Water-Quality Assessment of the Valley, Colorado, New Mexico, 7.nd -- Communities at Selected Sites, 993-95

By Lisa F. Carter

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 97-4017

Albuquerque, New Mexico 1997 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director

Any use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey.

For additional information write to: Copies of this report can be purchased from:

District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services Water Resources Division Box 25286 4501 Indian School Road NE, Suite 200 Denver, CO 80225-0286 Albuquerque, NM 87110-3929

Information regarding the National Water-Quality Assessment (NAWQA) Program is available on the Internet via the World Wide Web. You may connect to the NAWQA Home Page using the Universal Resource Locator (URL) at: /the U.S. Geological Su This information will help st he de\ elopment USGS is the quantity and quality o': and e of mar Jlatory, and moni- earth resources of the Nation and to provide informa- toring det,„3ions by milt Federd, 3tate, and local tion that will assist resource managers and policymak- agencies to protect, use, and enhance water resources. ers at Federal, State, and local levels in making sound The goals of the NAWQA Program are being decisions. Assessment of water-quality conditions and achieved through ongoing and proposed investigations trends is an important part of this overall mission. of 60 of the Nation's most important basins and One of the greatest challenges faced by water- aquifer systems, which are referred to as study units. resources scientists is acquiring reliable information These study units are distributed throughout the that will guide the use and protection of the Nation's Nation and cover a diversity of hydrogeologic set- water resources. That challenge is being addressed by tings. More than two-thirds of the Nation's freshwater Federal, State, interstate, and local water-resource use occurs within the 60 study units and more than agencies and by many academic institutions. These two-thirds of the people served by public water-supply organizations are collecting water-quality data for a systems live within their boundaries. host of purposes that include: compliance with permits National synthesis of data analysis, based on and water-supply standards; development of remedia- aggregation of comparable information obtained from tion plans for a specific contamination problem; oper- the study units, is a major component of the program. ational decisions on industrial, wastewater. or water- This effort focuses on selected water-quality topics supply facilities; and research on factors that affect using nationally consistent information. Comparative . An additional need for water-quality studies will explain differences and similarities in information is to provide a basis on which regional observed water-quality conditions among study areas and national-level policy decisions can be based. Wise and will identify changes and trends and their causes. decisions must be based on sound information. As a The first topics addressed by the national synthesis are society we need to know whether certain types of , nutrients, volatile organic compounds, and water-quality problems are isolated or ubiquitous, aquatic biology. Discussions on these and other water- whether there are significant differences in conditions quality topics will be published in periodic summaries among regions, whether the conditions are changing of the quality of the Nation's ground and surface water over time, and why these conditions change from as the information becomes available. place to place and over time. The information can be This report is an element of the comprehensive used to help determine the efficacy of existing water- body of information developed as part of the NAWQA quality policies and to help analysts determine the Program. The program depends heavily on the advice, need for and likely consequences of new policies. cooperation, and information from many Federal, To address these needs, the Congress appropri- State, interstate, Tribal, and local agencies and the ated funds in 1986 for the USGS to begin a pilot pro- public. The assistance and stwgestions of all are gram in seven project areas to develop and refine the greatly appreciated. National Water-Quality Assessment (NAWQA) Pro- gram. In 1991. the USGS began full implementation of the program. The NAWQA Program builds upon an Robert M. Hirsch existing base of water-quality studies of the USGS, as Chief Hydrologist well as those of other Federal, State, and local agen- cies. The objectives of the NAI,VQA Program are to: •Describe current water-quality conditions for a large part of the Nation's freshwater streams, . and aquifers. -Describe how water quality is changing over time. •Improve understanding of the primary natural and human factors that affect water-quality conditions.

di

P

CONTENTS Pa e ;tract . 'lroduction . 2 Purpose and scope 2 Description of study area 2 Acknowledgments ...... ...... ...... ...... ...... ...... 5 Methods of sampling and analysis. 7 Fish community sampling 7 Analytical approach ...... ...... ...... ...... 8 Fish communities 9 Spatial pattern of community structure 13 Temporal pattern of community structure 19 Summary 25 References cited 26

