IMPACT OF EVIRONMENTAL FACTORS ON THE DISTRIBUTION AND DENSITY OF THE SIBERIAN SCULPIN (Cottus poecilopus Heckel) IN THE POPRAD RIVER BASIN

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1 Acta Sci. Pol., Piscaria 4(1-2) 2005, MPACT OF EVRONMENTAL FACTORS ON THE DSTRBUTON AND DENSTY OF THE SBERAN SCULPN (Cottus poecilopus Heckel) N THE POPRAD RVER BASN Leszek Augustyn 1, Andrzej Witkowski 2, Piotr Epler 3 1 Professional and Vocational College, Nowy S cz, Poland 2 Wroc aw University, Wroc aw, Poland 3 Agricultural University, Kraków, Poland Abstract. Distribution of the Siberian sculpin (Cottus poecilopus) was studied based on data collected from 138 sites in the Poprad River catchment area (the Vistula basin, southern Poland). The population density was found to range from 3 to 203 inds 100 m -2. Large differences in fish density were found between the streams and between sites within a stream. The Siberian sculpin were significantly more abundant at shallow sites: densities of up to 50 inds 100 m -2 were recorded at sites of mean depth <15 cm. n low gradient stream sections (<25 m km -1 ) with numerous pools (>50% bed surface area), the density exceeded 50 inds 100 m -2. The species density was statistically significantly, negatively correlated with the distance from the stream origin (r = ), stream bed gradient (r = ), and mean depth (r = ). On the other hand, a significant negative correlation was found between the pools sections and the density (r = ). The relationships between the density and the environmental factors analysed are presented in the form of multiple regression. Key words: Cottus poecilopus, density, distribution, environmental factors, mountain streams NTRODUCTON The Siberian sculpin (Cottus poecilopus Heckel) is a Eurasian species. n Central Europe, it is found only in mountain streams of the Carpathians and the Sudety Mountains where it inhabits stream sections closest to the stream origins, i.e., the upper part of the brown trout domain [Starmach 1965, 1972, iha 1969]. Outside that area, a few lacustrine sites of the species have been reported [Duncker 1925, Witkowski 1984, 2001, Kotusz et al. 2004]. Corresponding author Adres do korespondencji: dr Leszek Augustyn, Okr g PZW Nowy S cz, ul. nwalidów Wojennnych 14, Nowy S cz, leszek.augustyn@pzwns.info.pl

2 18 L. Augustyn, A. Witkowski, P. Epler Besides taxonomy [Starmach 1972, Witkowski 1979] and genetics [Pa ko and Ma lak 2003], research on C. poecilopus focusws on its interactions with the brown trout [Olsen and Vøllestad 2001, 2003, Hesthagen and Heggenes 2003, Holmen et al. 2003, Hesthagen et al a,b]. The Siberian sculpin is a demersal species: during the day, the fish stay hidden under boulders and fallen trees [Witkowski 2005], which in connection with their cryptic coloration [Zalewski 1986] and specific resistance to electric field [Barrett and Grossman 1988] renders them hard to catch by electrofishing. This is the reason why papers on distribution of C. poecilopus along a stream profile as well as on density, biomass, and habitat preferences in streams and lakes are scant [Holmen et al. 2003, Kotusz et al. 2004]. The present study was aimed at identifying the environmental factors controlling the highest densities of C. poecilopus in streams of the Poprad River basin (southern Poland). MATERAL AND METHODS The present study on the Siberian sculpin was conducted within the framework of the monitoring of the River Poprad basin fish fauna [Augustyn 2004]. A total of 138 sites, each 100-m long, were surveyed in 17 streams. The sites were located in 5 firstorder streams (Baraniecki, zwor, Rohacz, Wapiennik, and Ma a omnica), in 6 secondorder streams (M odowski, Ma a Wierchomla, Czerte, Potasznia, Kokuszka, and Szczawniczek), and in 6 third- and fourth-order ones (Ma a Roztoka, Wielka Roztoka, Rzeczanowski, Przysietnicki, Szczawnik, and omniczanka) (Table 1; Fig. 1). The streams drain of the Radziejowa (1.262 m asl) and Jaworzyna Krynicka (1.114 m asl) mountain ranges in the Beskid S decki area. The major ranges are accompanied by lower hills ( m asl) resembling a high piedmont area; they slope down, step-wise, towards the Poprad valley. Beds of the streams surveyed incise the flysch of the Magura nappe made up by thickbedded sandstones intersected by shale bands. The small (2-3 km 2 ), totally (100%) forested, drainage areas of the streams suffer no flood surges. Therefore the beds feature boulders and fallen trees forming numerous (3-6 m -2 ) refuges utilised by the fish. At all the sites, C. poecilopus occurred sympatrically with the brown trout (Salmo trutta m. fario) [Augustyn et al. 1996, Augustyn 1999]. The Siberian sculpin were electrofished with an UP-12 device, two harvesting operations being conducted at each site. The fish density was calculated using the Carle- Strub method [Cowx 1983]. The following variables were determined at each site: distance from the stream origin (km); gradient (m km -1 ); altitude (m asl); pool index, i.e., pool surface expressed as a percentage of the total stream surface (%); mean width and depth (cm); and the Siberian sculpin density (inds 100 m 2 ) (Table 1). Acta Sci. Pol.

