Coast Of Cameroon Research Articles

MIGRATION AND IDENTITY IN SOUTHWEST REGION OF CAMEROON: THE GRAFFIE FACTOR, C.1930S-1996

O presente artigo foca nas dinâmicas de migração interna, tomando o caso dos migrantes naturais das Planícies Bamenda no litoral de Camarões, e destaca como tais migrações deram origem ao enigma identitário entre aqueles que vieram a ser chamados graffie e os locais. Questiona como a politização da identidade pode ser compreendida dentro das dinâmicas históricas e políticas de Camarões. O artigo também defende que, no início da colonização britânica, muitos habitantes da região migraram para o complexo industrial do litoral de Camarões como mão de obra para as plantations, além de como auxiliares em outros serviços coloniais. Depois de trabalhar nestes serviços eles se aposentaram e tornaram-se empreendedores, para desgosto dos locais. Eles foram, assim, pejorativamente denominados graffie. Usando o conceito de identidade em migração o artigo questiona por que e como os graffie lidaram com sua identidade em espaços heterogêneos, como a região sudoeste de Camarões.

Hidden founders? Strong bottlenecks and fine-scale genetic structure in mangrove populations of the Cameroon Estuary complex

Fine-scale genetic structure (FSGS) is common in plants, driven by several ecological and evolutionary processes, among which is gene flow. Mangrove trees rely on ocean surface currents to spread their hydrochorous propagules through space. Since pollen dispersal is generally restricted to local scales, high level of short-distance propagule dispersal is expected to result in FSGS in Rhizophora spp. We investigated FSGS, recent bottleneck events, as well as historical and contemporary expansion patterns in Rhizophora racemosa populations from the entire coast of Cameroon, using 11 polymorphic microsatellite markers. Populations of the Cameroon Estuary complex (CEC) showed significant FSGS and significant reduction in effective population sizes (recent bottlenecks), compared to the other areas. Additionally, our results indicate stark differences between historical and contemporary expansion models. These suggest that contemporary processes such as restricted propagule dispersal, bottleneck events from high indirect and direct anthropogenic pressure, and recolonization by founders from ancient local pockets/refugia most plausibly shape the patterns of FSGS in the CEC.

Local Perception of Climate Change and Adaptation in Mangrove Areas of the Cameroon Coast

Mangroves supply essential ecosystem services to tropical informal economies. In the Cameroon coastal region, the impacts of various projections on change in temperatures and precipitations sound low compared to the pressure of human activities. This survey evaluated the sensitivity of local population on the impact of climate change and the vulnerability of coastal ecosystems. An investigation carried out on 425 individuals was based on the major income and development activities, the knowledge of the subject, the information sources, the origin of changes, perceptible effects, risks and consequences. More than 90% of interviewees have heard about climate change essentially from radio (20%). Industries (47.53%) are perceived to have major responsibility for temperature (78%) and precipitation (67%) changes and increased inundation (39.07%) was perceived as the highest risk. Compared with Cartesian predictions in the area, the results have shown the sensitivity of population to local variation of climate factors. No efficient endogenous measure has been recorded. Forest and specially mangroves are the most affected ecosystems by local activities. Expected extension of the dry season could affect the natural regeneration and the structure of mangrove forests. Considering the importance of woody species in the local economies, the lack of appropriate actions and adaptation measures will lead to the total degradation of mangroves.

Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae) from West and Central Africa.

African clawed frogs, genus Xenopus, are extraordinary among vertebrates in the diversity of their polyploid species and the high number of independent polyploidization events that occurred during their diversification. Here we update current understanding of the evolutionary history of this group and describe six new species from west and central sub-Saharan Africa, including four tetraploids and two dodecaploids. We provide information on molecular variation, morphology, karyotypes, vocalizations, and estimated geographic ranges, which support the distinctiveness of these new species. We resurrect Xenopus calcaratus from synonymy of Xenopus tropicalis and refer populations from Bioko Island and coastal Cameroon (near Mt. Cameroon) to this species. To facilitate comparisons to the new species, we also provide comments on the type specimens, morphology, and distributions of X. epitropicalis, X. tropicalis, and X. fraseri. This includes significantly restricted application of the names X. fraseri and X. epitropicalis, the first of which we argue is known definitively only from type specimens and possibly one other specimen. Inferring the evolutionary histories of these new species allows refinement of species groups within Xenopus and leads to our recognition of two subgenera (Xenopus and Silurana) and three species groups within the subgenus Xenopus (amieti, laevis, and muelleri species groups).

