Department of Science Education, Gazi Faculty of Education, Gazi University, Ankara, Turkey
Atherina boyeri is a translocated and invasive fish species that is known to pose problems to the native fish fauna and other. In this study, twenty three morphometric properties of the sand smelt, A. boyeri population in Süreyyabey Dam Lake was investigated for the first time. Twenty three morphometric characters of samples were measured and evaluated. These characteristics were standard length, fork length, total length, body weight, pre orbital distance, eye diameter, inter orbital distance, head length, head width, dorsal fin I nose point distance, dorsal fin II nose point distance, pre anal distance, pre pectoral distance, pre ventral distance, dorsal fin I base length, dorsal fin II base length, anal fin base length, pectoral fin base length, ventral fin base length, maximum body height, caudal peduncle height, body width, caudal peduncle width. The fork length of individuals which were caught (FL) were between 5.30 and 7.30 cm, and their weight (W) were ranged between 1.12 and 3.57 g. This paper reports the first occurrence of A. boyeri from Süreyyabey Dam Lake in YeÅilÄ±rmak Basin.
Atherina boyeri; Sand smelt; Morphometric properties; Süreyyabey dam lake
Turkey has the richest freshwater ichthyofauna in the Mediterranean R egion with approximately 380 species . Turkey also has rich fish diversity and has ratio of endemism . Atherina boyeri Risso, 1810 is both a native and translocated fish in Turkish waters, in terms of distribution . Translocated or invasive fish species may cause problems to the native fish fauna and other species and may lead to the introduction of exotic diseases and parasites [3,4].
The sand smelt, A. boyeri, is a kind of Atherinid fish that generally occupies coastal and estuarine waters, including coastal lagoons, over a wide range of salinities from freshwater to hyper saline conditions . As a carnivores or opportunistic predator species, it feeds on zooplankton and benthic organisms .
It is an euryhaline that mostly reside in coastal and shallow brackish waters including coastal lagoons, salt marshes and inland waters [6-13]. In recent years, A. boyeri, a marine species, has been expanding its distribution area to inland waters [3,14-26]. In recent years, the distribution of this species in inland waters has been expanding because of accidental or ıntentional grounds and the increasing demand in the international market have made the species more popular among fishermen .
Sand smelt, A. boyeri has large adaptation talent and exhibits regional differentiation for its morphological and biological characteristic . Since it easily adapts to new environments and form large populations in various salinities, A. boyeri has succeeded in colonizing again in water systems .
Fish morphology means a range of anatomical design among fish species. Body architecture can be analyzed in characteristic depth, predation style, other swimming specializations required for the survival success of a given species. For example, the type, size and arrangement of a fish’s fins are completely in line with its ecological niche . Morphometric assessment is also used in the identification of the differences in fish population [28,29].
In this study, the first occurrence of A. boyeri from Süreyyabey Dam Lake in the Yeşilırmak Basin was reported. This research describes the area where these were found and document the morphometric data of the population.
Süreyyabey Dam Lake is located approximately 82 km northeast of Yozgat (35° 28' N and 35° 33' N latitudes and 39° 55' E and 40° 03' E longitudes) (Figure 1). Süreyyabey Dam, Yozgat province on the Çekerek Creek, was constructed for irrigation, energy and flood control. The area of lake is 41,34 km2 with a rock body fill type dam. The Çekerek River, one of the most important branches of Yeşilırmak, is located between the Deveci Mountains (1892 m) and Dagni Mountain (1755 m) .
The samples (A. boyeri) were collected from Süreyyabey Dam Lake. During the study, 46 fish specimens were caught in 2016 (Figure 2). The samples were preserved in 4% formaldehyde solution and measured weight to the nearest 0.01 g and total, fork and standard length to the nearest 0.01 mm. Measurements for twenty three morphometric characteristics were recorded in Table 1.
