Iran. J. Ichthyol. (March 2019), 6(1): 31-40 Received: August 17, 2018 © 2019 Iranian Society of Ichthyology Accepted: November 1, 2018 P-ISSN: 2383-1561; E-ISSN: 2383-0964 doi: 10.22034/iji.v6i1.285 http://www.ijichthyol.org Research Article Reproductive biology of the invasive sharpbelly, Hemiculter leucisculus (Basilewsky, 1855), from the southern Caspian Sea basin Hamed MOUSAVI-SABET*1,2, Adeleh HEIDARI1, Meysam SALEHI3 1Department of Fisheries, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran. 2The Caspian Sea Basin Research Center, University of Guilan, Rasht, Iran. 3Abzi-Exir Aquaculture Co., Agriculture Section, Kowsar Economic Organization, Tehran, Iran. *Email: [email protected] Abstract: The sharpbelly, Hemiculter leucisculus, an invasive species, has expanded its range throughout much of Asia and into the Middle East. However, little is known of its reproductive information regarding spawning pattern and season that could possibly explain its success as an invasive species. This research is the first presentation of its reproductive characteristics, which was conducted based on 235 individuals collected monthly throughout a year from Sefid River, in the southern Caspian Sea basin. Age, sex ratio, fecundity, oocytes diameter and gonado-somatic index were calculated. Regression analyses were used to find relations among fecundity and fish size, gonad weight (Wg) and age. The mature males and females were longer than 93.0 and 99.7mm in total length, respectively (+1 in age). The average egg diameter ranged from 0.4mm (April) to 1.1mm (August). Spawning took place in August, when the water temperature was 23 to 26°C. Average gonado-somatic index values for females at the beginning of the reproduction period (March) and in ripe mature spawning females (August) were 2.90% and 16.97%, respectively. The averages of absolute and relative fecundities were 19978.6 and 607.1 eggs, respectively. The absolute fecundity was significantly related to body weight, ovary weight and age. A potentially high reproductive capacity, comparatively small eggs, short time of eggs’ development, fast sexual maturation, short life span, tolerance to a wide range of environmental conditions, all promote the invasion of this invasive sharpbelly in freshwater ecosystems of the temperate climate zone. Keywords: Gonado-somatic index, Fecundity, Freshwater ecosystem, Spawning season. Citation: Mousavi-Sabet, H.; Heidari, A. & Salehi, M. 2019. Reproductive biology of the invasive sharpbelly, Hemiculter leucisculus (Basilewsky, 1855), from the southern Caspian Sea basin. Iranian Journal of Ichthyology 6(1): 31-40. Introduction of aquaculture fish species, the sharpbelly has Exotic fishes can be caused the greater problem for invaded many other countries including Iran (Holcik the indigenous fish fauna and other organisms (Coad & Razavi 1992; Patimar et al. 2008; Jouladeh- 1980). A variety of exotic fish species have Roudbar et al. 2015), Iraq (Coad & Hussain 2007), introduced in Iranian freshwaters (Coad & Abdoli Kazakhstan (Petr & Mitrofanov 1998), Uzbekistan 1993; Esmaeili et al. 2018). Sharpbelly Hemiculter (Borisova 1972), Turkmenistan (Sal’nikov 1998), leucisculus (Basilewski, 1855) is a small cyprinid fish and Russian Federation (Kolpakov et al. 2010). with an original distribution extending from China, Sharpbelly is a non-indigenous fish in the Caspian Korea, Vietnam, to the far-eastern region of Russia Sea basin. In Iran, H. leucisculus is reported from and is the dominant species in many of the water some international wetlands, including the Alma- bodies in those regions (Gao et al. 2010; Tan et al. Gol, Adji-Gol and Ala-Gol (Patimar et al. 2008). 2010). Apparently through the associated movement Esmaeili et al. (2011) reported it from Zarivar Lake, 31 Iran. J. Ichthyol. (March 2019), 6(1): 31-40 Fig.1. Location of the sampling site in the southern Caspian Sea basin, Sefid River, in north of Iran. Abdoli (2000) recorded this species from the lower periods. Knowledge of gonadal development and the Sefid River, Anzali Wetland and the middle Aras spawning season of a species allow the subsequent River and Radkhah et al. (2016) reported it from the studies on spawning frequency of its population, Hamun-e-Jazmourian basin, southern Iran. which is important for its management (Chakraborty Hemiculter leucisculus found in rivers, lakes, small et al. 2007; Eagderi et al. 2013). Within a given ponds and swamps but there is a little information species, fecundity may vary as a result of different available about its habitat requirements (Coad 2017). adaptations to environmental habitats (Witthames et There are many studies on the age and growth of H. al. 1995). Fecundity assessments have been useful in leucisculus in its native ecosystems (e.g., Cao & Wen racial distinction, progeny survival studies, stock 1996; Li et al. 2009). In the invaded ecosystems, evaluation and aquaculture-based induced spawning however, Patimar et al. (2008) did research in three and egg incubation (Bagenal & Braum 1978; Coates lakes