Assessment of trace metal pollution in sediments and intertidal fauna at the coast of Cameroon.

Coastal systems act as a boundary between land and sea. Therefore, assessing pollutant concentrations at the coast will provide information on the impact that land-based anthropogenic activities have on marine ecosystems. Sediment and fauna samples from 13 stations along the whole coast of Cameroon were analyzed to assess the level of trace metal pollution in sediments and intertidal fauna. Sediments showed enrichment of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn. However, pollution of greater concern was observed for Cd, Cr, Cu, Ni, and Zn at the northern stations. Some sites recorded trace metal levels higher than recommended in sediment quality guidelines. Species diversity was low, and high bioaccumulation of trace metals was observed in biological samples. Some edible gastropod species accumulated trace metals above the safety limits of the World Health Organization, European Medicine Agency, and the US Environment Protection Agency. Although industrial pollution is significant along Cameroon's coast, natural pollution from the volcano Mount Cameroon is also of concern.

Invasive aquatic species on the Atlantic coast of Cameroon: A need for policy formulation

Invasive aquatic species on the Atlantic coast of Cameroon: A need for policy formulation

Invasive aquatic species on the Atlantic coast of Cameroon: A need for policy formulation

Invasive aquatic species on the Atlantic coast of Cameroon: A need for policy formulation

Overview of Tide Characteristics in Cameroon Coastal Areas Using Recent Observations

Time series of sea level heights have been collected at different stations along the Cameroon coast. The dataset covers a period ranging from 2007 to 2012. Tide data measured by float type recorders have been digitalized and quality-controlled with tools developed at Laboratoire d’Etudes Geophysique et Oceanographie Spatiale (LEGOS). Short gaps in the data have been interpolated while large gaps were not. Tide constituents were retrieved through harmonic analysis using 123 waves having a period ranging from long ones to eighth-diurnal ones. The reconstructed signal is used to assess the quality of both the data and the analysis and the erroneous records were examined and corrected. The effect of the hourly averaging of the raw data on the quality of the analysis is also investigated. The tide constituents having the largest amplitudes are, as expected, the semi-diurnal, diurnal, fourth-diurnal and long term constituents. The major components of semi-diurnal waves are the M2 and S2 tides. The M2 tide height ranges between 0.5 and 0.85 m. The maximum height is found at Cameroon estuary and the minimum at the Kribi station located in the South coast. The S2 constituent varies similarly as the M2 constituent. Its amplitude ranges between 0.18 and 0.52 m. The lowest S2 amplitude occurs also at Kribi station. In the Dibamba estuary the spectrum shows a larger number of significant semi-diurnal and fourth-diurnal waves than other zones. Concerning diurnal waves, the dominant one is the K1 tide and its amplitude is homogeneous along the coast. The influence of the long-term components is the strongest in the Cameroon estuary due to important fluctuations of the rivers run-off.

The Lobé Waterfall, an exceptional geocultural heritage on the coast of cameroon between sustainable tourism and the conservation of cultural identities

Situated mid-way along the west coast of Cameroon, the city of Kribi is a crucial location with regard to three aspects: industry, tourism and the environment. This area, endowed with abundant natural, cultural and tourist resources, remains undervalued despite timid initiatives by the local populations and the central administration to develop tourism. This article looks at the challenges of developing tourism around the Lobe Waterfall, a singular geosite at the crossroads of three coastal civilisations (Pygmy, Batanga and Mabi), proposed by the administration of Cameroon in 2006 for inclusion on the UNESCO World Heritage List. Its definitive recognition as heritage is hindered by the prevarications of the decision-makers who favour industrialisation over integrated management and sustainable tourism, as recommended by the UNWTO and the UNIDO via the COAST STEP project. The objective of this text is to analyse the failure of this process, via observations, field work and interviews, taking into account at the same time the introduction of sustainable tourism in this beach area, the contribution of the stakeholders and the problems of development. The information collected provides evidence of the considerable and diversified potential for tourism (natural, cultural and historic) characterised by an attractive physical environment (relief, climate and vegetation) and the existence of motivated populations. However, the emergence of agricultural-industrial, extraction and mining activities, which do not consider the environment and social participation, and the anarchic spatial implementation of tourism, are factors that may compromise future tourism in Kribi and its geosite, with the corollary of the disappearance of the Pygmy culture.

