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Tilapias are important aquaculture fishes that have been introduced widely all over the world, often carrying their monogenean parasites with them. An extensive investigation on monogeneans of invasive tilapias was conducted in 19 natural water sources in south China between July 2015 and December 2017. We found nine known species of monogeneans, i.e., Enterogyrus coronatus, E. malmbergi, Cichlidogyrus cirratus, C. halli, C. sclerosus, C. thurstonae, C. tilapiae, Scutogyrus longicornis, Gyrodactylus cichlidarum, and one unknown Gyrodactylus species. In addition to reporting ten new hosts and four new geographical records, we observed new morphological characteristics of these species. Observation on living specimens of Enterogyrus spp. demonstrated that these two species have characteristic opisthaptoral retraction capacities, while the opisthaptor glands were not observed in our specimens of E. coronatus and E. malmbergi. The morphological differences of the accessory piece of the male copulatory complex between C. cirratus and C. mbirizei (character for species differentiation) could result from the observation at different perspectives, which indicates that C. mbirizei is likely a synonym of C. cirratus. A more detailed structure of the sclerotized parts of Cichlidogyrus spp. and S. longicornis were revealed by scanning electron microscopy. As was the case for the monogeneans found on alien tilapias from other geographic regions, the present study confirmed the high potential of these monogeneans to establish populations in new habitats.

Tilapias are important aquaculture fishes that have been introduced widely all over the world, often carrying their monogenean parasites with them. An extensive investigation on monogeneans of invasive tilapias was conducted in 19 natural water sources in south China between July 2015 and December 2017. We found nine known species of monogeneans, i.e., Enterogyrus coronatus, E. malmbergi, Cichlidogyrus cirratus, C. halli, C. sclerosus, C. thurstonae, C. tilapiae, Scutogyrus longicornis, Gyrodactylus cichlidarum, and one unknown Gyrodactylus species. In addition to reporting ten new hosts and four new geographical records, we observed new morphological characteristics of these species. Observation on living specimens of Enterogyrus spp. demonstrated that these two species have characteristic opisthaptoral retraction capacities, while the opisthaptor glands were not observed in our specimens of E. coronatus and E. malmbergi. The morphological differences of the accessory piece of the male copulatory complex between C. cirratus and C. mbirizei (character for species differentiation) could result from the observation at different perspectives, which indicates that C. mbirizei is likely a synonym of C. cirratus. A more detailed structure of the sclerotized parts of Cichlidogyrus spp. and S. longicornis were revealed by scanning electron microscopy. As was the case for the monogeneans found on alien tilapias from other geographic regions, the present study confirmed the high potential of these monogeneans to establish populations in new habitats.

Scutogyrus sp.* HOSTS. — Actinopterygii (gills). GEOGRAPHIC DISTRIBUTION. — Veracruz. Centro Acuícola en Nautla: Oreochromis mossambicus, Oreochromis niloticus, "Pargo UNAM" (Aguirre-Fey et al. 2015). SPECIMENS IN COLLECTIONS. — None., Published as part of Mendoza-Garfias, Berenit, García-Prieto, Luis & León, Gerardo Pérez-Ponce De, 2017, Checklist of the Monogenea (Platyhelminthes) parasitic in Mexican aquatic vertebrates, pp. 501-598 in Zoosystema 39 (4) on page 527, DOI: 10.5252/z2017n4a5, http://zenodo.org/record/4578694

A checklist of the 23 species of Ancyrocephalidae (Monogenea) parasitizing Tilapia species sampled from both sides of the Cameroon Volcanic Line is provided. As already reported elsewhere, Cichlidogyrus aegypticus in Cameroon shows two different shape of its vagina, and C. tilapiae, C. arthracanthus and C. tiberianus were found on a wide range of host species. Among the 23 studied species of Monogenea, three are considered new species and are described herein: Cichlidogyrus berminensis n. sp. from Tilapia bemini, characterized by a short penis with marked narrow heel, a simple and straight accessory piece ending in a large hook, and a medium sized pair of uncinuli I; Cichlidogyrus gillesi n. sp. from Tilapia guineensis, characterized by a large and trapezoid heel of the penis and a S-shaped and wrinkle walled vagina; and Scutogyrus vanhovei n. sp. from Tilapia mariae, characterized by the presence of a distinct swollen portion of the penis. From a parasite’s point of view, the CVL has no influence on species dispersion/distribution.

