, California, in field character. Large, roundish spots cover 1864. Two subsequent introductions of rainbow the body evenly and extend onto the head and trout into Blue Lake resulted in hybridization often to the ventral surface. Other sub- before the establishment of the present stock species of interior cutthroat trout typically in Heenan Lake. The Heenan Lake "cutthroat" lack spots on the head and ventral region, bears a good phenotypic resemblance to 2. 2. and have spots more concentrated posteriorly henshawi, but the lower number of scales and on the caudal peduncle area. Coloration of gillrakers (Behnke 1960) and the makeup of its the Lahontan cutthroat is dull when compared blood serum (Utter and Ridgway 1966) disclose with that of the Colorado River cutthroat or the rainbow trout influence. Thus, the trout the greenback trout. The crimson, gold and widely propagated as 2. 5. henshawi is in orange colors, if present at all, are much reality a counterfeit of the real thing, and subdued. the widespread introduction of the Heenan Lake stock in California and Nevada is not considered as part of the distribution of the DISTRIBUTION true &. 2. henshawi.

The Lahontan cutthroat trout at one time Occurred in abundance throughout the Lahontan STATUS AND POPULATION TREND Basin of California and Nevada, with major lacus trine populations in Pyramid Lake, Walker Commercial fisheries harvested vast num- Lake, Independence Lake and Lake Tahoe, bers of Lahontan cutthroat trout, famed for California, and Summit Lake, Nevada; fluvial its abundance and size, from Pyramid Lake, Populations occurred in the carsson, Walker and Walker Lake and Lake Tahoe during the last Truckee River systems of California and in the half of the nineteenth century, supplying the Humboldt drainage of Nevada. needs of towns and mining camps in the area and shipping surplus fish by Wells Fargo race became extinct. In Lake Tahoe, damming, express to San Francisco and other cities. pollution and siltation of its tributaries Robert Behnke, in a 1974 report prepared for resulted in the demise of the native cutthroat the Paiute tribe's litigation over the water soon thereafter. The cutthroat trout of rights and fishery values of Pyramid Lake, Walker Lake held on until 1948 when 16 large conservatively estimated that the cutthroat spawners were trapped near the mouth of the trout of Pyramid Lake alone could have sup- Walker River, which, due to irrigation diver- ported a fishery of 454,000 kg per year in sions, no longer had flows sufficient for the the nineteenth century. And yet the famed reproductive requirements of the trout in the Pyramid Lake cutthroat stock was allowed to lake. The Nevada Department of Fish and Game become extinct in 1938 (Sumner 1940) despite removed spawn from these trout and began a the fact that it was the largest of all brood stock; the present population of Walker western trouts; the average size of fish Lake is maintained by hatchery propagation caught in 1938 was nine kg (Sumner 1940), and (Behnke 1960, Johnson 1974). even though the official record for this trout (and the world record cutthroat trout) S. 2. henshawi possessed an evolutionary was 18.6 kg, the Indian fishery at Pyramid heritage which made it highly adapted and Lake reported trout weighing up to 28 kg successful in lake environments; it was much (Wheeler 1969). lesszuited for stream existence and quite vulnerable, in fluvial environments, to dis- Fish commission reports of Nevada and placement by brook, brown and rainbow trouts California and other early literature con- and to hybridization with rainbow and non- demned rampant poaching, uncontrolled exploi- native cutthroat trouts. Today only a very .tation and damming, diversion and pollution few streams shelter pure stocks of Lahontan of the rivers. But overfishing did not bring cutthroat trout (see page 22). about the virtual demise of g. 5. henshawi. Blockage of spawning tributaries decimated The purity of the Walker Lake stock, the lacustrine populations, and the intro- propagated in Nevada, is in doubt. No duction of non-native trouts into the streams ancient museum specimens exist for study of of the Lahontan basin caused replacement or the original population, and ample opportunity hybridization of the native cutthroat trout for hybridization in the Walker River has in the rivers. existed for more than half a century. Indeed, specimens of the stock raised at Verdi, Nevada, It may seem strange that such a large have slightly lower gillraker counts and scale trout, once so abundantly distributed through- counts than is typical of pure 2. henshawi out the great area of the Lahontan basin (Behnke 1960). But the highly alkali=aker could so rapidly slide toward extinction. Lake environment, lethal to all other trouts, The populations inhabiting Pyramid, Tahoe probably exerted selective pressures strong and Walker Lakes were specialized to exist in enough to maintain the genotype of the Walker a lacustrine habitat; they had adapted very Lake cutthroat without significant modification highly to their environment. These stocks from hybridization. The cutthroat trout of appeared greatly resistant to the effects of Walker Lake may play an increasingly signifi- hybridization, perhaps through negative cant role in propagation efforts involving a selection toward any' hybrids produced. The large, lacustrine predator. Cutthroat trouts original cutthroat trout of Pyramid Lake and of Walker and Independence Lakes are the only Lake Tahoe maintained their stocks until the existing stocks that have historically coexisted 19301s, despite massive stocking of rainbow with other dements of the native fish fauna of trout into the lakes and tributaries since the Lahontan basin and as such might be before 1890, and deliberate experimental expected to possess the genetic programming hybridization in hatchery propagation (Behnke for maximizing effective coexistence with and 1960). But in 1906, the Newlands Irrigation utilization of this associated fauna in other project constructed Derby Dam on the Truckee lakes. River, 30 miles above Pyramid Lake. Thus, the Pyramid Lake cutthroat trout were denied access to most of the spawning habitat of The native cutthroat trout of the ~umboldt the Truckee River (Snyder 1917). Even so, River drainage of the Lahontan Basin of Nevada these trout were to maintain their numbers has fared better than 5, 2. henshawi in the until the 19201s, when diversion of the rest of the basin. This trout, evidently more entire flow of the Truckee became more fre- specialized for stream life and apparently quent, with consequent great losses of highly adapted to the harsh flood-dr,ought spawning trout. The last spawning run of cycle of this arid region, has persisted in trout in the Truckee River occurred in 1938 many small streams despite repeated introduc- (Sumner 1940), but streamflow was insufficient tions of non-native trouts. Pure or essentially for reproductive success and this magnificent pure populations exist in about 20 streams (R. J. Behnke, personal notes and data). The LIFE HISTORY ,,tire trout populations in some small streams be restricted to a few small pools and Snyder (1917) made many general observa- beaver ponds in late summer, when the streams tions relating to life history of Lahontan become intermittent. Although the undescribed cutthroat trout, mainly the Pyramid Lake stock. of the Humboldt drainage persists Juday (1907) published some data on Lake Tahoe in several localities, it cannot be considered cutthroat. Calhoun (1944a, 1944b) described as common or abundant, and merits the same some life history attributes of the partially for protection and restoration hybridized Heenan Lake trout in Blue Lake and ,, 5. c. henshawi. Heenan Lake. Lea's (1968) M. A. thesis on the Independence Lake cutthroat contains the most Bond (1961, 1966) listed 5. 5. henshawi comprehensive data on a pure population of as the native trout of the Alvord desiccating -S. 2. henshawi. basin, which is contiguous with the northern Lahontan basin on the Oregon-Nevada border. A11 of the above studies were based on Behnke (1960) recognized that there were two lacustrine stocks. The work of Calhoun (1944a), distinct groups of cutthroat trout in this which points out the variability in growth, basin (or basins), one in the Virgin Creek - age at maturity, food habits and other life Trout Creek drainage of the Alvord Lake sump history factors between populations of the and one in Willow and Whitehorse Creeks, which same stock (the Heenan Lake strain) living in drain out onto the desert east of Alvord Lake Blue Lake and in Heenan Lake demonstrates that at a higher elevation. At that time Behnke the specific details gained from any life believed that the trout collected from Virgin history study must be restricted in application Creek, which possessed 21-25 gillrakers, were to the site of the studies. Broad generaliza- probably introduced Lahontan cutthroat trout tions applied to other populations might prove and that the Willow and Whitehorse Creek pop- erroneous. ulations constituted an undescribed subspecies. Subsequent information and re-examination of Based on all these studies, particularly the Virgin Creek specimens has caused Behnke that of Lea (1968), it may be assumed that in to reject his previous belief that these lakes, g. g. henshawi tends to feed more in specimens are 5. g. henshawi. Though the the pelagic zones and on the surface. When Lahontan cutthroat may have gained access to available, fish become predominant in its Virgin Creek and the Alvord basin via an diet when it reaches a size of about 30.5 cm. ancient connection with Summit Lake, the In Independence Lake, the redside shiner, specimens are sufficiently dissimilar to be kokanee salmon and Paiute sculpin were the classified as a new subspecies (Behnke 1972b, main fish eaten. 1973). The native trout of the Virgin Creek - Trout Creek drainage of the Alvord basin of The geologic history of the Lahontan Nevada and Oregon are presumed extinct, since basin and the distinctive characters of 2. 5. no specimens have been collected since 1934. henshawi indicate that this trout has had the The characteristics of the cutthroat trout in longest period of evolution of any western Willow and Whitehorse Creeks are close to the trout in which to specialize as a large Humboldt cutthroat of the Lahontan basin and predator in a lacustrine environment (Behnke their origin may have resulted from a headwater 1972~). stream capture from the Humboldt system. Na- tive trout still exist in Willow and Whitehorse The weak link in the life cycle of 5. 