Aerosol-cloud-land surface interactions within tropical sea breeze convection

In this study, the influence of aerosols, surface roughness length, soil moisture, and synergistic interactions among these factors on tropical convective rainfall focused along a sea breeze front are explored within idealized cloud-resolving modeling simulations using the Regional Atmospheric Modeling System (RAMS). The idealized RAMS domain setup is representative of the coastal Cameroon rainforest in equatorial Africa. In order to assess the potential sensitivity of sea breeze convection to increasing anthropogenic activity and deforestation occurring in such regions, 27 total simulations are performed in which combinations of enhanced aerosol concentrations, reduced surface roughness length, and reduced soil moisture are included. Both enhanced aerosols and reduced soil moisture are found to individually reduce the precipitation due to reductions in downwelling shortwave radiation and surface latent heat fluxes, respectively, while perturbations to the roughness length do not have a large impact on the precipitation. The largest soil moisture perturbations dominate the precipitation changes due to reduced low-level moisture available to the convection, but if the soil moisture perturbation is more moderate, synergistic interactions between soil moisture and aerosols enhance the sea breeze precipitation. This is found to result from evening convection that forms ahead of the sea breeze only when both effects are present. Interactions between the resulting gust fronts and the sea breeze front locally enhance convergence and therefore the rainfall. The results of this study underscore the importance of considering the aerosol-cloud-land surface system responses to perturbations in aerosol loading and land surface characteristics.

Impact Assessment on By-catch Artisanal Fisheries: Sea Turtles and Mammals in Cameroon, West Africa

The by-catch assessment has been carried out along Cameroon coastline to map artisanal fishing effort and quantify impact of by-catch on sea turtles and marine mammals during three months from June to September 2011 and specific objectives include: - To interview fishermen in various fishing villages or ports in Cameroon regarding fishing effort and catch. - To estimate fishing gears used in these fishing ports. - To evaluate impacts of by-catch on marine mammals and sea turtles. In total 30 fishing ports were been planned but 23 were covered with 932 files in total (245 long forms and 685 short forms). In total we have 4121boats (none motorized and motorized) and the common gears used are gillnet and surround seine. The results reveal that, yearly around 1228 turtles with back (green, hawksbill and olive) were caught and 13 Leatherback; most not intentionally. But in Sandje port we noted the intentional catch by local fishermen with around 400 individuals per year for international commercial uses. These numbers are low according to certain data on sea turtles surveys along Cameroon coast. About cetaceans and manatee we had the following data 97 and 292 respectively for each group, but most manatees are caught intentionally for bush meat trade. The survey was limited in time and lack of baseline information on the issue but in future it could be good to involve more permanent data collectors and scientific observers. These results must be feedback to official services for good monitoring of marine faunal and their ecosystem.

Gravity Model for an Anomalous Body Located in the NW Portion of the Douala Sedimentary Sub-Basin, Cameroon (Central Africa)

