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Ibaka Estuarine in Mbo, Nigeria, has little or no information on its basic properties, therefore its water samples were studied from March to June 2018 in three different stations and compared with International Standards to evaluate its physic-chemical properties as well as heavy metal contents. The physic-chemical properties studied include pH, salinity (g/L), EC (μs/cm), turbidity (NTU), total suspended solids (mg/L), total dissolved solids (mg/L), dissolved oxygen (mg/L), BOD5 (mg/L), and chemical oxygen demand (mg/L). In addition, some metal concentrations of manganese, iron, copper, lead, zinc, cadmium, chloride and magnesium were determined by atomic absorption spectroscopy (AAS). The range of metal concentrations manganese (0.08-0.12 mg/L), copper (0.05-0.09 mg/L), lead (0.01-0.03 mg/L), iron (1.86-4.66 mg/L), zinc (0.68-1.16 mg/L), cadmium (0.04-0.08 mg/L), chloride (675.0-791.25 mg/L), magnesium (10.66-14.30 mg/L). The study infers that anthropogenic pressure plays damaging role to its properties in addition to general health implication of high values for Fe, Zn, Cd, Cl and Mg which exceeded international standard.

There has been little attention to the glycogen and protein profiles of Clinostomum tilapiae Ukoli, 1966 (Digenea: Clinostomidae) and recently studied Clinostomum Morphotype1 as well as the epidemiological status of the later. The protein content of the cyst membrane 10.10 +/- 0.90 g/dL and host muscle tissue 11.9 +/- 0.80 g/dL are higher than the protein content of Clinostomum Morphotype1 tissue 7.9 +/- 0.40 g/dL. Conversely, the host muscle tissue glycogen content 8.25 +/- 1.07 mg/kg is slightly lower than both the cyst tissue 9.20 +/- 0.54 mg/kg and Morphotype1 9.06 +/- 0.79 mg/kg, respectively. However, the glycogen content of Clinostomum tilapiae 13.10 +/- 0.92 mg/kg is higher than both host muscle tissue glycogen content 8.25 +/- 1.07 mg/kg and the cyst tissue 9.20 +/- 0.54 mg/kg. Clinostomum tilapiae exhibited the invasive characteristic of trematodes. Season influenced the occurrence of Morphotype1 with higher prevalence in dry (54.01%) than rainy season months (45.98%).

In the Afrotropic region, the genus Clinostomum is represented by four accepted and four unnamed species distinguished using molecular data. Here, we describe one of the four unnamed species as Clinostomum ukolii n. sp. based on metacercariae from siluriform fishes (Synodontis batensoda, Schilbe intermedius) collected in Nigeria and South Africa. The new species is distinguished by molecular data (39 new sequences of partial cytochrome c oxidase I≥ 6.7% divergent from those of other species) and morphological differences from named and unnamed species in the same region. Metacercariae of C. ukolii n. sp. can be distinguished based on size, tegumental spines, and various aspects of the genital complex, including its position, lobation of the anterior testis, and the disposition and shape of the cirrus pouch. Although descriptions of new species of digeneans are typically based on the morphology of adults, we argue that in cases where data are available from metacercariae from regionally known species, new species can be described based on metacercariae, particularly when supported by molecular data, as here. Moreover, sub-adult reproductive structures can be clearly visualized in metacercaria of Clinostomum. Considering metacercariae as potential types for new species could advance clinostome systematics more rapidly, because metacercariae are encountered much more often than adults in avian definitive hosts.

DNA barcoding is widely used for specie cataloging for unambiguous identification and conservation. In the present study, baseline information on the DNA barcoding of mitochondrial CO1 gene of some randomly caught West African birds were provided with five newly reported sequences for Tringa sp, Streptopelia decipens, Francolinus bicalcaratus, Tyto alba and Francolinus squamatus. Species identifications were made by comparing unknown CO1sequences against the DNA barcodes of known species through distance-based tree construction and alignment searching. The newly generated sequences are deposited in GenBank under accession numbers JX160000 - JX160017 and JX220905. Current study may contribute towards the development of a reference DNA barcoding database of West African birds.