2. Creeks but remain unclassified. henshawi concerns its reproductive requirements; it is an obligatory stream spawner. The sub- Due to the extreme rareness of pure species' superb adaptability t6 the Truckee -S. c. henshawi, the U. S. Department of the River - Pyramid Lake system was negated by the Interior endowed it with the status of blockage of access to spawning habitat in the "endangered." But to facilitate management Truckee River. and restoration efforts, the status of the Lahontan cutthroat trout was changed from -S. g. henshawi well illustrates certain ''endangered" to "threatened" (Federal Register ideas regarding intraspecific variability in 40(137), 16 July 1975). This action also ecological, physiological, and behavioral avoided the problem of attempting to enforce traits. The various stocks, isolated thousands the "no taking" provision of the Endangered of years ago by the desiccation of Lake Species Act of 1973 in the popular sport Lahontan, were subjected to their own unique fishery at Pyramid Lake, where pure 2. 2. genetic programming under natural selection in henshawi from Summit Lake, partially hybridized different environments. and this was oarticular- 5. 5. henshawi from the Heenan Lake stock and ly true in lacustrine versus fluvial popula- F1 rainbow x cutthroat hybrids have all been tions. Probably only the Pyramid Lake Stocked together to provide angling. population of 2. 2. henshawi continuously evolved in a large lake environment with a PROTECTIVE MEASURES full range of the Lahontan basin fauna. The Threatened Trout Committee of the Interpretation of this evidence suggests California Department of Fish and Game has that no existing trout classified as 2. 2. conducted surveys to find remnant populations henshawi, introduced into Pyramid Lake, can be of 2. c, henshawi and to determine sites for expected to duplicate the adaptive success and establishment of new populations by transplants, large size of the original Pyramid Lake S. g. A successful transplant of this subspecies henshawi, due to subtle differences in their from Macklin Creek to the barren headwaters of life history characteristics. This interpreta- nearby East Fork Creek took place in 1970 and tion is supported by the fact that in almost 1971. Propagation of Independence Lake cut- two decades of stocking "2. g. henshawi" into throat began primarily to maintain the stock Pyramid Lake, the maximum size recorded has in Independence Lake; 32,000 trout from eggs not reached the average size of the original taken in 1974 were on hand in 1975. Of these, stock recorded during its 1938 spawning run, 5000 were marked and stocked in Heenan Lake and only reaches one-third to one-half the to facilitate future propagation and 25,000 maximum size once attained by the now-extinct were restocked into Independence Lake (Threat- Pyramid Lake cutthroat (Behnke 1968, 1972a, ened Trout Committee, California Department 1972c; Trojnar and Behnke 1974). of Fish and Game minutes of meetings; Stephen Nicola, personal communication to Robert Behnke). Removal of the beaver dams which HABITAT REQUIREMENTS AND LIMITING FACTORS blocked the spawning run from Independence Lake in 1964 greatly increased the success of The lack of suitable stream spawning natural reproduction of this stock (Lea 1968). habitat has limited lacustrine populations of -S. g. henshawi. Although hatchery propagation The impact and potential threat to the and stocking into lakes provide a means of Independence Lake cutthroat stock by the avoiding this limiting factor, until brood planned Walt Disney Productions resort to be stocks of 5. 2. henshawi are greatly expanded, built at Independence Lake, is difficult to the introduction of 2. g. henshawi x 2. forecast. The obvious threat of eutrophication gairdneri hybrids cannot be considered an exists, but more important might be a demand authentic restoration of the Lahontan cut- for stocking great numbers of trout to meet' throat. increased fishing pressure in Independence Lake. Hopefully, developers will recognize the Stream populations of Lahontan cutthroat uniqueness and value of the native Lahontan have suffered from hybridization with rainbow cutthroat of Independence Lake and design a trout, except in the Humboldt River basin. propagation program and special regulation Many of the streams in which the Humboldt fishery based on this fish and perhaps kokanee cutthroat occurs have a long history of stock- salmon. ing with rainbow trout, Yellowstone cutthroat, and brook and brown trout. The only reasonable The U. S. Fish and Wildlife Service explanation for the resistance of the Humboldt propagates the pure strain of 2. 2. henshawi cutthroat to displacement and hybridization in Summit Lake with the objective of restoring might be this trout's superior adaptation to it in Pyramid Lake. The ultimate goal is to re- its harsh environment. establish natural reproduction in the Truckee River, once adequate flows and fish passage A unique tolerance to high alkalinity facilities become a reality in the lower levels, which can be attributed to a physio- Truckee River (Gary Rankel, U. S. Fish and logical adaptation to the environments of Wildlife Service, personal communication to Lake Lahontan during its period of desiccation Robert Behnke). But as noble as this goal and increasing concentrations of dissolved may be, present conditions in the Truckee, solids, allows 5. 2. henshawi (or trout with particularly the potential for hybridization a predominant 2. g. henshawi genotype) to with the abundant rainbow trout population thrive in waters such as Walker Lake which which exists there, indicates that its reali- are lethal to all other trouts (Johnson 1974). zation will be difficult if not impossible. The mechanisms of "alkalinity toxicity" and precisely which ions are toxic to other trouts, In recognition of the significance of the yet tolerated by S, 2. henshawi, remain un- Mahogany Creek watershed, the only spawning known. But this unique adaptation to an tributary available to the Summit Lake cutthroat environmental extreme by S. 5. henshawi could stock, the Bureau of Land Management removed prove useful in establishing fisheries in the watershed from mining exploration to pro- lakes where other trouts could not survive. tect this stream from further degradation. But it failed to institute the grazing controls which had been proposed, and consequent effects One promising option of a propagation of overgrazing resulted in the need to remove program should be tested and that concerns the silt buildup at the mouth of the streim each propagation from parents surviving in the new year to allow the spawning trout to enter the environment to take advantage of natural selec- stream. The BLM cited the effects of live- tion favoring certain heriditary traits. For stock grazing on the Summit Lake cutthroat in example, the stocking of Summit Lake cutthroat its environmental impact statement on grazing trout into Pyramid Lake is presently accom- inNevada (Anonymous 1974) as an example of plished by an annual egg take at Summit Lake the problems of multiple-use management on so that each generation in Pyramid Lake is public lands when livestock interests wield derived directly from Summit Lake. A compari- the predominant influence--despite national son should be made over several generations regarding the survival of an in relation to survival and contribution to species. the Pyramid Lake fishery, between fish propagated from eggs taken at Summit Lake and In the Humboldt drainage, a successful from eggs taken from Summit Lake trout transplant of the native trout from Frazer surviving to maturity in Pyramid Lake. An creek to Sherman Creek, Elko County, Nevada item in the Sport Fishing Institute Bulletin has taken place, with future transplants (April, 1976) is of particular relevance in anticipated. The new Sherman Creek population this respect. A race of Columbia River coho has been observed in water temperatures reah- salmon stocked in the Lamprey River, New ing 25.6' C., perhaps a record high tempera- Hampshire, gave a total survival of adults ture for cutthroat trout in natural conditions returning to the home stream of 1.22 percent, (pat Coffin, Nevada Fish and Game Department, but the F1 generation resulting from eggs personal communication to Robert Behnke). taken from the returning salmon yielded a total survival of 5.75 percent or a 4.7 fold increase in survival and also a 50 percent increase in average weight of surviving salmon. The importance of the Lahontan cutthroat trout both in propagation as a sport fish and The Walker Lake strain needs an evalua- for the role it plays in fisheries management tion of its relative purity. The Humboldt dictates two goals for the management and native cutthroat needs an established lake, restoration of this trout: similar to Heenan Lake, for its propagation. This trout possesses a good fisheries manage- 1. Identification, protection and ment potential, acquired during its recent transpllntg of pure population evolution under the harsh climatic regime of northeastern Nevada. When it has gained 2. Propagation of pure S. 2. henshawi access to reservoirs from its headwater strong- to replace the hybridized Heenan Lake strain holds during high runoff years, the Humboldt for srocking in the Lahontan basin. cutthroat has greatly exceeded hatchery trout in both growth and survival (Behnke 1968 and Some compromises might be encouraged in personal data). selection of stocks in order to create the best-adapted genotype for waters such as A propagation program for 2. 5. henshawi Pyraaiid Lake. The Summit Lake population, and the Humboldt cutthroat should have as one the major pure stock of 2. 2. henshawi avail- of its goals that of demonstrating the prac- able for propagation, has probably been tical values of preserving and utilizing the isolaed from all other fishes for several genetic diversity of rare and endangered thousand years. Crossings of the Summit Lake trouts to again make these fish a dominant trout with Independence Lake cutthroat and/or element in their native range. Walker Lake cutthroat might result in a broader base of herterozygosity and greater adaptability to new waters. Because virtually all introductions of hatchery-propagated -So c.-henshawi occur in lakes where natural reproduction does not occur, no negative impact would be expected from experimental interracial\ hybridization in a restoration progrkm for pure S. 5 henshawi. Of course, the only trout stocked into Independence Lake, where natural reproduction does occur, should be from the native population. AUTHORITIES 1972c. The systematics of salmonid fishes 1. Robert Behnke of recently glaciated lakes. Jour. Fish. Dept. of Fishery and Wildlife Biology Res. Bd. Canada 29(6):639-671. Colorado State University Fort Collins, CO 80521 Benson, S. B. and R. J. Behnke. 1961. Salmo evermanni a synonym of Salmo (taxonomy of 2. 2. henshawi, Humboldt clarki henshawi. Calif. Fish and Game cutthroat and trout of contiguous basins) 47(3):257-259.

