HISTORICAL AND PRESENT DISTRIBUTION AND RECENT HABITAT USE OF NASE, CHONDROSTOMA NASUS, IN THE LOWER JAGST RIVER (BADEN- WURTTEMBERG, GERMANY)

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1 FOLI ZOOLOGIC - 46(SUPPL. I): 51-6(1997) HISTORICL ND PRESENT DISTRIBUTION ND RECENT HBITT USE OF NSE, CHONDROSTOM NSUS, IN THE LOWER JGST RIVER (BDEN- WURTTEMBERG, GERMNY) Berthold M. KPPUS, Wolfgang JNSEN, Received March 3, 1997 Jurgen BOHMER and Hinrich RHMNN ccepted November 19, 1997 Institute of Zoology, University of Hohenheim, Stuttgart bstract The nase, Chondrostoma nasus, belongs to the autochthpnous fish fauna of the Jagst River, where it has generally become rare over the last few decades. We conducted literature searches to obtain information about its historical occurrence. For more recent data, we interviewed local fishermen, conducted electrofishing surveys, and between 198 and 1996, inspected potential spawmng sites on the downstream river ki'lometres. Historical records suggest that approximately 1 years ago, the nase was found abundantly throughout the Jagst River, and 1 tributaries also held 'good' populations. However, a recent fish survey for Baden-Wuttember^ lists just 13 sites with known occurrence of the nase. Only five of these sites were described as having 'abundant' populations, but school sizes did not approach the thousands of fish reported a century ago. In^pril 1996^ spawning was confirmed for the first time at a location two'kilometres upstream of the mouth^of the JagsfRiver. In two electrofishing surveys, the nase represented 4% of the total number of fish captured. Despite recent signs of a stabilizing population, the nase is likely to remain threatened by extinction in the Jagst River system as longys the majority of the 65 existing barriers continue to hinder the extensive migration's of this species, and water quality problems threaten the survival of the early life stages. Key words: nase, southern Germany, distribution, spawning sites, habitat use, endangerment Introduction The nase, Chondrostoma nasus (Linnaeus, 1758), is a typical rheophilic species found in the barbel zone of most central European rivers (Nelva 1985, Lelek 1987). This species usually occurs in large aggregations of -8 (M a i e r et al. 1995) or'even more fish that often migrate considerable distances both up and downstream (B rus ch ek 1978) in order to reach their spawning grounds in shallow, fast flowing river sections over extensive gravel beds (Heuschmann 1957, M a i e r et al. 1995) or their feeding grounds later in the year. Individual fish have been reported to cover distances of up to 3 km day^ (S t'ein m ann et al. 1937). The nase is part of the autochthonous fish fauna of the Jagst River, but has generally become rare within the^drainage basin over the last few decades (Kappus &Kappus 1994). This development is in agreement with reports from other river systems in Baden-Wurttemberg (Berg et al. 1989, Berg 1995), Bavaria (Harsany & schenb ren n er 1995), Switzerland" (M a i e r et al. 1995) and the Czech Republic (Lusk 51

2 1995a). The aim of this study was to summarize available data on the historic and present distribution, the spawning habitats and the abundance of the nase in the Jagst River system. Study rea With a length of km, an average width of 17 m, and a drainage basin of 186 km, the Jagst River is the largest tributary of the Neckar River, which itself flows into the Rhine river at the city of Mannheim. The source of the Jagst River lies near the town ofellwangen (Fig. I) in the geological formation of the 'white Jura' at an altitude of 519 m. fter flowing mainly through areas formed by limestone bedrock, the Jagst empties into the Neckar River at an altitude of 143 m. The mean gradient is 1.97oo and 1.67oo for the downstream section, where the mean width is 5 m. Importantly, 65 weirs