SUMMARYThe genus Clinostomum Leidy, 1856 (Digenea: Clinostomidae) has been reported in all ecozones of the world and a clear separation between the species of the ‘Old World’ and ‘New World’ has been recognized based on molecular studies. Recent works on Afrotropical species include redescriptions of C. cutaneum and C. phalacrocoracis, while C. tilapiae has yet to be studied using modern taxonomic approaches. In the present research, morphological redescription of C. tilapiae metacercariae from a new host, Synodontis batensoda sampled at Anambra River Basin, Nigeria, together with molecular analysis of nuclear internal transcribed spacer rDNA and cytochrome c oxidase 1 mtDNA are reported. We also provide morphological and molecular data from four further putative species of Clinostomum (morphotypes 1–4) from different areas of Africa, as well as the first report of C. phalacrocoracis in South Africa.

Histopathology of fish in a concomitant infection of three different species of clinostomatid metacercariae: Clinostomum tilapiae, Clinostomum complanatum, and Euclinostomum heterostomum has become necessary due to its want of knowledge. Description of enormous debilitating skin damages, occasional deaths, unilateral exophthalmus, and degeneration of skin, myositis, haemorrhages, eosinophils, necrosis and economic destruction of Tilapia zillii values by these metacercariae were studied. These parasites dry body weights (mg); C. complanatum (0.0071 ± 0.0023b) and E. heterostomum (0.0067 ± 0.0023b) did not show any significant difference (P < 0.05 %), whereas C. complanatum and E. heterostomum showed significant difference with C. tilapiae (0.0050 ± 0.0015a). The effects of hydrological regime showed that reduced rains (153.54 ± 109.42 cm3) and floodplain influenced the occurrence of these digenean parasites which peaked during dry season months (Nov 2007 – March 2008) when the habitat contracted.

DNA barcoding is a widely used molecular approach for species cataloging for unambiguous identification and conservation. In the present study, DNA barcoding of some West African mammals were performed with six new mitochondrial CO1 sequences for Civettictis civetta , Tadarida nigeriae , Orycteropus afer , Heliosciurus gambianus , Equus africanus asinus and Funisciurus anerythrus which are absent in public databases such as BLAST/NCBI and BOLD. Sequence identifications were made by comparing unknown sequences against the DNA barcodes of known species through distance-based tree construction and alignment probing. The sequences have been deposited to GenBank/NCBI. Keywords: mtDNA, West African mammals, conservation, biodiversity.

Baseline information on the parasites of frequently caught species of the characids namely Hydrocynus vittatus, Alestes baremoze, Brycinus macrolepidotus and Brycinus leuciscus was investigated in Anambra River from August 2004 to July 2005. The parasites recovered were the Myxosporid, Myxobolus sp (Protozoa), Polyopistocotylids, Diplozoon ghanense and Neodipolzoon polycotyleus (Monogeneans), the Caryophyllid Caryophylleus sp (Cestoda) and Rhabdochona sp (Nematoda). The prevalence of Caryophylleus sp in B. macrolepidotus (14.2%) and A. baremoze (8.1%) as well as Rhabdochon sp and Myxobolus sp in H. vittatus (9.6% and 7.8% respectively) was relatively high (>7.0%); while the other parasite species Myxobolus sp in B. leuciscus (2%), D. ghanense in B. macrolepidotus (1.9%) and N. polycotyleus in A. baremoze (1.9%) had a much lower prevalence (2.7%). Distribution of parasites was clearly seasonal. Dissolved oxygen (8.0–14.0) mg l−1 and pH (5.5–7.0) influenced the occurrence of the parasites whereas temperature (20.1–27.5 DC) showed no much effect. Resume Les informations de reference sur les parasites des especes frequemment capturees de Characides Hydrocynus vittatus, Alestes baremoze, Brycinus macrolepidotus et Brycinus leuciscus ont eteetudiees dans la riviere Anambra entre aout 2004 et juillet 2005. Les parasites retrouves sont le Myxosporide, Myxobolus sp. (Protozoaire), les Polyopistocotylides, Diplozoon ghanense et Neodipolzoon polycotyleus (Monogenes), les Caryophyllides Caryophylleus sp. (Cestodes) et Rhabdochona sp. (Nematodes). La prevalence de Caryophylleus sp. chez B. macrolepidotus (14,2%) et A. baremoze (8,1%) ainsi que de Rhabdochon sp. et Myxobolus sp. chez H. vittatus (9,6% et 7,8% respectivement) etait relativement forte (>7,0%), alors que les autres especes de parasites, Myxobolus sp. chez B. leuciscus (2%), Dipolzoon ghanense chez B. macrolepidotus (1,9%) et Neodiplozoon polycotyleus chez A. baremoze (1,9%) avaient une prevalence beaucoup plus faible (2,7%). La distribution des parasites etait nettement saisonniere. L’oxygene dissous (8,0–14,0 mg/l) et le pH (5,5–7,0) influencaient l’occurrence des parasites alors que la temperature (20,1–27,5°C) n’avait pas beaucoup d’effets.

