The Küçük Menderes River (Western Anatolia) drainage has an agricultural character, and this area covers almost half of the river basin (Aksoy 2020). As this kind of agricultural area needs to be irrigated regularly, the river basin is under pressure. Otherwise, the area has been urbanized, and there are many industrial facilities that need water actively (Eris et al. 2020). The water needed is mainly supplied from groundwater (Yağbasan 2016). The importance of the river basin has been studied in terms of water management by state-owned organizations (TUBITAK 2010). In recent years, there have been many changes in the basin, where anthropogenic pressure is extremely high. It has been observed that – depending on human activities in terms of agricultural, fishing, industry and land uses – aquatic habitats have changed.
Türkiye is remarkable in terms of having extraordinarily rich natural wildlife, and there are many freshwater fish species known as endemic (Freyhof et al. 2014; Çiçek et al. 2018). Endemic species are vulnerable for native fish fauna (Crivelli 1995). The invasion of alien species have been increasing, and this affects the freshwater wildlife (Tarkan et al. 2015) together with the main anthropogenic pressures such as degradation, pollution, habitat loss, and excessive water extraction (Fricke et al. 2007).
The family Nemacheilidae is very diverse (Kottelat 2012; Çiçek et al. 2018, 2020; Jouladeh-Roudbar et al. 2020). It is distributed in the freshwaters in Asia, Europe, and north-eastern Africa (Nelson et al. 2016). The genus
The genus
To manage the conservation of endemic species, the biological and ecological data should be available for every species. Knowledge of these kinds of parameters are basic requirements; however, not enough data is available for all three –
The length-weight relationship (LWR) is used to investigate age structures, find growth rates, and for many other parameters. The LWRs provide fundamental data for many kinds of fishery research (Sparre, Venema 1998; Froese 2006). The LWRs allow us to compare given populations among different regions (Petrakis, Stergiou 1995; Froese 2006). The fish morphology ensures the opportunity to understand the population structures in different aquatic areas (Moutopoulos, Stergiou 2002; Sangun et al. 2007), and these kinds of data can easily be applied to fisheries research studies.
To take an action for the conservation for freshwater fishes from both anthropogenic pressure, and invasive species, the number of scientific studies on the fish should be increase. Therefore, a perceived deficiency exists in the fundamental parameters characterizing populations. The objective of this study is to explore growth patterns in
Küçük Menderes River drainage area is approximately 3225 km2. The river is 140 km long up to where it meets the sea (Saraçoğlu 1990). The river bed has a very narrow character, and its gradient decreases as it reaches the plain downstream in the western part from the mountain area upstream in the eastern part. The river drainage shows characteristics of the Mediterranean climate, as winters are warm and rainy while summers are hot and dry (Peel et al. 2007).
In the scope of the study, to determine the fish fauna of the river drainage, the sampling was conducted seasonally at 21 stations (15 lotic and 6 lentic water resources) from the source to downstream in 2018 and 2019 (Figure 1 & Figure 2). But because of the lack of sampling of the size of the fish, just one lotic and 4 lentic water resources’ fishes were examined in the present study. The fish sampling was investigated from Akgöl, Gebekirse, and Belevi (Selçuk/İzmir), Beydağı Reservoir (Beydağ/İzmir), and Akçay Stream (Ödemiş/İzmir) (Figure 2). The map (Figure 1) was created using the Qgis v. 2.6.1-Brighton software.
A total of 379 specimens of freshwater fish species were collected from the Küçük Menderes River drainage, Western Anatolia. In the sampling carried out in seasonal periods, a Samus 725G model electro-shocker was used in lotic habitat, and standard nets were used in accordance with the criteria of “TS-EN 14757 Water Quality-Taking fish samples with dense mesh nets with changing meshes” in lentic habitats. After anaesthesia, the fish were preserved in 5% formaldehyde and stored in 70% ethanol.