FIGURES Figure 1. Map showing location of fish community sample sites, physiographic provinces, and ecoregions 4 2-5. Photographs showing: 2. The Saguache Creek near Saguache, Colorado, is within the San Luis Closed Basin and is representative of streams in the Southern Rocky Mountains physiographic province and the Southern Rocky Mountains ecoregion...... 6 3. The Rio Grande below Taos Junction Bridge, near Taos, New Mexico, is representative of streams in the Southern Rocky Mountains physiographic province and the Arizona/New Mexico Plateaus ecoregion 6 4. The Rio Grande at El Paso, Texas, is representative of streams in the Basin and Range physiographic province and the Southern Deserts ecoregion 7 5. Electrofishing was the primary method of collecting fish 8 6-8. Maps showing: 6. Percentage of native and introduced fish from samples collected in 1994 14 7. Percentage of trophic groups of fish from samples collected in 1994 16 8. Percentage of tolerant and intolerant fish from samples collected in 1994 17 FIG TRES—Concluded

9-12. Graphs showing: 9. Relative abundance and total number of individual fish in samples collected from three reaches at sites 8T and 9M in 1995...... ...... 18 10.Mean daily discharge and interquartile range of mean daily discharge for period of record at selected sites in the Rio Grande Basin, 1993-95 ...... 20 11.Relative abundance and total number of individual fish in samples collected at selected sites in the Rio Grande Basin, 1993-95 22 12.Indicators of the biotic integrity of fish communities at selected sites in the Rio Grande Basin, 1993-95 24

TABLES 1. Site number, station name and number, elevation, and contributing drainage area for fish collection sites, and the number of reaches sampled per year in the Rio Grande Basin 3 2. Fish collected in the Rio Grande Basin, 1993-95 10

CONVERSION FACTORS AND VERTICAL DATUM Multiply By To obtain

foot (ft) 0.3048 meter mile (mi) 1.609 kilometer square mile (mi2) 2.590 square kilometer

Sea level: In this report sea level refers to the National Geodetic Vertical Datum of 1929--a geodetic datum derived from a general adjustment of the first- level nets of the United States and Canada, formerly called Sea Level Datum of 1929.

vi W A-QUALITY ASSESSMENT OF THE RIO GRA, VALLEY, COLORADO, NEW MEXICO, AND TEXAS--FISH COMMUNITIES AT SELECTED SITES,1993-95

By Lisa E Carter

ABSTRACT Fish communities at 10 sites in the Rio Grande Basin were sampled during low-flow periods between 1993 and 1995 as part of the U.S. Geological Survey National Water-Quality Assessment Program. The ecology of fish communities is one of several lines of evidence used to characterize water-quality conditions. This report describes the fish communities at selected sites in the Rio Grande Basin and relates the structure of these fish communities to the physical and chemical characteristics of the streams. Twenty-nine of fish representing 10 families were identified in 25 samples collected during this study. Species richness ranged from 1 to 13. Cluster analysis of the 25 samples collected during this study delineated four groups of sites that were based on the similarity of the fish communities. The first two groups were individual sites with low species richness. The third group contained the most samples, and the fourth group consisted of samples from the Rio Grande at Isleta, New Mexico, and the Rio Grande at El Paso, Texas. The shift in community structure of samples from group 3 to group 4 reflects changes from predominantly coldwater to warmwater fishes. Four metrics of biotic integrity (percentages of introduced individuals, , tolerant individuals, and anomalies) were used in this study to provide a broad overview of the community structure. The relative percentages of introduced species at the Rio Grande near Del Norte, Colorado; Saguache Creek near Saguache, Colorado; Rio Grande below Taos Junction Bridge, near Taos, New Mexico; and Rio Grande at Isleta are indicative of biological stress on the communities at these sites. The dominance of omnivores in samples from the Rio Grande below Taos Junction Bridge, near Taos; Rio Chama near Chamita, New Mexico; Rio Grande at Isleta; and Rio Grande at El Paso is an indication of environmental stress at these sites. In 1995, tolerant species account for the entire fish community at the Rio Grande at Isleta. In all samples the occurrence of anomalies was less than 2 percent of the individuals, with the exception of the sample from the Rio Grande at Isleta. On the basis of the relative percentages of introduced individuals, omnivores, tolerant individuals, and anomalies, the biotic integrity at the Rio Grande at Isleta appears to be the most impaired of all sites and shows indications of potential chemical and physical perturbations. Fish communities from three reaches at the Santa Fe River above Cochiti Lake, New Mexico, and the Rio Grande at Isleta were sampled in 1995 to assess small-scale spatial patterns in the structure of fish communities. The spatial pattern at these sites might be associated with natural variability of the fish communities or with the presence of habitat features such as pools.