2. Virgil K. Johnson Nevada Department of Fish and Game Bond, C. E. Box 10678 1961. Keys to Oregon freshwater fishes. Reno, NV 89510 Agric. Exp. Sta., Oregon State Univ., Corvallis. Tech. Bull. 58. 42 p. (management of Pyramid Lake fisheries)

3. Don King and Gary Rankel 1966. Endangered plants and animals of U.S. Fish and Wildlife Service Oregon, Vol. I. Fishes. Agric. Exp. Sta., 300 Booth St., Rm. 4005 .Oregon State Univ., Corvallis. Spec. Re- Reno, NV 89502 port 205. 8 p.

(Federal projects on restoration and Galhoun, A. J. management of 2. 5. henshawi) 1944a. The food of the black-spotted trout in tno Sierra Nevada lakes. Calif. Fish 4. Stephen Nicola and Game 30(2):80-85. California Department of Fish and Game

(5. 5. henshawi projects in California) 1944b. Black-spotted trout in Blue Lake, Cal'if ornia. Calif. Fish and Game 30 (1) : 22 -42. REFERENCES

Anonymous. California Department of Fish and Game. 1974. Effects of livestock grazing on wild- 1965. Species plans: Lahontan cutthroat life, watershed, recreation and other re- trout. In California Fish and Wildlife source values in Nevada. Bureau of Land Plan, ~acf.Dept. of Fish and Game, Management, Nevada State Office, Reno. Sacramento. Vol. 11: 119, 147.

Behnke, R. J. 1960. Taxonomy of the cutthroat trout of Johnson, K. the Great Basin with notes on the rainbow 1974. Angler's guide to Walker Lake. Nevada Outdoors and Wildlife Review 8(1): series. M. A. Thesis, Univ. of California, 15-18. Berkeley. 98 p: Jordan, D. S . and B . W. Evermann. 1898. The fishes of North and Middle America. 1968. Rare and endangered species: the Bull. U. S. Nat. Mus. 47 (pt. 3):2184-3136. native trouts of western North America. Proc. West. Assoc. State Game and Fish Comm. 48:533-535. Juday, C. 1907. Notes on Lake Tahoe, its trout and trout fishing. Bull. U. S. Bur. Fish. 1972a. The rationale of preserving genetic 26:133-146. diversity: examples of the utilization of intraspecific races of salmonid fishes in LaRivers, I. fisheries management. Proc. West. Assoc. 1962. Fishes and fisheries of Nevada. Nev. State Gam'e and Fish Comm. 52:559-561. Fish and Game Comm., Reno. 782 p.

1972b. Rare and endangered trouts of the Lea, R. N. Southwest. In Symp. on Rare and Endan- 1968. Ecology of the Lahontan cutthroat gered ~ildlizof the Southwestern United trout, Salmo clarki henshawi, in Inde- States. New Mexico Department of Game pendence Lake, California. M. A. Thesis, and Fish, Santa Fe. p. 129-133. Univ. of California, Berkeley. 95 p. ~~Afee,W. R. Trojnar, J. R. and R. J. Behnke. 1966. Lahontan cutthroat trout. 3 A. J. 1974. Management implicabions of ecological calhoun (ed. ) Inland Fisheries ~dagement - - . ., - . segregation between two introduced popu- calif. Dept. of Fish and Game, Sacramento. lations of cutthroat trout in a small p. 225-231. Colorado lake. Trans. Am. Fish. Soc. 103 (3) :423 -430. Rankel G. L. 1976. Fishery management program, Summit Lake Indian Reservation, Humboldt County, Nevada. U.S. Fish and Wildlife Serv., Div. Fish Services, Reno, Nevada, Special Utter, F. M. and G. Ridgway. Rep. 35 P. 1966. Serological evidence for inbreeding of Lahontan cutthroat trout, Salmo clarki snyder, J. 0. henshawi, in Summit Lake, Nevada. Calif. 1917. Fishes of the Lahontan system of Fish and Game 52 (3) :180-184. Nevada and northeastern California. Bull. U. S. Bur. Fish. 35:31-86.

