The First Certified Record of the Endemic Fish Species Pachychilon

Turkish Journal of Zoology Turk J Zool (2015) 39: http://journals.tubitak.gov.tr/zoology/ © TÜBİTAK Research Article doi:10.3906/zoo-1402-35

The first certified record of the endemic fish species Pachychilon macedonicum (Steindachner, 1892) in a lake complex outside of its nominal range, with notes on its biological features

Dimitra C. BOBORI*, Olga PETRIKI, Emmanouel TSAKOUMIS Laboratory of Ichthyology, Department of Zoology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece

Received: 15.02.2014 Accepted/Published Online: 29.12.2014 Printed: 00.00.2015

Abstract: The cyprinid Pachychilon macedonicum (Steindachner, 1892) is a species that is endemic to the southern Balkan Peninsula with limited distribution in Greece. Here we confirm the species’ expansion and establishment in a complex of 4 lakes located outside of its currently known distribution range and provide, for the first time, some of its biological features. The species’ presence was certified in 3 (Vegoritida, Petron, Chimaditida; northern central Greece) of the 4 lakes studied (Lake Zazari was also sampled), which now constitute a new western limit for its distribution in Greece. Pachychilon macedonicum specimens in Lake Vegoritida were longer (mean length: 5.8 ± 0.04 cm) than those in Lake Petron (mean length: 5.5 ± 0.05 cm), with the longer and heavier specimens recorded from depths of between 9 and 12 m in Lake Vegoritida (ANOVA, P < 0.001). The highest rate of individuals per 100 m2 of nets (NPUE) and weight of individuals per 100 m2 of nets (BPUE) were observed in the upper depth strata (0–3 and 3–6 m). The densities, in terms of NPUE, as well as the extracted length-frequency distributions, show evidence for the species’ establishment in Lake Vegoritida and for a newly existing population in Lake Petron. The estimated length–weight relationships revealed positive allometric growth of the species in both lakes, Vegoritida (b = 3.3235) and Petron (b = 3.4594). In general, Pachychilon macedonicum exhibited an adaptive selection to littoral environments and an occupation of the epilimnion, avoiding the deeper water strata.

Key words: Range expansion, southern Balkan Peninsula, Pachychilon macedonicum, length–weight relationship, NPUE, vertical distribution