Gravity studies have been carried out in the Douala sub-basin which is a sedimentary basin located both onshore and offshore on the South coast of Cameroon between latitudes 3°03'N and 4°06'N and longitudes 9°00' and 10°00'E, covering a total surface area of 12,805 km2. On its onshore portion, the Douala sub-basin has a trapezoic shape and covers a total surface area of about 6955 km2 while the offshore part covers an area of about 5850 km2. Gravity data used in this study are constituted of 912 gravity data points located between longitudes 8°10.2' to 10°59.4'E and latitudes 2°30.6' to 4°59.4'N and the study area is located to the NW section of the onshore portion of the Douala sub-basin. This study area is characterised by considerably high positive anomalies attaining peak values of about 104.1 mGals at longitude 9°9.9' and latitude 4°1.1' with contour lines which are mostly oriented in the NNE direction. Residual anomalies were extracted by upward continuation of the Bouguer anomaly field at an optimum height of 30 km. This residual field and those obtained by the separation of polynomial of order 4 had a very high correlation coefficient factor of 0.979. The multi-scale horizontal derivative of the vertical derivative (MSHDVD) method was applied on the extracted residual anomalies for the delimitation of possible contacts in the source while the amplitude spectrum was used to estimate the depth to the top of the potential field source. The MSHDVD method did not delimite any clear cut contacts in the source but the amplitude spectrum estimated the potential field source at a depth of about 4.8 km. The ideal body theory was used to determine the density contrast along a 65 km NW-SE profile yielding a value of 0.266 g/cm3. 2.5D modelling aimed at bringing out the underlying structural layout of this study area presents a source body which is very probably an intrusive igneous block surrounded by sedimentary formations and having a density of 2.77 g/cm3 at a depth of about 5.88 km below the surface and an average thickness of about 26.95 km.

Environmental Consideration Leads to Successful Decommissioning of FSO

This article, written by Editorial Manager Adam Wilson, contains highlights of paper SPE 157017, ’Decommissioning of an FSO Containing Hazardous Waste: A Successful Story,’ by Claude-Henri Chaîneau, Jean-Claude Bourguignon, Guillaume Goubard, and Pierre Bang, Total E&P; Philippe Jean, SPE, PJN Consulting; Benoit Lefebvre, SITA France; Tom Peter Blankestijn, Sea2Cradle; and Emmanuel Tambe Ayuk, SNH, prepared for the 2012 SPE/APPEA International Conference on Health, Safety, and Environment in Oil and Gas Exploration and Production, Perth, Australia, 11-13 September. The paper has not been peer reviewed. Ship dismantling issues have never been as sensitive as they are now. In this context, the Rio del Rey partnership, represented by Total E&P Cameroun, planned the Serepca-1 (SR1) tanker’s end of life. SR1 was a Suezmax type oil tanker moored off the coast of Cameroon. The ship was a significant source of raw material and contained waste that could turn its dismantling into a health hazard and an environmental hazard. Various environmental surveys were made to identify hazardous materials and to produce the ship’s Green Passport. The end of life of any tanker has economic, environmental, and social implications. Introduction SR1 was a former oil tanker, built in 1974. In 1984, it was converted into a floating storage and offloading unit (FSO) and positioned in the Biafra bight, off the coast of the Republic of Cameroon. Its 14 tanks stored Kolé crude oil extracted from the Rio del Rey oil field. However, given the oil tanker’s age, the company decided to replace it. SR1’s oil storage activities ceased in May 2007, and it is in this context that a full decommissioning project was set up. Given the large quantity of steel contained in the structure, an oil tanker constitutes a significant source of raw material. The elimination strategy selected, however, can turn such a tanker and the various polluting, toxic, or inflammable substances onboard into a health and environmental hazard. Several decontamination phases must be carried out in precise sequences before any dis-mantling operation, to prevent environ-mental and health risks. When one looks at the international situation, one sees that, during the last two dozen years, most of the world’s commercial ships and warships have been sent to developing countries to be dismantled in conditions damaging to the environment and to health. The evolution of environmental regulations in the member countries of the Organization for Economic Cooperation and Development (OECD) during the 1980s caused the cost of hazardous waste disposal operations to increase in industrialized countries. As a result, hazardous wastes have been exported to developing countries, where environ-mental regulations were less thorough. It is in reaction to this situation that the international community implemented the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal.

