Artemia sites in Iran T.J. Abatzopoulos* } , N. Agh OP , G. Van Stappen P , S.M. Razavi Rouhani $ and P. Sorgeloos P *Department of Genetics, Development and Molecular Biology, Faculty of Sciences, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece. O Artemia and Aquatic Animals Research Center, PO Box 165, Urmia University, Urmia, Iran. P Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Gent, Belgium. $ Faculty of Veterinary Medicine, Urmia University, Urmia, Iran. } Corresponding author, e-mail: abatzop@bio.auth.gr Field surveys were conducted in order to collect information on the occurrence of wild Artemia popula- tions in hypersaline environments such as salt lakes, lagoons and salty rivers. The mating behaviour of Artemia populations and the presence or absence of males were carefully recorded. Sampling involved the use of plankton nets. Collected cysts were characterized on the basis of their diameter and chorion thick- ness, while nauplii (instar-I) were characterized on the basis of their total length. Artemia populations were found at 17 di¡erent geographical locations scattered over 12 Iranian provinces. All Iranian Artemia popu- lations are parthenogenetic with the exception of Artemia urmiana from Urmia Lake. During the last ¢ve years severe salinity increase has caused a dramatic reduction of population sizes in several hypersaline settings in Iran.The study of cyst and naupliar biometry revealed substantial di¡erences between popula- tions and can be used, to some extent, for their discrimination. Cyst diameter mean values range from 243.2 to 285.4 mm. For some Iranian parthenogens, cyst diameters were among the smallest recorded so far for parthenogenetic Artemia. The total length of newly hatched nauplii ranges from 455.5 to 529.8 mm. INTRODUCTION Artemia was ¢rst described in Lymington (England) by Schlosser in 1755 (Kuenen & Bass-Becking, 1938). Since then, many Artemia sites have been recorded. The ¢rst trial to list all known Artemia sites dates back to 1922 when Artom reported 18 of them. Later, Stella (1933) and Barigozzi (1946) reported the occurrence of Artemia popu- lations in 28 and 29 sites respectively, spread over the ¢ve continents. However, the ¢rst systematic e¡ort to make an inventory of the various known Artemia populations was carried out by Persoone & Sorgeloos (1980), who listed 244 sites/populations. The same authors also pointed out that many Artemia sites have been abandoned or destroyed (e.g. Artemia has disappeared from Germany and Great Britain). Vanhaecke et al. (1987), in their updated review, reported the presence of Artemia in 360 geographically distinct areas. The most recent investigations on Artemia biogeography have been published by Triantaphyllidis et al. (1998) and Van Stappen (2002), and report 505 and 598 Artemia sites, respectively. The increasing number of Artemia sites indicates that their real number must be higher, since vast areas in sub-Saharan Africa and conti- nental Asia remain largely unexplored (Van Stappen, 2002). Genetic studies performed a century ago revealed two distinct modes of reproduction in Artemia: parthenogenesis and zygogenesis (Artom, 1907). Artom’s cytogenetic analyses unveiled the existence of several ploidy levels (2n to 5n) in Artemia parthenogenetic forms, as opposed to the diploidy (2n ¼42) of bisexual Artemia (Artom, 1907, 1922). Initially, the binomen Artemia salina was used for all Artemia populations. It took some time before the e¡ect of salinity on the morphology of Artemia was recognized as a non-heritable factor (Gilchrist, 1960). Recently, genetic markers were adopted as more e¡ective tools for character- izing Artemia species (Abatzopoulos et al., 2002b; Gajardo et al., 2004; Baxevanis et al., 2005; Mura et al., 2005). Although the presence of Artemia in Urmia Lake was ¢rst reported over a century ago (Gu« nther, 1899), a long period of time elapsed before this population was charac- terized. Clark & Bowen (1976) assigned the binomen Artemia urmiana. However, very little information has been available until recently and its mode of reproduction remains ba¥ing. Based on cytogenetics, and analysis of repetitive DNA and heterochromatin, Barigozzi et al. (1987) and Badaracco et al. (1987) found that the Urmia population was exclusively parthenogenetic. As a result, Barigozzi & Baratelli (1989) proposed to abandon the binomen A. urmiana. Subsequent studies showed that both sexual and asexual populations exist in Urmia (Browne & Bowen, 1991). Therefore, a more detailed investigation was needed in order to con¢rm the reproductive status of Artemia in Urmia Lake. Ahmadi (1987) reported the presence of a possible parthenogenetic Artemia population in Shurabil Lake at Ardabil (north-west of Iran). Agh & Noori (1997) and Agh et al. (2001) also reported the presence of a morpho- logically distinctive parthenogenetic population in the small lagoons in the vicinity of Urmia Lake. Makhdomi (1992) announced the presence of Artemia in the Incheh and Shor lakes while Piri & Tehrani (1997) found Artemia in Varmal Lake. As no other Artemia sites have been reported in the literature so far, this investigation aims to present an updated, systematic inventory of Artemia sites in Iran, providing additional information on the reproduc- tive mode of these populations. J. Mar. Biol. Ass. U.K. (2006), 86, 299^307 Printed in the United Kingdom Journal of the Marine Biological Association of the United Kingdom (2006)