ICHTHYOFAUNISTIC CRITERIA FOR CIBIN RIVER (TRANSYLVANIA, ROMANIA) HUMAN IMPACT ASSESSMENT

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1 Travaux du Muskum National dlhistoire naturelle ((Grigore Antipa)) Vol. XLII pp ICHTHYOFAUNISTIC CRITERIA FOR CIBIN RIVER (TRANSYLVANIA, ROMANIA) HUMAN IMPACT ASSESSMENT DORU BANADUC Abstract. Ichthyofauna study along Cibin River reveals the following criteria for its human impact assessment optimization: species richness, fish assemblages (Salmo trutta fario - Cotha gobio gobio; Percajluviatilisjluviatilis - Leuciscus cephalus cephalus - Phoxinus phoxinus phoxinus), dominant species on particular habitat (Sabanejewia romanica) and indicatory species for specific biotope conditions (Salmo trutta fario and Cottus gobio gobio). R6sum6. L'Ctude de I'ichtyofaune le long de la Rivitre Cibin releve les 'critkres suivants pour I'optimisation de I'haluation d'impact anthropique sur cette rivikre: le nombre des espkces, la structure des communautb des poissons (Salmo trutta fario - Cotha gobio gobio; Perca jluviatilis fluviatilis - Leuciscus cephalus cephalus - Phoxinus phoxinus phoxinus), les espkces dominantes dans les types particuliers de habitat (Sabanejewia romanica) et les esptces indicateurs pour des certaines conditions de biotope (Salmo trutta fario et Cottus gobio gobio). Keywords: ichthyofauna, biotope, human impact, Cibin River. INTRODUCTION The Cibin River Watershed is situated almost in the middle of Romania (between 45'0' and 46'20' northern latitude and between 23'4' and 24'59' eastern longitude) in the south-west part of Transylvania Depression (Roqu, 980). It springs in the northern slope of Cindrel Mountain and it is properly formed at the confluence of Rdul Mare River (watershed surface = 95 km2, length = 20 km) and Rhl Mic River (watershed surface = 46 km2, length = 2 km). The first one springs from the glacial Iezerul Mare Lake (surface = 34,00 m2, depth = 3.3 m) at 920 m altitude and it is considered the origin of the Cibin River (Ujvari, 972). In the upper sector (springs - Gura Rhlui Village), the river has a medium slope of 50%, an iregular longitudinal profile and rapids at Cibinului Gorge, Gura Siidurelului, Gdtul Berbecului and Tiliqca. In the Sibiu Depression, which is drained by Cibin River, the medium slope decrease to -2.5%0 (Posea, 982). The main tributaries are: Siiliqtei River (watershed surface = 25 km2, length = 26 km), Hdrtibaciu River (watershed surface =,03 km2, length = 88.2 krn), Sebeqului River (watershed surface = 94 km2, length = 28 km) and Sadu River (watershed surface = 30 km2, length = 45 km). The Cibin River (80.3 km length and 2,237 km2 watershed surface), is the main tributary of the Olt River middle sector (Ujvari, 972). Because of the Gura Rdului Dam on Cibin River and of an important damhydroelectric power station system on Sadu River, Cibin River has not a natural regim from the hydrological point of view.

