Barbus oligolepis, (Steindachner, 1897)
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publication ID |
https://doi.org/ 10.3906/zoo-1603-34 |
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persistent identifier |
https://treatment.plazi.org/id/03C70D21-FFCF-FFD6-FFC0-FC15FF19F976 |
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treatment provided by |
Felipe |
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scientific name |
Barbus oligolepis |
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3.1. B. oligolepis (Steindachner, 1897) View in CoL
The gut contents of 76 B. oligolepis specimens collected from August 2007 to July 2008 were examined. The guts of 20 specimens were empty. The mean TL and W of these specimens were 17.4 ± 3.95 cm (11.1–28.1) and 60.23 ± 45.95 g (12.1–213.4), respectively. The male-to-female ratio was 2.31, and the condition factors of females and males were 1.32 ± 0.17 and 1.30 ± 0.13, respectively. There were no statistical differences between female and male condition factors (F = 0.35, F = 1.54; P> 0.05). There were no statistical differences in condition factors of specimens among different size groups (F = 1.59, F = 0.61; P> 0.05). The condition factor values of specimens were lower in the fall than in the spring and summer (F = 8.04, F = 11.7; P <0.001) .
The mean gut length of examined B. oligolepis specimens was 23.42 ± 7.12 cm. There was no statistical difference between the relative gut length of females (1.40 ± 0.20) and males (1.34 ± 0.27) (P> 0.05). There was no statistical difference in the relative gut length among different size groups (P> 0.05). The mean gut lengths of B. oligolepis showed seasonal variation. The mean gut length of B. oligolepis was longer in spring than in other seasons (F = 6.28; df = 1; P = 0.001). There was also seasonal variation in the relative gut lengths of specimens (F = 5.84; df = 3; P = 0.001). There was a linear relationship between TL and gut lengths of examined specimens that had full guts (r 2 = 0.61, n = 54, P <0.001, Figure 2 View Figure 2 ). There was no statistical correlation between fish weight and gut length of B. oligolepis (P> 0.05). There was a relationship (fish weight = 4.7 × gut weight + 10.0 × fish TL – 123.5) among fish weight, GCW, and TL (F = 314.7; P <0.001).
The main food sources of B. oligolepis were benthic algae; Bacillariophyceae members constituted 95.3% of all dietary organisms ( Figures 3 View Figure 3 and 4 View Figure 4 ). Macrophytes (4.4%) and macroinvertebrates (0.2%) were additional important food groups. Fish eggs and zooplankters had little importance in the diet of B. oligolepis . In terms of the frequency of occurrence, macroinvertebrates such as Diptera larvae 1 (head length ~100–150 µm), other insect larvae, and benthic algae (particularly siliceous algae) were the most popular food sources in the gut contents ( Table 2). We found that 99.8% of the gut contents contained plant materials; thus, it can be said that this species feeds mainly on plant materials. Anabaena sp. (98%) was the most abundant food source among the cyanobacteria. The most frequently encountered organisms in this group were Oscillatoria sp. 1 (5.2%) and Oscillatoria sp. 2 (3.5%). Fragilaria sp. (400 µm) was the most abundant (49.2%) and frequent (41.4%) dietary resource in the gut contents among the Bacillariophyceae. Cocconeis sp. was the second most abundant and frequently encountered Bacillariophyceae, which was particularly identified on filamentous algae in the gut contents. Other siliceous algae (<50 µm) were found in considerable amounts in the gut contents. Filamentous algae, particularly those of 50 µm × 60 µm in size, were the most abundant food resources among the Chlorophyceae members. Cosmarium sp. (17.2%) and Vaucheria sp. (10.3%) were the most frequently encountered organisms among the Zygnemophyceae and Xanthophyceae, respectively. Therefore, the gut content analysis concluded that B. oligolepis is a generalist feeder in the Karamenderes River.
The percent abundance and frequency of occurrence of food organisms varied between females and males ( Table 3). Both sexes fed primarily on Bacillariophyceae, Chlorophyceae, and Insecta. Zooplankters, fish eggs, Zygnemophyceae, and Bryophyta were found only in the gut contents of males. The diet of males was more diverse than that of females.
