scholarly journals Cambios y Evolución de las Pesquerías en al Atlántico Centro-Oriental

1973 ◽  
Vol 30 (12) ◽  
pp. 2301-2307
Author(s):  
C. Bas
Keyword(s):  
Species Composition ◽  
Primary Production ◽  
Continental Shelf ◽  
West African ◽  
Biological Characteristics ◽  
Marine Fisheries ◽  
The West ◽  
West African Coast ◽  
African Coast ◽  
Very High

This paper deals with the marine fisheries off the West African coast, between the Straits of Gibraltar and Mauritania, an area which is characterized by its relatively narrow continental shelf, the presence of the Canary Current, and intensive upwelling resulting in very high primary production and rich bottom fauna.The main fisheries (for sardines, sardinellas, hakes, sparids, cephalopods, and demersal crustaceans) are analyzed with regard to their evolution, species composition, fishing areas and seasons, the biological characteristics of the exploited stocks, and the effect of fishing on them.The criteria to be considered when planning the control and regulation of these fisheries are also analysed.

Informed Consent: Ezenwa–Ohaeto between Past and Future Uses of Pidgin

Matatu ◽  
2006 ◽  
Vol 33 (1) ◽  
pp. 115-134 ◽  
Author(s):  
Chantal Zabus
Keyword(s):  
Informed Consent ◽  
First Language ◽  
West African ◽  
The Other ◽  
Wole Soyinka ◽  
The West ◽  
West African Coast ◽  
African Coast ◽  
The 1950S ◽  
The One

The essay shows how Ezenwa–Ohaeto's poetry in pidgin, particularly in his collection (1988), emblematizes a linguistic interface between, on the one hand, the pseudo-pidgin of Onitsha Market pamphleteers of the 1950s and 1960s (including in its gendered guise as in Cyprian Ekwensi) and, on the other, its quasicreolized form in contemporary news and television and radio dramas as well as a potential first language. While locating Nigerian Pidgin or EnPi in the wider context of the emergence of pidgins on the West African Coast, the essay also draws on examples from Joyce Cary, Frank Aig–Imoukhuede, Ogali A. Ogali, Ola Rotimi, Wole Soyinka, and Tunde Fatunde among others. It is not by default but out of choice and with their 'informed consent' that EnPi writers such as Ezenwa–Ohaeto contributed to the unfinished plot of the pidgin–creole continuum.

scholarly journals Trains of African Easterly Waves and Their Relationship to Tropical Cyclone Genesis in the Eastern Atlantic

2017 ◽  
Vol 145 (2) ◽  
pp. 599-616 ◽  
Author(s):  
Abdou L. Dieng ◽  
Saidou M. Sall ◽  
Laurence Eymard ◽  
Marion Leduc-Leballeur ◽  
Alban Lazar
Keyword(s):  
West African ◽  
Dynamical Structure ◽  
African Easterly Waves ◽  
The South ◽  
The West ◽  
Easterly Waves ◽  
West African Coast ◽  
African Coast ◽  
Tropical Depressions ◽  
The Relationship

In this study, the relationship between trains of African easterly waves (AEWs) and downstream tropical cyclogenesis is studied. Based on 19 summer seasons (July–September from 1990 to 2008) of ERA-Interim reanalysis fields and brightness temperature from the Cloud User Archive, the signature of AEW troughs and embedded convection are tracked from the West African coast to the central Atlantic. The tracked systems are separated into four groups: (i) systems originating from the north zone of the midtropospheric African easterly jet (AEJ), (ii) those coming from the south part of AEJ, (iii) systems that are associated with a downstream trough located around 2000 km westward (termed DUO systems), and (iv) those that are not associated with such a close downstream trough (termed SOLO systems). By monitoring the embedded 700-hPa-filtered relative vorticity and 850-hPa wind convergence anomaly associated with these families along their trajectories, it is shown that the DUO generally have stronger dynamical structure and statistically have a longer lifetime than the SOLO ones. It is suggested that the differences between them may be due to the presence of the previous intense downstream trough in DUO cases, enhancing the low-level convergence behind them. Moreover, a study of the relationship between system trajectories and tropical depressions occurring between the West African coast and 40°W showed that 90% of tropical depressions are identifiable from the West African coast in tracked systems, mostly in the DUO cases originating from the south zone of the AEJ.