2 366 DORU BANADUC MATERIAL AND METHOD Cibin River was researched along its entire course, 2 sampling stations (Fig. ) were chosen according to: the valley morphology, the type of the river substratum, the confluence with main tributaries and of the human impact presence (hydrotechnical works, pollution sources). At this 2 sampling stations on Cibin River another 2 were added on the tributaries Hirtibaciu River and Sadu River (H and S stations) both of them, at km upstream of these rivers confluence with Cibin River. For the description of the biotope conditions we considered: prevalent river substratum, maximum riverbed width, medium flow and maximum depth. There were utilized also some physico-chemical parameters provided in kind by the Aquatic Biology Laboratory of "Lucian Blaga" University: temperature, ph, total suspensions and DO. The fish sampling was made in October 999, with a net (6.5m) handled by two persons and a hand-net. The ichthyological material was fixed in 4% formaldehyde solution, than preserved in alcohol 70% and included in the collections of "Grigore Antipa" National Museum of Natural History from Bucharest and of the Department of Ecology of University from Sibiu. Fig. - The map of the sampling stations

3 ICHTHYOFAUNISTlC CRITERIA FOR CIBIN RIVER (TRANSYLVANIA, ROMANIA) 367 RESULTS AND DISSCUSIONS In table no are presented some physico-chemical features of the sampling stations, the sampled species and the number of specimens. Cibin River ichthyofauna. The qualitative difference between the 50-ties, the earliest period with a relatively complex ichthyofauna distribution data (Biiniirescu, 964) and 999 Cibin River ichthyofauna is determined by the appearance of four new species in the river (Carassius auratus gibelio, Lepomis gibbosus, Pseudorasbora pawa and Gymnocephalus cernuus) and the disappearance of seven native species (Cottus gobio, Barbus barbus, Alburnus alburnus, Gobio uranoscopus fric'i, Gobio kessleri kessleri, Carassius carassius, Aspro streber). In the context of the Carassius carassius regress in Danube Watershed and its replacement by its more competitive congener Carassius auratus gibelio introduced in Transylvania Region in the late 40-ties (Biiniirescu, 993), in the Cibin River only the last species is present now. The North American species Lepomis gibbosus introduced in 89 in Germany was spread in the Danube and Odra watersheds. First time reported in Romania in 9 0 in Banat Region (Biiniirescu, 993), missing before 964 in Cibin River (Biiniirescu, 964), it is now recorded in this river too. Gymnocephalus cernuus, a well-known common species in Olt River (Biiniirescu, 964), can be found in present in its tributary Cibin River, too. The incidental introduction of Pseudorasbora pama in Romania in 960 and the success of its natural reproduction and spreading, transform this species in a common one in lower and middle Danube Watershed (Biiniirescu, 993). Now this species is a common presence in Cibin River, too. Except the intraspecific competition of Carassius carassius and Carassius auratus gibelio, there is no evidence that the new introduced species determined the disappearing of the native species. The causes of present ichtyofauna structure analysis. The variation of species number from one sampling station to another (C,-C,,), along the longitudinal profile of the Cibin River reflect the human impact presence and the main tributaries quality at their confluence (H and S stations), (Fig. 2). Fig. 2 -The species number variation along the Cibin River and at the confluence with the main tributaries

4 368 DORU BANADUC Sampling stations and material Table I S t a t i o n CI C C3 C4 C5 C6 C7 Sampling station location 6km Iezeml Mare Lake 8 km Iezeml Mare Lake (Cibin Gorge) 0.5 km upstream the confluence with R5ul Mic River Gura Rlului Dam Lake km Gura Rhlui Dam Lake km Gura Rlului Village km Orlat Village Biotope features Species maximum river bed width (m); medium flow (m3/s); maximum depth (m); prevalent substratum; DO (mgil); Temp. (T); ph, total suspensions (mgfl) m.r.b.w.-7; m.f.-.9; Salmo trutta fario m.d.-0.50; p.s.-stones, cobbles; DO-9; T- ; t. s.-59; ph-7,s. m.r.b.w.4; m.f.-.70; Salmo trutta jario m.d.-.20; p.s.-cobbles, pebbles; DO-8.50; T- 0.5; t. s.-85; ph-6.8. m.r.b.w.-6; Salmo trutta fario m.d.-.30; p.s.-cobbles, pebbles. 