Scutogyrus vanhovei n. sp. (Fig. 5) Type host: Tilapia mariae Boulenger. Site: Gills. Type locality: Lake Ossa, Cameroon (3 �� 47 ��� 24 ���N; 10 ��01��� 22 ��� E). Specimens deposited: Holotype MNHN n�� HEL 278. Paratypes MNHN (3) n�� HEL 279 [on the same slide there are 2 voucher specimens of Cichlidogyrus testificatus Dossou, 1982]; NHMUK (3) n�� 2012.8. 30.4 [note that on the same slide there are voucher specimens of Cichlidogyrus digitatus Dossou, 1982 (1) n�� 2012.8. 30.7 and Cichlidogyrus slembroucki Pariselle & Euzet, 1998 (1) n�� 2012.8.30.8]; RMCA (1) n�� 37707 [note that on the same slide there are voucher specimens of Cichlidogyrus digitatus Dossou, 1982 (1) n�� 37708, Cichlidogyrus ouedraogoi Pariselle & Euzet, 1996 (1) n�� 37709 and Cichlidogyrus slembroucki Pariselle & Euzet, 1998 (1) n�� 37710]. Etymology: Named after Maarten M. P. Vanhove, a PhD student working on monogenean species of cichlid fishes from Lake Tanganyika. Description (based on 16 individuals): adults 480 (378���591) (16) long. 89 (70���109) (16) large at level of penis. Large and globular pharynx: 52 (41���64) (16) in diameter. Dorsal anchor with guard longer than shaft, and regularly curved blade: a = 31 (29���35) (25), b = 24 (20���27) (25), c = 8 (6���10) (24), d = 11 (8���14) (25), e = 9 (7���11) (25). Dorsal transverse bar typical of Scutogyrus with long auricle and lateral expansions: x = 46 (42���49) (16), z = 26 (22���31) (16), w = 4 (4���6) (16), y = 14 (11���16) (16), h = 31 (25���35) (16). Ventral anchor with guard two times longer than shaft, blade regularly arched: a = 31 (29���32) (27), b = 28 (26���30) (27), c = 5 (3���7) (27), d = 10 (8���12) (27), e = 11 (9���14) (27). V���shaped ventral transverse bar typical of Scutogyrus (supporting a large plate), branches straight: x = 39 �� 1.4 (36���41) (30), w = 30 (23���37) (16). First uncinuli of small size, third to seventh long: U I = 16 (15���18) (16), U II = 12 (10���13) (9), U III = 28 (24���30) (11), U IV = 31 (27���33) (14), U V = 32 (27���36) (16), U VI = 27 (25���32) (11), U VII = 27 (26���28) (13). MCC made up of a straight penis showing a distinct swollen portion (Sp) at first third, a marked heel, and a simple and straight accessory piece ending in a large and strong hook: Pe = 48 (41���64) (16), Sp = 13 (12���15) (16), He = 3 (3���4) (16), AP = 39 (35���46) (16). No sclerotised vagina. Remarks: S. vanhovei n. sp. resembles all the species of the genus by the morphology of its haptoral sclerotised pieces and that of the accessory piece of the penis. It can be distinguished by the presence of a distinct swollen portion of the penis., Published as part of Pariselle, Antoine, Bitja Nyom, Arnold R. & Bilong Bilong, Charles F., 2013, Checklist of the ancyrocephalids (Monogenea) parasitizing Tilapia species in Cameroon, with the description of three new species in Zootaxa 3599 (1), DOI: 10.5281/zenodo.221201, {"references":["Dossou, C. (1982) Parasites de Poissons d'eau douce du Benin III. Especes nouvelles du genre Cichlidogyrus (Monogenea) parasites de Cichlidae. Bulletin de l'IFAN, 44, 295 - 322.","Pariselle, A. & Euzet, L. (1998) Five new species of Cichlidogyrus (Monogenea, Ancyrocephalidae) from Tilapia brevimanus, T. buttikoferi and T. cessiana from the Guinea, Ivory Coast and Sierra Leone (West Africa). Folia Parasitologica, 45, 275 - 282.","Pariselle, A. & Euzet, L. (1996) Cichlidogyrus Paperna, 1960 (Monogenea, Ancyrocephalidae): gill parasites from West African Cichlidae of the subgenus Coptodon Regan, 1920 (Pisces), with descriptions of six new species. Systematic Parasitology, 34, 109 - 124. http: // dx. doi. org / 10.1007 / BF 00009685"]}