1. Introduction List (Smith and Darwall, 2006). In Greece it is referred The freshwater fish fauna of Greece comprises more than to as locally ‘vulnerable’, and it is threatened mainly by 170 species (Leonardos and Bobori, 2013), 28% of which are water abstraction (Economidis, 1991). The species was endemic to the country. Moreover, 25% of the species have initially described by Steindachner (1982) as Leuciscus a rather broader distribution in the neighboring Balkan macedonicus; since then, its taxonomic position has been countries, and they are considered as endemics or near revised several times (see Karaman, 1972; Howes, 1981). endemics to the Balkan Peninsula, occurring south of the However, osteological (Šorić, 1992) and genetic (Ráb Danube River, mostly in the transboundary water systems et al., 2000) studies have confirmed that Pachychilon at the country’s borders. Thus, Greece is considered as one macedonicum is clearly distinct from Rutilus species. of the most endemic-rich countries in Europe (Smith and It belongs to the Danubian cyprinid species that Darwall, 2006). However, the taxonomic status of some dispersed during the upper Pliocene and Pleistocene, species has not yet been verified (Economou et al., 2007; possibly through the Morava-Axios basin (Economidis Kottelat and Freyhof, 2007). In addition, data concerning and Banarescu, 1991), and were established mainly in the the distribution, biology, ecology, and threat statuses of Axios River basin, which is shared between Greece and several species are deficient (Smith and Darwall, 2006; the Republic of Macedonia. However, the species has a Economidis, 2009). restricted distribution in the Axios River (for a synopsis, The cyprinid Pachychilon macedonicum (Steindachner, see Kottelat and Freyhof, 2007). Its presence is further 1892) is endemic to the southern Balkan Peninsula reported in the transboundary Lake Doirani (Economidis, and it is recognized as a rare species, although its threat 1991; Economou et al., 2007; Bobori and Salvarina, 2010; status has not yet been assessed in the IUCN Red Data Vavalidis et al., 2010; Kostov et al., 2011), in the lower * Correspondence: [email protected] 1 BOBORI et al. / Turk J Zool parts of the Aliakmon and Pinios rivers, and in the basin complex, since the lakes are connected. Lake Zazari is of Lake Karla (Economidis, 1991; Economidis and Bobori, located at the highest elevation within the catchment area 2003; Economou et al., 2007). Moreover, Economou (Table 1) and drains through a ditch to Lake Chimaditida et al. (2007) considered the species’ presence in Lake during the high-precipitation period. The excess water Vegoritida as doubtful, while Leonardos et al. (2008), of the latter is diverted to Lake Petron through the based on this literature, cited the presence of the species in Amintas stream, and finally to Lake Vegoritida through an Lake Chimaditida. Furthermore, the species’ biology and artificial channel (Figure 1). The latter is the largest and ecology are very little known (Bobori and Salvarina, 2010; deepest lake and is situated at the lowest elevation of the Bobori et al., 2010; Vavalidis et al., 2010). whole catchment area (Table 1). Several small torrents, Here we have documented the expansion and discharging directly into the lakes, are also included in establishment of the endemic species Pachychilon the hydrographic network of the lakes’ catchment. The macedonicum in a complex of lakes located outside of certified ichthyofauna of the lakes’ complex includes 18 its currently known distribution range. Some additional species (Economou et al., 2007), 5 of which (27.7%) are data on species population dynamics, such as the length- endemic species of the Balkan Peninsula (Table 2). frequency distributions, the length–weight relationships, The fishing surveys took place from late June to and gillnet catches, are provided for the first time. early October, from 2010 to 2012, in the framework of a monitoring project for lake fish communities, following 2. Materials and methods the demands of Directive 2000/60 (European Commission, Lakes Vegoritida, Chimaditida, Zazari, and Petron form 2000) for water-quality assessment at the catchment scale. a complex of lakes that share the same catchment area A stratified fish sampling method was applied in the lakes (2119 km2), the older large Eordaia basin (northern using 2 types of multimesh gillnets: the benthic Nordic central Greece, Figure 1). The 4 lakes are included in the type (1.5 m height × 30 m long, composed of 12 panels, Natura 2000 network as special protected areas and sites of 2.5 m in length, with mesh sizes of 5, 6.25, 8, 10, 12.5,15.5, community importance. Their hydrological system is quite 19.5, 24, 29, 35, 43, and 55 mm) and the pelagic Nordic

Greece

L. Vegoritida

L. Petron

L. Zazari

L. Chimaditida

Figure 1. The studied area. Arrows indicate the possible movement of Pachychilon macedonicum through the hydrographic network connecting the lakes.

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Table 1. Morphological and limnological features of the studied lakes and fish sampling effort per lake.

Lakes Parameters Vegoritida Chimaditida Zazari Petron Subbasin (km2) 1766 107 124 122 Altitude (m) 509 593 602 572 Surface area (km2) 45 9.6* 1.7 12.36 Maximum depth (m) 48 3 6 3.5 Mean depth (m) 20 1.2 1.7 1 Eutrophication status Mesotrophic Eutrophic Eutrophic Eutrophic Sampling effort (days) 6 1 2 2 Number of strata 6 1 2 1 Total number of nets 48 8 16 16

*The lake surface with open waters (without the extensive reed beds, surface area is 1.53 km2).

Table 2. The known fish fauna of the complex of lakes Vegoritida, Chimaditida, Zazari, and Petron (northern central Greece) (Economou et al., 2007). Bolded species are endemic to the Balkan Peninsula.

