FIRST RECORD OF IMPERIAL BLACKFISH, SCHEDOPHILUS OVALIS (ACTINOPTERYGII: PERCIFORMES: CENTROLOPHIDAE), FROM THE TUNISIAN COAST, CENTRAL MEDITERRANEAN

Two specimens of imperial blackfi sh, Schedophilus ovalis (Cuvier 1829), were found for the fi rst time off the Tunisian coast, in northern area. Both specimens are described, and occurrence of the species in the area and the Mediterranean Sea is discussed and commented.

Imperial blackfi sh, Schedophilus ovalis (Cuvier 1833), is widely distributed in the eastern Atlantic from Spain to South African waters, and occurs also around Azores, Madeira, and Canaries Islands (Haedrich 1986(Haedrich , 1990. However, Haedrich (1986) and Fischer et al. (1987) wrongly reported that S. ovalis is present throughout the Mediterranean Sea. In the western Mediterranean Schedophilus ovalis is only known from the Balearic Islands (Deudero et al. 1999), Spain (Stefanescu and Massutí 1992), French waters, including Corsica (Francour and Javel 2003), and eastwards, to Italian waters (Orsi- Relini et al. 1990, Relini 1995, Psomadakis et al. 2006), including Sardinia (Follesa et al. 2006). In the eastern Mediterranean the fi sh has been reported from the Aegean Greek waters (Corsini-Foka and Frantzis 2009) and the Turkish Mediterranean coast, in Antalya Bay (Filiz and Güzelaydın 2014), and Iskanderun Bay (Erguden et al 2013); the coast of Israel being its easternmost extension range (Golani 1996(Golani , 2005. Conversely, imperial blackfi sh is unknown to date from the south-eastern Mediterranean, and in this paper, the collection of two juvenile specimens off the Tunisian coast is reported. The fi rst specimen was caught on 10 February 2011 at 2.5 m depth (37°14′17.00′′N, 10°08′04.80′′E), and the second one on 11 February 2011, at 5 m depth (37°14′28.77′′N, 10°07′32.21′′E). Both specimens were captured by trammel net of 26-mm stretched mesh size, on sandy rocky bottom partially covered by algae. They were preserved in 10% buffered formalin and deposited in the Ichthyological Collection of the Faculté des Sciences de Bizerte, receiving catalogue numbers FSB-Sche-ova-01 and FSB-Sche-ova-02, respectively (Fig. 1).
The identifi cation of both specimens was carried out based on the following diagnosis: body deep and compressed, elongate oval shape, with greatest body depth at about vent; back and belly moderately arched; caudal peduncle short and deep; eye large surrounded by a low rim; lips thin; unpaired fi ns long and rather high, low anteriorly with short spines grading into longer branched rays. Colour dark grey to brownish with dark spots somewhat arranged in longitudinal lines.
Additionally, morphometric measurements were recorded to the nearest 1 mm and weighed to the nearest 1 g, following Francour and Javel (2003); they are presented for both specimens in Tables 1 and 2. Morphology, morphometric measurements (in absolute values as well as expressed in percent of standard length), meristic counts, and colour are in agreement with previous descriptions of the species (Haedrich 1986, Orsi-Relini et al. 1990, Stefanescu and Massutí 1992, Psomadakis et al. 2006).
The presently reported two fi ndings constitute the fi rst records in the Tunisian waters of Schedophilus ovalis, which could be included in the Tunisian ichthyofauna, enlarging the number of fi sh species reported to date in the area (Bradai et al. 2004). Additionally, these fi ndings constitute also the fi rst records of the species in the southern Mediterranean Sea. Apart, from S. ovalis in Tunisian waters, another its congener-the Cornish blackfi sh, Schedophilus   (2004). Schedophilus ovalis can be distinguished from S. medusophagus occurring in Tunisian waters by the presence of very strong spines in the median fi ns and body rigid, large scales, and the dorsal fi n count (Haedrich 1986). Rigid and fi rm body of Schedophilus ovalis explicitly differs from the soft and limp body of S. medusophagus.
These new records of Schedophilus ovalis from Tunisia show that the species signifi cantly extended southward its distribution in the Mediterranean Sea (Fig. 2). Francour and Javel (2003) noted that the species is regularly captured in north-western Mediterranean, offshore, around buoys or FADs, but did not constitute a dominant species in fi sh assemblages. Dulčić et al. (1999Dulčić et al. ( , 2012 and Francour and Javel (2003) noted an increase of captures in the Adriatic Sea and off the Mediterranean coast of France, probably due to the water warming. Similar pattern could explain the recent occurrence of S. ovalis off the Tunisian coast.
However, the species has a pelagic way of life during juvenile stages and juveniles could be carried away by sea currents that probably play a more and less important role in widening its expansion throughout the Mediterranean. Yet, these two fi ndings do not support that a sustainable population is a present established in its new region as in other Mediterranean areas (Francour and Javel 2003), therefore further and more records are needed to support such hypothesis.