L'examen des parasites branchiaux de #Sarotherodon occidentalis$ (Daget) (#Pisces$, #Cichlidae$) en Guinée et en Sierra Leone (Afrique de l'Ouest) a révélé la présence de sept espèces de Monogènes. Deux ont déjà été décrites : #Cichlidogyrus halli$ (Price et Kirk, 1967) et #Scutogyrus ecoutini$ Pariselle et Euzet, 1995. Cinq espèces, appartenant toutes au genre #Cichlidogyrus$ Paperna, 1960, sont considérées comme nouvelles, #C. bouvii$ n. sp., #C. fontanai$ n. sp., #C. guirali$ n. sp., #C. paganoi$ n. sp. et #C. sanjeani$ n. sp. (Résumé d'auteur)

Scutogyrus gravivaginus (Paperna & Thurston, 1969) Cichlidogyrus longicornis gravivaginus Paperna & Thurston, 1969: 20-23, fig. 3c, e-g. Cichlidogyrus gravivaginus – Douëllou 1993: 172, 173, fig. 73. Scutogyrus gravivaginus – Pariselle & Euzet 1995b: 163- 165, figs 6, 7. TYPE MATERIAL. — Holotype: MRAC M.T. 35.932 (Paperna 1979). Paratypes: private collection of Paperna. OTHER MATERIAL. — MNHN 129 HF (Douëllou 1993). TYPE HOST. — Oreochromis leucostictus (Trewavas, 1933). TYPE LOCALITY. — Jinja and Albert Lake, Uganda. ADDITIONAL HOSTS. — Oreochromis variabilis (Boulenger, 1906) (Paperna 1979); Oreochromis mortimeri (Trewavas, 1966) (Douëllou 1993). SITE. — Gills. ADDITIONAL LOCALITY. — Kariba Lake, Zimbabwe on Oreochromis mortimeri (Trewavas, 1966) (Douëllou 1993). REMARKS Dossou (1982) suggested that C.longicornis gravivaginus could be raised to species level, this was done by Douëllou (1993)., Published as part of Pariselle, Antoine & Euzet, Louis, 2009, Systematic revision of dactylogyridean parasites (Monogenea) from cichlid fishes in Africa, the Levant and Madagascar, pp. 849-898 in Zoosystema 31 (4) on page 856, DOI: 10.5252/z2009n4a6, http://zenodo.org/record/4520413, {"references":["PAPERNA I. & THURSTON J. P. 1969. - Monogenetic Trematodes collected from cichlid fish in Uganda; including the description of five new species of Cichlidogyrus. Revue de Zoologie et de Botanique africaines 79: 15 - 33.","DOUELLOU L. 1993. - Monogeneans of the genus Cichlidogyrus Paperna, 1960 (Dactylogyridae: Ancyrocephalinae) from cichlid fishes of Lake Kariba (Zimbabwe) with descriptions of five new species. Systematic Parasitology 25: 159 - 186.","PARISELLE A. & EUZET L. 1995 b. - Scutogyrus n. g. (Monogenea, Ancyrocephalidae) for Cichlidogyrus longicornis minus Dossou, 1982, C. longicornis and C. l. gravivaginus Paperna and Thurston, 1969, with descriptions of three new species parasitic on African Cichlids. Journal of the Helminthological Society of Washington 62: 157 - 173.","PAPERNA I. 1979. - Monogenea of inland water fish in Africa. Annales du Musee royal d'Afrique centrale, ser in- 8 ° (Zool.) 226: 1 - 131.","DOSSOU C. 1982. - Parasites de poissons d'eau douce du Benin III. Especes nouvelles du genre Cichlidogyrus (Monogenea) parasites de Cichlidae. Bulletin de l'I. F. A. N. 44: 295 - 322."]}