1 The total number of individuals and relative abundance in a sample var s Iv during this study. All sites, with the exception of the Rio Grande near E :.ad a decline in total number of individuals in a sample. The temporal decline in the tctal number of individuals at these site might be associated with the natural variability within the fish communities.

INTRODUCTION The U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program is a multidisciplinary approach to defining the current status of and trends in the quality of the Nation's surface- and ground-water resources (Gilliom and others, 1995). In 1991, the Rio Grande Valley and 19 other study units were selected for initiation of an intensive study of water quality throughout the Nation. Physical, chemical, and biological data from stream reaches influenced by natural and anthropogenic factors allow for an integrated approach to characterizing surface-water quality within the Rio Grande Valley study unit. The ecology of fish communities is one of several lines of evidence used to characterize water-quality conditions. Although natural variability within fish communities may be high they may still be a useful indicator of ecosystem health (Moyle, 1994). A fish community is a group of fish species that occupy the same general area and can be defined by its structural and functional relations. The structure of a fish community is characterized by the types of fish present; their relative abundances, life stages, and sizes; and their spatial and temporal distributions (Meador and others, 1993). Changes to physical and chemical characteristics of the stream can affect the fish community structure. These changes can be detected through repeated analysis of the total number of fish collected, functional groups, species diversity and relative abundance (Wootton, 1990).

Purpose and Scope This report describes fish communities at selected sites in the Rio Grande Valley study unit and relates the structure of these fish communities to the physical and chemical characteristics of the streams. Fish communities were sampled at 10 sites in the study unit from June 1993 through September 1995 (table 1). The influence of a stream's physical and chemical characteristics on the fish community was determined through regression, correlation, and multivariate statistical analysis, and community structure analysis.

Description of Study Area The Rio Grande Valley study unit covers approximately 45,900 square miles in Colorado, New Mexico, and Texas (fig. 1). The Rio Grande crosses several climatological zones as it traverses about 750 stream miles from its headwaters in the San Juan Mountains in southwestern Colorado to El Paso, Texas. Climatic differences are extreme from the headwaters of the Rio Grande (alpine tundra) to the lower boundary of the study unit (Chihuahuan desert). Climatological characteristics and the environmental setting of the Rio Grande Valley study unit were described by Ellis and others (1993).

2

:ion lcr. ...oniributir rea for •:ollection sit and sai _ ar in the F , asin

, ure ; N not collecl

:71 te name , 7,980 1,311 , Colo. 2C 13 8,030 512

B -150 15.3

4T 7,495 o. 5N1 6,050 u rrction

\lex. 6T 0000 5,653 near 7T Rito lus 08313350 6,140 in Bandeik. 1. .;nLIrrier ex. 8T 082:17220 5,505 228 U

9N1 nde 4,896 i-1,537

Rik; '22 30,076 at 1-,

1n-T1 01.1.A isL:lxh during ApHI d:10. No\enTher 1994 and arc eiidere.i Figure 1.-- Location of ash cc: n-1 unity sampie sites, physiographic provinces, and ecoregiu

4 attempt iogeneous an nian (IV40) identities uiree major (raride 1): the Southern Mountains redorado Plateaus, and RL.rir. -rovinces, Physic comh-ion ne and structur,-, (1987) ider 's in the stuis ecological are classified by spai V . phys se and cover, and ncar s the f-? SOUthern i\CA viounuins Crd il( aos junction e, near Taos. Nevi. ytexii.u,

tAl MS h rcgrarhic province and the xiCe (tie 1 lit (-ranch.' al ri Paso, Texas, is .motive SLIV.:1111S Ole \ince and the Southern region 1.111 to reflect the differences among the

,•=iten i -reserve :rye „Ind strearriflow contributions .from s.everal

- itet sLrearnilow of the result in serial discontinuity CiNard and i83) rattitr ttdfl a river and others., iror-r Del scveral trirutaries ow it., int-, Grande ario, ihere are relatively iversions. Near Dc [cant irriga10ri diversions occur, dnd the voter is diverted into the uis Bashi which is sepor,.ited from ground-v,ia dividc. Sites '‘,.-ere silected in asin, ' e or these tr do m dire the tin rrit-.:aut season, streams t1d1n MOUPtaillS uthivst of Al.lmosd, Celcrado, and de Cristo- INdountains JdfliOsa are and little oi nowatier kici Grande, i,,,round-water disci e to the Rio substantial cont stream fiow het;-. -en the C.olorado-iNew :'‘ilexico State

At-1,s ov,r' I c -Tilents

Fish communities we7,-! sampled •itil the ss1stance of individuals from the U.S. Fish and life Si Colorado Division o New Mexico Deportment of Game and 'lex '

Figure 3.--The PrD Giande below Taos Junction Bridge, near Taos, New Mexico, is representative ot streams in the Southern Rocky Mountains physiographic province ard tne Arizona/ New Mexico Plateaus ecoregion. Photograph by L.M. Bexfield.