or other barriers interfer with the longitudinal continuum of the Jagst River (K u 11 a k 1993). s a consequence, approximately 64% of the river section belonging to the 'barbel zone' (H u e t 1959) are more or less impounded, with morphometrical and ecological characteristics similar to those of the 'bream zone'. In terms of overall water quality, the Jagst and its tributaries are considered as 'fertile' waters, with a high carbon content, good buffering capacity, and only moderate contamination with organic wastes, i.e. German water quality class II (L fu 199). Fig. 1. Map of the Jagst River system showing relevant tributaries, towns, and the location of five sampling sites of an electrofishing survey near Jagsthausen. 5

3 Material and Methods To reconstmct the historical distribution of the nase in the Jagst River system, we conducted a literature search, checked the provincial archives in the city of Stuttgart, and questioned local residents, that have fished for and/or have observed fishes for many decades. For more recent data, the first author has observed the Jagst fish fauna, particularly the downstream section, intensively for the past 18 years. Furthermore, on June 16, 1986 and October 3, 1993 we conducted two electrofishing (8 kw, D.C., Fa. 'Korinegg', Leutkirch, Germany) surveys near the towns ofzuttlingen and Jagsthausen, respectively (Fig. 1). For these, we collected all fish caught over a 5 m (Zuttlingen) and 5 m (Jagsthausen) long river section, identified species, and estimated length to the nearest 5 cm length-class. The 5 km of river length fished near Jagsthausen could be divided into five stmcturally distinct sections (Fig. 1), and data were recorded separately for each section. In addition, during the survey at Zuttlingen, all fish were measured (±. 1 cm) and weighted (±1 g) on a digital field balance. Between 198 and 1996, potential sites on the most downstream river kilometres were inspected yearly for spawning activity, and between pril and May 1996 we regularly visited a known spawning site near the weir at Duttenberg (Fig. 1). There, we measured water depth and water temperature daily between 7: and 9: hours, estimated current speeds and sediment particle sizes, and observed fish activity. Results Historical Distribution The first documented reference of the nase to the Jagst River (and its tributary Brettach) comes from Oberamt Gerabronn (1847). ccording to Sieglin (1896), Oberamt Crailsheim (1884), and Oberamt Ellw an ge n (1886), the nase was found throughout the main stem of the Jagst River as far upstream as the town of Lauchheim, 15 km from its source. Most records describe the occurrence of the nase as 'abundant', and Table 1. Historical distribution and abundance of the nase in nine tributaries of the Jagst River (data were taken from Si egl i n 1896). River section: name of the town most distant 7rom the confluence with the Jagst River; River zone: D = down stream, M = middle, U = upstream; bundance class: F = "few", = "abundant"). Tributary River section River zone bundance class Schefflenz Seckach Brettach Reigersbach Rotbach Fischbach Sechta Speltach Sizenbach Hochstberg Roigheim Brettheim Gebertshofen Roth Jagstzell Rohlingen Oberspeltach Schrezheim D D u M M D M M D F F F 53

4 approximately 1 tributaries also held 'good' populations, including the Schefflenz, Seckach, and Brettach rivers (Table 1), where nase were known to migrate into the upstream sections (see Sc h u mm 198). pproximately 1 years ago, the nase occurred in such numbers in the Neckar near Heilbronn and in most of the tributaries in this area (Gti nth e r 1853, Klun zing e r 1881) that it was the most common fish of the district (Oberamt Neckarsulm 1881). In the Jagst River, the nase was most abundant in the downstream section between Mockmuhl and Jagstfeld (Oberamt Neckarsulm 1881). In particular with