Sumner, F. H. 1940. The decline of the Pyramid Lake Wheeler, S. S. fishery. Trans. her. Fish. Soc. 69:216- 1969. The desert lake. Caxton Printers, 224. Caldwell, Idaho. 133 p. PAIUTE TROUT --Salmo clarki seleniris

TYPICAL MERISTIC CHARACTERS character to Snyder that he described 'I- seleniris" as a new species and became some- Scale counts what poetical in his selection of a specific lateral series name which suggested "...a fanciful resemblance (two rows above lateral of its evanescent tints to the lunar rainbow" line) 150-180 (Snyder 1934). and above lateral line (origin of dorsal fin Snyder's publication, however, provided to lateral line) 33-40 little data on the taxonomic characters of the Paiute trout, particularly concerning its Vertebrae 60-63 range of variability and an adequate compari- (mean 61.8) son with 2. c. henshawi. No published taxonomic data has appeared since to supplement his Gillrakers 21-27 original work, but a Master of Arts thesis by (mean 24) Behnke (1960) and subsequent data which he has accumulated reveals that 2. 2. seleniris has Pyloric caecae 50-70 nearly identical values to 2. 2. henshawi- in all of its meristic characters. Data on 2. 5. Basibranchial teeth 2-15 seleniris which appear above are published (Behnke 1960, personal data from here for the first time. s,pecimens taken from Silver King Creek, California, 1933-1956) The gillraker number indicates that the separation of 2. 2. seleniris in Silver King SPECIES DESCRIPTION Creek from an ancestral g. 5. henshawi occurred after g. 2. henshawi had attained its ultimate The Paiute (sometimes spelled Piute) number of gillrakers in pluvial Lake Lahontan trout was described by Snyder (1933) from under lacustrine selective pressures, no more above a barrier falls in the headwaters of than about 5,000 to 8,000 years ago. The Silver King Creek, Alpine County, California. Paiute trout, then, probably was not derived from the primordial trout which invaded the Silver King Creek is tributary to the Lahontan basin, but developed instead rather East Fork of the Carson River of the Lahontan recently, differing from g: 2. henshawi only basin. Snyder recognized the affinities and in spotting pattern. Most likely the phylo- derivation of the Paiute trout from 2. 2. genetic separation of 2. 2. seleniris from henshawi, the trout native to the Lahontan -S. 2. henshawi in the Carson River drainage basin. The absence of spots on the body occurred after the isolation of the various seemed like such a striking diagnostic stocks of 5. 2. henshawi in the Truckee, Carson and Walker river systems by the des- Four Mile Canyon Creeks (isolated tribu- iccation of Lake Lahontan. taries to Silver King Creek); North Fork Cottonwood Creek and Cabin Creek, Mono County; Even the absence of spots on the body as Birchim Lake, Inyo County; and Delany Creek, a character to differentiate g. 5. seleniris Yosemite National Park, where the National from 5. 5. henshawi cannot be used as absolutely Park Service is attempting to remove brook as believed. Stephen Nicola, trout to sustain the Paiute population. California Department of Fish and Game, care- fullyexamined 79 of the specimens of 2. 5. seleniris taken from Silver King Creek in STATUS AND POPUIATION TRENDS i-found that while 47 specimens had no spots,32 had from one to nine spots on the Silver King Creek was closed to fishing body (s. Nicola, personal communication to above Llewellyn Falls in 1933, after 2. c. R. Behnke, 5 June 1974). seleniris was discovered there. But when angling restrictions were removed in 1952 it was found that Paiute trout, like most cutthroat trout living in streams, was easily caught and vulnerable to over-exploitation. But it was men Snyder described the Paiute trout the apparently inadvertant stocking of 5000 in 1933, he assumed that it had originated in rainbow trout above Llewellyn Falls by the Silver King Creek above Llewellyn Falls and California Department of Fish and Game in 1949 ,S limited to the known distribution at that which dealt the final blow to the Paiute trout time. But Silver King Creek above Llewellyn as a pure form in Silver King Creek. A common Falls was originally barren of fish; it had fishery management practice at that time was been stocked by a sheepherder with trout taken to "seed" headwater mountain streams with from lower Silver King Creek in 1912. Another "new blood" in the form of hatchery trout fry, transplant above the falls took place in 1924. even though evidence had long accumulated to The subsequent discovery in 1946 of Paiute demonstrate the worthlessness of such stocking. trout in Corral Valley and Coyote Valley, two After the 1949 rainbow trout stocking, isolated tributaries to lower Silver King Lahontan cutthroats were mistakenly dropped Creek, was attributed to an early but: unknown by airplane into Whitecliff Lake, which flows introduction by man, which may have occurred into Bull Creek and joins Silver King Creek as early as the 1860's when Canadian loggers just above Llewellyn Falls. worked in the area (Baugh 1973). Stephen Nicola kindly provided to Robert Behnke the In 1957, investigators found hybrid fish information on these transplants,which is with spots above Llewellyn Falls and by 1963 filed in the office of the California Depart- they considered the silver King Creek popula- ment of Fish and Game, Sacramento, and taken tion a hybrid swarm. Paiute trout populations from statements made in 1944 by Mr. Virgil in Corral and Coyote Valleys had by 1963 also Connell, a stockman who pastured sheep in the thoroughly hybridized with rainbow trout from Silver King watershed. an unknown introduction; half the specimens lacked basibranchial teeth, and gillraker Mr. Connellls statements raise a question numbers ranged from 19-24, versus 21-27 in on the original distribution of Paiute trout. pure Paiute trout. These specimens also If the stream above Llewellyn Falls was devoid exhibited a profusion of spots on the body of trout prior to 1912, and if the introduced (R. Behnke, personal notes and data). trout came from lower Silver King Creek, then the original range must have included the Fortunately, pure Paiute trout had been Silver King drainage above some natural barrier introduced and established into formerly which prevented interbreeding with the typical barren Fly Valley, Four Mile Canyon and North Lahontan cutthroats of the East Carson River Fork Cottonwood Creeks to ensure its perpetua- SYs tem. tion. Treatment with rotenone in 1964 of Silver By the time Snyder described 5. 2. selen- King Creek above Llewellyn Falls attempted to &in 1933, the trout below Llewellyn Falls eliminate hybrids, and pure Paiute trout were had thoroughly hybridized with rainbdw trout re-introduced (MclLfee 1966, Staley 1965). But (Behnke 1960). It would be interesting to some hybrids survived the poisoning because of know the date of the first introduction of extensive beaver pond areas which made thorough rainbow trout, and of Lahontan cutthroat trout, treatment difficult and by 1968 fish with spots into the Silver King drainage. on the body again occurred.