6

4.--The Rio Grande at El Pa.so, Tcxas. sfepresentative oi streams in tl,u basin and Range physiegraphic province and The So:Ahern Desers ecpfeoion. Photograph by S.D. Porter.

METHODS OF SAMPLING AND ANALYSIS iral-n-sterr, . lies. and Fish sae:pies were collect's-d. frcin ialirt stern 1), Sites ;vere identitiied nianurica 1 to tw, • "- n <;?.--: Luis Closed Ti tie alphabetical (•ist:tint-i(n of main st tributai t„ or San ta3).

(-)r- suction of strcini, -:srihe t= fish ocimmur tr that re';ertt ti-- COndi tiOr fne • Thnt Fach reach selectJ2:1. (-4eetd. diversity that St twf.- labitat 111c, 57,s-r-leous with abitat v: 'e, he ler:th th( reach 20 chatinul One reach at each site, -evil at sites and ftityl. in 1995 three reaches, at ilea-,t 30u meters ‘.-(.1 .e selected at sites ST an 9M to cleterinne i: -. treani variability of fish communities and red chemical characteristics hetween reaches. At sites 8T and 9M, the three reaches identified from upstream to dc; stream a' A , B, and C. All fish collected at: a particular reach a single sampling event were considered one sample. fish communities at 10 sites in the study unit ere sampled between 1993 and 1995 table I). Most samples were collected each year du ring the miner period - S(.:.ptember). At ,;ite ISM sampleswere cr-41ected during April and Nov,,17.- ,,•er 1994. rauld not be collected at each site during each sampling season because ot prohibition c. local restrictions or unacceptable sampling conditions such as high flow, or turbid , Luting the 1993 and 1994 sampling seasons, attempts to collect samples at site 8T were ur ucessful because high flow and turbid waters reduced visibility

7 and

11 the plicabilityand efficienc , ack 5)

have relate data ;Ddit.1( r a • based. Regres:-..ii.JranaIvQa can be used to vironn chiln.-teristi aid chemica related to recies Pr; omponen( can be us€-,...1 to det,Trn:ne the overall oro.- ;cai al -ha r,letclistic. 111:,ter an :il,npute?

1111.1 -11:' cr-mth..4 on-. the Q11.1!---

Figure-Sector g was he primmethod of cone ing fish. Photograph by 6D. Porter.

Y structu . ics, ne tai conditions. Iwo ineulous u cletermim, been p, biolNrical Condit: he

: ace and e t ie index i into tht.,- 1,..arr nor a nd %Yinect It) Inc existing C 'TM ,t .,.ca : a s need e c. f these Pt Rio G — did r: t Hci u dt2 developrni?nt of a basin- -colic index of -au iv ieHc r.tetrics (percentages of introduced individuals, or '1:hvores, tuierani. individu 7ropi tsed by Karr (1981) were used to provide an i ,verview c,f and biotic integrit- ,.- the Rio Grande Basin. individual fish duped trophic group, al ..,(1 C.'31 torleance to water rju aiit anitat L :no lassifications established bv 'Plat:Kin and others iataria (Universi N lexica, c-,ra1 commun., 199(.5). On

rigui a 11 , eCieS ad either oath - introduced. Although introduced resencc ad trod iced lis11 species rreir. -wctc.(1.