Acanthocephalan fauna are distributed globally as visceral parasites of vertebrates and arthropods. Morphological description of four known species of the newly described class Polyacanthocephala has been replete with controversies. However, Mitochondrial COI gene of two new cystacanths sequences; Polyacanthorhynchus nigerianus n.sp. (NG1 KC904074) and Polyacanthorhynchus echiyensis n.sp. (NG5 KC904075) infecting some parentenic individuals of Synodontis batensoda in Nigeria were sequenced. The resulting sequences were aligned with 36 other sequences of acanthocephalans representing three widely recognized classes; Archiacanthocephala, Palaeacanthocephala and Eoacanthocephala. The only representative of the new class Polyacanthocephala in the GenBank/NCBI Polyacanthorhynchus caballeroi (DQ089724) formed a common clade with these two new sequences. This study thus supports existence of the new class Polyacanthocephala as an independent class within Acanthocephala.

Praziquantel (PZQ) is an acylated quinoline-pyrazine originally developed for veterinary application but now one of the most used anti-helminthic drugs for treatment of certain trematodes and cestodes in both human and other animals. The present study investigated the mutagenic and physiological responses in the juveniles of African catfish, Clarias gariepinus following short term exposure to praziquantel. Based on the 53.52 mg/l 96 h LC50 of PZQ obtained, two sublethal concentrations of 5.35 and 10.70 mg/l of the drug were selected and fish were exposed to these concentrations and control for 15 days. Micronuclei induction in the peripheral blood of PZQ-exposed fish was highest on day 10 but the fish morphological parameters were not affected. The packed cell volume (PCV) was significantly reduced (p0.05) from day 5 while red blood cells (RBC) and hemoglobin (Hb) significantly declined (p0.05) on day 15. Macrocytic anemia was observed on day 1 of study and thereafter microcytic anemia developed on day 5 of study. The white blood cell (WBC) was significantly (p0.05) elevated from day 10 of exposure while values of mean cellular volume (MCV), mean cellular hemoglobin (MCH) and mean cellular hemoglobin concentration (MCHC) were not significantly different (p0.05) from the control. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glucose levels significantly increased while protein reduced (p0.05) throughout the exposure period but a mixed trend was observed in the leukocyte differentials. PZQ should be used with caution as sublethal exposure elicited micronucleus induction and alterations of hematological and biochemical parameters in the fish.

The present study was aimed at evaluating the effects of different concentrations of the most commonly used fish antimicrobial drug, chloramphenicol (CAP), on the behavior and hematological parameters of Clarias gariepinus. Fish specimens were exposed to three (2.5, 5.0 and 10.0 mg L(-1)) sublethal concentrations of CAP and a control. Abnormal behavioral changes were observed in fish exposed to higher concentration of CAP. Blood erythrocytes were sampled on days 1, 5, 10 and 15 postexposure to evaluate hematological parameters. Results showed concentration- and time-dependent significant increase in packed cell volume after day 5 of exposure (p 0.05). Hemoglobin values also significantly decreased from day 5, whereas values of mean cellular volume significantly decreased throughout the experimental period (p 0.05). A mixed trend was observed in the mean values of red blood cells, white blood cells, mean cellular hemoglobin and mean cellular hemoglobin concentration as well as neutrophils. Activities of lymphocytes were significantly increased in all CAP-treated fish during the exposure period, whereas no significant differences were observed in values of monocytes, eosinophils and basophils among the treatment groups and control. Consequently, precautions must be taken, especially when high concentrations of CAP are used in long-term treatments of C. gariepinus in aquaculture.

Scarcely use of Opi Lake for many years (1995-2007) due to road cut to its site by erosion during which parasite survey of its major fish composition was carried out established host specificity disparity especially when compared with entirely human disturbed Oguta Lake and Anambra River Basin in Southeast, Nigeria. The infection prevalence had dispersed infection in mainly skin musculature micro-habitat in encysted forms in the later reservoirs. Conversely, the parasites occupied more host micro-habitats of eye, skin and buccal cavity with high rate of excysted forms in the former reservoir. The record of mainly encysted forms in the latter reservoirs is indicative of immune resistance host-parasite relationship. Also, human disturbance which has complimentary environmental influence on both parasite and host upsets parasite-host location strategies in aquatic communities within human vicinities where the reservoirs are used for numerous domestic chores. To the best of our knowledge, hitherto the latter had little or no clinostomatids parasites report.

