No abstract

An investigation of gill monogeneans from the Nile tilapia Oreochromis niloticus and the blue spotted tilapia Oreochromis leucostictus (50 individuals per species) was done between the months of November 2014 to February 2015 in Lake Naivasha, Kenya. Standard parasitological procedures were used to examine fish gills for the presence of monogeneans. The observed monogeneans were collected, preliminarily identified using identification keys, quantified and fixed in 4 % formalin for morphological studies and absolute ethanol for molecular studies. Four parasite species comprising of three species of the genus Cichlidogyrus and one species of the genus Scutogyrus were recovered. Cichlidogyrus sclerosus and Cichlidogyrus tilapiae infested both fish species but the C. sclerosus was most prevalent in O. leucostictus (Prevalence (P) = 100 %, Mean intensity (MI) = 3.4) and C. tilapiae in O. niloticus (P = 8 %, MI = 4). Cichlidogyrus tilapiae had a P = 12 % and MI = 5.0 and a P = 6 % and MI = 3.0 in O. niloticus and O. leucostictus, respectively. Cichlidogyrus halli (P = 4 %, MI = 15.5) and Scutogyrus gravivaginus (P = 2 %, MI = 1.0) were only found in O. leucostictus. This is the first time that these monogeneans have been identified from Lake Naivasha, Kenya, presenting new geographical records. It was concluded that Ancyrocephalids (Cichilidogyrus spp.) dominated the two cichlid fish species in Lake Naivasha, Kenya.

A parasitological study carried out in May 2022 and March 2023 in the Nyando River of Lake Victoria Basin, Kenya, disclosed two parasitic lernaeid copepods: Lamproglena cleopatra Humes, 1957, from the gills of a cyprinid, the Ningu Labeo victorianus Boulenger, 1901, endemic to the Lake Victoria drainage system, and Lamproglena clariae Fryer, 1957, from a clariid, the North African catfish Clarias gariepinus (Burchell, 1822). The copepods were studied and supplementary taxonomic information was presented using scanning electron micrographs and genetic data. Scanning electron microscopy (SEM) provided information on the morphology of L. cleopatra’s antennae, oral region, thoracic legs (2–5), and furcal rami not previously reported. Analyses of the partial fragments of 18S and 28S rDNA and cytochrome c oxidase subunit 1 (cox1) of the two parasites showed them to be distinct from all other Lamproglena taxa retrieved from GenBank. This study presents new taxonomic information on morphology using SEM and provides the first ribosomal (18S and 28S rDNA) and mitochondrial (mtDNA) data for these two parasite species. The cox1 data provided are the first for all 38 nominal species of Lamproglena. Notably, the study also provides a new host record for L. cleopatra and extends the geographical information of this species to Kenya.

No abstract

The present study describes the first record of 83 Dwarf Victorian mouthbrooder (Pseudocrenilabrus multicolor victoriae Seegers, 2000) newly discovered in Lake Naivasha, Kenya, in January 2016. Membership of the species was determined on the basis of morphometric characteristics and molecular analysis. The average length (±SD) of the fish was 6.95 ± 0.86 cm, and average weight was 5.59 ± 1.99 g. The body is normal/fusiform, the dorsal head profile convex‐shaped, the mouth is terminal with bright blue lips, and the anal fin with a reddish tip, being distinctive features of the fish. The sequences of subunit I cytochrome oxidase (COI) and cytochrome b (cyt b) genes obtained in the present study were compared with records deposited in BoldSystem and NCBI databases. Using two genetic markers enabled unambiguous determination of the species membership. The queried specimen was assigned to the Cichlidae family, as Pseudocrenilabrus multicolor victoriae (100–96.68% similarity). These results constitute the baseline study for this fish in Lake Naivasha.

Hydrological dynamics affect water levels and thus affecting ecosystem structure and functions. Lake levels in tropical ecosystems affect phosphorous input through runoff from adjacent watersheds. The resultant biological community, water and sediment quality of the lakes due to water level changes is a reflection of the geology of the area and the anthropogenic activities in the watershed. The study conducted between January 2018 and December 2019 was to explore relationships between the phosphorous input and Water Level Fluctuations (WLF) recorded by Water Resource Authority (WRA). Lake water samples were analyzed in the laboratory for phosphorous using molybdenum blue-ascorbic method and recorded using spectrophotometer.Chlorophyll-a was determined by extracting a filtered sample with 15 ml acetone and incubating overnight and thereafter read using a double beam spectrophotometer. Total Suspended Solids (TSS) was determined by filtering 200 ml of a water sample and dried overnight at 105˚C. The lowest and highest phosphorous concentrations recorded were 0.2 mg/l and 0.42 mg/l at NST7 and NST2, respectively. Measurements of Chlorophyll-a were 0.32 mg/l and 0.42 mg/l at NST9 and NST2, respectively. Secchi transparency measurements were 32.9 cm at NST3 and 84 cm at NST1. The highest and lowest TSS concentrations were 0.14 mg/l and 0.13 mg/l at NTS1 and NST8, respectively. The hydrodynamic regime in most tropical lakes plays a signifi-

Females of species of Lamproglena von Nordmann, 1832 are parasitic on the gills of teleost fishes and the 38 nominal species are based on mainly morphological data. Only four of these species have been genetically characterised and no mitochondrial data are available for the genus. The present study aimed to provide representative ribosomal DNA (rDNA) data for two additional

No abstract