- -in hiet: or the disiurban,es ass otted with introduced (ion, anti dis.-, lacemeini nativc Tri.-..phic groups lerbiyorei are based 1 -nefiloci a of a al tf an Si Cer. era iia -d dati or. of . Omni\ ores 111 particular art' hcant quantities of bi 't. plant and materiai, iet rthis .' domina t corn munities as specific components of the anti (-.thers in misstud: were classified as either physical p.,erturbatior. are ; , d intolerant sr:ecies eg the first to dis1 rereentaige of individuals hair Id Les 1 icr su-ess viati iv unimpaired sites the pe.rcentage L in idnals wan a nalies commo v.ereas at sites clo-v.nistream thAr_ point sources anornalie:s can be high (Hafkin and others,

IrISI-I COMMUNITIES

r 4ecies of fish representing 10 fandlies were identified in 25 -,-. —Ties collected is study (table 2). Species richness, a measure of di% ersit ,, that reters to the number of irei- I siet ies in a sample, commuiiin) , or habitat, ranged from I to 13. Flit' number of species pit art. eiatc d h. vie con tributi: drainage area at each site. Species richness increased hnas e area (r2 = 0.92). Shelton (1968'], Goldstein (1981), and (199 ,orted ar increases in:species richness with the dow eam succession of a in er ystern's fish commu:

9 Table 2,—Fish collected Tiber locatic fish bas 1991 •-•am-stern L.:2k'. • 0, a

Comrn Toter .n,..-: MI C13 .- C ' .4 .icitiac Herrin--; Dorosoma cepedianlum Gizzard shad 0 Intolerant (yprinidae Carps and minium s Cyprinella lutrensis Red shiner 0 Tolerant Cyprinus car 0 Tolerant pandora Rio Grande chub 0 Intolerant Hybognathus amarus Rio Grande silvery H Intolerant Pimephales promelas Fathead minnow 0 Tolerant IL,iiciv Hut minnov. 0 Tolerant Platygobio gracilis Flathead chub I Tolerant Rhinichthys cataractae I Intolerant + Suckers Catpiodes carpio River carpsucker 0 Tolerant

::;US C(' ,.':/:) ..1i \V l' ; ''' ueker 0 fir[ pleheius Rio Grande sucker H Intolerant 3,,sucidat Pikes

Nr1: crr i 1 ' P Intolerant +

Saintonidae Onchorynchus clarki Rio Grande cutthroat I Intolerant

Onclu ,rmhn R z . r bow trout I Intolernnr

.c(Tipn( i::11.(i I toleranl

:: ' :ii..c.i.i.‘: I iRicrnrt I ctaiuridae Bullhead low bullhead I Tolerant

r ,: Aiins Channel C Tolerant

Si( lis olil f;ri., Flathead catfish P Tolerant

10

3ublette and oth_ Platania 91 (shaded are -sten Basin site; T ivorp• P, pre . seflt

S , ...... - .. I

,1 - :: , TOlerant 11111 Ga,:le -o,liidae :'-i cidekit k IIIMIIIIIIIIIIIIIIIIIIMII III Cultic(' inconstaris Brook stickleback T Intolerant IR Percich t It) itiiie - 11113C rat fe basci-s IIIMIIIIIIIIIIIIIIIIIIIIIIIIIIII ME11111111111.11111M P 'ler` - IIIMIUIIUIIINIIIIIIII iitrarctiiiiiit, Sunfishes IIIIIIIIIIIIIIIIIIIIIIIIIIIIMIMIIIIIIII 4itui wit iiii., Green suiiiili i. i . rt 1111.1111111111 Lepoinis macrochirus Blueeill I Into IIIIII El IIII I & nge,, : fish . '11 'ra:11 1111111111111111111 III . :Fil 5,,ecies i IIIIIIIIIIIIMIIIIIIIMMII . .;s 11111111111111.1111111 •.ti bass P tritIera71 11111111111111111111111IIIIIIIIIIEIIIIIIIIMIIII IIIIIIIIIIIIIIIIDII 111 s.0

aIIIIIIIIIIIIMIMMIIIIIIIIIIMIII 7 II

ti onuliN,i-t, IIIIIIIIIMIIIIIIIIIIIHIIIII 4 EMI C' . .1 toitraiii 'f1ivi(itiais

9S9-, Subleta rid. 199n t'civ Nlexico,. oral CoinrIlir 1996 S.P. exico, oral c(I:i1iUL, 1990 h:He

uriia rid l94 and fri u I L • h (.1 iii 995

11 rtcc also r do; addition. to cvprinid tt in :,do (Woo .G ( ed lakes and r Ric ',.:;rande Lia in ( other H, to be s ethers ;1alf

rep :'.cc arnor Hes Liitai tt_

Clu:- h, ) relati of the t tour grou uals) in lit. ,I:1 ail j i.i-c t. . tee WaS 10" 0-- slinilan wess -

4 'la.' , fni 'ad III] nil( fluence gr our. ors 'c

trk

tt at:( undance -• .1%- ' • nil Rio This indicaLes thee. brown as and Rio Grande sucker