American Presbyterian Missionaries, Enslavement, and Anti-Slavery in Nineteenth-Century Gabon

When American Presbyterian and Congregationalist missionaries arrived in the Gabon Estuary in the 1840s, they entered a world marked by vibrant commerce; violence and inequality; widespread slavery and slave-trading; British, French, and U.S. Anti-Slavery Patrols; and incipient French colonialism. This article draws on the published accounts by two U.S. missionaries, John Leighton Wilson, who served in Gabon from 1842 to 1851, and Robert Hamill Nassau, who worked on Corisco Island, the Gabon Estuary and Ogowe River, and the southern Cameroon coast from 1861 to 1906. Together, their writings provide insights into early colonialism and especially the long decline of enslavement and slave trading. While Wilson witnessed the establishment of Libreville in the 1840s, Nassau encountered slave trading first on Corisco and later on the Ogowe during the period of French colonial exploration. Both men, shaped by their African experiences as well as their respective social locations in the United States, held strong views on African domestic slavery and the slave trade. Wilson, from the South, was an ambivalent abolitionist who railed against the Atlantic Slave trade while hesitating to denounce slavery and racial inequality in his native South Carolina. Nassau, from New Jersey and educated at conservative Princeton University, was prompted above all by the missionary impulse. He sought to convert and “uplift” formerly enslaved Africans while nevertheless underlining their “servile” characters and benefitting from their labor as docile, socially vulnerable mission workers.

A New Squeaker Frog (Arthroleptidae: Arthroleptis) from Bioko Island, Equatorial Guinea

Abstract A new species of squeaker frog (genus Arthroleptis) is described from Pico Basile on Bioko Island (Equatorial Guinea), which lies just off the coast of Cameroon in the Gulf of Guinea. A previous molecular phylogenetic study indicates that this new species is nested within a species complex—Arthroleptis poecilonotus—that comprises morphologically indistinguishable populations that represent several cryptic species. The new species from Bioko is, however, easily distinguishable from both closely related and geographically proximate Arthroleptis by a combination of its moderately large body size (approximately 25% larger than frogs in the remaining poecilonotus species complex) and unique ventral color pattern. It is further distinguished from all other Arthroleptis by the presence of spines on the crus in large males and from other populations in the poecilonotus species complex by the occasional presence of a supernumerary tubercle at the base of pedal digit II. Statistical analyses of measurement...

Biogeographical analysis of Cameroonian puddle frogs and description of a new species ofPhrynobatrachus(Anura: Phrynobatrachidae) endemic to Mount Oku, Cameroon

Patterns of species divergence amongst 13 species of Phrynobatrachus from Cameroon were analysed using phylogenetic analyses of mitochondrial DNA sequence data from 12S rRNA, valine-tRNA, and 16S rRNA. A clade endemic to the mountains of western Cameroon and eastern Nigeria, part of the geologic rift zone termed the Cameroon Volcanic Line, supports the view that montane regions have acted as centres of speciation. Bioko Island (Equatorial Guinea), located 32 km off the coast of Cameroon, is populated by three different lowland Phrynobatrachus species from the mainland. Two of these species, Phrynobatrachus auritus and Phrynobatrachus cornutus reach submontane elevations on Bioko Island (up to 1200–1300 m) but are present only at lowland elevations on mainland Cameroon. A new miniature species of puddle frog of the genus Phrynobatrachus restricted to Mt Oku in the Republic of Cameroon is diagnosed on the basis of morphological characters and molecular data. Unlike all other miniature Phrynobatrachus (snout–vent length < 20 mm), males of this species have unique ventral coloration characterized by a black throat, dark brown to black pectoral and abdominal regions, and a light or white area on the proximal hind limbs. Minute spines cover the venter in males, often appearing as white asperities. The description of this new species supports the significance of this montane ecoregion as a biodiversity hotspot for anurans.

Ciguatera: the detection of neurotoxins in carnivorous reef fish from the coast of Cameroon, West Africa