reference to the towns of Schontal and Berlichingen, both on the Jagst River, the importance of nase for the local fishery, and thus it's economical value, was emphasized (Oberamt Kiinzelsau 1883). The nase was used as a food source in the region, and according toklunzinger (1881) it was,jceine unwichtige Speise fur den gemeinen Mann..." (not an unimportant dish for the commoner). t the time, the nase was caught preferably during spawning time on the shallow gravel banks, using special boats, so called,, Nachen" und nets (x cm mesh) with a lead line and a 'Treiber' (Herr Gerhard D o d, Siglingen, pers. commun., 1995). ccording to the same source, large ( m square) dip nets ('Senknetze'), called 'Hamen' with 1x1 cm mesh were also used to catch nase, as were wire traps. The yearly catch of nase of a part-time fisherman in the 19's on a river section approximating 6 ha in size was 5-5 kg. It seems that the nase population of the Jagst started to collapse from 1971 onwards, mainly caused by river channelization, shore line armouring, and the local removal of gravel. Such a dramatic decrease in nase stock is known from a loccation within the town limits of Widdem near Mockmiihl, where until the 195's thousands ofnase came to spawn on the gravel banks (Helb ri c h 1994). Recent Distribution s part of a general fish inventory for Baden-Wurttemberg, over the last 1-15 years, the nase has been reported from 13 sites on the Jagst River, including all tributaries (Berg et al. 1989). Of these, a third have been described as 'good' populations, for example, near Untergriesheim, Mockmiihl, Ruchsen in 198, and Berlichingen and Westemhausen in The sightings near Dorzbach and Forst-Oberregenbach in 198 were classified as 'intermediate population size'. Only the nase populations in the downstream section of the Jagst River are considered 'stable' and 'abundant'. However, also in this river section, the nase has virtually disappeared from some locations, for example near the town of Widdem (Helb ri c h 1994, also see above). From the upstream section, only individual finds of nase have been reported (J akob a s 1988), for example near the city ofcrailsheim (Fig. 1). The catch statistics from the local angling clubs for the above two river sections, and particularly those for the area close to Jagsthausen, indicate that catches of nase have declined since the late 197's, when up to 3 fish were landed in a given year (Fig. ). During the same time period, overall fishing effort has remained stable, if not has increased. However, because of the strongly declining catches, gear suitable for catching nase is hardly used anymore. Since 199, almost no nase have been caught from either river section, and at 54

5 Duttenberg, zero catches date back to the period The average weight recorded for 31 years of data from Neckarsulm was 554 g. However, this value varied between 37 and 8 g between years, showing a trend towards increasing weights in the more recent years. For Jagsthausen, the average weight for the period between 1971 and 199 was 444 g, with yearly means ranging between 9 and 539 g. Contrary to the results from Neckarsulm, there was no obvious trend towards increasing weights over the years. 5 nneckarsulm, n=1646 QJagsthausen, n=74 Year Fig. ^ Catch statistics of nase_ caught by angling by members of two fishery associations on the Jagst River for the period 1965 anct 1995 (JagstFTausen = "Fischereiverein Jagsthausen e. V.", data were available for the period only); FuSV Neckarsulm = "Fischerei- und Sportanglerverein Neckarsulm und Umgebung e. V.'"). Near Zuttlingen (Fig. 1), in June of 1986, we caught a total of 8 nase weighing 3. 6 kg, which represented 3.4% by numbers and 17.