Of the thr ie selected chemical vo,tiabies, c(a-reletion with specific -clative abunclanct .,nducw1 ', undante of s was nc , eh; 'Led ith spec i4- •an -- ,ir.. ei v an- ink .1 C' ulus or ..._ ogen 0.r srecti‘ :Lis indicates that ow n ut ,-'ild longaose ciai e are indioR Grande siliker are n': re abundantsites re specific conductance and ammonia plus nitrogen is high. Furthermore, the rdat:vi: abur -“ian& of the brown trout, Iorignose dace, and Rio

12

f -ILAN t - 1110.141[7:71 tm 14.4t s anua nd tPr temperati .-. can influence ibu

It.' ....duced spe ies ( 1,...Oble 2 ...se (table tilt.- number nine (i e trr1 anitnlic than of

5)

the limited to. sites

" 7 11a t iO n P e rt:l in l• ..ind biotic 11 ither six (sites e T.

k :duals, aild anornalit- -.: :41'llti,':i envircvniental 1.-:-. v. -ert.: dc,hdnant. at site- . 2(.13, 5N1,

nc:tive .- --, cion-on -,,e ,. (2,1 -I OM ( .1k-ernber relati ve of brvrtr ,...., ut arO \-...::: e - ckrr site I\i (34 and 2 rce nt . rep, - el 1...- i ;I .....:rd 'nu, ective - ‘ the , , ,.i cit. species \ . - ith a e a ., 1 d,q --.tt , v on percent; bro ,,,:n in '',, -; cr.. corripc ,..-,ed le.;_-; 5 percent of thc' hs.b. comtounttv. Introduced channel catti onimor carp, and white sc.• . with relative ..::c:arc ' .1, r, and 25 percert, dominant at site ' The relatis. -t, ,, ,,-,.f.-.---, of introduced 5-.;pec. i, , ate-,-- 1:‘i. 203, 5\1, and 9M ...- , yr. , L(r.,,1:::: t:-.1e , lmunities at thee site5. "I he natiVe Rio Grande chub and (.., .-, - 'rcert of the f .:sn con-11:-., ;nit- At site 1.UN1 th a : .eldtisce Silrlipfe ' native .,..., cni t.,-- e ccvdnmrt specic abl.ndance of 5.3 ilercent.

13 Figure 6.--Percentage of native and introduced fish from samples collected in 1994. 11.'41

:en 1611.F. II s .j.te is an indication of potential phvsicochen .abitat degradation _vcr ach site dui - and lominant

1":2•*r

anc. 1 1:11'.77- t• el-cent, r nu -,Icr and -ple) ar, toles is a -, ercent, . of the c , -sucker w inni tolerant . 1:.,ccies tes. tolerant species; con-snu: 9M in I994 st:ng il chemical or p s site. in ziercent the in tb : observe- - 14 hilt; at this site.

Jan at icier as

4 the deeiCaSe ih' • the a.se relative which onliv •-• ti•eL tati-iead

CO! . might nces of habitat

1,1-IC appears to s from those at reaches A react tiiie sucker, and channel atfish had similar relative and .t). and at reacr. b. common carp and white had a relative abunda C Tcent and channel catfish had a relative abundance of 41 percent At reach C t t incre: e abundance of cominen cap (53 percnt) appears to nclances ref w-bite sucker and channel ciitlish (12 and

--rrcThti bc'tween pnvsicnl variables (channel width, depth , rate) tcr tempera: a.- t i.i-scived. oxygen and specific ctance; reach. sitec M. The spa a I i;h comar.uities at site 9M could be attribu natIrci variati' the fish cori -Irnuni ies. Figure T—Percentage of trophic groups of fish from sar - pic collected in 1994.

