Studies on the recently discovered crayfish, Austropotamobius torrentium (Shrank, 1803), in Turkey: morphological analysis and meat yield

The only native freshwater cray¢sh species of Turkey is the narrow-clawed cray¢sh, Astacus leptodactylus (Esch.,1823) (Geldiay & KocataS1970; Erenc in & K ̨ksal1977; K ̨ksal1988; Holdich 2002; Skurdal & Taugbol 2002; Harliogfl lu 2004). This species was ¢rst identi¢ed from Kayseri, Bursa and İstanbul (Bott 1950). It is naturally and widely distributed in lakes, ponds and rivers in di¡erent parts of Turkey, and some very large populations exist. According to Geldiay and KocataS (1970) three subspecies of Astacus exist in Turkey. These areA. leptodactylus leptodactylus, A. leptodactylus salinus and A. colchicus. However, Albrecht (1983) considered A. colchicus to be a subspecies of A. astacus. Therefore, A. astacus may also be present in Turkey, but up to now there have been no reports of it (Holdich 2002). Starobogatov (1995) also mentioned that A. colchicus might be found in the vicinity of İstanbul, and it could have been introduced in easternTurkey. Freshwater cray¢sh is a popular luxury food in many West European countries. Since the domestic consumption of cray¢sh inTurkeywas very low (Erenc in & K ̨ksal 1977),Turkey was the largest supplier of A. leptodactylus toWestern Europe from1970 (or possibly earlier) until 1986 (K ̨ksal 1988; Oray 1990). The peak cray¢sh production was reached in the early 1980s, with over 5000 tonnes being exported in1984. Cray¢shwere exported to a numberof Europeancountries, of which France and Sweden were the main buyers (K ̨ksal 1988). After 1985, cray¢sh production was reduced dramatically in most Turkish lakes as a result of the cray¢sh plague fungus (Aphanomyces astaci Schikora) whose presence was reported by several authors (Rahe & Soylu1989; Oray1990). Astacus leptodactylus has been introduced to many freshwaters in Turkey after 1985 because of its commercial importance and declining catches from traditional good ¢sheries. Today, there are 33 important A. leptodactylus harvesting areas throughout Turkey (Harliogfl lu, Barim,Tˇrkgˇlˇ & Harliogfl lu 2004). The total harvest value from these areas in 2002 was reported to be 1850 tonnes (Anonymous 2002). However, culture of this species in captivity is not practiced inTurkey. The stone cray¢sh, A. torrentium, is indigenous to Europe and is mainly con¢ned to central and southeastern countries. It reaches its northerly limit in Germany and the Czech Republic, westerly limit in Luxembourg, southerly limit in Greece, and easterly limit in Bulgaria (Holdich 2002). It had not been previously recorded fromTurkey (Erenc in & K ̨ksal1977; K ̨ksal1988; Holdich 2002; Skurdal & Taugbol 2002). However, its presence has recently been noted in the Velika River (a tributary of the Rezovska River) in EuropeanTurkey byTrontelj,Yoichi and Boris (2005). Little is known about this cray¢sh in European Turkey so it was decided to undertake an analysis of its morphologyand abdominal meat yield in order to assess it potential for aquaculture in this study.