This work examined 64 large, carnivorous reef fish from the coastal waters of Cameroon for toxicity commonly associated with an incidence of ciguatera fish poisoning. The samples were also subjected to m-DNA analyses to confirm their taxonomic identification. The analyses showed that a subgroup of fish locally referred to as groupers are actually in the snapper family (Lutjanus spp.). Extracts from 22 barracuda Sphyraena barracuda and 42 snapper Lutjanus spp. samples were prepared and examined for the presence of ciguatera-like toxins. Sodium-channel activation was assessed by a sodium-channel-specific bioassay using mouse neuroblastoma (N2a) cells. Extracts were also subjected to chemical analysis via liquid chromatography/mass spectrometry (LC/MS) to compare the mass of peaks of interest to the molecular weights of fish toxins previously described. Two barracuda and one snapper tested positive for a sodium-channel activator, i.e. presumptive ciguatoxin, in the N2a assay. LC/MS analyses showed that only these three samples contained high-intensity peaks, with masses of 1 222 amu and 1 279 amu. These results represent the first analytical report indicating the presence of sodium-channel-specific neurotoxins in fish from along the coast of West Africa. Given the importance of such marine carnivores to the nutrition and socio-economy of the coastal populace, education and disease management appear to be warranted.

The oil industry along the Atlantic coast of Cameroon: Assessing impacts and possible solutions

While the oil industry along the Atlantic coast of Cameroon has made important contributions to the national economy, this has been accompanied with adverse environmental impacts. There has been significant pollution from oil drilling, refinery waste, oil spillage, gas and flaring. After discussing these impacts, this paper argues that prevailing regulations are inadequate and need overhauling. It proposes that cleaner production requires: (i) specific laws to protect dwellers in the neighbourhood of oil refineries, filling stations, service stations and pipelines; (ii) adoption of national standards for levels of industrial effluents, and allocation of sufficient resources for monitoring these standards; (iii) formation of industry–government research partnerships; (iv) the divorcing of gas flaring; and (v) a more comprehensive legislation enabling a robust public participation in environmental impact assessment and nomination of indicators to evaluate corporate environmental management plans.

Susceptibility of Anopheles gambiae Giles (Diptera: Culicidae) to pyrethroids, DDT and carbosulfan in coastal Cameroon

Natural populations of Anopheles gambiae s.s. M form and An. melas were assessed for susceptibility to pyrethroid (deltamethrin and permethrin), DDT and carbosulfan insecticides in three localities in coastal Cameroon. Anopheles melas was recorded only from Limbe and Idenau localities, with all samples susceptible to the four insecticides. Anopheles gambiae M form from all three villages was 100 % susceptible to deltamethrin and permethrin, but showed 6.3 % survival on 4 % DDT in Tiko village. Resistance in An. gambiae M form to carbosulfan was found at all three sites, with mortality rates ranging from 53 to 90 %. These findings provide a baseline for evidence-based planning and implementation of malaria vector control activities in the surveyed areas and can be used for comparison in vector control monitoring activities.

Malaria vectors and transmission dynamics in coastal south-western Cameroon

BackgroundMalaria is a major public health problem in Cameroon. Unlike in the southern forested areas where the epidemiology of malaria has been better studied prior to the implementation of control activities, little is known about the distribution and role of anophelines in malaria transmission in the coastal areas.MethodsA 12-month longitudinal entomological survey was conducted in Tiko, Limbe and Idenau from August 2001 to July 2002. Mosquitoes captured indoors on human volunteers were identified morphologically. Species of the Anopheles gambiae complex were identified using the polymerase chain reaction (PCR). Mosquito infectivity was detected by the enzyme-linked immunosorbent assay and PCR. Malariometric indices (plasmodic index, gametocytic index, parasite species prevalence) were determined in three age groups (<5 yrs, 5–15 yrs, >15 yrs) and followed-up once every three months.ResultsIn all, 2,773 malaria vectors comprising Anopheles gambiae (78.2%), Anopheles funestus (17.4%) and Anopheles nili (7.4%) were captured. Anopheles melas was not anthropophagic. Anopheles gambiae had the highest infection rates. There were 287, 160 and 149 infective bites/person/year in Tiko, Limbe and Idenau, respectively. Anopheles gambiae accounted for 72.7%, An. funestus for 23% and An. nili for 4.3% of the transmission. The prevalence of malaria parasitaemia was 41.5% in children <5 years of age, 31.5% in those 5–15 years and 10.5% in those >15 years, and Plasmodium falciparum was the predominant parasite species.ConclusionMalaria transmission is perennial, rainfall dependent and An. melas does not contribute to transmission. These findings are important in the planning and implementation of malaria control activities in coastal Cameroon and West Africa.