Background

Climatic changes and human activities have worked to pave the way for alien species to invade new areas far from their native habitats (Sandilyan et al., 2018). Climate changes have made the environmental conditions suitable for species to leave their original habitat due to temperature increase, salinity increase and food habit changes (Vallerga et al., 2003, Drago et al., 2004, RAC, 2009., Ibrahim et al., 2010, Eissa and Zaki, 2011). Human activities, such as Suez Canal opening, and ships movement across the world, open the road for marine species to move into new environments (Ibrahim et al., 2002, Zenetos et al., 2004, AlShawy et al., 2017, Alshawy et al., 2019a,b). Up to now, more than 100 Lessepsian fish species had invaded the Mediterranean Sea from the Indian and Pacific oceans and the Red Sea (Zenetos et al., 2012, Boussellaa et al., 2018). Belonidae species (Needlefishes), spread into wide water bodies (Froese and Pauly, 2019), and some exist in the Mediterranean Sea (Whitehead et al., 1984, Carpenter and De Angelis, 2016). However, up to now, only two species of this family (Belone belone and Tylosurus choram) had been recorded in the marine waters of Syria (Ali, 2018). Hence, the present study reports that the Flat Needlefish Ablennes hians has been recorded for the first time in the marine waters of Syria, and for the second time in the eastern Mediterranean.

Methods

On 18/2/2019, a field trip was performed in the marine waters facing Banyas city, Syria (N: 35°14′35.11″, E: 35°55′12.56;(Fig. 1) to collect fish samples using a gillnet (18 mm mesh size, 3 m height, 200 m length: with duplicates), with assistance of fishing boat (9.5 m and 19HP). Fish individuals were identified according to Carpenter and Niem (1999), Hailey (2011) and Roul et al. (2018). The morphometric measurements (length to the nearest mm, weight to the nearest g), and meristic counts were recorded. They were then photographed, preserved in 7% formaldehyde and placed at the Fish Biological Laboratory of the High Institute of Marine Research -HIMR (Tishreen University - Lattakia, Syria) as reference samples.

Fig. 1
figure 1

A map showing the collection site of A.hians specimens from the Syrian marine waters

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Results

Two individuals of the Flat Needlefish Ablennes hians (Valenciennes, 1846) (Fig. 2) were caught. They have the following diagnostic characteristics: the body is elongated and compressed laterally, upper and lower jaws elongate with small sharp teeth. Front part of the dorsal and anal fins are longer than the rest of fins, and curved backwards. The caudal fin is forked. The body is coloured bluish green above and silvery white on sides. The dorsal and caudal fins and the lobes of the front part of the pelvic, pectoral and anal fins are black. Dark vertical bars cover the body. The morphometric measurements are shown in Table 1 and the fin formula is: D,25;P,14;V,6;A,27;C,19. These 2 individuals are females with single lobed ovary in pre-spawning stage. It should be noted here that the local fishermen had confirmed the existence of this species several times in their catches during the last few months.

Fig. 2
figure 2

a-A specimen of Flat Needlefish A.hians, caught on 18-2-2019 from Banyas coastal area, Syria. b-The ovary of the specimen

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Table 1 Morphometric measurements of A.hians captured from the coastal water of Banyas, Syria
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Discussion

The Flat Needlefish A. hians spreads in tropical and subtropical waters (Eastern Atlantic, Western Atlantic, the Indian Ocean, Western Pacific, Eastern Pacific, and Red sea) (Carpenter, 1997, Carpenter and Niem, 1999, Carpenter and Niem, 2001, Golani and Fricke, 2018). A. hians had been recorded for the first time in the eastern Mediterranean (the coast of Netanya city) by Golani (2019); It had never been recorded in the western Mediterranean yet (Collette et al., 2015, Froese and Pauly, 2019). Therefore, the occurrence of this species in the eastern Mediterranean may largely due to its migration through the Suez Canal and its direction eastward. The previous record of this species in the Egyptian coast of the Red Sea (Golani and Fricke, 2018), and not that of other areas of Mediterranean Sea (Galil et al., 2015, Haroun et al., 2017, Golani and Fricke, 2018) supports this hypothesis. This record adds an additional species to fish checklist of the Syrian marine waters, and confirms that the changes in the environmental conditions of the Mediterranean facilitate species introduction (Coll et al., 2010, Hallom et al., 2014, Alshawy et al., 2019c). However, despite the presence of these two individuals, in addition to the previous observations of this species in the catches, more studies should be conducted to verify whether the Flat Needlefish A. hians had established itself in the marine water of Syria.

Conclusion

This study reveals that the Flat Needlefish A.hians exists in the marine waters of Syria. It has been recorded for the first time in this area, and for the second time in the eastern Mediterranean Sea. Suez Canal is thought to be the main root of introduction.