Scutogyrus chikhii Pariselle & Euzet, 1995 Scutogyrus chikhii Pariselle & Euzet, 1995b: 171, 172, figs 12, 13. TYPE MATERIAL. — Holotype: MNHN 464 HF Tg 64. Paratypes: BMNH 1994.4.7.5; MRAC 37.361. TYPE HOST. — Oreochromis mossambicus (Peters, 1852). TYPE LOCALITY. — Cayo Lake, Congo. SITE. — Gills., Published as part of Pariselle, Antoine & Euzet, Louis, 2009, Systematic revision of dactylogyridean parasites (Monogenea) from cichlid fishes in Africa, the Levant and Madagascar, pp. 849-898 in Zoosystema 31 (4) on page 857, DOI: 10.5252/z2009n4a6, http://zenodo.org/record/4520413, {"references":["PARISELLE A. & EUZET L. 1995 b. - Scutogyrus n. g. (Monogenea, Ancyrocephalidae) for Cichlidogyrus longicornis minus Dossou, 1982, C. longicornis and C. l. gravivaginus Paperna and Thurston, 1969, with descriptions of three new species parasitic on African Cichlids. Journal of the Helminthological Society of Washington 62: 157 - 173."]}

Scutogyrus minus (Dossou, 1982) Cichlidogyrus longicornis minus Dossou, 1982: 309-312, figs 19-23. Cichlidogyrus minus – Pariselle & Euzet 1995b: 158-161, figs 2, 3. Scutogyrus minus – Pariselle & Euzet 1995b. TYPE MATERIAL. — Holotype: MNHN Tj141. Paratype: MNHN Tj142. OTHER MATERIAL. — MNHN 460 HF Tg 55; MNHN 460 HF Tg 56 and Tg 57; BMNH 1994.4.7.1; MRAC 37.357 (Pariselle & Euzet 1995b). TYPE HOST. — Sarotherodon melanotheron Rüppel, 1852. TYPE LOCALITY. — Ouémé and Couffo Rivers, Benin. SITE. — Gills. ADDITIONAL LOCALITIES. — Guinea and Côte d’Ivoire (Pariselle & Euzet 1995b). REMARKS Dossou (1982) suggested that Cichlidogyrus longicornis minus could be raised to species level. Douëllou (1993) indicated that this sub-species is uncertain and had to be invalidated. Pariselle & Euzet (1995b) did not agree with Douëllou., Published as part of Pariselle, Antoine & Euzet, Louis, 2009, Systematic revision of dactylogyridean parasites (Monogenea) from cichlid fishes in Africa, the Levant and Madagascar, pp. 849-898 in Zoosystema 31 (4) on pages 855-856, DOI: 10.5252/z2009n4a6, http://zenodo.org/record/4520413, {"references":["DOSSOU C. 1982. - Parasites de poissons d'eau douce du Benin III. Especes nouvelles du genre Cichlidogyrus (Monogenea) parasites de Cichlidae. Bulletin de l'I. F. A. N. 44: 295 - 322.","PARISELLE A. & EUZET L. 1995 b. - Scutogyrus n. g. (Monogenea, Ancyrocephalidae) for Cichlidogyrus longicornis minus Dossou, 1982, C. longicornis and C. l. gravivaginus Paperna and Thurston, 1969, with descriptions of three new species parasitic on African Cichlids. Journal of the Helminthological Society of Washington 62: 157 - 173.","DOUELLOU L. 1993. - Monogeneans of the genus Cichlidogyrus Paperna, 1960 (Dactylogyridae: Ancyrocephalinae) from cichlid fishes of Lake Kariba (Zimbabwe) with descriptions of five new species. Systematic Parasitology 25: 159 - 186."]}

Scutogyrus bailloni Pariselle & Euzet, 1995 Scutogyrus bailloni Pariselle & Euzet, 1995b: 165, 166, figs 8, 9. TYPE MATERIAL. — Holotype: MNHN 462 HF Tg 60. Paratypes: MNHN 462 HF Tg 61; BMNH 1994.4.7.3; MRAC 37.359. TYPE HOST. — Sarotherodon galilaeus (Linnaeus, 1758). TYPE LOCALITY. — W National Park, Mékrou River, Niger. SITE. — Gills., Published as part of Pariselle, Antoine & Euzet, Louis, 2009, Systematic revision of dactylogyridean parasites (Monogenea) from cichlid fishes in Africa, the Levant and Madagascar, pp. 849-898 in Zoosystema 31 (4) on page 857, DOI: 10.5252/z2009n4a6, http://zenodo.org/record/4520413, {"references":["PARISELLE A. & EUZET L. 1995 b. - Scutogyrus n. g. (Monogenea, Ancyrocephalidae) for Cichlidogyrus longicornis minus Dossou, 1982, C. longicornis and C. l. gravivaginus Paperna and Thurston, 1969, with descriptions of three new species parasitic on African Cichlids. Journal of the Helminthological Society of Washington 62: 157 - 173."]}