% by biomass of all fish captured. mong the 15 species recorded (for complete list see K a p p u s 199), the nase was the forth most abundant, with eel (nguilla anguilla) dominating the fish assemblage (54% by number, 76% by biomass), and roach (Rutilus rutilus) and chub (Leuciscus cephalus) also abundant. Within the 5 m long section fished, all nase were caught just below a weir from a 1x15 m large area with a depth of 1,8 m, representing the maximum depth measured at the sampling site. For the 1 nase for which all data were available, mean (±SE) total length was 43.7±. 1 cm (range ), weight was 865±148 g (range g), and condition factor was 1.3±. 1 (range ). During the 1993 fish sampling, we captured 81 nase between Jagsthausen und Olnhausen (Table ), representing 4. % of the total catch. gain, the distribution of these nase was not uniform, catches were restricted to three of the five morphologically and hydrologically distinct river sections. Of all nase caught, 59 (=73%) came from section 3, a fast-flowing stretch of the river with an almost unifomi depth of.5 m, whereas directly downstream, in the partially impounded and slow by flowing section 4, only 3 fish were captured (Table ). Contrary to many nase caught in the deep pool below the weir at Zuttlingen, at Jagsthausen, no nase were caught in the deeper, scoured section downstream of the weir. However, a school of 17 nase was captured in a deeper, fast flowing stretch 55

6 outside of the low-flow channel. Here, as well as in sampling section 3, the nase was associated with rather dense aggregations of other rheophilic species, such as barbel (Barbus barbus), bulfhead (Cottus gobio), and riffle minnow (lbumoides bipunctatus). Similar to the situation in Zuttlingen in 1986, the sizefrequency distribution of the 81 nase caught at Jagsthausen clearly documents the lack of juveniles. Except for three -5 cm long fish, all other nase were larger than 3 cm (Fig. 3).. 3 (.S fl) ^J-U Length (cm) Fig. 3. Length frequency distribution of nase caught in the Jagst River near Jagsthausen in Oktober Length values indicate the upper class liimt (K a p p u~s 1993). Table. Number of fish caught and relative proportion ofnase during experimental electrofishing at five sampling locations (see Fig. 1, insert) on the Jagst River near Jagstfiausen and Olnhausen on October 3, 19?3. Species Sampling locations 1 3 Sum (1-5) % of Total lbumoides bipunctatus lbumus albumus nguilla anguilla Barbatula barbatula Barbus barbus Chondrostoma nasus Cottus gobio Esox lucius Gobio gobio Leuciscus leuciscus Leuciscus cephalus Perca fluviatils Rutilus rutilus Salmo trutta m. fario Stiwstedion lucioperca Tinca tinca Total % nase , ,8 117,6 63,7 38 4, 1 Observations on a Spawning Ground in 1996 fter frequent observations over the previous two weeks, on pril 11, 1996, we noticed nase spawning activity just below the first weir on the Jagst River at 56

7 Duttenberg, approximately km upstream of the river mouth (for location see Fig. 1). The spawning ground was located in the middle of the 8^15 m wide "river bed> the remaining flow over the weir of approximately. 3 m3. s'' providing a water depth of between. 1 and 4 m Bottom sediments were generally of relatively large grain size although quite heterogenous, ranging in diameter between 5 and 1 cm. lthough the exact start of the spawning activity is not known, it seems reasonable to assume, that spawning started near the peak of the second major increase in water temperature of the Jagst River in the spring (Fig. 4)'. The lack of spawning activity during the first rapid increase in water temperature in spring (March J 5^6) to values above 8 C indicates, that temperature alone might not be a sufficient stimulus and that perhaps photoperiod also controls the beginning of spawning activity in nase. Date Faign4;vw^eLtemgSrat^re^f, tte.j^rlvct-mms^^^^ theweir ofduttenberg during the period to May rrow indicates observed spawing activity. bout^3 nase gathered at the Duttenberg spawning site within a river!^?