Animal ( Insecta and Oligochaeta setae) and plant ( Bacillariophyceae, Chlorophyceae, and Cyanobacteria) materials were found in all seasons in the gut contents of B. oligolepis ( Table 4). Zooplankton was found only in spring and summer of 2008.
Zooplankton was consumed by fish species that were <15.2 cm in TL ( Table 5). Fish eggs were found only in
YALÇIN ÖZDİLEK / Turk J Zool the size group of 17.4–19.4 cm for males in the summer of 2008. The siliceous algae and insects were consumed abundantly and frequently by almost all size groups. All size classes of fish fed on Chlorophyceae members, particularly filamentous algae ( Chlorophyceae), which were found abundantly in the gut contents of fish specimens with a TL of> 21.5 cm. The number of components in food was highest in the size group of 13.2–15.2 cm.
3.2. Squalius cii (Richardson, 1857)
The gut contents of 82 S. cii specimens were examined between August 2007 and July 2008. The guts of 13 specimens were empty. The mean TL and W of these specimens were 19.2 ± 5.92 cm (7.8–36.7) and 112.2 ± 126.2 g (3.5–730), respectively. The male-to-female ratio was 2.83, and the condition factor values were 1.57 ± 0.41 and 1.37 ± 0.13 for females and males, respectively. There were no significant differences between the condition factors of females and males (F = 0.11, F = 0.37; P> 0.05). There was a statistical difference among the condition factors of specimens among different size groups (F = 3.20, F = 2.44; P <0.05). There were no seasonal differences in the condition factors (F = 0.48, F = 2.23, P> 0.05) ( Table 1) .
There were no statistical differences between the mean gut length (19.63 ± 7.62 cm) and TL (19.21 ± 5.92 cm) of S. cii species (F = 0.15; df = 1; P> 0.05). The relative gut lengths of female S. cii (1.24 ± 0.28) were longer than those of males (0.96 ± 0.28) (F=9.2; P <0.05). There was no size-dependent variation with regard to the relative gut length of the specimens (P> 0.05). The mean gut lengths and relative gut lengths of S. cii showed seasonal variation (F = 2.86; P <0.05; F = 3.69, P <0.05). The mean and relative gut lengths were lowest in the summer of 2008 ( Table 1). As seen in Figure 2 View Figure 2 , a linear relationship was found between TL and gut length of the fish (r 2 = 0. 633; n = 62; P <0.001). A correlation was found between body weight (BW) and GCW of the fish (r = 0.845; n = 60; P <0.001), and there was an exponential relationship between TL and GCW, similar to that between TL and W ( Figure 5 View Figure 5 ). Therefore, it can be said that fish weight was affected by GCW and that GCW increases as TL increases, or vice versa. Fish weight was a function of TL and GCW according to the formula W = 9.1 GCW + 13.9 TL – 192.6 (F = 251.7; P <0.001).
Benthic algae were found in nearly all gut contents of fish specimens, accounting for 97.4% of all dietary organisms. While macroinvertebrates were present in low abundances, they were the most frequently encountered and basic food resource ( Figure 3 View Figure 3 ). Benthic algae were also among the most frequently encountered organisms, and Cyanobacteria were among the most abundant dietary organisms ( Figure 4 View Figure 4 ). Diptera larvae were the most frequently consumed insects ( Table 2). The Cyanobacteria primarily included Oscillatoria sp. (2.5 µm × 5 µm), Fragilaria sp. (400 µm), Cymbella sp. (20 µm × 80 µm), and Gomphonema sp. However, the branched and unbranched algae could not be adequately identified because of digestion; the unbranched algae (50 µm × 60 µm cell size) were the most abundant (24.7%) and frequently (30%) encountered Chlorophyceae in the gut contents. In terms of Zygnemophyceae members, Desmidium sp. was the most abundant (80.3%) and Cosmarium sp. was the most frequently identified (17.1%) in the gut contents. The gut content analyses indicate that S. cii is a generalist feeder in the Karamenderes River.
