First record of the Indian anchovy Stolephorus indicus ( van Hasselt , 1823 ) ( Clupeiformes : Engraulidae ) in the Mediterranean Sea

The Indian anchovy Stolephorus indicus (van Hasselt, 1823) was recorded for the first time in the Mediterranean near Tel-Aviv, Israel on 15 May 2015. This Indo-West Pacific species evidently reached the Mediterranean via the Suez Canal from the Red Sea. Several specimens of Stolephorus insularis were also collected, which suggests that species has established a viable population in the Levant.

The Indian anchovy, Stolephorus indicus (van Hasselt, 1823), was originally described from India.It was considered as a valid species in a revision by Whitehead et al. (1988: 412-413

Materials and methods
On 15 May 2015 the first two authors (RF and DG) collected 1 intact specimen of S. indicus (van Hasselt 1823) from a nocturnal trawl catch in the port of Jaffa, Israel; other specimens were partially damaged and were therefore used only for color description.In the Hebrew University Fish Collection (HUJ), one specimen of the Indian anchovy, Stolephorus indicus (Hasselt, 1823) (74.3 mm SL) (Figure 1), was deposited that had been collected on 15 May 2015 from a nocturnal catch of the commercial trawler F/V Bilu, using a 44 mm mesh size cod-end net, between Ga'ash (ca.32°14'49'' N 34°49'03'' E) and Jaffa (ca.32°02'49''N 34°44'22''E), in the vicinity of Tel-Aviv, Israel.Details of the collecting depth are not available, but the species was probably collected not far from the coast, in the upper 30 m above sand bottom.The specimens are registered under the catalogue number HUJ 20443.Counts and measurements follow Hubbs and Lagler (1947), fin-ray counts follow Fricke (1983) and Whitehead et al. (1988); the classification follows Eschmeyer (2015), the references follow Fricke (2015).

Description of the Mediterranean specimen (Figures 1 and 2)
Body slender, elongate, round in cross-section, belly with 2 small needle-like pre-pelvic scutes, the first located under the middle of pectoral fin, the last well in front of pelvic fin.Maxilla tip pointed, reaching to or just beyond anterior border of preoperculum.Preoperculum distally convex, rounded.Isthmus evenly tapering anteriorly.Lower gill-rakers 24.Dorsal-fin rays iii,12.Anal fin short, with iii, 17 rays, its origin below the middle of dorsal fin base.Pectoral-fin rays i,15.
Colour (based on fresh specimens): body light transparent fleshy brown, with a silver stripe on the side; no dark pigment lines between head and dorsal fin.Eyes silver-grey with black pupil.

Discussion
This species was first described as Engraulis indicus by van Hasselt (1823: 329) from Vizagapatam, India (based on an illustration by Russel, 1803: 71, pl. 187; see footnote in Alfred 1961: 83).The name is available with van Hasselt as the author according to Kottelat (1987: 370).It was treated as a valid species in a revision by Whitehead et al. (1988: 412-413), distributed in the Red Sea and the Indo-West Pacific.The species was subsequently reported by Paxton et al. (1989: 161) as occurring south to Mackenzie Island, Queensland, Australia at 23°31'S, by Young et al. (1994: 222) from Taiwan, by Myers (1999: 62)  The species is placed in the genus Stolephorus Lacepède, 1803 due to the normally shaped (not tapering or rat-tailed) body, the anal fin not joined to the caudal fin, the upper pectoral-fin rays not detached from each other, the presence of needlelike prepelvic scutes (Figure 2), no postpelvic scutes, the isthmus evenly tapering anteriorly, and the anal fin with less than 25 fin-rays (see Whitehead et al. 1988: 309-310, 401).Counts and proportions of the Mediterranean specimen of S. indicus are consistent with those of Red Sea and Indo-West Pacific specimens (Table 1).Stolephorus indicus schools over soft bottoms mainly around 20-50 m depth, but young fish occur shallower, and larvae are found in estuaries.The biology of the species is poorly known (Whitehead et al. 1988: 413).However, Hajisamae et al. (2003) examined the food and feeding habits of the species in Singapore.Since the opening of the Suez Canal in 1869, many fish species have emigrated from the Gulf of Suez (Red Sea) into the eastern Mediterranean, the so-called Lessepsian migrants (Golani 2010).In the early years, Lessepsian migrants were relatively few, as the Suez Canal was narrow and crossed some salt lakes (Bitter Lakes).After several enlargements and washing out of salt deposits, the passage for fishes is now easier, which results in higher numbers of Lessepsian migrant species reported from the eastern Mediterranean in recent years.The first anchovy migrant was reported by Fricke et al. (2012, Stolephorus insularis).As S. insularis and S. indicus are found in mixed schools, and S. indicus was reported from the Red Sea previously (Golani and Bogorodsky 2010), a Lessepsian migration of S. indicus was to be expected, which is confirmed by the present finding of S. indicus.The species may be more common in the eastern Mediterranean, but anchovy specimens in catches are often damaged so that the scutes on the belly cannot be distinguished.In the engraulids collected on 15 May 2015 near Jaffa, Israel, a total of approximately 1,000 specimens were examined.Most of these represented the common Mediterranean species Engraulis encrasicolus (Linnaeus, 1758), but about 10 specimens could be identified as S. insularis, and just a single specimen as S. indicus.Stolephorus indicus is the second anchovy to invade the Mediterranean.It may have been included in earlier collections, but was probably missed due to its external similarities with Engraulis encrasicolus.Stolephorus indicus cooccurs with the Mediterranean indigenous species  (Whitehead et al. 1988: 412-414).In the northwestern Indian Ocean, another species of the genus is found, which was not yet reported from the Red Sea (S. commersonnii Lacepède 1803).Stolephorus commersonnii is quite similar to S. insularis and S. indicus (Table 2).
).The species is native to the Red Sea and the Indo-West Pacific from South and East Africa east to Society Islands, north to Hong Kong (China), south to Gulf of Carpentaria (Australia).On 15 May 2015, a specimen of S. indicus was collected in the eastern Mediterranean Sea off Israel; this finding is reported and discussed in the present paper.It represents the arrival of a new Lessepsian migrant species of Red Sea origin in the Mediterranean Sea.

Table 1 .
Comparison of selected counts and proportions of Stolephorus indicus from the eastern Mediterranean and the Indo-West Pacific.

Table 2 .
Comparison of selected characteristics of species of Stolephorus in the Red Sea, northwestern Indian Ocean, and eastern Mediterranean.Engraulis encrasicolus differs mainly in the absence of needle-like prepelvic scutes; the anal fin which begins well behind the second dorsal-fin base; and a higher number of lower gill-rakers(27-43 in E. encrasicolus, 20-28 in S.  insularis).The other Red Sea congener, S. insularis, is distinguished from S. indicus by having 4-8 (usually 6-7) needle-like pre-pelvic scutes [ compared to 2-6 (usually 3-5) scutes in S. indicus]; iii,14-17 anal-fin rays (iii,16-18 in S. indicus); the maxilla reaching to or beyond posterior border of preoperculum (reaching to or only just beyond the anterior border of preoperculum in S. indicus); and a characteristic golden hue (silvery, grey or bluish colouration in S. indicus)