In the blood vascular system of a typical fish, the blood is sent from the heart to the gills for oxygenation and thence to the rest of the tissues, before returning once more to the heart. This is a so-called "Single Circulation". Where lungs make their appearance in the vertebrate series however, their blood supply is derived from the last of the aortic arches and is returned via the newly formed pulmonary veins, directly to the heart. A part of the blood leaving from the heart is sent to t...
Abstract Background: Some MSP-119 specific antibodies that inhibit merozoite invasion also inhibit the secondary processing of MSP-1. However the binding of these inhibitory antibodies can be blocked by another group of antibodies, called blocking antibodies, which recognize adjacent or overlapping epitopes, but themselves have no effect on either MSP-1 processing or merozoite invasion. These antibodies have been reported to be present in individuals living in a malaria endemic area. Methods:...
Abstract Phytoplankton community composition in the Southern Ocean (SO) determines levels of primary production, which support marine ecosystems and export of material to the deep sea. Nanoplankton (cell diameters 2-20 µm) are poorly resolved by traditional microscopy, and it is becoming apparent that unknown diversity and ecosystem functionality may be contained in this size class: for example, small diatoms (
Table of Content Acknowledgment Short Abstract General Abstract Chapter 1: Introduction Chapter 2: Stable isotope turnover in blood and toenails: A case study in captive African penguins Chapter 3: Insights from stable isotope into African penguins foraging behaviour during the pre-moult period Chapter 4: Temporal and spatial variation of Cape Gannet diets: lessons from stable isotopes Chapter 5: The pattern and location of moult in White-chinned Petrels Chapter 6: White-chinned Petrel...
Abstract This thesis investigates the impacts of the demersal trawl fishery on infaunal, epifaunal and fish assemblages in the southern Benguela upwelling system for the first time. In the absence of representative areas of similar habitat protected from trawling in the southern Benguela region, infaunal and epifaunal assemblages were compared between heavily and lightly trawled areas to assess the impacts of the otter-trawl fishery. Infauna were sampled at four sites, from southern Namibia t...
ABSTRACT Studies have been carried out at Nguruman, south-western Kenya, on Glossina longipennis Corti, a little known member of the fusca group of Glossina. The first objective was to develop an efficient trap suitable for both sampling and control purposes. Studies were then carried out on the population dynamics of G. 1ongipennis using the newly developed sampling methods. Lastly the trap/odour bait system was tested in a control situation. Replicated Latin square design experiments were u...
Toxicity of ammonia, which can reach toxic levels in aquaculture systems, was investigated for Haliotis midae. Toxic FAN (free un-ionized ammonia) was estimated from TAN (total ammonia nitrogen) measurements. It was found that commonly used Nesslers and Palintest methods underestimated TAN. Tolerance of H midae to ammonia increased with increasing size, as indicated by 36 h LC50 values; farmed juvenile abalone (1 - 2.5 cm shell length) had the smallest LC50 of 9.8 f,lg rl FAN, whereas LC50 wa...
ABSTRACT This thesis addresses the recruitment patterns of barnacles and mussels at a range of spatial and temporal scales and attempts to relate them to larval and adult abundance, as well as to local productivity and oceanographic conditions that would influence larval transport and the connectivity of adult populations. In Chapter 1, I investigated the spatial and temporal patterns of mussel recruitment and adult bed dynamics offour mussel species (Aulacomya ater, Mytilus galloprovincialis...
ABSTRACT This thesis explores the relationships between commercial data and those obtained from research surveys in an attempt to broaden the database available for management, and to cover seasonal and inter-annual changes in density estimates of Cape hake (Merluccius capensis). It also attempts to explain hake variability of in terms of environmental indices based on satellite remote sensing, carefully chosen to reflect underlying oceanographic processes. The influence of various factors on...
The primary focus of this thesis was to investigate the movement patterns of the South African West Coast rock lobster, Jasus lalandii, using a diverse range of techniques. These were (1) an examination of long-term data from an ongoing tag-recapture program, (2) observations on rock lobsters in a mesocosm aquarium, (3) surveys that monitored the seasonal fluxes in activities and abundance of rock lobsters in the field, (4) video recordings of movement behaviour in small aquaria and (5) acous...
ABSTRACT A revised generic diagnosis of the genus Rheotanytarsus Thienemann et Bause is given. Seven new Afrotropical species are described, R. kjaerandseni sp. n. as male, female, pupa and larva; R. plerusunguisus sp. n. as male and female; R. aquilus sp. n., R. atrius sp. n., R. saetheri sp. n., R* abonae sp. n., and R, weijensis sp. n. as males only. One species is redescribed, R. fuscus (Freeman, 1954). The genus can be divided into 7 species groups primarily based on the pupal morphology...
ABSTRACT Bats are reservoirs for many emerging zoonotic RNA viruses, including rabies virus (RABV), SARS-like coronavirus, henipaviruses and filoviruses. Several bat species have been associated with Lagos bat virus (LBV) infection. They include Wahlberg‟s epauletted fruit bat (Epomorphorus wahlbergi), the straw-colored fruit bat (Eidolon helvum), the Egyptian fruit bat (Rousettus aegyptiacus), and an insectivorous bat, the Gambian slit-faced bat (Nycteris gambiensis). Bats are important fo...
ABSTRACT Insects associated with citronella were surveyed in the south-eastern part of Ghana for 11 months. Using two different sweep nets, intensive and extensive surveys showed that the foliage of citronella was associated with a diverse insect fauna comprising 10 orders and 102 families as follows: Hymenoptera (29), Diptera (32), Homoptera (8), Hemiptera (12), Coleoptera (10), Dictyoptera (2), Orthoptera (3), Lepidoptera (2), Dermaptera (1), and Neuroptera (3). The shoot of citronella was ...
ABSTRACT The behavioural responses o f two schistosom e host snails (Bitlinus Iruncattts and Biomphalaria pfeifferi) to tw enty-six naturally occurring (crude and sem i-processed) products weic measured in diffusion olfactom eters. 15 out o f these 26 m aterials (i.e. 57% ) were found to act as statistically significant attractants for adult 13. pfeifferi w hile only 5 (19%) o f the lest materials clicited statistically significant responses from the adults o f B. truncatus. The juveniles oil...
ABSTRACT Study was conducted to determine the abundance and distribution of mosquitoes and the prevalence of malaria parasites in Yabo Local Government Area. Mosquito breeding sites identification employed the use of a digital camera to snap pictures of areas where mosquitoes were observed. Mosquitoes eggs, larvae, pupa were collected and identified using the dipping method while indoor mosquitoes were caught from rooms,/toilets between the hours of 8 - 10pm using insecticide spray. A to...