The second record of the Seychelles dragonet Synchiropus sechellensis in the Northeastern Mediterranean coasts of the Turkey

Two female and one male specimens of the Seychelles dragonet Synchiropus sechellensis were caught by a commercial trawl at a depths of about 55-65 m on 04 November 2017 from the Aydıncık coast, Turkey. The present paper reports the second record of S. sechellensis with its extention to eastward coast of Mediterranean of Turkey. The present observation also indicate that S. sechellensis has established population in the southern coast of Turkey.

In 2014, the first record of S. sechellensis was reported from the Gulf of Antalya in the Mediterranean Sea (Gökoğlu et al., 2014) and then the presence of the species in the southern Aegean Sea and east Mediterranean waters were reported with two locations, Kastellorizo Island and Rhodes, in Greeke marine waters (Kondylatos et al., 2016).Later, this species was reported from Moni, south Cyprus in the eastern Mediterranean Sea (Michailidis & Chartosia, 2016).Eventually, Akel & Rizkalla (2017) obtained a large number of specimens of S. sechellensis from Egyptian Mediterranean waters.
The present study first report the occurrence and extention of S. sechellensis with the female specimens and second record of the lessepsian dragonet, S. sechellensis in the southern coasts of the Turkey (Northeastern Mediterranean Sea).

Materials and Methods
On 04 November 2017, two female (76-105 mm standard length, SL) and one male (82 mm standard length, SL) specimens of S. sechellensis (Figure 1) were collected by a commercial trawler from Aydıncık, Mersin province (36° 07' N, 33° 16' E) on a sandy bottom at a depths of about 55-65 m (Figure 2).The specimens were taken to the Laboratory of Molecular Ecology and Fisheries Genetic Laboratory, Iskenderun Technical University for further examination, where the main morphometric measurements were collected by means of a digital caliper with an accuracy of 0.01 mm.The specimens were identified according to Fricke (1983Fricke ( , 2000) ) and Gökoğlu et al. (2014).The collected specimens were preserved in 4% formalin and deposited in the Museum of the Faculty of Marine Sciences and Technology, Iskenderun Technical University, (MSM-PIS/2017-2).

Results
The distinguishing meristic and morphometric characteristics of the specimens are given in Table 1, compared with Gökoğlu et al. (2014) and Michailidis & Chartosia (2016).Additionally, record details of S. sechellensis in Mediterranean waters between 2014 and 2017 are shown in the Table 2.
Color of fresh female and male specimen; the body is elongated and slightly depressed.In females, the first dorsal fin is shorter than that of the male and the membrane between the spines is orange with few black blotches.Snout short and rounded, eye large.However, in males, the first spine of the first dorsal fin is long, followed by three little and shorter spines and between the spines there is a yellow membrane with small black blotches at the fin base increasing in size upward to the distal part of the fin.Snout long and not rounded.In females and males; Second dorsal fin rays reddish-orange.Pectoral fin rays reddish and at the tip of the fin is black.Anal fin rays are red colored distal parts dark black.Caudal fin has vertical dark colored bands with two arches.

Discussion
The present study is the first documantation of female specimens of S. sechellensis collected from the southern coasts of the Turkey (Northeastern Mediterranean Sea) after from Egyptian waters, southern part of the Mediterranean Sea (Akel & Rizkalla, 2017).According to Akel & Rizkalla (2017) this species has established a large population in the Egyptian waters in the Mediterranean.
S. sechellensis is found in a wide range from the Indo West Pasific to the Red Sea and lastly Mediterranean.They commonly feed on worms, snails and crustaceans.Dragonets are oviparous, with pelagic eggs and larvae (Fricke, 1986).
The S. sechelensis can be easily distinguished from S. phaeton by dorsal fin (in S. phaeton; dorsal fin with black blotch), anal fin rays (VI, I for S. sechelensis, 8-9 for S. phaeton) and a dissimilar overall color pattern.
The increasing of water temperature has been considered as the main reason for the increasing introductions of non-indigenous fish species in the Mediterranean Sea (Ben Rais Lasram et al., 2010, Turan et al., 2016).However, rapid expansion may also affect diversity and abundance of native species in the near future.In the last ten years, an increasing number of lessepsian species seem to have extended their distributions from the eastern Mediterranean (Galil & Zenetos 2002).Many fish species are now well established in the Mediterranean Sea, Turkey (Ergüden et al., 2016).Gökoğlu et al. (2014) point outed that S. sechelensis reported from the Mediterranean Sea may has been accidentally introduced to by marine traffic and shipping activities.However, Michailidis & Chartosia (2016) stated that that the introduction of this species was not accidental but via the Suez Canal.We also think that the occurrence of this species in the Mediterranean Sea is most probably due to Lessepsian migration phenomenon.
In this study, the second record of S. sechellensis is presented in the southern coasts of Turkey.According to the present observations, the species can now be considered as established in the southern coasts of Turkey.

Figure 1 .
Figure 1.Map shoving capture sites of Synhiropus sechellensis in the Mediterranean Sea (•, the previous reports; , the present record).

Table 1 .
Comparison of morphometric and meristic characteristics of the specimens with previous records in the Northeastern Mediterranean Sea.

Table 2 .
Details of records of Synchiropus sechellensis in the Mediterranean waters over the 2014-2017 period.