The present known distribution of Paiute The Threatened Trout Committee of the trout consists entirely of introduced popula- California Department of Fish and Game, in tions which include those in Fly valley and light of the failure of chemical treatment in Silver King Creek, has instituted an alterna- good chance of success only in waters barren tive management practice of annual electro- of other fishes. fishing in the creek above Llewellyn Falls with selective removal of fish which display more than five spots on the body. The HABITAT REQUIREMENTS AND LIMITING FACTORS efficacy of this technique is currently being tested (Ryan and Nicola, 1976). Although the ancestral trout of the Lahontan basin lived as a large, lacustrine The U. 6. Department of the Interior had predator in pluvial Lake Lahontan, the Paiute officially listed 5. 5. seleniris as an trout has evolved in a small, cold stream endangered species, but because of management environment. Since it thrives also in problems resulting from the "endangered" Birchim Lake, it can be expected that the classification (see chapter on 2. 2. stomias, Paiute trout can adapt successfully to vir- page 19), the California Department of Fish tually any suitable trout waters. The ultimate and Game petitioned the Interior Department limiting factor, though, may be the presence to change the status to "threatened." The of other fishes, particularly trouts. official change in status from "endangered" to "threatened" took place in July, 1975 Schneegas and Pister (1967) and Ashley (Federal Register 140 (37), 16 July 1975). (1970) have written habitat management plans for the Paiute trout. All present pure populations of self- reproducing Paiute trout occur in small, PROTECTIVE MEASURES isolated environments, but the nucleus exists to intensify restoration projects. To insure protection of the upper Silver King Creek watershed, the Toiyabe National Forest and the Sierra Pacific Power Company transacted a land exchange in 1971 which made most of the watershed public land. The U. S. Marine Corps agreed to discontinue its use of LIFE HISTORY the watershed for survival training in 1963. After the poisoning of Silver King Creek to Some life history information appears remove hybrids in 1964, pure Paiute trout were in McAfee (1966). Darrel Wong (1975) and reintroduced. But hybrids reappeared and the James Diana (1975) present more detailed data California Department of Fish and Game is based on studies of the North Cottonwood attempting to control them by annual electro- Creek population. fishing. The construction of a barrier on Four Mile Canyon Creek in 1972 will hopefully insure Paiute trout attain a length of only 23 the isolation of Paiute trout there. to 25 cm in small streams such as the headwaters of Silver King Creek, but are known to Transplant programs have established reach lengths of up to 46 cm in larger bodies several new populations (see page 29). of water such as Birchim Lake (McAfee 1966). The Threatened Trout Committee of the The most significant life history attri- California Department of Fish and Game bute of the Paiute trout in relation to man- provides the structure to coordinate state agement must be implied from a knowledge of and federal efforts to protect and enhance its evolutionary history. 5. 2. seleniris the distribution and abundance of this trout. has been completely isolated from other species of fish for probably several thousand years, ever since its separation, in Silver King Creek, from a Lahontan cutthroat trout ancestor. The cutthroat in other areas of RECOMMENDATIONS the Lahontan basin evolved with a diverse fauna of several species of minnows and Pure populations of 2. 2. seleniris no suckers, a whitefish, and a sculpin. Selec- longer exist in its native waters. The extreme- tive pressures can differ greatly between ly limited natural distribution and catas tro- populations coexisting with a diversity of phic decline in abundance of such a fish may species and those developing in isolation, make it a matter of common sense not to with the result that life history and be- restrict restoration efforts to the native havioral characteristics of isolated fishes range. Although California's Threatened may prevent them from coexisting successfully Trout Committee has not yet formalized its pith other species. It must be assumed that thinking in this matter, the current view is n transplant of Paiute trout will stand a that Silver King Creek and its tributaries down to a point below the confluence of Corral Valley Creek and North Fork Cottonwood REFERENCES creek will be the extent of its restoration efforts, although protection of Paiute trout Ashley, R. R. in Cabin Creek and Birchim Lake will remain 1970. Habitat management plan, Piute trout. in force also (S. Nicola, personal communica- USDA Forest Service, Toiyabe Nat. For. 15 p. tion to R. Behnke) . Baugh, T. The Paiute trout could become an integral 1973. To save a species. Nevada Outdoors *art of trout management in mountain lakes if 7 (3) :24-26. a brood stock lake, similar to Heenan Lake for 5. 2. henshawi propagation, were estab- Behnke, R. J. lished, since many mountain lakes lack 1960. Taxonomy of the cutthroat trout of adequate Spawning area for trout of the genus the Great Basin with notes on the rainbow salmo to maintain self-reproducing populations, series. M. A. Thesis, Univ. California, Sustbe stocked with trout fry dropped Berkeley-. 98 p. from aircraft. The potential of S. c. seleniris, as a rare and beautiful trout, Dunham, D. K. lure hikers to more remote and little-used 1968.. Preliminary survey analysis of Silver areas of national forests could serve as a King Creek habitat above Llewellyn Falls, "crowd dispersal" technique in Alipine County, California. U.S. For. Serv, fishery and wilderness management. Toiyabe Nat. For. 10 p.

Streams with natural barriers and small McAfee, W. R. lakes having potential spawning tributaries 1966. Paiute cutthroat trout. 3 A. J. but now harboring non-native trouts should be Calhoun (ed.), Inland Fisheries Management, considered for chemical treatment to eliminate Calif. Dept. Fish and Game, Sacramento. present trout populations and to establish p. 231-233. additional self-perpetuating populations of -S. c. seleniris. Ryan, J. H., and S. J. Nicola. 1976. Status of the Paiutz cutthroat trout, --Salmo clarki seleniris Snyder, in Califor- AUTHORITIES nia. Draft Rep. of Threatened Trout Comm., Calif. Dept. Fish and Game. 59 p. 1. Robert Behnke Dept. of Fishery and Wildlife Biology Schneegas, E. R. and E. P. Pister. Colorado State University 1967. Piute trout habitat management plan. Fort Collins, CO 80523 USDA Forest Service, Inyo Nat. For. 30 p.

(taxonomic investigations) Snyder, J. 0. 1933. Description of Saho seleniris, a 2. Stephen Nicola, Chairman new California trout. Proc. Calif. Acad. Threatened Trout Committee Sci. 20(11):471-472. California Dept. of Fish and Game 1416 Ninth St. Sacramento, CA 95814 1934. A new California trout. California Fish and Game 20(2) :105-112. (protection and restoration programs) Vestal, E. H. 3. Philip Pister 1947. A new transplant of the Piute trout 407 W. Line St. (Salmo clarki seleniris) from Silver King Bishop, CA 93514 Creek, Alpine County, California. Calif- ornia Fish and Game 33 (2): 89-96. (data regarding introduced populations in North Cottonwood Creek and Birchim Lake) GILA TROUT -Salmo gilae

TIP1CA.L MERISTIC CHARACTERS SPECIES DESCRIPTION

Scale counts Although a native trout was historically lateral series known from the Gila River basin of New Mexico, (two rows above lateral it was not until this trout was on the brink line) 135-165 of extinction that it was recognized as dis- and above lateral line tinct and described as a new species by R. R. (origin of dorsal fin Miller (1950). to lateral line) 29-38 A problem with providing an adequate Vertebrae 59-6~~ diagnosis of Salmo gilae is that the original description is based on a population in tiny, PylorZc caecae 25-46 intermittent Main Diamond Creek and certainly (means 33-36)y does not encompass the range of natural vari- 43-57 ability of this trout throughout its original (mean 47.2)rl range. Miller (1972) considered the original range of the Gila trout to include the Verde Basibranchial teeth ~bsen& River sys tern of Arizona (where the native trout is now extinct). Four specimens collect- L-Taxonomic data from Behnke (1973) and - ed from Oak Creek, south of Flagstaff, in 1888 personal data; and from David (1976) .-/ and 1889, and now in the U. S. National Museum, have the spotting pattern typical of d~eanvalues for samples from four the species (Miller 1972, fig. 5), but three localities range from 59.7 for Spruce Creek of the four possess basibranchial teeth, a specimens to 61.7 for McKenna Creek specimens. character not previously reported in $5.silae Uvalues from specimens from Main Diamond, in the Gila River basin of New Mexico. How- South Diamond and McKenna Creeks ever, David (1976) found basibranchial teeth dvalues from specimens from Spruce in four of 12 specimens of Gila trout from Creek Spruce Creek, a tributary of the San Francisco &/~bsentin all New Mexico specimens River system of New Mexico. examined except those in Spruce Creek. Basibranchial teeth were also present in A distinctive feature of S. gilae is the three of four specimens collected from Verde profuse pattern of small, irregularly-shaped River drainage of Arizona in 1888-89. spots, mainly above the lateral line on the UTAH I COLORADO

/"3~i\oRiver

Tucson I

I I Salmo opoche Kilometers

Map 4. Indigenous distrLbution of Saho gilae and Salmo apache. body, onto the head, and on the dorsal and River (the next drainage west of the Verde caudal fins. The basic coloration is yellowish sys tem) , were collected by Mr. Gary Edward, or olive-yellow on the sides of the body; a of the Arizona Department of Game and Fish faint rose band may be present along the and sent to Robert Behnke for identification, lateral line in adults. A yellow cutthroat anal and mark is present and the dorsal, Although the Sycamore Creek population has pelvic fins are tipped with white or yellow. hybridized with rainbow trout, enough of the original genotype remains to indicate that -Salmo -is reputed to have a unique the native trout of Sycamore Creek had a karyotype (number and morphology of chromo- spotting pattern typical of S. gilae. somes) which differentiates it from all other trouts (R. R. Miller, personal communication to R. Behnke). Mr. Robert David, New Mexico Thus, 2. gilae was probably native to State University, has studied the chromosomes both the Verde and Agua Fria drainages of of 2. gilae a£ter completion of his thesis. Arizona. Needham and Gard (1959) described , Preliminary analysis indicates a karyotype trout from the Rio Yaqui of Mexico, a con- different from any other trout (personal tiguous basin with the Gila River, which communication to R. Behnke). appears similar to 2. gilae.