658 m altitude, 3.5 km length m width and 65 ha surface. m.r.b.w.-4; m.f ; m.d.-0.3; p.s.-cobbles, pebbles; DO-9.6; T- ; t. s.-6; p~-6.6. m.r.b.w. - 5; m.d. - ; p.s. -cobbles, pebbles. m.r.b.w. - 8; m.d. -.50; p.s. - cobbles, pebbles, sand. Salmo truffa fario Leuciscus cephalus cephalus Phoxinus phoxinus phoxinus Perca fluviatilis fluviatilis Phoxinusphoxinusphoxinus Orthrias barbatulus barbatulus Phoxinus phoxinus phoxinus Orthrias barbatulus barba~ulus Phoxinus phoxinus phoxinus Sabanejewia romanica S P e c i m e n S C8 3 km Orlat Village m.r.b.w.- 20; m.f. 4.24; m.d ; p.s. - cobbles, pebbles, sand; DO-9.8;T-.5; S. t. - 23; ph Leuciscus cephalus cephalus Alburnoides bipunctatus bip. Barbus peloponnesius petenyi Cyprinus carpio carpio Carassius auratus gibelio Sabanejewia romanica 2 4 4

5 ICHTHYOFAUNISTIC CRITERIA FOR CIBIN RIVER (TRANSYLVANIA, ROMANIA) km upstream Sibiu km upstream Mohu Village.5 km Sibiu cleaning plant km upstream of the confluence with Cibin River km upstream the confluence with Cibin 3km upstream the confluence with the Olt River m.r.b.w. - 20; m.f ; m.d. -.8; p.s.': pebbles, sand, mud; DO ; T - 4; S. t. - 54; ph m.r.b.w. - 8; m.d. - 2; p.s. - pebbles, sand, mud; m.r.b.w. - 8; m.f ; m.d. -.2; p.s. - pebbles, sand, mud; DO ; T - 0.5; m.d. -.20; p.s. - cobbles, pebbles sand. m.r.b.w. - 6; m.d. - ; p.s. - cobbles, pebbles sand. m.r.b.w. - 35; m.f ; m.d. -.2; p.s. - pebbles, sand, mud; DO - 8.6; T - 8; S.t.-76; ph-7.. Table (conti Leuciscus ce~halus ceahalus Pseudorasbora parva Barbus peloponnesius petenyi Cyprinus carpio carpio Carassius auratus gibelio Cobitis taenia danubialis Sabanejewia romanica Lepomis gibbosus Percajluviatilis jluviatilis ~~mn~ce~halus~cernuus ~seudorasbora parva Barbus peloponnesius petenyi Cobitis taenia danubialis Gobio gobio obhtsirostris Pseudorasbora parva Leuciscus cephalus cephalus Alburnus alburnus alburnus Albumoides bipunctatus bip. Rhodeus sericms amarus Pseudorasbora pama Barbus peloponnesius petenyi Carassius auratus gibelio Cobitis taenia danubialis Sabaneiewia romanica Sabanejewia aurata balcanica Leuomis nibbosus - Gymnocephalus cernuus Gobio aobio - obhtsirostris Salmo trutta fario Orthrias barbatulus barbatulus Leuciscus cephalus cephalus Chondrostoma nasus nasus Rhodeus sericeus amarus Orthrias barbatulus barbatulus. Sabanejavia aurata balcanica -

6 370 DORU BXNADUC C,-C, sector. The indicator species Salmo trutta fario with the well known biotope preferences in all its life cycle reveals the responsible stream fishe distribution controlling factors in the sector: medium river slope 50%, the high DO values, the low temperature, rapids and stony riverbed. The missing of human impact is reflected by the continuum presence of this pretentious species at least in the last 40 years (Bhiiriiscu, 964). From this point of view this sector (25% from the river length), due to the relative isolation of the area, is a singular situation on the river. C,. The replacement of the local mountaneous fish association (Salmo trutta fario and Cottus gobio gobio) with another one (Perca fluviatilis fluviatilis, Leuciscus cephalus cephalus, Phoxinus phoxinus phoxinus and Salmo trutta fario) is an efect of a discontinuity in the lotic continuum of the river due to Gura Rfiului Dam Lake formation. These new species on the area, more competitive in the new biotope conditions, induce a continuous numeric decreasing (local foresters' information) for Salmo trutta fario and completly eliminate Cottus gobio gobio. C,-C, sector. The status of the inferior trout subzone indicator species (Cottus gobio gobio), dominant here before the dam construction is uncertain in the present. It wasn't sampled at all and has not been reported since 995 by the local fishermans. The actual inexistence of this ichtiological subzone (8 krn long in the past), reveal major modifications due to the new hydrological regime, mainly caracterized by a water discharge variation between 0 m3/s and 832 m3/s, due the lake water management. The presence of a small second water acumulation 0.5 km the dam, offer a refkge area in the periods with low or no water on the river, for species like Leuciscus cephalus cephalus, Phoxinus phoxinus phoxinus and Gobio gobio obtusirostris, which live now in the past bullhead area. C,-C9 sector. The first appearance of Sabanejevia romanica in samples, reflect the river contact with the Sibiu