^ ^ \about^ r. le? th' of, which approximately fish were resting within^anarea of 1 m x m at the beginning of the weir pool. The remainii individuals stayed further downstream. "n pril 13, the nase were stiii"at'th^ ^pawning site. Within the following week they disappeared from the site. I^w:ever' nase ^erc Jound in the l()wer Jagst untill the end of pril:"dum?ff^i?.ncy, c?nt, rols?^a step and pool fishway at the weir in Sigiingen, an individual of about 35 cm length was observed (Herr Willi Eb'elTsTglir 1996 pers. communication). - ' , -o»-o*-' Discussion lthough catch statistics cannot be directely translated into fish population size, the catches of local fishermen indicate that the nase stock has strongly decreased over the last years within the whole catchment of the Jagst river. This decrease corresponds well with similar findings in other rivers such as the Kocher'andThe Tauber (see M i c he 1 b a c h 1983~). One reason for the decline' In "stocks"is direct mortality. In the sixties, at least one massive nase mortality occurred in the middle region of the Jagst downstream of Langenburg. No suggestions as to the 57

8 cause of this mortality could be found in any records. However, one likely reason is high oxygen deficits due to increasing inputs of organic wastes. The nase is known to require high oxygen levels (R i ede ). Other reasons for the decrease in nase stocks in the Jagst drainage include the destruction of spawning habitats and the increasing numbers of migration barriers. Spawning sites have mainly been destroyed by river channelization below weirs and similar construction work, as can be seen at the weirs in Neudenau and Zuttlingen (K a p p u s &Kappus 1994). lso, within the town ofwiddem, spawning sites were destroyed by the excavation of gravel and channelization. Similar reports are given by H e 1 b r i c h (1994), M a i e r et al. (1995) andharsany &schenbrenner (1994). Besides eutrophication and pollution, Berg (1995) equally states river channel ization, migration barriers and loss of habitat as major reasons for the endangerment of the nase. The migration of nase to its (former) spawning grounds is largely prevented by the 65 weirs on the Jagst River. This strongly disturbs the integrity of the population (K u 11 a k 1993, L u s k 1995b, Kap p u s et al. 1994). In addition, the remaining spawning habitats are often of poor quality. few spawning sites are located below weirs. There, often very little discharge is present since most of the water is diverted through hydroelectric power stations. These low flow conditions severely disturb spawning and hatching. Thus, reproductive failiure also contributes to the population decline. Based on the length and weight frequency distributions of our electrofishing surveys, all nase caught during 1986 and 1993 were adults aged 6-1 years (Ri e de , M a i e r et al. 1995). This indicates an averaged population. Not much is known about the fate of juvenile nase. Due to an impassable weir, immigration of nase into the Jagst River system from the Neckar River is prevented except for the first two kilometers. Furthermore, migrations of juvenile nase in the entire Jagst River are substantially hindered, and juvenile habitats are largely destroyed by human activities. Extensive migrations are known to represent an important part in the ecology of juvenile nase (Ne 1 v a 1988). The timing of spawning activities and the corresponding water temperatures in the Jagst corresponded well with results from Bavarian (Harsany & schenbrenner 1994) and Swiss rivers (M a i e r et al. 1995). In 1996, spawning took place from the middle to the end of pril. It commenced at a water temperature of about 8 C, which roughly coincides with the data given by Lelek &Penaz (1963). The characteristics of the spawning habitat, particularly the size distribution of the substratum and