Spatial variability of helminth parasites and evidence for stock discrimination in the round sardinella,Sardinella aurita(Valenciennes, 1847), off the coast of Tunisia

Abstract

Three digeneans - Parahemiurus merus (Linton, 1910), Aphanurus stossichii (Monticelli, 1891) and Lecithochirium sp. - and one tetraphyllidean cestode larva were used as biological tags to discriminate the stock of Sardinella aurita (Valenciennes, 1847). In total, 579 fish were examined in five zones off the Tunisian coast, including Bizerte and Kelibia in the north, Mahdia in the east, Gabes and Zarzis in the south. Discriminant analyses used for the separation of S. aurita allowed for the identification of two discrete stocks. Sardinella aurita from Bizerte, Kelibia and Zarzis clumped together as a single stock. Parahemiurus merus and A. stossichii were the most important species in determining the location of sampled fish from these regions. Specimens from Mahdia and Gabes were grouped as one stock characterized by the presence of Lecithochirium sp. and larvae of the Tetraphyllidea. These results were corroborated by comparing the parameters of prevalence and mean abundance of parasites among zones. The separation of S. aurita between localities after pooling specimens from Bizerte, Kelibia and Zarzis and separately pooling those from Mahdia and Gabes also allowed the identification of two discrete stocks, one in offshore waters from Bizerte, Kelibia and Zarzis characterized by the digeneans P. merus and A. stossichii and one in inshore waters from Mahdia and Gabes characterized by Lechithochirium sp. and tetraphyllidean larvae.

Parasitic fauna of Sardinella aurita Valenciennes, 1847 from Algerian coast

“…The parasitic fauna of S. aurita is diverse and the Digeneans are well represented. Our results corroborate those reported by Derbel et al (2012) and Feki et al (2015). Bartoli and Gibson (1991) in Mullus surmuletus captured in the western Mediterranean Sea.…”

“…The following ten parasite taxa were collected: Aphanurus stossichii, Parahemiurus merus, Derogenes latus, Lecithochirium sp., Hemiurinae sp., Hemiurus communis, Clavellisa emarginata, Hysterothylacium sp., Tetraphylidea larvae and an unidentified Microsporidian (molecular study will be required for species identification). Thirteen nominal parasite species of this host species are well known from their previous records from different localities in the Atlantic-Mediterranean region (Bartoli et al 2000;Derbel et al 2012;Feki et al 2015 and the present study). The majority of the parasite species we identified had previously been reported from S. aurita off the coast of Tunisia (Derbel et al 2012;Feki et al 2015), and from other fish species caught in different localities (the Atlantic-Mediterranean region and the Black Sea) ( Bartoli et al 2000Bartoli et al , 2005Mackenzie et al 2008;Merzoug et al 2012;Ichalal et al 2015;Öztürk and Özer 2016;Ider et al 2018).…”

“…from S. aurita, which is a previously unknown host of this parasite. It is very important to update the inventory of the parasitic fauna infesting S. aurita because parasites have often been used as biological markers for discrimination among different stocks of S. aurita (Feki et al 2015) in fish population studies (Mackenzie 2002;Mackenzie and Abaunza 2005) and for investigations of fish migratory movements (Oliva 2001). Our parasite indices show that rates of S. aurita infestation with all identified parasite species are relatively low, with the highest abundance of Hemiuridea sp.…”

Lecithochirium monticellii digenetic trematode parasites of Trichiurus lepturus (Actinopterygii) from the state of Rio de Janeiro, Brazil, with notes on its taxonomy

“…Parasites of the genus Lecithochirium Lühe 1901 (Hemiuroidea, Hemiuridae, Lecithochiriinae) are commonly observed in the stomach and intestine of marine teleost fish throughout the world (Yamaguti 1971, Bray 1991, Gibson et al 2002, Shih et al 2004, Kohn et al 2007, Al-Zubaidy 2010, Feki et al 2016, Claxton et al 2017. Species of this genus have been described as having complex morphology, with variation in, and different combinations of, internal and external structures that provide specific taxonomic characteristics.…”

Helminth parasites of the chub mackerelScomber coliasoff the Tunisian coast and their use in stock discrimination

“…In this study, the parasite species L. excisum, P. orientalis, M. filiformis, G. cochlear, P. minor, K. scombri and anisakid larvae contributed most to the separation of samples from the four localities into three distinct areas, demonstrating that they satisfy the criteria of good biological tags for stock discrimination. Indeed, adult hemiurid digeneans are good biological tags for discriminating stock of anchovy from Argentinian waters (Timi, 2003), of Sardinella aurita from Tunisian waters (Feki et al , 2016) and of cod from waters off Greenland (Boje, 1987). Moreover, Kabata et al (1988) used digeneans from the families Fellodistomatidae and Hemiuridae to distinguish the offshore seamount stock and the continental slope stock of Anoplopoma fimbria from the west coast of Canada.…”