A New Lautoconus Species Radiation from Gambia, West Africa

The Festivus ◽  
2018 ◽  
Vol 50 (3) ◽  
pp. 164-172
Author(s):  
Edward Petuch ◽  
David Berschauer
Keyword(s):  
New Species ◽  
West Africa ◽  
River Mouth ◽  
Sympatric Species ◽  
West African ◽  
The West ◽  
Species Radiation ◽  
West African Coast ◽  
African Coast ◽  
Reef Fauna

Six sympatric species of the cone shell genus Lautoconus Monterosato, 1923 have been discovered on an isolated rock reef near the Gambia River Mouth, Gambia, West Africa. Of these, four were found to be new to science and, together, they represent a previously unknown Gambian endemic species radiation. These include: Lautoconus fernandi new species, L. gambiensis new species, L. rikae new species, and L. wolof new species. The poorly-known Gambian endemic cone, Lautoconus orri (Ninomiya and da Motta, 1982) was also found to be a component of the rock reef fauna, as was the wide-ranging L. guinaicus (Hwass, 1792) (Senegal to Ghana). The Gambian cluster of sibling species represents the farthest-south separate radiation of Lautoconus known from the West African coast.

scholarly journals DESIGN AND REALIZATION OF A SANDBAR BREAKWATER, LEKKI, NIGERIA

2020 ◽  
pp. 7
Author(s):  
Bart-Jan van der Spek ◽  
Bas van de Sande ◽  
Eelco Bijl ◽  
Cypriaan Hendrikse ◽  
Sanne Poortman ◽  
...  
Keyword(s):  
Construction Material ◽  
West African ◽  
Gulf Of Guinea ◽  
Construction Time ◽  
The West ◽  
West African Coast ◽  
African Coast ◽  
Coastal Retreat ◽  
Natural Dynamics ◽  
Port Infrastructure

The nature-based concept of the Sandbar Breakwater was born based on the typical natural dynamics of the West African coast (Gulf of Guinea). Learning from the development and coastal impact of the existing port infrastructure in West Africa, the application of sand as a construction material for marine infrastructure seemed very obvious. Along this coast, ports experience heavy sedimentation at the western updrift side of the breakwaters, leading to the rapid burying of valuable armour rock. The Sandbar Breakwater concept is based on this principle by using natural accretion as the basis for the port protection. Such a concept is advantageous as a large sediment drift naturally supplements the sand lling works during construction and the required rock volumes are reduced signicantly, saving construction time and minimising the environmental impact. To counteract the downdrift coastal retreat, a replenishable sand engine completes the scheme. The realisation of a Sandbar Breakwater at Lekki, Nigeria, in 2018, with subsequent safe and continuous port operations, proves the feasibility of the concept. Sustainable future development is further pursued by integrated maintenance campaigns following the Building with Nature principles to guarantee the operability of the port while preserving the alongshore sediment balance and minimising the environmental impact.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/-1wCqqB9f8E

scholarly journals High-resolution measurements of atmospheric molecular hydrogen and its isotopic composition at the West African coast of Mauritania

2012 ◽  
Vol 9 (12) ◽  
pp. 18799-18829
Author(s):  
S. Walter ◽  
A. Kock ◽  
T. Röckmann
Keyword(s):  
High Resolution ◽  
Isotopic Composition ◽  
Molecular Hydrogen ◽  
H2 Production ◽  
West African ◽  
Mixing Ratio ◽  
The West ◽  
Isotopic Signatures ◽  
West African Coast ◽  
African Coast

Abstract. Oceans are a net source of molecular hydrogen (N2) to the atmosphere, where nitrogen (N2) fixation is assumed to be the main biological production pathway besides photochemical production from organic material. The sources can be distinguished using isotope measurements because of clearly differing isotopic signatures of the produced hydrogen. Here we present the first ship-borne measurements of atmospheric molecular H2 mixing ratio and isotopic composition at the West African coast of Mauritania (16–25° W, 17–24° N). This area is one of the biologically most active regions of the world's oceans with seasonal upwelling events and characterized by strongly differing hydrographical/biological properties and phytoplankton community structures. The aim of this study was to identify areas of H2 production and distinguish H2 sources by isotopic signatures of atmospheric H2. Besides this a diurnal cycle of atmospheric H2 was investigated. For this more than 100 air samples were taken during two cruises in February 2007 and 2008, respectively. During both cruises a transect from the Cape Verde Island towards the Mauritanian Coast was sampled. In 2007 additionally four days were sampled with a high resolution of one sample per hour. Our results clearly indicate the influence of local sources and suggest the Banc d'Arguin as a pool for precursors for photochemical H2 production, whereas N2 fixation could not be identified as a H2 source during these two cruises. With our experimental setup we could demonstrate that variability in diurnal cycles is probably influenced and biased by released precursors for photochemical H2 production and the origin of air masses. This means for further investigations that just measuring the mixing ratio of H2 is insufficient to explain the variability of a diurnal cycle and support is needed, e.g. by isotopic measurements. However, measurements of H2 mixing ratios, which are easy to conduct online during ship cruises could be a helpful tool to easily identify production areas of biological precursors such as VOC's for further investigations.

