Molecular and morphological confirmation of an invasive American isopod; Livoneca redmanii Leach, 1818, from the Mediterranean region to Lake Qaroun, Egypt

Abstract

In 2015, unknown cymothoid isopod parasites were found in Lake Qaroun, a high-salinity closed inland lake in north-central Egypt, which were linked to substantial fish mortalities. The parasites infected a wide range of commercially important fish hosts, including Redbelly tilapia, Tilapia zillii, European Seabass , Dicentrarchus labrax, Common Sole, Solea solea, and mullets Mugil spp. and Liza spp., and continue to present a threat to local fisheries. A number of recent publications (in aggregate) have suggested this introduction reflected a near simultaneous introduction of up to four cymothoid species in Lake Qaroun; however, many of the provided photographs and illustrations were incorrect at the generic and species level. Cymothoid isopod samples were collected from Shakshouk village on Lake Qaroun. An integrative taxonomic approach was applied in the current study, incorporating traditional taxonomic analysis and DNA barcoding through mitochondrial COI gene sequencing, as well as genetic phylogenies to delimit isopods collected in Lake Qaroun. All isopods examined were identified as Livoneca redmanii Leach, 1818, an estuarine-marine species native to the western Atlantic. These samples were genetically and phylogenetically identical to their counterparts collected from Chesapeake Bay in the East of the USA. This species was characterized by pigmentation on cephalon, pereonites, pleonites, telson, pereopods and slightly bent to the left. A review of the recent literature of cymothoids in Lake Qaroun and adjacent marine areas concluded that the majority of individuals identified as species other than L. redmanii were actually L. redmanii, or unidentifiable juvenile cymothoids, with the exception of a juvenile Anilocra sp.. Likewise, L. redmanii is also present in eastern Mediterranean and Suez Canal. The likely introduced vector into Lake Qaroun are fish stockings originating from the Mediterranean Sea and River Nile estuary (as is surmised with the introduced American ctenophore species, Mnemiopsis leidyi). This information can help fishery managers better understand parasite-host dynamics in Lake Qaroun and develop biocontrol strategies to mitigate its impact in Lake Qaroun and limit its spread among adjacent lacustrine, estuarine and coastal systems.

Livoneca redmanii Leach, 1818 (Cymothoidae) a parasitic isopod infesting the gills of the European seabass, Dicentrarchus labrax (Linnaeus, 1758): morphological and molecular characterization study

“…The isolated isopod was identified as L. redmanii based on morphological traits previously described by NL Bruce [ 14 ], RC Brusca and GD Wilson [ 23 ]. Morphological characteristics were similar to those described for comparable parasites isolated from other Egyptian fish hosts, such as A. regius [ 20 ], M. cephalus [ 17 ], S. solea [ 18 ], mugiliid fry [ 22 ], and T. zillii [ 19 ].…”

“…In addition, prevalence rates of L. redmanii in cultured A. regius in Egyptian northern lakes were 77.1, 77.9, and 78.9% in Al-Madiyyah, Sidi Krier, and El Matareya, respectively [ 20 ]. T. zillii infested with L. redmanii had a 66% prevalence [ 19 ]. Similarly, isopodiosis has been reported in a variety of fish species.…”

“…The parasite was recently discovered in a variety of hosts in the estuary waters of Lake Maracaibo, Venezuela [15], as well as in the Atlantic bumper, Chloroscombrus chrysurus, in Brazilian coastal waters [16]. In Egypt, L. redmanii was isolated from flathead gray mullet, Mugil cephalus [17], common sole, Solea solea in Lake Qarun [18], redbelly tilapia, Tilapia zillii [19], and cultured meager, Argyrosomus regius, in northern lakes [20]. Adult parasites are usually seen in male/female pairs in their host's branchial cavities [21].…”

Nova Ocorrência De Livoneca Redmanni (Isopoda: Cymothoidae) No Litoral Nordeste Do Brasil

“…Os descritores ecológicos foram calculados de acordo com Bush et al (1997). A identificação foi realizada através de comparações morfológicas obtidas em descrições de literatura científica: Bruce (1990), Bakenhaster (2004), Mohammed-Geba et al (2019), Fadel et al (2020. Uma lista de espécies sinônimas foi feita utilizando informações em Bruce (1990) e adicionada a classificação taxonômica.…”

Prevalence of parasitic isopods (Cymothoidae and Gnathiidae) on Actinopterygii fishes from the Alexandria coast off the Mediterranean Sea, Egypt

“…The Egyptian parasitic isopod fauna near the Mediterranean is relatively poorly known, and thus far, investigations around this neglected group are still scarce on marine fishes from the Egyptian coasts. In total, 15 species from the family Cymothoidae have been reported from Morocco, 16 species from Algeria, 11 cymothoid species from Tunisia, and seven from Egypt (see Geba, et al, 2019). Because cymothoid fauna are common in most marine environments, some cymothoid species, such as Ceratothoa, have been linked to significant outbreaks in endemic areas, e.g., the Adriatic Sea and the Aegean Sea.…”