Plant material was abundant in the gut contents of both sexes of S. cii . Animal food components (i.e. different species consumed) were more abundant in the gut contents of males than females ( Table 3). While members of Cyanobacteria were abundant in the gut
Fragilaria sp. 1 (150 µm)
Fragilaria sp. 2 (8 µm × 215 µm)
Fragilaria sp. 3 (8–320 µm)
Fragilaria sp. 4 (10 µm × 200–250 µm)
Fragilaria sp. 5 (400 µm)
Fragilaria sp. 6 (370–500 µm)
Bacillariophyceae (<50 μm)
Branched filamentous algae (40 µm × 250 μm) Branched filamentous algae (50 µm × 400 μm) Branched filamentous algae (150 µm × 200 μm) Unbranched filamentous algae (10 µm × 50 μm) Unbranched filamentous algae (20 µm × 20 μm) Unbranched filamentous algae (30 µm × 100 μm) Unbranched filamentous algae (50 µm × 60 μm) Unbranched filamentous algae (25 µm × 5–10 μm) Unbranched filamentous algae (50–60 µm × 75 μm) Unbranched filamentous algae (70 µm × 80 μm) Unbranched filamentous algae (20 µm × 30 μm) Unbranched filamentous algae (120 µm × 100 μm) Unbranched filamentous algae (40–50 µm × 200 μm) Unbranched filamentous algae (100 µm × 200–300 μm) Oedogonium sp.
Table 2. Continued.
Particles of higher vascular plants
Fungus
Number of components in food
Condition value
Vacuity index
Repletion index
Relative gut length
Shannon–Wiener diversity index
Evenness
Morisita–Horn index
Schoener overlap index
0.019 1.43 1.710 13.79 1.934 18.57 1.118 3.45 2.323 25.86 1.830 10.00 49.223 41.38 6.131 58.57 7.166 15.52 0.134 8.57 0.151 3.45 1.538 36.21 0.310 24.29 0.063 3.45 0.001 1.43
<0.001 1.43 0.044 8.62 0.183 3.45 0.112 1.43 0.020 10.34 <0.001 2.86 0.066 10.34 <0.001 2.86 8.152 13.79 0.455 12.86 0.017 1.72 0.009 1.72 <0.001 4.29 0.010 5.17 0.012 6.90 0.010 10.34 <0.001 1.43 1.015 8.62 0.031 4.29 0.035 1.72 0.885 12.86
0.009 1.43
<0.001 1.43
0.007 5.71 0.463 3.45 0.450 20.00 2.288 13.79 0.647 30.00
0.125 5.71
0.215 8.57
0.011 1.43 0.033 3.45 <0.001 1.43
0.002 4.29
0.053 10.00
0.010 4.29 0.149 3.45 0.180 7.14
0.173 11.43 0.068 17.24 0.042 17.14 0.185 5.17 0.020 47.14 0.399 10.34 0.022 7.14
0.090 8.57 64 66 1.27 ± 0.13 1.35 ± 0.3 23.7 15.9 2.42 ± 1.29 3.76 ± 2.33 1.3 ± 0.2 1.0 ± 0.3 2.05 1.07 0.49 0.25 0.07 0.16 contents of S. cii males, members of Bacillariophyceae and Chlorophyceae were abundant in the gut contents of females.
Bacillariophyta and Chlorophyceae were abundant in a variety of size classes ( Table 6). Zooplankter species such as Rotifera, Amphipoda, Copepoda, and Cladocera were consumed by specimens that were <20 cm in size. Insects were identified in the gut contents of fish across all size groups. Fish eggs were found only in the gut contents of the size group of 17.1–20.1 cm in the summer of 2008; the number of food components was highest in this size group.
Cyanobacteria were found frequently and abundantly only in the summer of 2007 ( Table 4). Insects were the most frequently consumed food item in the summer and spring. The greatest diversity of food resources in the gut contents was encountered during the summer of 2008. Bryozoa statoblasts were found in the gut contents in the fall of 2007 and spring and summer of 2008; fish were found primarily in the gut contents in the fall and spring, and fish eggs were found in the gut contents in the summer of 2008.
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Université Paul Sabatier |
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