The identification of the species followed Freyhof et al. (2018), Bayçelebi (2019), İlhan et al. (2021) and Yoğurtçuğlu et al. (2022)(Table 1). Due to unespied sexual dimorphism in all the fish specimens, the LWRs parameters were calculated for all specimens. In the laboratory, the total length (
Taxonomic updated fish species of Küçük Menderes River and its drainage, based on previous records
No | Saç et al. (2021)* | İlhan et al. (2021)** | Current Taxonomic Status |
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1 | |||
2 | |||
3 | |||
4 | - | - | |
5 | - | ||
6 | |||
7 | |||
8 | |||
9 | - | ||
10 | |||
11 | - | ||
12 | |||
13 | |||
14 | |||
15 | |||
16 | |||
17 | |||
18 | |||
19 | - |
The species were recorded from subbasin of the river* and those were based on previous literature** were excluded.
In the scope of this study, seven species (
The present research provides the length and weight distribution, LWRs and CF of the 7 species. The specimens’ length and weight data with their standard error were given for the study areas (Table 2). The descriptive statistics of length and weight with the parameters of the LWR; regression parameters
The length and weight distribution, mean length and weight and their standard errors of fish species
Locality | Species | n | ||||||
---|---|---|---|---|---|---|---|---|
Aktaş Stream | 188 | 3.00 | 17.00 | 7.28 ± 0.258 | 0.28 | 58.27 | 7.72 ± 0.777 | |
Beydağ Reservoir | 42 | 6.40 | 20.50 | 7.55 ± 0.394 | 3.36 | 90.00 | 7.94 ± 2.591 | |
Aktaş Stream | 25 | 3.40 | 7.50 | 5.09 ± 0.290 | 0.32 | 3.75 | 1.35 ± 0.204 | |
Akgöl Lake | 5 | 3.00 | 7.00 | 6.06 ± 0.690 | 0.16 | 2.36 | 1.79 ± 0.370 | |
Belevi Lake | 10 | 13.50 | 22.20 | 17.18 ± 0.861 | 39.98 | 197.43 | 104.24 ± 15.923 | |
Akgöl Lake | 50 | 7.00 | 22.00 | 14.35 ± 0.609 | 7.10 | 228.40 | 72.73 ± 8.102 | |
Gebekirse Lake | 59 | 5.80 | 9.50 | 6.76 ± 0.088 | 1.20 | 4.04 | 2.16 ± 0.084 |
Endemic to the area,
Invasive
LWR parameters and growth types of fish species
Species | n | a | b | SEb | R2 | SEr | ttest | GT |
---|---|---|---|---|---|---|---|---|
188 | 0.012 | 2.980 | 0.038 | 0.980 | 0.086 | tcal = 0.653 < t0.05, n = 187 = 1.66 | I | |
42 | 0.012 | 2.990 | 0.057 | 0.984 | 0.034 | tcal = 0.169 < t0.05, n = 41 = 1.68 | I | |
25 | 0.009 | 2.959 | 0.081 | 0.964 | 0.042 | tcal = -0.497 > t0.05, n = 24 = 1.71 | I | |
5 | 0.004 | 3.176 | 0.067 | 0.986 | 0.058 | tcal = 2.643 < t0.05, n = 4 = 2.13 | A (+) | |
10 | 0.013 | 3.121 | 0.204 | 0.966 | 0.043 | tcal = -0.006 < t0.05, n = 9 = 1.83 | I | |
50 | 0.024 | 2.914 | 0.062 | 0.978 | 0.061 | tcal = 1.376 < t0.05, n = 49 = 1.68 | I | |
59 | 0.008 | 2.884 | 0.195 | 0.792 | 0.060 | tcal = 0.591 < t0.05, n = 58 = 1.68 | I |
A (+): Positive allometric growth, I:Isometric growth,
Endemic to the area,
Invasive species for area
The endemic species of the river,
The invasive species of the river –
According to current study, the coefficient of determination results in all study area were highly correlated. The regression coefficient (
In the current study, the
Condition factors (
N | Min | Max | Mean | SD | Var | SE | CI | |
---|---|---|---|---|---|---|---|---|
KF | 188 | 0.391 | 3.080 | 1.129 | 0.236 | 0.056 | 0.017 | 0.034 |
KR | 188 | 0.350 | 2.746 | 1.018 | 0.211 | 0.045 | 0.015 | 0.030 |