Gila trout which have hybridized with Unfortunately, the almost complete elb. rainbow trout are common in many tributaries ination of both S. gilae and 2. apache from of the upper Gila River. They exhibit erratic their native ranges before either of these spotting and coloration, higher vertebral and species was studied, prevents a better under- caecal counts and lower scale counts. standing of their original distribution.

Presently, pure or essentially pure DISTRIBUTION populations are known from Main Diamond, South Diamond and McKenna Creeks, New Mexico. Little information exists to accurately The Spruce Creek population in the San Fran- define the original distribution of the Gila cisco drainage is attributed to an early trout. Miller (1950) documented its occur- introduction, but the lower number of vertebrae, rence throughout the upper Gila River water- higher number of pyloric caecae and the report shed downstream to the town of Cliff, New of basibranchial teeth in specimens from Mexico, in 1896, but it reputedly was absent this population indicate that Spruce Creek from the San Francisco drainage of New Mexico and Arizona. Miller (1972) evaluated museum trout are well-differentiated from other This might be con- specimens collected from the Verde drainage, S. ~ilaein New Mexico. strued as evidence supporting the indigenous Arizona, a tributary to the Salt River of occurrence of S, gilae in the San Francisco the Gila River basin, and pronounced them to drainage. Further support of such native be Salmo gilae. The present population of distribution is given by the former occurrence Gila trout in Spruce Creek, New Mexico, a of S. ailae Eagle Creek, the next major headwater tributary in the San Francisco in tributary to the Gila River west of the San drainage, is attributed to an introduction Francisco River (Mulch and Gamble 1956). in 1905 (Miller 1950). David (1976) discovered a population of pure The zoogeography of the distribution of -S. gilae in Iron Creek, an isolated tributary to the Middle Fork of the Gila River. -S. ~ilaeis puzzling. One would expect that -S. apache, the native trout in the headwaters of the Salt River system, should also be the A cooperative project between the U. S. trout native to the Verde drainage of Arizona. Forest Service, New Mexico Department of Game And if S. gilae once had direct communication and Fish, and New Mexico State University from the upper Gila basin of New Mexico with introduced Gila trout from Main Diamond the Verde drainage of Arizona, why were no Creek into McKnight Creek of the Mimbres remnant populations discovered in the San River basin in 1970 and 1972, after construc- Francisco River system? This distributional tion of a barrier and elimination of a sucker enigma is further compounded by the fact that population. These trout have successfully the only known museum specimens of native reproduced (R. David and Douglas'Jester, New trout from the San Francisco River system Mexico State University, personal communica- (K. P. Creek, Arizona) have the typical spot- tion to R. Behnke) . ting pattern of 2. apache (Miller 1972, fig. 4). Another project transplanted 89 Gila trout from Main Diamond Creek into barren In 1975, trout specimens from Sycamore Sheep Corral Creek, a tributary to Sapillo Creek, Arizona, a tributary to the Agua Fria Creek in,the Gila drainage, New Mexico. stream improvement devices were likely to do well in almost any trout habitat, into Sheep Corral Creek, the problem as long as no other fish are present. The of livestock overgrazing remains and the growth potential of 2. & almost certainly degraded habitat has had no chance to recover. is greater than the 23 cm maximum size it A 1975 sunrey of Sheep Corral Creek found 15 attains in Main Diamond Creek. trout from the 1972 transplant, but no sign ,,isted that successful reproduction had Most probably, the original 5. gilae ,,curred. Probably 2. gilae cannot become found in the upper Gila basin did not consist ,,tablished in Sheep Corral Creek until the of a single homogeneous population, but grazing problem is corrected (R. David, instead was composed of several discrete personal communication to R. Behnke). stocks in the smaller tributaries and probably another stock utilizing the main river and The Arizona Game and Fish Department larger tributaries; these separate stocks transplanted 5. gilae from Main Diamond Creek, probably possessed slightly differing life New Mexico into Gap Creek, a barren tributary history characteristics. The assumption of --,,f the Verde drainage in 1974, in an attempt discrete populations and genetic heterogeneity to restore this species to the Verde system. is supported by the taxonomic differences A more ambitious program to restore the Gila found between existing populations, particu- trout to its historic range in Arizona was larly when Spruce Creek specimens are compared delayed by the loss of a hatchery brood stock with other samples of 5. gilae. in 1974 (Gary Edwards, Arizona Game and Fish Department, personal communication to R. ~ehnke). HABITAT REQUIREMENTS AND LIMITING FACTORS Present 5. gilae populations appear sufficiently adaptable to live in any waters suitable for any species of trout, even though STATUS AND POPULATION TREND originally this species probably consisted of disjunct populations with differing ecological Miller (1950, 1961) described the former specializations. A major limiting factor, abundance and rapid decline to almost extinc- though, remains the presence, in potential tion of 2. gilae. Hybridization throughout Gila trout habitat, of other species of the upper Gila basin resulting from the intro- trout; rainbow trout hybridize with 5. gilae duction of rainbow trout was so extensive and brook and brown trout compete with it that by 1950 the very few pure populations of for food and space. Any stream presently Gila trout which remained were all isolated holding brook, brown, or rainbow trout can by barriers in small headwater streams. Sub- provide suitable habitat for 2. gilae after sequent re-introduction programs in New all exotic trouts are eliminated and prevented Mexico and Arizona have met with modest success from re-invasion. and the distribution and abundance of this rare trout have increased in recent years. PROTECTIVE MEASURES -Salmo gilae is officially recognized as an endangered species under the Endangered Main Diamond, South Diamond, McKenna, Species 'Act of 1973. Iron and Spruce Creeks are in the Gila Wilder- ness Area of the Gila National Forest; thus they are endowed with some extra legal protection from habitat degradation.

LIFE HISTORY The "endangered" status granted the Gila trout under the Endangered Species Act of Two Master of Science theses have been 1973 prohibits its "taking" or "harassment, " prepared on the Gila Trout of Main Diamond but prohibiting angling for an endangered Creek (Regan 1964, Hanson 1971). Although trout, particularly in remote areas, may not these studies present detailed information on be relevant to the protection of the species age, growth, food habits and fecundity of the except in a negative way, since any large- trout and on physical, chemical and biological scale restoration effort must be based on parameters of the water, this information introduction into public waters. Subsequent reveals but certain life history characteris- closure of such waters to angling can create tics as determined by the harsh environment unfavorable response to such projects and of Main Diamond Creek. These studies are of inhibit realization of the desired goal. How- limited value in predicting adaptability to ever, due to the extreme rarity of 2. gilae, new waters except to indicate that a trout it may not be wise to remove the species from which can thrive in Main Diamond Creek is the endangered list until the Little Creek AUTHORITIES restoration project has been successfully completed. 1. Gila Trout Recovery Team Carl Schmit t , Leader McKnight Creek has suffered habitat New Mexico Game and Fish Department degradation from livestock overgrazing. The State Capitol U. S. Forest Service initiated corrective Santa Fe, NM 87503 measures in 1975 and also plans to institute grazing control in the Sheep Corral water- Members : shed in 1976 (Douglas Jester, personal com- Bruce Anderson munication to R. Behnke). U. S. Forest Service, Gila Natl. Forest

The Gila trout recovery team has drafted Bruce Rosenlund an outline of a Gila trout recovery plan U. S. Fish and Wildlife Service (January 19, 1976). Included in the plan is a re-introduction of 5 ~ilaeinto Little William Silvey Creek after construction of a barrier and Arizona Game and Fish Department elimination of hybrids. 2. Robert Behnke The Arizona Department of Game and Fish Dept. of Fishery and Wildlife Biology plans to re-establish a brood stock of Gila Colorado State University trout for introductions into the Verde and, Fort Collins, CO 80521 perhaps, Agua Fria drainages (G. Edwards, personal communication to R. Behnke). (taxonomic investigations)