Depression, with important changes in biotope characteristics (the medium slope decrease to -2.5%0, the apearance of sandy substrata, the decreasing of water velocity and the increasing of water volume), oportunities for a continuous increasing in species number till the confluence with Olt River. This increasing exists in fact only between C7 and C9 stations. The prevalence of Sabanejewia romanica in C8 station, (4 specimens in comparison with 4 to specimens of the rest of the sampled species), is the result of the riverbed exploatation for building materials in the area. The maximum species richness in C9 station ( species) is due to the most favourable ratio between the river dimensions, biotope diversity and the human activity pressure. C,,-Cll sector. The drastic decreasing of species richness from eleven species (C9) to only four species (Clo), is due to the fact that not all water users from Sibiu (a town with almost 200,000 inhabitants) are connected to the centralized water waste drainage system and to the waste water treatment plant. The abovementioned decreasing continues toward CI station (to only two species) the inefficient Sibiu cleaning plant.

7 ICHTHYOFAUNISTIC CRITERIA FOR CIBIN RIVER (TRANSYLVANIA, ROMANIA) 37 C,,. The decreasing of species richness Sibiu is incomplete recovered 3 km upstream the confluence with the Olt River (6 species), in spite of the tributaries Hdrtibaciu and Sadu large quantities of good quality water. The difference between C, (two species) and H (thirteen species) species richness values and the presence o!~almo trutta fario at the confluence of Hdrtibaciu River with Cibin River are arguments which prove the positive influence of these tributaries for the river self cleaning processes (Curtean, 2000) of the Cibin River. Conclusions Due to its dimensions, biotope variability and diverse human impact, Cibin River is characterized by a diverse fishe assemblages along its course. The distribution patterns of fishe assemblages seems to be correlated with the preferences of the fish species for one or many certain biotope conditions and with their resistance to different human stress factors. Large differences were noted in the way some species of the same family and even of the same genera (Gobio, Barbus and Sabanejewia) responded to the longterm human impact stress. Within each such group, there were some species that are adaptable to such different type of stress and some which simply disappear (Alburnus alburnus alburnus, Gobio uranoscopus fric'i, Gobio kessleri kessleri, Barbus barbus barbus, Cobitis taenia taenia, Aspro streber streber and Cottus gobio gobio). These disappearance and in fact the present river ecological state are the effects of the regional industrialisation and river regulation policy impact. is the single species, which have a widespread distribution pattern in the Cibin River. This species proves that it is a "habitat generalists", able to live in various environmental conditions. Natural biotope diversity and the human influence on the water physicochemical characteristics are considered to be the most important variables for explaining fish assemblages composition and their spatial variation. These results do not preclude that the other biotic factors can be important factors in fish assemblage formation and maintaining. In Cibin River the optimum fishes species richness, an important factor for the fish assemblage stability, can be achieved through the maintaining of a consistent stream flow in the sector C,-C, and a pollution reducing integrated management strategy for the whole Cibin Watershed. Hdrtibaciu and Sadu rivers can be considered as main factors in the selfcleaning processes of the Cibin River, due to their quantitative and qualitative water parameters and the main causes for the water improvement quality Sibiu cleaning plant. Also these tributaries can be considered as "fish diversity reservoirs", as well the Cibin-Olt rivers confluence has a similar potential through its high value of species richness due to the pollution decreasing since 990 in Olt River (Bgniduc, 999). The main result of this study do highlight the fact that the ichthyofauna offers reliable criteria for Cibin River human impact assessment, due to the local interrelations between fish assemblages (even individual fish species) and biotope characteristics.