The study of teleost parasites in an ecologically altered ecosystem through dam construction that evidently facilitate parasitic infections and aggravate public health concerns is essential. The study of stream linked dam showed that Tilapia zillii (Gervais, 1848), Pelmatolapia mariae (Boulenger, 1899) and Clarias gariepinus (Burchell, 1822) form the major fish composition of these reservoirs. They serve important food resource globally especially places bereft of extensive aquaculture practices. Although, knowledge about the gill parasites of P. mariae is inexistent the examined individual P. mariae showed that it had 54% Heterophyes heterophyes infection, C. gariepinus had no parasitic infection whereas T. zillii had a relatively very low Batrachobdelloides spp (1.7%). Besides, the highest DO levels in the dam occasioned by high agitation and floatation the physical factors conditions - pH and DO (> 6 mg.L^-1) had suitable levels for biodiversity.

Seasonal occurrence of acanthocephalans is replete with controversies stemmed from hosts' activities and environmental conditions etc. Ergo, recent mitochondrial DNA resolved two new cystacanths sequences in a parentenic host Polyacanthorhynchus nigerianus NG1 KC904074 and Polyacanthorhynchus echiyensis NG5 KC9040745 has necessitated the present study between wet and dry seasons. Though the trend of infection followed a similar pattern, NG5 had higher prevalence than NG1 with highest prevalence 5.3% in January. However, the trend changed from March-July when the occurrence of NG1 had relatively much lower monthly prevalence < 2.6%. Their differential body size NG5 994.61 +/- 110.07 mm and NG1 237.58 +/- 30.34 mm, respectively, resulted in a trade-off between their body sizes and numbers.

In ever competitive environment of nature, evolution of most attributes of an organism - anatomy,physiology, and behaviour are determined by the environment through selection. The same is the microhabitats of Sarotherodon melanotheron where three Clinostomatids; Clinostomum tilapiae, Clinostomum complanatum, and Euclinostomum heterostomum, were recovered from Opi Lake (GPS N06.75275*, E00749104*), were studied from (November 2007– October 2008) using multiple fishing gear techniques; cast nets, hook and line, and seine nets (150 mm – 200 mm), showed signiicant dfference (p < 005) in all other anatomical parts but the distance between oraand ventral suckers. The prevalence was low; (20.8 %) was recorded in C. complanatum, (6.4 %) in E. heterostomum and (21.1 %) in C. tilapiae. But mean intensity was high which was suggestive of heavy parasite burden; C. complanatum (2.7), C. tilapiae (5.8) and E. heterostomum (5.1). In therank-abundance curve for parasite communities C.tilapiae was more abundant than the other twospecies. Differential parasitic implications was due o selection for relatively better adaptiveness tohost’s microhabitats, more population size, better host location, and larger body size. Consequently, this resulted in a trade-off between larger morphometric parts and population size among the parasites.Key words: Clinostomum sp, co-parasitism, Morphometrics, E. heterostomum, Opi Lake, Selection

Co-infection and morphometrics of helminth parasites of Tilapia guinensis in Opi Lake (GPS N06.75275*, E007.49104*), were studied from (Nov 2007– Oct 2008) using multiple fishing gear techniques; cast nets, hook and line, and seine nets (150 mm – 200 mm). The parasites recovered were C. tilapiae, C. complanatum and E. heterostomum. The prevalence was low, indicative of parasitic infection in the wild. Prevalence of (33.9 %) was recorded in C. complanatum, (7.2 %) in E. heterostomum and (12.6 %) in C. tilapiae. But high mean intensity was suggestive of heavy parasite burden; C. complanatum (4.8), C. tilapiae (2.8), and E. heterostomum (5.1). Morphometrics of the parasites showed no significance difference in the distance between oral and ventral suckers. However, they differed in all other parts significantly (p < 0.05). In the rank-abundance curve for parasite communities, C. complanatum was most abundant (pi 0.63). Differential parasitic effects were due to selection for relatively better adaptiveness to host’s microhabitats, more population size, better host location, and larger body size. Consequently, this resulted in a trade-off between larger morphometric parts and population size among the parasites