Section 7 of the Endangered Species Act 3. Robert David of 1973 directs all federal agencies to Dept. of Fishery and Wildlife Science carry out programs for conservation of en- New Mexico State University dangered and threatened species and to pre- Las Cruces, NM 88003 vent any of their activities from jeopardizing the continued existence of these species. (graduate thesis on taxonomy of S. gilae

4. John Hubbard New Mexico Game and Fish Department State Capitol If the Little Creek restoration project Santa Fe, NM 87503 meets with success, the Gila trout should be changed in status from "endangered" to (in charge of endangered and threatened "threatened." This change will facilitate species program in New Mexico) management of the species and stimulate further transplants into public waters. 5. Douglas Jester Dept. of Fishery and Wildlife Science The population in South Diamond Creek New Mexico State University exhibits the most uniform appearance of all Las Cruces, NM 88003 known existing populations of S. gilae; as the most ideal representative of the species, (long involvement with Gila trout projects, at least some future transplants should be first with New Mexico Game and Fish Dept., made from this population. presentliy as faculty member at NMSU)

Robert David's research has revealed 6. Paul Turner some populations of trout which, although Dept. of Fishery and Wildlife Science slightly hybridized, exhibit a predominant New Mexico State University -S. gilae p3anotype. Such populations should Las Cruces, NM 88003 be protected against future introductions of non-native trout. (cooperative projects with U. S. Forest Service and New Mexico Game and Fish Department) REFERENCES 1961. Man and the changing fish fauna of Behnke, R. J- the American Southwest. Pap. Mich. Acad. 1970. New information on Gila trout, Salmo Sci., Arts, Letters 46:365-404. Rare and endangered species report. &.colorado Cooperative Fishery Unit, Colo- rado State University, Ft. Collins, 12 p. 1972. Classification of the native trouts (mime01 of Arizona with the description of a new species, Salmo apache. Copeia 3:401- 422. -73. Gila trout, Salmo gilae. Endangered -.s~ecies report, prepared for U.S. Fish and Mulch, E. D. and W. C. Gamble. wildlife Service, Region 11, Albuquerque, 1956. Game fishes of Arizona. Arizona N.M. 5 p. (mimeo) Game and Fish Department, Phoenix. 19 p. David, R. E. Needham, P. R. and R. Gard. 1976. Taxonomic analysis of Gila and Gila x rainbow trout in southwestern New Mexico. 1959. Rainbow trout in California and M.S. thesis, New Mexico State University, Mexico with notes on the cutthroat series. Las Cruces, N.M. 36 p. Univ. of Calif. Publ. 2001. 67(1): 124 p.

Hanson, J. N- Regan, D. 1971. Investigations on Gila trout, Salmo 1964. Ecology of the Gila trout (Salmo -Miller, in southwestern New Mexico. gilae) in Main Diamond Creek, New Mexico. M. S. Thesis, New Mexico State University, M. S. Thesis, Colorado State Univ., Ft. Las Cruces. 44 p. Collins. 57 p.

Miller, R. R. 1950. Notes on the cutthroat and rainbow 1966. Ecology of Gila trout in Main Diamond trout with the description of a new Creek, New Mexico. U. S. Fish and Wild- species from the Gila River, New Mexico. life Service, Tech. Pap. Sport Fish. 5. Occ. Pap. Mus. 2001. Univ. Mich. 529. 42 p. 24 p. ARIZONA NATIVE TROUT -Salmo apache

TYPICAL MERISTIC CHARACTERS displays larger roundish or oblong spots, similar to interior cutthroat trouts, over Scale counts the sides of the body, onto the top of the lateral series head and on the dorsal, caudal and adipose (two rows above lateral lines) 133-172 fins (Miller 1972, fig. 2). S. apache typically possesses the largest dorsal Tin of any (mean 146-158) and above lateral line American trout. (origin of dorsal fin 32-40 to lateral line) (mean 34-36) The unique karyotype of 2. apache shows 56 chromosomes with 106 arms, and miy be derived from a cutthroat trout-like ancestor Vertebrae 58-61 (mean 59.5-60) (Miller 1972).

Pyloric caecae 21-41 DISTRIBUTION (mean 26.7- 32.9) Cope and Yarrow (1875) first recorded Basibranchial teeth Vestigial trout in the White River, Arizona (in the headwaters of the Salt River system of the SPECIES DESCRIPTION. Gila River Basin) in 1873, and referred to them as a variety of the Colorado River cut- Pyloric caecae counts are among the throat trout. Jordan and Evermann (1896) lowest of American trouts; basibranchial referred to the trout in the headwaters of teeth are vestigial, with only five to 10 the Little Colorado River in Arizona also as percent of the specimens of some populakions the Colorado River cutthroat. When Miller possessing these teeth (Behnke 1970, 1973, (1950) described 2. gilae, he also mentioned personal data). native trout in the headwaters of the East Fork of the White River in Arizona and pro- The basic coloration of Salmo apache visionally included them with the Gila trout resembles that of 5. gilae, with olive-yellow as 2. gilae. After further study and examina- to golden-yellow on the sides and ventral tion of many more specimens Miller became region, a yellow cutthroat mark and whitish convinced of the uniqueness of this trout and tips on the dorsal, pelvic and anal fins. described it as a new species, Salmo apache While 2. apache lacks the rose-red lateral (Miller 1972). band typical of 2. -, the spotting pattern constitutes the most pronounced phenotypic By this time, the range of S. apache had difference between the two trouts. 2. apache been so diminished that the original Was impossible to determine with STATUS AND POPULATION TREND certainty. Miller (1972) considered its native range to include the upper Salt River Even though 2. apache possesses many system of Arizona (Black and White River distinctive characters including a unique drainages) and the headwaters of the Little chromosome complement, no genetic barriers River. A museum specimen taken in exist against hybridization with rainbow or 1904 from K. P. Creek, a tributary of the cutthroat trout. The introduction of rainbow Blue River of the San Francisco drainage of trout into waters of the White Mountains of Arizona, shows spotting patterns characteristic Arizona began hybridization which spread of 2. apache and not 5. Rilae (Miller 1972, throughout the watersheds until only remnant fig. 4). Perhaps both species were native pure populations of 2. apache persisted in a to the San Francisco drainage of Arizona, but relatively few headwater areas. Due to this in this case it would be expected that hybridi- precarious situation, the U. S. Department ,,tion between them would have produced an of the Interior listed the Arizona trout as array of intergrading populations. endangered. But the endangered status inter- fered with management and restoration efforts and prohibited angling (Christmas Tree Lake on the Fort Apache Indian Reservation was constructed and stocked with 2. apache for use as a native trout fishery), so the status of 5. apache was officially changed from The present known liatural distribution of "endangered" to "threatened" (Federal Register S. Ord Creek, Firebox Creek, apache includes: 40 (137), 16 July 1975). -Deep Creek, and headwaters of the East Fork of the White River; the upper Bonito Creek While '2.apache has been virtually elim- rntershed, a tributary to the Black River. inated from its native range, it has survived dl of these streams are on the Fort Apache in greater numbers than 2. gilae. In some Indian Reservation. The only known population streams, such as upper Ord Creek, g. apache of 5. apache in the Little Colorado River had been found to coexist in good abundance between the towns basin exists in Paddy Creek, with both brown trout and brook trout. But of Alpine and Nutrioso, Arizona, near the New 1974 electrofishing in Ord Creek showed brook Mexico border. A survey conducted in 1967 trout to be dominant and Arizona trout, rare by John Anderson, U.S. Fish and Wildlife (Ron Gumtow, personal communication to Service biologist, and Robert Behnke deter- Robert Behnke, 2 October 1975). mined that recently introduced brook trout had become abundant in Paddy Creek. Thus, LIFE HISTORY the outlook for the perpetuation of the only known population of apache in the Little 2. As Miller (1972) pointed out, almost Colorado River basin appears doubtful. nothing is known of the life history of -S. apache except for the significant fact that its reproductive season and spawning behavior must be sufficiently similar to rainbow trout to permit hybridization. Not all S. apache populations are completely isolated from S. apache has been propagated at the introduced trouts. But while brook trout, sterl?ng Springs Hatchery, Arizona, and a brown trout, rainbow trout, and rainbow X population has been established in Christmas -S. apache hybrids have replaced pure 5. apache Tree Lake, a sport fishing lake created in larger streams at lower elevations and in specifically for this species' restoration disturbed habitat, S. apache has been able to on the Port Apache Indian Reservation. The survive with brook trout and brown trout in Sterling Springs Hatchery is under renovation Ord Creek and has persisted in the headwaters and a new brood stock is currently being of the East Fork of the White River and in established (Joe Stone, personal communication the upper Bonito Creek watershed without pro- to Robert Behnke). The propagation and tection by absolute physical barriers or reintroduction program for 2. apache conducted from introductions of non-native trouts. by the Arizona Department of Game and Fish Such situations resemble examples of native has resulted in the establishment of new cutthroat trout maintaining their integrity Stream populations in Grant, Home, Mineral, in undisturbed headwater areas where they and North Canyon Creeks and streams on .Graham possess the most fit genotypes for colder Mountain (Robert Jantzen, Director, Arizona waters and associated environmental conditions. of Game and Fish, letter to Lynn Disruption and degradation of pristine head- Greenwalt, Director, U. S. Fish and Wildlife water environments typically lead to hybridi- Service; Joe Stone, personal communication zation with rainbow trout and/or replacement to Robert Behnke) . by brown trout or brook trout. The growth potential of S. apache remains Ken Harper (Arizona Cooperative Fishery unknown, but the largest specimen known from Unit, USDI, 210 Biological Sciences East, Christmas Tree Lake, a spent female, measured University of Arizona, Tucson, Arizona, 85721) 48.8 cm and weighed 0.9 kg (Ron Gumtow, is conducting graduate research to determine personal communication to Robert Behnke). the effects of logging on 2. apache in the Bonito.Creek watershed. This project, initia, ted in 1974, is due for completion in 1976. HABITAT REQUIREMENTS AND LIMITING FACTORS