3 a mpact of evironmental factors 19 Table 1. Site characteristics in individual streams Tabela 1. Charakterystyka stanowisk w poszczególnych potokach Number Nr Stream name Nazwy potoków Szczawniczek Szczawnik Baraniecki Ma a Wierchomla Potasznia zwor Wapiennik omniczanka Czerte Ma a omnica Rohacz Kokuszka M odowski Ma a Roztoka Wielka Roztoka Rzeczanowski Przysietnicki Distance from origins Odleg o od róde Gradient Spadek Mean altitude Po o enie n. p. m. Pool index Wska nik plos Mean width rednia szeroko Mean depth rednia g boko km m km -1 m % m cm D u n S. Site a.. j e Przys etn ck R c o L O V d P o p r z.... t o ka Ks y Rzeczanowsk Cz e rcz A K Kokuszka km om n c zanka W A e rchomla P o p r M k l k ad czek zawn Szczawn Szc Fig. 1. Location of sampling sites in the Poprad River system Rys. 1. Lokalizacja stanowisk w dorzeczu Popradu Piscaria 4(1-2) 2005

4 20 L. Augustyn, A. Witkowski, P. Epler Statistical analytical techniques were used to identify the environmental variables most important for the occurrence and the maximum density of the Siberian sculpin in the streams surveyed. The distribution of C. poecilopus in the Poprad basin streams was modelled by means of multiple regression. RESULTS The Siberian sculpin density in the Poprad basin streams surveyed was found to vary over a wide range of 3-63 individuals per 100 m 2 (Table 2). t was only in once case, at a site located in the Ma a Roztoka, that a record-breaking density of 203 inds per 100 m 2 was recorded. The highest within-stream density variations were observed in the: Kokuszka, zwor, Ma a omnica, and Ma a Roztoka. Table 2. Siberian sculpin density ranges in individual streams Tabela 2. Zakresy zag szcze g owaczy w poszczególnych potokach Number Numer Stream Potok Szczawniczek Szczawnik Baraniecki Ma a Wierchomla Potasznia zwor Wapiennik omniczanka Czerte Ma a omnica Rohacz Kokuszka M odowski Ma a Roztoka Wielka Roztoka Rzeczanowski Przysietnicki Density Zag szczenie n 100 m Statistical analyses showed non-linear regressions (Fig. 2) to provide the best fit to the relationship between the C. poecilopus distribution in the Poprad tributaries and the environmental variables taken into account. n the first-order streams, the Siberian sculpin densities averaged 80, 35, 20, and 10 inds 100 m -2 at a distance of 1, 2, 3, and 5 km away from the stream origins, respectively. The density-distance correlations were statistically significant (r = ; p<0.0001). Correlations between density and stream gradient were reverse as well: the highest densities (>30 inds 100 m -2 ) accompanied low (<25 m km -1 ) gradients, while high gradients (on the order of 100 m km -1 ) were associated with densities <10 inds 100 m -2 (r = ; p< ). Stream sections with shallow pools taking up >50% bed area (r = ; p<0.0001) Acta Sci. Pol.