Family Species Anguillidae Anguilla anguilla (Linnaeus, 1758) Coregonidae Coregonus lavaretus (Linnaeus, 1758) Cyprinidae Alburnus thessalicus (Stephanidis, 1950) Barbus balcanicus Kotlik, Tsigenopoulos, Rab & Berrebi, 2002 Carassius gibelio (Bloch, 1782) Cyprinus carpio Linnaeus, 1758 Gobio bulgaricus Drensky, 1926 Rhodeus meridionalis Karaman, 1924 Rutilus rutilus (Linnaeus, 1758) Scardinius erythrophthalmus (Linnaeus, 1758) Squalius vardarensis Karaman, 1928 Tinca tinca (Linnaeus, 1758) Esocidae Esox lucius Linnaeus, 1758 Salmonidae Oncorhynchus kisutch (Walbaum, 1792) Oncorhynchus mykiss (Walbaum, 1792) Salmo trutta Linnaeus, 1758 Salvenius fontinalis (Mitchill, 1814) Siluridae Silurus glanis Linnaeus, 1758

3 BOBORI et al. / Turk J Zool type (6 m height × 27.5 m long, composed of 11 panels, for comparison of the regression lines. To determine 2.5 m in length, with different mesh sizes of 6.25, 8, 10, significant differences of the estimated b values from 12.5, 15.5, 19.5, 24, 29, 35, 43, and 55 mm), in accordance the isometric value of b = 3, a one-sample t-test (Zar, with the requirements of Directive 2000/60 (European 1999) was applied. Student’s t-test was also used on log- Commission, 2000) and the manual of the European transformed data to test for differences in the mean lengths Commission Standards for fish sampling in lakes (CEN, and weights of the specimens caught in lakes Vegoritida 2005). For the 3 shallow lakes (Chimaditida, Zazari, and and Petron. Possible differences among the depth strata Petron), only benthic habitats were surveyed, while for were tested by one-way ANOVA. The length-frequency Lake Vegoritida both benthic and pelagic habitats were distributions between lakes and among depth strata were surveyed. The nets were set in the evening and were analyzed through a Kolmogorov–Smirnov test (Zar, 1999). retrieved the next morning (10–12 h fishing duration). The Bhattacharya’s method was used to split the age groups total number of nets set in each lake and the strata depths from the length-frequency distributions, using FiSAT II are shown in Table 1. Catches were separated by station (Gayanilo et al., 1995). and mesh size, and fish were preserved in 10% formalin solution. In addition, electrofishing was conducted in 3. Results the littoral zone of each lake in order to catch species A total of 928 specimens of Pachychilon macedonicum were or smaller-bodied specimens that might have escaped caught in 3 out of the 4 lakes studied. The most specimens through the nets (Appelberg, 2000). All specimens were were caught in Lake Vegoritida (785 individuals), while identified to species level according to Kottelat and no specimens were recorded in Lake Zazari (Table 3). The Freyhof (2007), and for each individual the total length mean total length of the specimens differed significantly (TL, cm ±0.1) and total weight (W, g ±0.1) were recorded. (P < 0.005) between lakes Vegoritida and Petron, while The species-specific catch per unit effort was calculated as no differences (P > 0.05) were observed between the average number (NPUE; number of individuals per 100 mean weights of the 2 populations. In total, Pachychilon m2 net) and average biomass (BPUE; weight of fish per macedonicum specimens from Lake Vegoritida were longer 100 m2 net) (Appelberg, 2000). Species’ scientific names (mean length: 5.8 ± 0.04 cm) than those from Lake Petron are in accordance with recent nomenclature (Kottelat and (mean length: 5.5 ± 0.05 cm). Differences in mean lengths Freyhof, 2007; Froese and Pauly, 2013). and weights were also detected among the depth strata of The length–weight relationships (LWRs) for the most Lake Vegoritida (ANOVA, P < 0.001), with the longer and abundant catches of Pachychilon macedonicum were heavier specimens recorded from depths between 9 and 12 estimated using the equation W = aTLb, where W is m (Table 3). The length-frequency distributions differed the total weight (in g), TL is the total length (in cm), a significantly (P < 0.001) between lakes Vegoritida and is the intercept, and b the slope of the regression line in Petron (Figure 2). The population from Lake Vegoritida the linear form of the relationship (i.e. after logarithmic exhibited a greater length range than the one from Lake transformation). Multiple regression analysis was used Petron (Table 3; Figure 2), including more young-of-the-