Genus Scutogyrus Pariselle & Euzet, 1995 TYPE SPECIES. — Scutogyrus minus (Dossou, 1982), by subsequent designation (Pariselle & Euzet 1995b). OTHER SPECIES INCLUDED. — Scutogyrus bailloni Pariselle & Euzet, 1995; S. chikhii Pariselle & Euzet, 1995; S. ecoutini Pariselle & Euzet, 1995; S. gravivaginus (Paperna & Thurston, 1969); S. longicornis (Paperna & Thurston, 1969). DIAGNOSIS. — Ancyrocephalidae. Three pairs of cephalic glands. Two posterior ocellae with lenses. Two small anterior ocellae, sometimes absent. Intestinal caeca without diverticula, joined posteriorly. Two pairs of anchors, one dorsal and one ventral. Dorsal transverse bar highly arched, enlarged laterally, winged, having in its median portion two very long auricles hollow at their bases. Ventral transverse bar arched, rigid, supporting one large, thin oval plate marked by fan-shaped median thickenings. Fourteen uncinuli.Testis median, posterior to the body. Vas deferens dextral, not encircling intestinal caeca. Seminal vesicle present. One prostatic reservoir. Male copulatory complex with penis and accessory piece. Median pre-testicular ovary.Vaginal opening sub-lateral, dextral; vagina tubular, sclerotised. Seminal receptacle present. Gill parasites of African cichlid fishes., Published as part of Pariselle, Antoine & Euzet, Louis, 2009, Systematic revision of dactylogyridean parasites (Monogenea) from cichlid fishes in Africa, the Levant and Madagascar, pp. 849-898 in Zoosystema 31 (4) on page 855, DOI: 10.5252/z2009n4a6, http://zenodo.org/record/4520413, {"references":["DOSSOU C. 1982. - Parasites de poissons d'eau douce du Benin III. Especes nouvelles du genre Cichlidogyrus (Monogenea) parasites de Cichlidae. Bulletin de l'I. F. A. N. 44: 295 - 322.","PARISELLE A. & EUZET L. 1995 b. - Scutogyrus n. g. (Monogenea, Ancyrocephalidae) for Cichlidogyrus longicornis minus Dossou, 1982, C. longicornis and C. l. gravivaginus Paperna and Thurston, 1969, with descriptions of three new species parasitic on African Cichlids. Journal of the Helminthological Society of Washington 62: 157 - 173.","PAPERNA I. & THURSTON J. P. 1969. - Monogenetic Trematodes collected from cichlid fish in Uganda; including the description of five new species of Cichlidogyrus. Revue de Zoologie et de Botanique africaines 79: 15 - 33."]}