16 30

801'

34 (

STUDY 33' - UNIT BOUNDARY

Figure 8.--Percentage of tolerant and intolerant fish from samples o ected in 1994. B REACH

E, Fathead minnow Flathead chub Rio Grande sL.cker Western m•squitot- - Green sunfish ANC

60

ABUND 50 VE

TI 40 62 49 32 RELA

1

C REACH EXPLANATION Common carp Flathead chub River carpsucker White sucker Rio Grande sucker Ohannei catfish 62 TOTAL NUMBER OF INDIVIDUALS IN A SAMPLE Figure 9.--Relative abundance and total number of individual fish in samples collected Iron -. three reaches at sites ET and 9M in 1995. 18 Although till . - tata may not De aciequate to establish a tri tet ire at sites 2C.B, 7T 9 p,..,_,,,,th .11) • : -=1 : - 1_1 1-1 r Pr f-; ciono.-, -r chen:I. ith r.i:ilizet co- ,--.3cki !- ciectror:si sae year. (sped conductance. d ammonia r . :ganic nitroge n ;

a:- int i+ L . I.. site is , the tim !tt iluraDon s :wear= nortant en ‘ -tronntental idctor intlucucir tt—Inq Tot in- total er cf inclivicittah= sites 1M, 2CB, 71, and 9M. be sse.ciatt'd cratural variab 11 mrnurfitie --, - it ariabiY:". r11-r. dna aege at these sites. Nk-an daily disch it sites ac-It: t the mean d ali e for the Le 9M. data trom ande ilutterc;1. esUmate the rre ,utdal lv o 1.1 a Ft -nod ecord at this s e'::1=efrL ?oral ctudine VidUak ttn t individuals Al-ter yE', s ft, PJ9.5. the total iai'- t. tun ipals in 1994. 1 1 :r of intliv: I rot !-virouruentai stream the :; -1 e:71: tuinediate 1995 exceed th.•

cd fa acer iva ls wa s a hou in 1 99'1 iith et um ber o f ind ivld u Mean daily disitthalt as o:t zwailable rear in time of salvulira at site /1 ITI 1993: the dailv discha .,: thi- , .t.;t at , s .,-..- ithin t .. icthartile range c...... :he

in V');:.. ....eVer at s.., 1 te 71 iii 1 i‹. i :OW e' ;{:,.. ,,_--, ,-ci_li'reci short . 1 ....iirm: -13. , (1 re. r. dailv difi. -: e exceea - intt. c rtiic- ,r He ns-cord during two perft..d.s within the in conts crier to sdrilhi number of indivicit.:i, is :.. -as abeabet in..rcent of the ii,..n-ribet of indi% -Lois in At site 9M (re;--Ici ,. B in 199. the esUmated an d schdrgeat 13) was within the estimated u-i uartiila the !ecord 199'5 Cne rit‘af: disc interquilyt: 0, for an oxtended period prior to sarnp total number of individ about 71 percent o the number of dividaais in 1991 and abet ercent of the nu tr.ber individuals in 1993.

19

(,D

100

R YEARS Site 1M penc,(' r,-,c,ord is water yczkis 1926 ,-95

LOCO

0

th

20

10 1993 1994 WATER YEARS Site 2GB period of recorr: water years 1915-95 Ef3PL„ INTEPOLAPULE 1-2, ;,NGE LIE:.."4 ;,JLY HARGE FOR 'ME RECORD

Figure 10.--Mean daiiy trterguartile range of mean daily discharge for period of record at se!ected sites in tho Rio Grande Basin, 1993-95.

20 Figure 10.--Meandailydiscr.age andint

DISCHARG E, IN CUBI C CU B IC FEET 10,000 2 at selectedsitesintheRio GrandeBasin,1993-95—Cncluded. Site 9r Site 7Tperiodofrec rtlie rangeo: 21 WATER YEARS W T

or dailydischarge forperiod of record ars 1984-95 1974-1995 DISCHARGE Uri 5

BO

70 Site 1M Site 2013 60 520 50 T 40 EN 30 20 PERC

IN 10

E, 0 I I , NC r minn DA S, ,, c1; -, w trout YNn trout Ir riaInnov:

ABUN 100 Site 7T 80 140 6P LATIVE 60 RE

40

20 10

0 10/0, 10/r i EXPLANATION: Hbow L , ut Ir , )1J1 100 c. -:!-;• ;.:

TOTAL NUN/IDE...Ai OF INflIVIDUALS iN A SAMPLE

Figure 11,--Relative abundance and total number of individual fish from samples collected at selected sites in the Rio Figure 12..--Indicatorsof the bioticintegrityoffishcommunitiesatselected sitesinthe VF PERC ENT RELAT I VE PERC ENT 100 40 60 80 20 Rio GrandeBasin,1953-95. Tric:MUCED 10; NIVORE EXPV , 24 7:,L - 17 HRANT 1S135 ANO PS

as ul gawp samrloL the or bb integs - at

- ,:enta the pe:: noti

, ta iduals : to the z). The dttributed sampling ,:!nber of

iduals be an co the prey.: ears.