Table 3. Descriptive statistics of the total length (TL, cm) and weight (W, g) of Pachychilon macedonicum specimens caught per depth zone in lakes Vegoritida, Chimaditida, and Petron (northern central Greece) during the summer period from 2010 to 2012. n = Number of individuals, NPUE = number of individuals caught per 100 m2 of net, BPUE = biomass (in g) of individuals caught per 100 m2 of net, depth zone (in m).

Depth TL W Lake n NPUE BPUE zone Mean SE Range Mean SE Range Vegoritida 0–3 5.7 0.05 3.7–8.8 2.5 0.07 0.5–10.5 515 114.4 281.7 3–6 6.0 0.07 3.7–8.6 2.8 0.07 0.4–8.0 223 49.6 137.2 9–12 6.2 0.14 3.7–9.2 3.1 0.21 0.5–9.1 43 8.0 24.3 12–20 4.3 0.06 4.1–4.4 0.7 0.10 0.5–1.0 4 1.3 0.9 Total 5.8 0.04 3.7–9.2 2.6 0.06 0.4–10.5 785 36.3 93.5 Chimaditida 0–3 6.7 0.99 5.4–9.2 4.5 2.50 1.7–11.0 4 1.1 5.0 Petron 0–3 5.5 0.05 4.3–8.6 2.3 0.09 0.9–10.9 139 19.3 43.7

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160 4 lakes studied. To our knowledge, there has been no 140 Petron other certified report of the species’ presence in this 120 Vegortda lake complex; thus, we can consider that the complex of 100 Vegoritida, Petron, and Chimaditida lakes now constitutes 80 the westward limit of the species’ distribution in Greece. 60 The presence ofPachychilon macedonicum in the 40

Number of specmens area cannot easily be explained, since the 4 lakes are not 20 connected with any closely located systems where the 0 species is known to exist (Kottelat and Freyhof, 2007).