The introduction of non-native trouts RECOMMENDATIONS may not pose as severe a threat to 2. apache as it does to 2. gilae in cold headwater The Apache Indian tribe has, in the past, streams as long as the integrity of the demonstrated a sincere interest in perpetu- habitat is not violated. The complete replace- ating the Arizona trout, but the recreational ment of %. apache at lower elevations and in resources of the reservation are nonetheless disturbed areas demonstrates that this a business enterprise and heretofore the species is placed at a competitive disadvant- tourist fishery has been based mainly on age in such situations. The entire upper stocking great numbers of rainbow trout, Bonito Creek watershed, which contains the par,ticularly in a series of recreational most abundant populations of 2. apache, is lakes created on the reservation. currently being logged. While guidelines for habitat protection have been provided to Ronald Gumtow, biologist with the U. S. the logging operation, they have no legal Fish and Wildlife Service, and advisor on standing and some damage to the stream has fisheries management to the tribe, stresses already occurred (Richard Baldes and Ron a greatly expanded emphasis on the use of Gumtow, personal communication to Robert -S. apache in sport fisheries management on Behnke). The impact. of logging on the Bonito reservation waters in the future. The former Creek watershed and on 5. apache is under endangered status of 2. apache prohibited study, but data sufficient for basing fore- angling and voided any economic gains to the casts are not yet available. tribe from the potential fishing in Christmas Tree Lake. Now that the status of g. apache has been changed from endangered to threatened, PROTECTIVE MEASURES the lake can be opened to fishermen (for a fee) and similar fisheries for 2. apache can The Apache Indian Tribe has closed the be established. waters of Ord Creek to fishing in order to protect the Arizona trout. The emphasis on native trout fisheries versus hatchery trout fisheries is one of The Office of Endangered Species, U. S. quality versus quantity; the greater value Department of the Interior, lists 2. apache lies with trout in the water rather than trout as a threatened species (Federal Register in the creel. The economic rationale is that 40 (137), 16 July 1975). with proper publicity and public interest, the tourist fisherman will be willing to pay The Arizona Department of Game and Fish more for the opportunity to fish for a rare has propagated %. apache at their Sterling and beautiful native trout than to fish for Springs hatchery .from brood stock developed the common hatchery rainbow trout. from Ord Creek trout. At: least four new stream populations have been established. Before %. apache can be widely used to The brood stock was lost in 1974 but the create new fisheries in reservation lakes, hatchery is undergoing renovation and a new data must be gathered from Christmas Tree brood stock is being established (Gary Edwards, Lake on age, growth, vulnerability to exploita- Joe Stone, personal communications to Robert tion and population structure under exploita- Behnke) . tion to provide information on optimum stocking rates and to design special regulations Bruce Rosenlund (U. S . Fish and Wildlife on size and bag limits to maintain maximum Service, Alchesay-Williams National Fish recreational values. Hatchery, Whiteriver, Arizona) has been conducting disease and parasite studies on 2. The watersheds of streams on the Apache apache to determine the presence of fish Reservation and elsewhere with populations of pathogens which could be serving as limiting 5. a~acheshould be granted special factors to endangered populations in the from possible future despoilation, comparable wild, and to determine the feasibility of to wilderness areas of national forests. transferring endangered fish to a hatchery for propagation. Off the reservation, the reintroduction REFERENCES of ;s apache into barren streams and gecrea- tional lakes should be stepped up. This Behnke, R. J. is, in part, dependent on the 1967. Gila and Apache trouts. Rare and of hatchery propagation. endangered species report. Colorado Cooperative Fishery Unit, Colorado State paddy Creek, the only known locality in University, Ft. Collins. 11 p. (mimeo) the Little Colorado River basin with a native pop~lationof S. apache, should be monitored to determine the impact of brook trout on 1970. New information on Gila trout, Salmo S. apache. The 1967 survey of Paddy Creek by gilae. Rare and endangered species report. Anderson and Behnke noted that the headwaters Colorado Cooperative Fishery Unit, Colo- above a barrier falls were barren of all fish. rado State university, Ft. Collins. 12 p. ~f 5. apache still exists in Paddy Creek, a (mimeo) above the barrier should be made as soon as possible. Cope, E. D. and H. C. Yarrow. 1875. Report upon the collections of fishes Specimens from previously unsampled made in portions of Nevada, Utah, Calif- localities should be evaluated for relative ornia, Colorado, New Mexico and Arizona, purity in an attempt to discover new popula- during the years 1871, 1872, 1873 and 1874. tions of 5. apache. Rept. Geog. and Geol. Expl. and Survey West of the 100th Merid. (Wheeler Survey) 5:635-703. AUTHORITIES Jordan, D. S . and B. W. Evermann. 1. Arizona Trout Recovery Team 1896. The fishes of North and Middle America, Joseph L. Stone, Leader part 1. Bull. U. S. Nat. Mus. 47:1240 p. Arizona Department of Game and Fish Box 387 Miller, R. R. Pinetop, AZ 85935 1950. Notes on the cutthroat and rainbow trout with the description of a new Members : species from the Gila River, New Mexico. William Silvey Occ. Pap. Mus. Zool. Univ. Mich. (529). Arizona Department of Game and Fish 42 p.

John Adams U. S. Forest Service 1972. Classification of the native trouts of Arizona with the description of a Ronald Gumtow new species, Salmo apache. Copeia 3:401- U. S. Fish and Wildlife Service 422.

2. Robert Behnke Department of Fishery and Wildlife Biology Colorado State University Fort Collins, CO 80521

(taxonomic investigations)

3. Ronald Gumtow U. S. Fish and Wildlife Service Box 39 Pinetop, AZ 85935

(fishery management advisor to the Ft. Apache Indian Reservation)

4. Robert R. Miller Museum of Zoology University of Michigan hn Arbor, MI

(taxonomy of 2. apache)

Agriculture-CSU, Fort Colllns