5 mpact of evironmental factors 21 and water depth<10 cm (r = ; p<0.0001) proved optimal for the Siberian sculpin persistence. On the other hand, no such significant effect on density was produced by the stream altitude (r = ; p<0.01). Density Zag szczenie, n 100 m -2 Distance Odleg o, km Altitude, m above sea level Wysoko, m n.p.m Gradient Spadek, m km -1 Pool index Wska nik PLOS, % Width Szeroko, m Depth G boko, m Fig. 2. Relationships between mean Siberian sculpin density and mean values of the environmental variables analysed: A distance from stream origin; B gradient; C altitude; D pool index; E bed width; F depth. Rys. 2. Zale no ci statystyczne mi dzy zag szczeniami g owaczy pr gop etwych a rednimi warto ciami analizowanych parametrów: A odleg o od róde, B spadków, C wysoko ci n.p.m., D wska nik plos, E szeroko ci koryt, F g boko ci. The multiple regression analysis produced a regression equation below, describing the C. poecilopus density in the Poprad basin streams in terms of the environmental variables considered; the density proved highly correlated (R = ; p< ) with those variables. The regression equation is as follows: Piscaria 4(1-2) 2005

6 22 L. Augustyn, A. Witkowski, P. Epler where : D, density (inds 100 m -2 ), s, gradient (n km -1 ), p, pool index (%), d, mean depth (cm). D = s p 0.88d, SE ± 4.5 (inds 100 m -2 ), DSCUSSON Similarly to the wide density ranges of the Siberian sculpin in this study, wide ranges were reported also from the streams Rogo nik ( inds 100 m -2 ), [Solewski 1963] and Bia ka Tatrza ska ( inds 100 m -2 ) [Solewski 1965] as well as in the Beskidy tributaries of the Wag: the Lušova (5-211 inds 100 m -2 ) and Brodská ( inds 100 m -2 ) [Helan et al. 1973]. n the Poprad tributaries, C. poecilopus prefer stream sections close to stream origins (1-3 km away from the springs), with a relatively low gradient (15-40 m km -1 ), narrow beds (<1.5 m), and showing domination of riffles (>70%) over pools, which most probably is a result of restricted interference competition-like interactions with the brown trout [Olsen and Vøllestad 2003, Hesthagen and Heggenes 2003, Holmen et al. 2003]. Such conditions are met both by the first-order (Kokuszka) and fourth-order (Ma a Roztoka) streams the beds of which incise rock formations making up the terraces of the high Beskid S decki piedmont. REFERENCES Augustyn L., Effectiveness of autumn stocking brown trout fry (O + ) (Salmo trutta m. fario L.) into streams of the Poprad River system [Efektywno zarybie podchowanym narybkiem jesiennym (O + ) pstr ga potokowego (Salmo trutta m. fario L.) w potokach dorzecza Popradu]. Rocz. Nauk. PZW 12, [in Polish]. Augustyn L., chthyofauna of the Polish part of the Poprad River [chtiofauna polskiej cz ci dorzecza Popradu]. Arch. Pol. Fish. 12 (Supl. 2), [in Polish]. Augustyn L., Skóra S., W odek J.M., chthyofauna of the Poprad drainage area [chtiofauna dorzecza rzeki Poprad]. Rocz. Nauk. PZW 9, [in Polish]. Barrett J.C., Grossman G.D., Effects of direct current electrofishing on the Mottled Sculpin. N. Am. J. Fish. Manag. 8(1), iha J., Taxonomical and ecological notes on Cottus gobio L., 1758 and Cottus poecilopus Heckel, 1836 (Osteichthyes: Cottidae). Acta Soc. Zool. Bohem. 33, Cowx J.G., Review of the methods for estimating population size from survey removal data. Fisheries Manage. 14, Acta Sci. Pol.