|PARAMETERS||Min||Max||Average||SD||CI||Margin of error||Upper bound||Lower bound|
|10||Dorsal fin I nose point distance||1.50||3.10||2.633||0.409||0.189||0.018||2.445||2.822|
|11||Dorsal fin II nose point distance||3.10||4.40||3.906||0.418||0.193||0.019||3.712||4.099|
|15||Porsal fin I base length||0.10||0.60||0.272||0.149||0.069||0.002||0.204||0.341|
|16||Dorsal fin II base length||0.20||0.90||0.556||0.243||0.112||0.006||0.443||0.668|
|17||Anal fin base length||0.30||1.10||0.756||0.250||0.116||0.007||0.640||0.871|
|18||Pectoral fin base length||0.10||0.80||0.450||0.209||0.097||0.005||0.353||0.547|
|19||Ventral fin base length||0.10||0.20||0.128||0.046||0.021||0.000||0.106||0.149|
|20||Maximum body height||0.80||1.50||1.094||0.189||0.087||0.004||1.007||1.182|
|21||Caudal peduncle height||0.20||0.50||0.333||0.091||0.042||0.001||0.291||0.375|
|23||Caudal peduncle width||0.10||0.30||0.178||0.065||0.030||0.000||0.148||0.208|
|10||Dorsal fin I nose point distance||2.10||2.90||2.557||0.210||0.078||0.003||2.479||2.635|
|11||Dorsal fin II nose point distance00||3.20||4.30||3.796||0.305||0.113||0.007||3.684||3.909|
|15||Porsal fin I base length||0.10||0.50||0.275||0.117||0.044||0.001||0.231||0.319|
|16||Dorsal fin II base length||0.20||0.70||0.511||0.126||0.047||0.001||0.464||0.557|
|17||Anal fin base length||0.10||1.80||0.779||0.321||0.119||0.007||0.660||0.898|
|18||Pectoral fin base length||0.10||2.50||0.493||0.445||0.165||0.014||0.328||0.658|
|19||Ventral fin base length||0.10||0.40||0.132||0.067||0.025||0.000||0.107||0.157|
|20||Maximum body height||0.80||1.30||1.093||0.178||0.066||0.002||1.027||1.159|
|21||Caudal peduncle height||0.20||0.40||0.296||0.058||0.021||0.000||0.275||0.318|
|23||Caudal peduncle width||0.10||0.40||0.189||0.096||0.035||0.001||0.154||0.225|
Table 1: Morphometric characteristics of A. boyeri specimens
The total length and weight (min-max) of the fish were 5.80 – 7.80 cm and 0.12 – 3.57 g, respectively. A sample sand smelt (n= 46; males= 28; females=18) was collected from Süreyyabey Dam Lake. Twenty three mensural characteristics including standart length (SL), fork lenght (FL) and total length (TL), and body weight were measured.
A. boyeri shows twenty three differences in terms of morphometric and meristics characteristics. However, these differences are at the population level in the Mediterranean Basin and there is no major distinction between these populations. The pre maxillary and colour differences, along with the shape of the vertebrae and scales, are the most significant distingushing aspects between their populations . A. boyeri is capable of adaptation and usually occupies at the changeable conditions of seas, lagoons and lakes such as temperature, salinity, turbidity, and currents [6,32].
Many morphometric characters of A. boyeri from the Süreyyabey Dam Lake show difference when compared to those in the Iznik Lake population  and Devegeçidi Dam Lake population , Izmir Basin population . Such differences between populations could be possibly explained by the changing morphometries of this polymorphic species with respect to physical and chemical variables characteristic of different environments  or errors by different researchers taking the measurements .
It is reported that morphometric characters may change not only in populations but also in regions . There are differences in the morphological characteristics of the population at the regional level as well as the morphometric diversity .
The studies on the A. boyeri populations which are spread widely in the inland waters of Turkey are very limited. There have not been many studies of these biometric features in Turkey.
Bartulovic et al.  in Mala Neretva River, Croatia (TL= 3.1 - 11.6 cm); Özeren  in İznik Lake (TL= 3.0 – 11.5 cm, W= 0.1- 11.0 g); Çetinkaya et al.  in İznik Lake (FL= 2.0 -10.6 cm, W= 0.06 - 10.5 g); İlhan and Sarı  in Marmara Lake (TL= 3.70 - 8.70 cm, W= 0.40 - 5.40 g); Apaydın and Yağcı et al.  in Eğirdir Lake (TL= 1.6 - 9.8 cm, W= 0.15 - 9.42 g); Saç et al.  in Büyükçekmece Reservoir (SB= 3.1 - 6.1 cm, W= 0.295 - 2.360 g); Gençoğlu and Ekmekçi  in Hirfanlı Dam Lake (TL= 29.20 - 88.92 mm, W= 0.12 - 10.48 g); Ünlü et al.  in Devegeçidi Dam Lake (TL= 43.3 - 59.9 mm, W= 0.7 – 8.0 g) are reported in the literature.
This paper reports the first occurrence of A. boyeri from Süreyyabey Dam Lake in Yeşilırmak Basin. This paper describes the area where this fish were found and its morphometric data of the population was recorded. Findings obtained in this study are very important because the previous studies about the morphometric properties of A. boyeri have not been investigated in this region. It is considered that the data obtained in this study will also contribute to future studies.