na

Bent

c

''''' ''''' '' , A ID

:nentai

, U St ,sitc L - h, and - 1993 toleran wdwdua R dition, the 1 +smAxb y tinyei sa

+. 1-0/

2nic facto he it iron dccu drileten, multivariate slat introd cted Wi th

: cc ( 1 (..,.. ciehneatec tour I 1 min fie,-. i i..- 1 The thir±t groiT coco ntained the I )st Sar. -tiet--, c e) N1 :-It tom. The shift in conullun;.t..,, structure ch:-ir fi On- ■:.'reliC. , :il..1 Lan ' i' . 1:01i,U,'.. iitti .

C he l".11

;St" f COI a11 I.' 1 t1_11' t::

; 1- 5 \at'on , 1--,..1a,.. I ( Ltance a i ,. Nio t on "tie\-atic., 1. riviat' c.cinc 1 .;--1( sti:4,..,st that ts, t. ,_.once of the ty: - .. _. aA c r.e , i'et .!-• i 7"!. dicatoi ,, ,. a

t yi ; to

, : 17111) ,0,..- ,.- 1 d bi , , .1 r fa , :::.i..rini'- , t ; ('It'. lic ,numaiie re\-, : Imp_ si nice-. ,f t i 'ntial i:i'l Vi 1.0 nmental r?- [-{;c;`; to c Lonunun iim; na E. sr; -, octi. ..1 fi , ininant at ,.,:ites 11\1, 2C1:`:,, 57,,,I, a nd 1 --CIttlpie) rel.i!-, %-‘:. p, vcvntages of illtrodu , 2 nt. rrh la , 2C14, ii(ati% ( (ti •! Ili: (7pinn -. at

...... site and 2C Own to11 (No\ ,Thc. wit) are 1.:tizard shad, sunfishes, •it.e ct , .picies-, white su both -ites oterant species account for the entire fish com•un, nonryittal ctress at this site.

25

'igh three con-in in strear , Ira tic:: important t. ann-tuna - total nu nev ot ihdi‘ ia k/F:IS iples oars :It: at sites I NI, 2(.. ft If, and is.1 (reach 7 An sit,;:- with i ii e 1OJ ite • of individuAs in a sample. The r of indi‘ these site be associated with the hill al

tt a number of indivitiu:Tils III 2f...11T7 „ an: M (rea The cornn in UILOCt 7c relatb. e

LI tt 1012

11LFLtU\_LS CITED

o:.- tuatior : in the 0_,Chiti 7.7im-Iena Pda.nrea,

Variable .fish comtn unities and the i ndex TranIsactions c.1 the i.\merican Fisher :es

Rio Gnu .de Vafle lc\ Amer --,.\\ater Resources Association, INat-r

iThvsical divisions of the United States: U.S. Go: ' Survey. ,

e r con.: (al:, parameters dci ed froni rec ctsi nic catches -Iters of er.eiontrienta I quality, iii hen:inar on if, d ter qualito manager: - -oral:tent:al Proto,-(ion :Agency, Wishingtori, D.C. IA

Piet ; 7777, 2nd Grirtz, I9.5 , Pesign of the National Water-Qua: :\sscssnent 1 . ! in--Occurrence and dif-trihution of water-quality conditions: U.S. Get- I've; Circular 1112.33 p.

26 t I .itudinal in impact assessment of n" -to-sociation 12est: v. 17, p. 75-

iicroconinuteff t 'o% L Kan-, 1.17.: grit H Sh con-111111n 6, p. five on water oual nvi: 'S. • I tfueier„ EL, Yant, P.R., and I

- aters--A rnethod and it:: r.;. I Lauber or

t -Q1 1i1 '1.

fkh coinn

it 00: ,1

1 q87, inous United \nnals of the Ass,..'ciat it-in of

Irtiour, t., hot 11 t protocols 1; imental l'rotec

p ie hthution: tern Ntiti: 1St ,

Shelt, -7- peCICS • p. 193-

he fishes of Nev,- A11-0

., and Cush CI The river Fisher, 2.,quatic tent_e ;al dIr! n.TinLrlty concept ot VPal nics of °tic eeosystei

, Ct little tishe,---A guide to the ii•Itint s aCId oth L-iate of Colorado: Cclora,! Division of Colo.„ ot:f'n, R. Ecology of teleost fish: ondon, Chapina- and I baIl 404 p.

27