7 mpact of evironmental factors 23 Duncker G., chthyologische Notizen. 2. Die Verbreitung von Cottus gobio L. und C. poecilopus Heck. in Nord und Mitteleuropa. Pallasia 2, Helan J., Kubi ek F., Sedlak E., Zelinka M., Production conditions in the trout brooks of the Beskidy Mountains. Fol. Sc. Nat. Univ. Purk. Brun. 19, Biol. 38, 4. Hesthagen T., Heggenes J., Competitive habitat displacement of brown trout by Siberian sculpin: the role of size and density. J. Fish Biol. 62(1), Hesthagen T., Hegge O., Skurdal J., Dervo B.K., 2004a. Age and growth of Siberian sculpin (Cottus poecilopus) and young brown trout (Salmo trutta) in subsiberian Norwegian river. Hydrobiologia. 521(1-3), Hesthagen T., Saksgård R., Hegge O., Dervo B.K. Skurdal J., 2004b. Niche overlap between brown trout (Salmo trutta) and Siberian sculpin (Cottus poecilopus) in subsiberian Norwegian river. Hydrobiologia. 521(1-3), Holmen J., Olsen E.M., Vøllestad L.A., nterspecific competition between stream-dwelling brown trout and Siberian sculpin. J. Fish Biol. 62(6), Horowitz R.J., Temporal variability patterns and the distributional patterns of stream fishes. Ecol. Monogr. 48, Kotusz J., Krappe M., Kusznierz J., Popio ek M., Riel P., Waterstraat A., Witkowski A., Distribution, density and habitat of Cottus poecilopus (Heckel, 1836) in Lake Ha cza (NE Poland) as compared with the situation in the Luzin lakes (E. Germany). Verh. Deutschegesellsch. chthyol. Olsen E.M., Vøllestad L.A., Within-stream variation in early life-history traits in brown trout. J. Fish Biol. 59(6), Olsen E.M., Vøllestad L.A., Microgeographical variation in brown trout reproductive traits: possible effects of biotic interactions. Oikos 100(3), Pa ko., Ma lak R., Genetics of the peripheral populations of the Siberian sculpin, Cottus poecilopus (Scorpaeniformes, Cottidae) in Poland. J. Zool. Systemat. & Evolut. Res. 41(3), Solewski W., Brown trout (Salmo trutta m. fario L.) in the Rogo nik stream. Acta Hydrobiol. 4, Solewski W., The ichthyofauna of the Bia ka Tatrza ska stream with special respect to the characteristics of brown trout ( Salmo trutta m. fario L.). Acta Hydrobiol. 7, Starmach J., Koppen in der Karpathenflüssen.. Antreten und Charakteristik der Buntflossenkoppe (Cottus poecilopus Heckel) und weisslossigen Koppe (Cottus gobio L.) in Raba flussgebiet. Acta Hydrobiol. 7, Starmach J., Charakterystyka g owaczy: Cottus poecilopus Heckel i Cottus gobio L. Acta Hydrobiol. 14, Witkowski A., A taxonomic study on fresh-water sculpins of genus Cottus Linaneus, 1758 (Cottus gobio L. and Cottus poecilopus Heck.) in Poland. Acta Univ. Wratisl., Prz. Zool. 10, Witkowski A., Morphological variability in lake and river populations of Cottus poecilopus Heckel, 1836 (Pisces: Cottidae). Acta chthyol. Piscat. 14(1-2), Witkowski A., Cottus poecilopus Heckel, [n: Polska Czerwona Ksi ga Zwierz t]. Ed. Z. G owaci ski. PWRiL, Warszawa, Witkowski A., Cottidae: Cottus poecilopus Heckel. Scorpaeniformes, vol. 7, The Freshwater Fishes of Europe, Aula Verlag, Wiesbaden. Zalewski M., Factor affecting the efficiency of electrofishing in rivers. Hydrobiologia (Sofia) 27, Piscaria 4(1-2) 2005

8 24 L. Augustyn, A. Witkowski, P. Epler WP YW CZYNKÓW RODOWSKOWYCH NA ROZSEDLENE ZAG SZCZENE G OWACZA PR GOP ETWEGO (Cottus poecilopus Heckel) W DORZECZU POPRADU Streszczenie. W dorzeczu Popradu (dorzecze Wis y, Polska Po udniowa) na 138 stanowiskach zbadano rozsiedlenie g owacza pr gop etwego (Cottus poecilopus). Zag szczenie g owacza pr gop etwego w poszczególnych potokach wynosi o od 3 do 203 ryb 100m -2. Stwierdzono du e ró nice zag szcze mi dzy ró nymi potokami, a nawet w tych samych potokach mi dzy ró nymi stanowiskami. G owacz pr gop etwy najliczniej (>50 ryb 100m -2 ) wyst powa w p ytkiej wodzie (<15 cm g boko ci), w odcinkach z ma ym spadkiem (<25 m km -1 ) z przewaga bystrzy nad plosami (>50%). Z przeprowadzonej analizy wynika, e istotnie statystycznie ujemny wp yw na zag szczenie g owaczy w potokach wywiera y: odleg o ci od róde (r = -0,7453) i ci le skorelowane z nimi spadki pod u ne koryt (r = -0,8652), a tak e rednie g boko ci koryt (r = -0,7078). Ponadto statystycznie istotny ujemny wp yw wywieraj odcinki plos (r = -0,7496). Natomiast nie odnotowano wp ywu szeroko ci koryt potoków i ich po o enia nad poziomem morza. W oparciu o analizowane czynniki rodowiskowe przedstawiono zale no w postaci regresji wielokrotnej mi dzy ich warto ciami a zag szczeniem C. poeciliopus. S owa kluczowe: Cottus poecilopus, czynniki rodowiskowe, rozmieszczenie, zag szczenie Accepted for print Zaakceptowano do druku: Acta Sci. Pol.