Scutogyrus longicornis (Paperna & Thurston, 1969) Cichlidogyrus longicornis longicornis Paperna & Thurston, 1969: 20-22, fig. 3a, b, d. Cichlidogyrus longicornis – Douëllou 1993: 170-172, fig. 71, 72. Scutogyrus longicornis – Pariselle & Euzet 1995b: 161- 163, figs 4, 5. Actinocleidus muelleri Ferdousi & Chandra, 2002: 56, 57, fig. 4. TYPE MATERIAL. — Holotype from Sarotherodon galilaeus: MRAC M.T. 35.931 (Paperna 1979). Paratypes: private collection of Dr Paperna. OTHER MATERIAL. — MNHN 128 HF (Douëllou 1993); MNHN 461 HF Tg58 and Tg59; BMNH 1994.4.7.2; MRAC 37.358 (Pariselle & Euzet 1995b). TYPE HOST. — Sarotherodon galilaeus (Linnaeus, 1758). TYPE LOCALITY. — Lakes Georges and Albert, Uganda. ADDITIONAL HOSTS. — Oreochromis niloticus (Linnaeus, 1758) and Tilapia zillii Gervais, 1848 (Paperna 1979) (for T. zillii: as species belonging to Scutogyrus are only found on mouthbreeder cichlid fishes, it is probably the result of a sampling error [mix of samples or contamination] or of host identification); Oreochromis mortimeri (Trewavas, 1966) (Douëllou 1993); O. mossambicus (Ferdousi & Chandra 2002). SITE. — Gills. ADDITIONAL LOCALITIES. — Kete Kratchi, Volta Lake, Ghana (Paperna 1969); Cairo, Nile River, Egypt on O. niloticus (Ergens 1981); Kariba Lake, Zimbabwe on O. mortimeri (Douëllou 1993). Senegal and Côte d’Ivoire on O. niloticus (Pariselle & Euzet 1995b). Bangladesh in BAU and BFRI fish farm ponds on introduced O. niloticus and O. mossambicus (Ferdousi & Chandra 2002). REMARKS Dossou (1982) suggested that C. longicornis longicornis could be raised to species level, this was done by Douëllou (1993)., Published as part of Pariselle, Antoine & Euzet, Louis, 2009, Systematic revision of dactylogyridean parasites (Monogenea) from cichlid fishes in Africa, the Levant and Madagascar, pp. 849-898 in Zoosystema 31 (4) on page 856, DOI: 10.5252/z2009n4a6, http://zenodo.org/record/4520413, {"references":["PAPERNA I. & THURSTON J. P. 1969. - Monogenetic Trematodes collected from cichlid fish in Uganda; including the description of five new species of Cichlidogyrus. Revue de Zoologie et de Botanique africaines 79: 15 - 33.","DOUELLOU L. 1993. - Monogeneans of the genus Cichlidogyrus Paperna, 1960 (Dactylogyridae: Ancyrocephalinae) from cichlid fishes of Lake Kariba (Zimbabwe) with descriptions of five new species. Systematic Parasitology 25: 159 - 186.","PARISELLE A. & EUZET L. 1995 b. - Scutogyrus n. g. (Monogenea, Ancyrocephalidae) for Cichlidogyrus longicornis minus Dossou, 1982, C. longicornis and C. l. gravivaginus Paperna and Thurston, 1969, with descriptions of three new species parasitic on African Cichlids. Journal of the Helminthological Society of Washington 62: 157 - 173.","PAPERNA I. 1979. - Monogenea of inland water fish in Africa. Annales du Musee royal d'Afrique centrale, ser in- 8 ° (Zool.) 226: 1 - 131.","ERGENS R. 1981. - Nine species of the genus Cichlidogyrus Paperna, 1960 (Monogenea: Ancyrocephalinae) from Egyptian fishes. Folia Parasitologica 28: 205 - 214.","DOSSOU C. 1982. - Parasites de poissons d'eau douce du Benin III. Especes nouvelles du genre Cichlidogyrus (Monogenea) parasites de Cichlidae. Bulletin de l'I. F. A. N. 44: 295 - 322."]}

Scutogyrus ecoutini Pariselle & Euzet, 1995 Scutogyrus ecoutini Pariselle & Euzet, 1995b: 167, 168, figs 10, 11. TYPE MATERIAL. — Holotype: MNHN 463 HF Tg 62. Paratypes: MNHN 463 HF Tg 63; BMNH 1994.4.7.4; MRAC 37.360. TYPE HOST. — Sarotherodon occidentalis (Daget, 1962). TYPE LOCALITY. — La Ramié, Bourouma River, Guinea. SITE. — Gills., Published as part of Pariselle, Antoine & Euzet, Louis, 2009, Systematic revision of dactylogyridean parasites (Monogenea) from cichlid fishes in Africa, the Levant and Madagascar, pp. 849-898 in Zoosystema 31 (4) on page 857, DOI: 10.5252/z2009n4a6, http://zenodo.org/record/4520413, {"references":["PARISELLE A. & EUZET L. 1995 b. - Scutogyrus n. g. (Monogenea, Ancyrocephalidae) for Cichlidogyrus longicornis minus Dossou, 1982, C. longicornis and C. l. gravivaginus Paperna and Thurston, 1969, with descriptions of three new species parasitic on African Cichlids. Journal of the Helminthological Society of Washington 62: 157 - 173."]}