The Dahomean Middleman System, 1727–c. 1818

1987 ◽  
Vol 28 (3) ◽  
pp. 357-375 ◽  
Author(s):  
David Ross
Keyword(s):  
Nineteenth Century ◽  
Eighteenth Century ◽  
West African ◽  
The West ◽  
Large Numbers ◽  
Supply Problem ◽  
West African Coast ◽  
African Coast ◽  
Trading Partners

During the first quarter of the eighteenth century, European merchants bought more slaves in the Bight of Benin than on any other part of the West African coast. From c. 1720 until 1727 much of their buying was concentrated in Savi, the capital of a small Aja state called Whydah. When the Dahomeans overran Savi in 1727 they stopped the inland slave suppliers from travelling to the coast, prevented the local Hueda from going inland to collect slaves, and insisted that the Europeans bought slaves only from Dahomean dealers. In an attempt to make sure that the Europeans had nothing more to do with their former trading partners the Dahomeans burned the factories in Savi and forced their European occupants to retire to Grehue, Savi's port, a spot on the coast where the Europeans maintained a number of fortified warehouses.The middleman policy did not at first operate satisfactorily. There were two reasons for this. The first was that the Dahomeans were, in practice, unable to prevent the Europeans from continuing to trade with the Hueda. The second was that the inland suppliers refused to sell slaves to Savi's conquerors. The Dahomeans solved their ‘coastal’ problem in the 1740S by placing a garrison in Grehue. This garrison kept the exiled Hueda at bay and held the Europeans in what amounted to open captivity. The Dahomeans were never able completely to solve their ‘supply’ problem. In the 1730s and 1740S the inland merchants took their slaves to ports which opened up on the Bight to the east of Grehue. Only in the 1750s and 1760s did they channel substantial numbers of slaves through Dahomey. In the last decades of the century they again boycotted the Dahomean market. Dahomey therefore prospered as a middleman state only between c. 1748 and c. 1770.An examination of their eighteenth century trading suggests that the Dahomeans were a slave-raiding community whose members realised in 1727 that they would soon run out of fresh raiding grounds. They appear to have introduced their middleman policy in an attempt to ensure that they would continue to profit from slave trading even after they had ceased to be able to take large numbers of captives themselves. Although the policy was by no means a complete success, it was important in that it seems to have led the Dahomeans to begin placing garrisons in the territories they ravaged. It appears, in fact, to have been the pursuit of their middleman goals that led them to begin creating the often described nineteenth century ‘greater’ Dahomean state. The middleman programme ceased to be of much importance after c. 1818, when the fall of Oyo enabled the Dahomeans to resume raiding widely in unexploited territory.

The Royal Navy and West Africa, 1843-1857

2008 ◽  
pp. 133-168
Author(s):  
Mark C. Hunter
Keyword(s):  
West Africa ◽  
Free Trade ◽  
West African ◽  
Economic Interest ◽  
Royal Navy ◽  
The West ◽  
The North ◽  
West African Coast ◽  
African Coast ◽  
American Diplomacy

This chapter analyses the British naval policies concerning West Africa between 1843 and 1857. During this period, Britain sought to encourage legitimate commerce and curtail slavery for its own economic interest, while domestically America feared the British domination of the West African coast. As such, suspicion and mistrust was rife between the two nations, and is in great detail via the abolitionist activity in the North of England; the actions of free traders and slavers; Royal Navy operations; the competition for trade between Britain and France; Commodore Charles Hotham’s slavery suppressing naval strategy; British free trade treaties; and the naval methods of enforcing British goals. It concludes in 1857, with British interests torn between strategic naval aims and domestic pressures, and British and American diplomacy still tense over West African policies.

Kru Mariners and Migrants of the West African Coast

2010 ◽  
pp. 110-123
Author(s):  
Cynthia Schmidt
Keyword(s):  
West African ◽  
The West ◽  
West African Coast ◽  
African Coast

The identity of John Rattray, diatomist and collector on the Buccaneer expedition (1885–1886) to West Africa

Phytotaxa ◽  
2019 ◽  
Vol 408 (4) ◽  
pp. 296-300
Author(s):  
ESTRELA FIGUEIREDO ◽  
DAVID WILLIAMS ◽  
GIDEON F. SMITH
Keyword(s):  
Sierra Leone ◽  
Royal Botanic Garden ◽  
West African ◽  
Botanic Gardens ◽  
Botanic Garden ◽  
The West ◽  
West African Coast ◽  
African Coast ◽  
Royal Botanic Gardens ◽  
The 19Th Century

Herbarium records show that during the second half of the 19th century John Rattray collected several plant specimens at ports of call along the West African coast (Canary Islands, Senegal, Guinea, Sierra Leone, Ghana, São Tomé, Príncipe, and Angola). At the herbarium (K) of the Royal Botanic Gardens, Kew, England, four such specimens are databased, three of which can be examined online. At the herbarium (E) of the Royal Botanic Garden, Edinburgh, Scotland, 26 specimens are databased, twenty of which are imaged. All the specimens we examined have printed labels stating ‘Collected by John Rattray, H.M. Challenger Commission, Edinburgh’ with only a handwritten indication of the locality, for example ‘Loanda’ (Luanda, Angola). The collecting date has been omitted from the labels and there are no further details on the specimens. An investigation of the literature revealed that there is some confusion regarding the origin of the material and the identity of John Rattray, the collector.

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