the water velocities, were similar to those from Swiss rivers (M a i e r et al. 1995). In addition to the reasons stated so far, in the lower Jagst basin the nase stock is threatened by canoeing, because the spawning areas are highly frequented and disturbed by gravel movement as soon as early pril. Blooms of algae, that regularly occur in spring after the first significant rise in water temperature (B. Kapp u s, pers. observ. ), may also threaten the spawning habitats of nase and other gravel spawners. The death and following decomposition of the algae often causes increased oxygen consumption and clogging of the interstitial spaces, which may affect embryonic and larval development. Similar conditions may be caused by the input of eroded, nutrient rich top soil from agricultural fields as has been observed in the Tauber River (Michelbach 1983). 58

9 For a number of resons, the nase populations of the Jagst catchment are rapidly declining. Some small populations are still present in the lower course of the river. Generally, the nase population of the Jagst can be assessed as regionally strongly endangered (Kappus &Kappus 199). This is in accordance with the statewide classification of a 'threatened' species (Berg 1995), and corresponds to the situation in the rivers Enz and Kocher, other major tributaries of the Neckar River. lthough severely reduced, the remaining nase populations of the Jagst are of high conservation value since this species is classified as 'highly threatened' throughout Germany (states of Northrhine-Westfalia, Hessia, and Bavaria). Even more dramatic, in nine other German states, the nase is extinct or without natural populations (Bless et al. 1994). Conclusions Chondrostoma nasus, a typical freshwater migratory species, is mainly threatened within the Jagst River drainage by river fragmentation due to an abundance of weirs, and river channelization or similar construction activities, especially directly downstream of weirs, where most of the present spawning sites seem to be located. nother reason for the decreasing stocks might be algae blooms during the spawning period, resulting in a clogging of the interstitial system of the spawing grounds. Therefore, today only a few small populations remain in the Jagst River system compared to their former widespread distribution and large population size. Most likely, the nase will remain threatened by extinction in the Jagst River system as long as the majority of the 65 existing barriers continue to hinder its extensive migrations. cknowledgements We wish^ to thank Volker G zi n g e r Stefan Kap pu s, and Rolf G ri m m (Zuttlingen) and Werner E r 1 e w e i n (Offenau) for additional data of spawning nase and water temperature of the Jagst River. The sportfishing associations FuSV Neckarsulm e. V. and FV Jagsthausen e. V. supplied informations about their annual fishing catches. LITERTURE BERG, R., 1995: Rote-Liste - Gefahrdete Fische und Neunaugen in Baden-Wurttemberg. In: Hoffmann, R. et al., Fische in Baden-Wurttemberg - Gefahrdung und Schutz. Ministerium fur Ldndlichen Raum, Emdhrung, Landwirtschaft und Forsten Baden-WUrltemberg, Stuttgart: 59-7 BERG, R., BLNK, S. & STRUBELT, T, 1989: Fische in Baden-Wtirttemberg. Information des Ministeriums fiir Landlichen Raum, Ernahrung, Landwirtschaft und Forsten Baden-Wilrttemberg, Stuttgart, 158pp. BLESS, R., LELEK,. & WTERSTRT,., 1994: Rate Liste und rtenverzeichnis der in Deutschland in Binnengewassem vorkommenden Rundmauler und Fische (Cyclostomata & Pisces). Schriftenreihe fur Landschaftspflege und Naturschutz, 4: BRUSCHEK, E., 1978: Fischwanderungen. Osterreichs Fischerei, 31(7): GUNTHER,., 1853: Die Fische des Neckars. Jahresheftfilr Naturkunde in Wiirttemberg, 9:4-37. ' HRSNY,. & SCHENBRENNER, P., 1995: Die Nase - Chondrostoma nasus (Linnaeus, 1758) Biologie und ufzucht. Osterreichs Fischerei, 4S (8/9): HELBRICH, D., 1994: Die Nase und die Jagst. Landessportfischerverband-Landesfische- 59