La dynamique saisonniere des populations de trois especes de monogenes branchiaux du poisson Sarotherodon melanotheron Ruppel, 1852 a ete etudiee dans le lac du barrage d’Ayame I, situe dans le sud-est de la Cote d’Ivoire. La presente etude, menee entre aout 2004 et juillet 2005, a porte sur 412 poissons. Une etude qualitative et quantitative a ete effectuee a l’aide d’une loupe binoculaire et d’un microscope. Ce travail a montre que l’infestation de ce poisson par Cichlidogyrus acerbus, C. halli et Scutogyrus minus varie en fonction des saisons. Les plus fortes valeurs d’intensites moyennes, de prevalences et d’abondances ont ete observees pendant la grande saison des pluies tandis que les plus faibles ont ete notees en grande saison seche. Par ailleurs, l’etude a revele que le nombre de parasites croit avec la taille du poisson. En revanche, le parasitisme evolue independamment du sexe. The seasonal dynamics of the population of three Monogenean gill parasites of the black-chinned tilapia Sarotherodon melanotheron Ruppel, 1852, was carried out in man-made Lake Ayame I (South eastern Cote d’Ivoire) between August 2004 and July 2005. A total of 412 hosts individuals were examined. A qualitative and quantitative study has been undertaken using a binocular microscope and a microscope. It showed seasonal variations of this fish infection by Cichlidogyrus acerbus, C. halli and Scutogyrus minus. Furthermore, higher mean intensities of infestation, prevalences and abundances were registered during the long rainy season and, the low ones in the long dry season. The result also revealed that the number of parasites increase in relation to fish length. Host sex was found to have no effect on the three groups of parasites. Mots-cles : Monogenes parasites, Sarotherodon melanotheron , lac d’Ayame I, Cote d’Ivoire.

BACKGROUND: Lake Tana is the largest lake in Ethiopia and the source of the Blue Nile. The lake harbours unique endemic cyprinid fish species, as well as the commercially important endemic Nile tilapia subspecies Oreochromis niloticus tana and the North African catfish Clarias gariepinus. Its endemicity, especially within the Labeobarbus radiation, its conservation importance and its economic indispensability attract scientific interest to the lake's ichthyofauna. Fish parasites of Lake Tana, however, are hitherto poorly known, and no formal report exists on its monogenean flatworms. For sustainable aquaculture and fisheries development, it is essential to study monogenean fish parasites in these economically most important fish species. Moreover, it remains to be verified whether this unique ecosystem and its endemicity gave rise to a distinct parasite fauna as well. RESULTS: Nile tilapia and North African catfish hosts were collected from Lake Tana in 2013. Nine species of monogenean parasites of two orders, Gyrodactylidea Bychowsky, 1937 and Dactylogyridea Bychowsky, 1937, were recovered. Gyrodactylus gelnari Přikrylová, Blažek & Vanhove, 2012, Macrogyrodactylus clarii Gussev, 1961, Quadriacanthus aegypticus El-Naggar & Serag, 1986 and two undescribed Quadriacanthus species were recovered from C. gariepinus. Oreochromis niloticus tana hosted Cichlidogyrus cirratus Paperna, 1964, C. halli (Price & Kirk, 1967), C. thurstonae Ergens, 1981 and Scutogyrus longicornis (Paperna & Thurston, 1969). CONCLUSIONS: Except for M. clarii, all species represent new records for Ethiopia. This first study on the monogenean fauna of Lake Tana revealed that the lake's North African catfish, as well as its endemic Nile tilapia subspecies, harbour parasites that are known from these host species elsewhere in Africa. ispartof: Parasites & Vectors vol:9 issue:1 ispartof: location:England status: published

Tilapia is one of the commercially important fish in Malaysia as well as in other parts of the world. An understanding of monogenean infection dynamics in tilapia fish may assist us in searching for some intervention measures in reducing the loss of fish caused by parasitic diseases. The present study aimed (1) to compare infection level of monogeneans between the wild and cultured Oreochromis niloticus, and between the cultured O. niloticus and cultured red hybrid tilapia, and (2) to examine the spatial distribution of monogenean species over the gills of the different host species. From a total of 75 fish specimens, six species of monogeneans from two genera: Cichlidogyrus (C. halli, C. mbirizei, C. sclerosus, C. thurstonae, C. tilapiae) and Scutogyrus (S. longicornis) were identified. Data showed that the infection level of cultured O. niloticus was higher than that of the wild O. niloticus, however, the former was lower than that of the cultured red hybrid tilapia. Higher species richness of monogeneans was observed in the cultured red hybrid tilapia as compared to the others. Results for spatial distribution showed that the monogeneans have no preference on the left or right sides of the gills. However, C. halli, C. mbirizei, and C. tilapiae showed preferences on specific gill arches in the cultured O. niloticus and red hybrid tilapia. In general, the gill arch IV harboured the least number of monogeneans. The susceptibility of monogenean infection between the different types of tilapia is discussed.