of Iran. In order to monitoring this species in its 1988). Sizes of eggs are also important parameters habitat, determination of reproductive biology of the used in reproduction studies to characterize fish fish is an essential factor. Also, descriptions of species and can also be used to predict the spawning reproductive strategies and the assessment of frequency of fish (Wootton 1979). Ecological fecundity are fundamental topics in the study of the conditions such as the water temperature and biology and population dynamics of fish species photoperiod influence the sexual maturity of fish (Cortes 2000; Jamali et al. 2015). greatly (Pawson et al. 2000; Rodríguez et al. 2001). Reproduction has three key components, The aim of the present study was to provide data including sexual maturity, reproductive period and on the reproductive characteristics of H. leucisculus, fecundity, which are vital demographic including gonado-somatic index, fecundity, oocyte characteristics, essential for understanding a species’ diameter, and spawning season/duration. We studied life history (Cortes 2000). Gonado-somatic index has the population inhabiting the down-stream of Sefid been used as an indicator of reproductive activity of River, in the southern Caspian Sea basin. Sefid River fish (Bagenal & Braum 1978; Coates 1988), and in (with 765km in length) is one of the most important the absence of information on eggs and larvae, this rivers in the southern Caspian Sea basin, in north of could be used to give an indication of peak spawning Iran (Fig. 1) (Heidari et al. 2014a, b; Coad 2017). The 32 Mousavi-Sabet et al.- Reproductive biology of Hemiculter leucisculus results were compared to data available for with eye or by use a binocular. In order to determine populations inhabiting different geographical regions the number of eggs, pieces were removed as well as for other cyprinid fish species to reveal the approximately 0.5-1g, each from the anterior and role of life history traits in promoting the species medial positions of both ovarian lobes. The pieces invasion in the southern Caspian Sea basin rivers were weighed and the eggs counted under a binocular system. microscope. The number of eggs in each female was calculated as the proportion of eggs in the sample to Materials and Methods the weight of the whole ovary. To calculate absolute Study area and Sampling: The research was carried fecundity, ovaries recognized at stages IV or V were out at one site on the down-stream of Sefid River used. The stage of gonad maturity was determined (36°59'31.01"N, 49°34'34.56"E). Samples were visually following the Nikolsky (1963). The relative taken from the shallow littoral pools in Sefid River, fecundity (Fr) was expressed by dividing the absolute clean water, slow water flow, the pools width were fecundity (Fa) to fish body weight (Bagenal & Braum about 5-15 m and maximum depth was up to 1.5m, 1978). To determine the oocyte diameter, the ovaries and the bed was rocky and gravel, somewhere with were preserved in 4% formaldehyde solution. The grassy shores and submergent plants. In total 235 diameters of 30 ova of each specimen were measured specimens were caught by electrofishing device using a binocular microscope M6C–10 which was (200-300V; distance between electrodes: 10-50 fitted with an ocular micrometer. meters; area covered each time: 100 meters; water Statistics: In order to compare significant differences depth covered: 40-120cm) at monthly intervals in the gonado-somatic index among various months throughout the year from March 2014 to February and various size samples, the analysis of variance and 2015. The water temperature of the fish catching site Tukey’s test were applied (P<0.05). The strength and was measured repeatedly. The water analysis in significance of the relationship between the absolute August showed that the water temperature was 23 °C; fecundity (Fa) and selected individual features of the -1 pH 6.5–7.9, O2 5–8 mg. L . All specimens were fixed females included in the study (standard length and and preserved in 4% formaldehyde solution and weight, the gonad weight and the fish’s age) were transferred to the laboratory for other studies. analyzed by determining Pearson’s correlation Measurements and indices used to qualify the coefficient r (P<0.05) and regression equations reproductive biology: For each specimen, total length (Thulasitha & Sivashanthini 2013). The data were (TL), fork length (FL) and standard length (SL) were analyzed by the SPSS version 16.0 software package measured by using measuring board to the nearest and Microsoft Excel 2010 software. 1mm; body weight (W) weighted by a digital balance with 1g accuracy. The fish’s age was assessed based Results on the annual growth of scales taken from the left side During this study, 235 individuals of H. leucisculus of the body, between the end of the pectoral fin and were collected from Sefid River. Fish body beginning of the dorsal fin (Bagenal & Braum 1978; measurements, including total length, fork length, Mousavi-Sabet et al.