10 reiverband Baden-Wiirttemberg, : HUET, M., 1959: Profiles and biology of western European streams as related to fish management. Transactions of the merican Fisheries Society, 88: JKOBUS, M., 1988: Untersuchungen zur Fischfauna naturbelassener Bache'mit besonderer Berucksichtigung der Kleinfische und zehnfussigen Krelrse. Studie des Landessportfischerverbandes Baden- Wurttemberg, (Stuttgart) (unpublished), 65 pp. KPPUS, B., 199: usfuhrungen zum Fischbestand der Unteren Jagst bei Zuttlingen. Landessportfischerverband-Landesfis- Baden-Wurttemberg, : 6-7. KPPUS, B,, 1993: Fischbestandsanalyse der Jagst bei Jagsthausen, Landkreis Heilbronn. Grundlagenerhebungen und Vorschlage fur die kunftige angelfischereiliche Nufzung. Bericht an den Fischereiverein Jagsthausen, Siglingen, November 1993 (unpublished), 68 pp. KPPUS, B: & KPPUS, M., 1994: Zur Fischfauna der Unteren Jagst. Fischokologie (ktuell), 7: KPPUS, B., JNSEN, W., FOK, P. & RHMNN, H., 1995: Threatened lam- )rey (Lampetra planeri} populations of the )anube basin within Baden-Wurttemberg, Germany. Miscellanea Zoologica Hungarica, 1: 85-^8. KLUNZINGER, C.B., 1881: Die Fische in Wiirttemberg, faunistisch-biologisch betrachtet, uncfdie FischereiverhaFtnisse daselbst. Jahresheft fiir Naturkunde in Wurttemberg, 37: ' KULLK, E., 1993: Die Jagst und die Fischerei. Landessportfischerverband-Landesfischereiver-band Baden-Wurttembers, 1: LNDESNSTLT FUR UMWELTSCHUTZ BDEN-WURTTEMBERG (LfU), 199: Gutezustand der Fliessgewasser in Baden- Wiirttemberg 7. Zustandsuntersuchung auf biologisch-okologischer Grundlage. Ministerium fur Umwelt Baden-Wurttemberg, Kraft-Verlag, Ettlingen, 64 pp. LELEK,. & PEIMZ,~M,, 1963: Spawning of Chondrostoma nasus (L.) in the'brumovka River. Zoologicke listy, 1(): LELEK,., 1987: Threatened fishes of Europe. The freshwater fishes of Europe, Vol. 9, ula-verlaa, Wiesbaden, 343 pp. LUSK, S., 1995a: The status of Chondrostoma nasus in waters of the Czech Republic. FoliaZool., 44(1): 1-8. LUSK, S., 1995b: Influence of valley dams on the changes jn fish communities inhabiting streams in the Dyje River drainage area. Folia Zool., 44(1):~ MIER, K.-J., ZEH, M., ORTLEPP, J. & ZBINDEN, S,, 1995: yerbreitung und FortpHanzung der in der Schweiz vorkommenden Chondmstoma-Mten. Bundesamt fur Umwelt, Wald und Landschaft (Hrsg. ), Bem, Mitteilungen wr Fischerei, 53: MICHELBCH, S., 1983: Fischartenerfassung der Tauber von Weikersheim bis zur Gemarkungsgrenze Lauda-Konigshofen. Faunistische und flonstische Mitteilungen qus dem Taubergrund (Bad Mergentheim), NELV,., 1985: Biogeographie, ddmographie et ecologie de Chondrostoma nasus nasus (L., 1758) (Hotu, Poisson, Telfosteen, Cyprinide). These Doct. d'etat, 365 pp. NELV,., 1988: Profil ecologique du Hotu, Chondrostoma nasus ~~ (Osteichtyen, Cyprinide) dans Ie Haut-Rhflne frangais: structure d'habitat ponctuel et statiorinel. da Oecologica, 9(3): OBERMT NECKRSULM, 1881; CRILS- HEIM, 1884; ELLWNGEN, 1886; KUNZ- ELSU, 1883; GERBRONN, 1847: Beschreibungen der Koniglichen Oberamter. RIEDEL, D., 1974: Fisch und Fischerei. Ulmer Verlag, Stuttgart, 87pp. SCHUMM, J., 198: Heimatbuch Crailsheim. Maier Verlag, Crailsheim, 34 pp. SIEGLIN, H., 1896: Die Fischereiverhaltnisse in Wurttemberg. Sonderabdruck des Wiirttembergischen Jahrbuchs fur Statistik und Landeskunde Jahrgang 1895, Heft, Stutt- 'art, Druck von W. Kohlhammer, 7 pp. STEINMNN, P., KOCH, W. & SCHEURING, L., 1937: Die Wanderung unserer SUBwasserfische. Dargestellt auf Grund von Markierungsversuchen. Zeitschrift fur Fischerei,!5(1): uthors' address: Dr. Berthold M. KPPUS, Wolfgang JNSEN, M. Sc., Dr. Jurgen BOHMER, Prof. D~r. Hinrich RHMNN Institute of Zoology, University of Hohenheim, Garbenstrafie 3, D-7593 Stuttgart, Federal Republic of Germany; kappus@uni-hohenheim.de 6