KM | 188 | 1.088 | 1.127 | 1.110 | 0.010 | 0.000 | 0.001 | 0.002 |
KF | 25 | 0.703 | 1.018 | 0.863 | 0.081 | 0.006 | 0.016 | 0.034 |
KR | 25 | 0.346 | 1.568 | 1.114 | 0.042 | 0.044 | 0.042 | 0.085 |
KM | 25 | 0.585 | 1.021 | 0.796 | 0.131 | 0.017 | 0.026 | 0.054 |
KF | 50 | 0.975 | 2.456 | 1.964 | 0.239 | 0.057 | 0.034 | 0.068 |
KR | 50 | 0.506 | 1.295 | 1.009 | 0.122 | 0.015 | 0.017 | 0.035 |
KM | 50 | 1.869 | 2.062 | 1.948 | 0.054 | 0.003 | 0.008 | 0.015 |
KF | 59 | 0.529 | 1.026 | 0.714 | 0.098 | 0.010 | 0.013 | 0.026 |
KR | 59 | 0.663 | 1.513 | 1.064 | 0.206 | 0.043 | 0.027 | 0.054 |
KM | 59 | 0.390 | 0.820 | 0.684 | 0.095 | 0.009 | 0.012 | 0.025 |
KF | 5 | 0.593 | 0.728 | 0.671 | 0.045 | 0.002 | 0.020 | 0.056 |
KR | 5 | 0.815 | 0.975 | 0.902 | 0.053 | 0.002 | 0.020 | 0.056 |
KM | 5 | 0.724 | 0.746 | 0.740 | 0.008 | 0.000 | 0.003 | 0.010 |
KF | 10 | 1.625 | 2.173 | 1.901 | 0.174 | 0.030 | 0.055 | 0.125 |
KR | 10 | 0.882 | 1.157 | 1.004 | 0.091 | 0.008 | 0.029 | 0.065 |
KM | 10 | 1.842 | 1.956 | 1.894 | 0.036 | 0.001 | 0.011 | 0.026 |
KF | 42 | 1.045 | 1.533 | 1.230 | 0.099 | 0.010 | 0.015 | 0.031 |
KR | 42 | 0.855 | 1.260 | 1.003 | 0.081 | 0.007 | 0.012 | 0.025 |
KM | 42 | 1.214 | 1.228 | 1.226 | 0.003 | 0.000 | 0.000 | 0.001 |
SD = Standard deviation, SE = Standard error, CL = Confidence intervals
Recently, fish fauna of Küçük Menderes was studied in two comprehensive papers (İlhan et al. 2021; Saç et al. 2021) (Table 1). Saç et al. (2021) recognised 21 species from 50 sampling sites. Only 24 of these 50 sampling sites were located directly on the Küçük Menderes River and its tributaries, and 17 of these 21 species were determined in the river and its drainages. On the other hand, İlhan et al. (2021) recognised 13 fish species from nine sampling sites. The
As per Froese (2006), the regression slope (
Although it is an endemic species of Western Anatolia water resources, there is still a lack of studies for local knowledge on the biological data of the
To date, the length and weight distribution were found to be
In previous studies, there has been a lack of knowledge about the invasive species of the area. The limited studies were made in one of the closest basins, the Gediz River Basin. The LWRs of the invasive species found from the Gediz River`s different water resources changed respectively between
The variability in the
In terms of growth type, isometric growth was determined for all specimens at the sampled localities except
In the current study, Fulton’s condition factor for all individuals ranged between 0.391 (
The specific goals of the study were to evaluate the LWRs, growth type, and condition data of the related fish species. Within the actual study, Küçük Menderes River drainage fish fauna was investigated in large frequency in the water resources of the western part of Anatolia. The present study considered basic information on the LWRs and CF for the established population of endemic, native, and invasive populations, which would be useful for fish researchers in the region. Although the simplicity of the methodology differed from basic methods by using limited data, the results of the study are useful for conservation studies, and fisheries management studies for the fish fauna of Küçük Menderes River basin. This may be the main reason for having a lower