3-3.5 3.5-4 4-4.5 5-5.5 5.5-6 6-6.5 6.5-7 7-7.5 7.5-8 8-8.5 8.5-9 9-9.5 Thus, the origin of the population, initially in Lake 9.5-10 TL (cm) Vegoritida, could be attributed to an accidental transport Figure 2. Length-frequency distribution of Pachychilon of the species, possibly during the illegal transfer of macedonicum from lakes Vegoritida and Petron. other species of commercial importance (e.g., Cyprinus carpio; Economidis et al., 2000). However, the existence and low abundances of the species in lakes Petron and year specimens and possibly 4 year-classes. Differences (P Chimaditida provide evidence for its easy adaptation to < 0.05) in length distributions were also observed in all these environments. cases among the different depth strata of Lake Vegoritida, Pachychilon macedonicum prefers to live in with the exception of the strata pairs 0–3 and 3–6, and 3–6 marshlands, lakes, and watercourses with little current on and 6–12 (P > 0.05). Pachychilon macedonicum densities low plains (Kottelat and Freyhof, 2007; Froese and Pauly, in terms of number (NPUE) and weight (BPUE) were 2013), while its biology and ecology are poorly known. higher in Lake Vegoritida than in the other 2 lakes (Table Typically, it prefers to live in small groups and in places 3). Moreover, differences in NPUE and BPUE values were where it is better protected, preying mainly on benthic observed within depth strata (Table 3). More individuals in macroinvertebrates (chironomids). Its trophic level has both number and biomass were caught in the upper depth been estimated as 3.2 ± 0.4 (Vavalidis et al., 2010), while strata (0–3 and 3–6 m; Table 3) than in the deeper strata, no data are available for its population dynamics. Thus, with the lower densities being recorded in depths between the length–weight relationships will be helpful, among 12 and 20 m (NPUE: 1.3 individuals/100 m2 net; BPUE: other factors, in further estimations of the weight-at-age; 0.9 g/100 m2 net; Table 3). The equations describing the along with the length-frequency distributions, they can be length–weight relationship for Pachychilon macedonicum used as a practical index of the condition of the species, in lakes Vegoritida and Petron were W = 0.0065TL3.3235, allowing life-history comparisons among regions (Petrakis R2 = 0.9665, P < 0.05, and W = 0.006TL3.4594, R2 = 0.9331, and Stergiou, 1995). The observed positive allometric P < 0.05, respectively (Figure 3), with the slopes of the growth pattern of the species in the lakes studied is in log-transformed equations not differing significantly (P accordance with previous observations in Lake Doirani > 0.05). However, the estimated b values differed from (b = 3.158; Bobori et al., 2010). However, this allometry the isometric value of 3 (Vegoritida: t-test = 4.284, P < may be a result of the differences existing between small 0.0005; Petron: t-test = 1.618, P < 0.05), denoting positive and large specimens’ conditions at the time of sampling allometric growth for the species in both lakes. (Froese, 2006), indicating the ability of the species to explore and adapt to the specific lakes’ environments. In 4. Discussion general, the species showed an adaptive selection to littoral The results presented here confirm for the first time the environments and an occupation of the epilimnion, presence of Pachychilon macedonicum in 3 out of the avoiding the deeper water strata, as other cyprinids do 12 (e.g., Alburnus alburnus and Rutilus rutilus; Vašek et al., 10 W = 0.006TL3.4594 2004). 8 R² = 0.9331 According to our results, we cannot yet support the 6 successful establishment of Pachychilon macedonicum in W (g) 4 all lakes examined. The species was not recorded in Lake W = 0.0065TL3.3235 Zazari, while in Lake Chimaditida it was present at very 2 R² = 0.9665 low densities. The population structure from Lake Petron 0 345678910 also does not support the species’ establishment in the TL (cm) lake. However, the densities recorded in Lake Vegoritida Figure 3. Length–weight relationships for Pachychilon and the multimodal length-frequency distribution with at macedonicum from lakes Vegoritida ◆ and Petron ■ . least 4 year-classes support a relatively new establishment

5 BOBORI et al. / Turk J Zool of Pachychilon macedonicum in the lake and successful previously known distribution area, with lakes Vegoritida, reproduction in previous years. Since Lake Vegoritida had Petron, and Chimaditida being now the westward limit of the highest densities and it is located at the lowest elevation its allocation in Greece. Furthermore, due to the existing compared to the other lakes, we can hypothesize that the connection of the lakes, the expansion of the species to expansion of the species to the other lakes started from Lake Zazari is also expected. At present, lakes Vegoritida Vegoritida through the hydrological network connecting and Petron can potentially act as reserves for ‘feeding’ the lakes. Thus, following an opposite direction from the the other lakes with Pachychilon macedonicum. Finally, lower to the higher elevations, Pachychilon macedonicum further studies on the current distribution, biology, and first reached Lake Petron, which drains into Lake ecology of the species is required in order to facilitate its Vegoritida through an artificial channel. The species’ establishment in the new systems, with the concurrent movement from Lake Petron to Lake Chimaditida may protection of its habitats. have been possible through the Amintas stream. The small number of specimens captured in this lake suggests Acknowledgments a very new and/or random presence of the species in The present work forms part of a research project co- Chimaditida, thus limiting the possibility for further financed by the European Union (European Social expansion. Consequently, the species’ absence from Lake Fund – ESF) and Greek national funds through the Zazari, which is located above Lake Chimaditida, would Operational Program “Education and Lifelong Learning” be expected. of the National Strategic Reference Framework (NSRF) - In conclusion, our findings confirm the existence and Research Funding Program: Heracleitus II. Investing in expansion of Pachychilon macedonicum westward of its Knowledge Society through the European Social Fund.

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