8 372 DORU BANADUC The following specific criteria, proposed for this river human impact assessment optimization, are: species richness, fish assemblages (Salmo trutta fario - Cottur gobio gobio; Perca fluviatilis fluviatilis - Leuciscus cephalus cephalus - Phoxinus phoxinus phoxinus), dominant species on particular habitat (Sabanejewia romanica) and indicator species for specific biotope conditions (Salmo truttafario and Cottus gobio gobio). ACKNOWLEDGEMENTS We thank Miss Angela Curtean for the data concerning the water physico-chemical parameters. CRITERII IHTIOFAUNISTICE PENTRU EVALUAREA IMPACTULUI ANTROPIC ASUPRA RAULUI CIBIN (TRANSILVANIA, ROMANIA) REZUMAT Datoritg strategiilor eronate de industrializare $i de regularizare a principalelor rhri din ultima jumgtate de secol, rlul Cibin a fost afectat continuu de numeroase tipuri de impact antropic generate in principa! de constructii hidroameliorative, poluare cu reziduuri industriale $i menajere. In urma studiului ihtiofaunei rlului Cibin $i a interrelatiilor acesteia cu conditiile de biotop, au putut fi stabilite criterile care pot fi utilizate pentru evaluarea impactului antropic asupra diverselor sectoare ale rlului Cibin: numirul de specii din probe, tipurile de asociatii de pe~ti (Salmo trutta fario - Cottus gobio gobio; Perca fluviatilis fluviatilis - Leuciscus cephalus cephalus - Phoxinus phoxinus phoxinus), dominants unor specii pe tipuri particulare de habitat (Sabanejewia romanica) $i specii care prin limitarea intregului lor ciclu de via@ la anumite conditii de mediu sunt considerate ca fiind indicatoare pentru conditiile respective (Salmo trutta fario $i Cottus gobio gobio). REFERENCES BANADUC, D., Data concerning the human impact on the ichthyofauna of the upper and middle sectors of the Olt River. Transylvanian Rewiew of Systematical and Ecological Research., : BANARESCU, P., Pisces-Osteichthyes. Fauna R.P.R., 3: Ed. Acad. R.P.R., Bucurevti (in Romania). BANARESCU, P., Considerations on the threatened freshwater fishes of Europe. Ocrot. Nat. med. Inconj., 37 (2): CURTEAN, A., Cibin River (Transylvania, Romania) ecological assessment, based on the benthic macroinvertebrates communities. Acta Oecologica, 7 (-2): POSEA, G., Enciclopedia Geograficg a Romlniei: Ed. $tiin{. $i pedag. Bucure~ti (in Romanian). RO$U, A., Geografia Fizicg a Romlniei Ed. didact. $i pedagog. Bucure~ti (in Romanian). UJVARI, I., Geografia apelor Romlniei: Ed. vtiint. Bucurevti (in Romanian). Received: June 6, 2000 Accepted: July 3, 2000 Muzeul de Istorie Naturals' Sibiu Str. Cetgfii nr., 2400 Sibiu Rombnia banaduc@yahoo.com