The first assessment of social organisation of the Indian Ocean humpback dolphin (Sousa plumbea) along the south coast of South Africa

2019 ◽  
Vol 97 (10) ◽  
pp. 855-865
Author(s):  
Thibaut Bouveroux ◽  
Stephen P. Kirkman ◽  
Danielle Conry ◽  
O. Alejandra Vargas-Fonseca ◽  
Pierre A. Pistorius

The Indian Ocean humpback dolphin (Sousa plumbea (G. Cuvier, 1829)) is the most endangered marine mammal species in South Africa, and the overall decline of its abundance and group size may affect the social organisation of the species, potentially accentuating its vulnerability. Understanding the social organisation is therefore particularly relevant to conservation efforts. From photo-identification surveys along the south coast of South Africa from March 2014 to June 2015, we quantified association patterns and investigated the social organisation of Indian Ocean humpback dolphins using the half-weight index, social cluster, and network analyses. During the 101 surveys conducted and 553 h of survey effort, 98 sightings of dolphins were recorded and 65 individuals identified. Using individuals seen at least three times, this study reveals that the social network is well differentiated, as strong social divisions exist between individuals that seem to be split into four distinctive social clusters. Network strength was low; approximately half of the associations were low to moderate, whereas some individuals were strongly associated, especially between four pairs of individuals. Although this study is based on a limited number of individuals, our study nevertheless suggests that the atypical strong social bonds recorded here could result from behavioural responses following the decline in group size and abundance.

2008 ◽  
Vol 02 (02) ◽  
pp. 133-155 ◽  
Author(s):  
J. J. WIJETUNGE ◽  
XIAOMING WANG ◽  
PHILIP L.-F. LIU

The 2004 Indian Ocean tsunami caused enormous loss of lives and damage to property in Sri Lanka and in several other countries bordering the Indian Ocean. One way of mitigating potential loss of lives from a similar event in the future is through early warning and quick evacuation of vulnerable coastal communities to safer areas, and such evacuation planning is usually carried out based on inundation maps. Accordingly, the present paper outlines the numerical modelling carried out to develop tsunami inundation maps on a grid of 10 m resolution for three cities on the south coast of Sri Lanka. The results give the tsunami arrival time contours and the spatial distribution of the extent of inundation, the maximum flow velocities as well as the hydrodynamic force in these three cities due to an event similar to the 2004 tsunami.


Author(s):  
Francis Kornegay

In a context of increasing South-South cooperation, the members of an important trilateral dialogue forum that represent the emergent powers – IBSA –, have been incorporated into another organization, BRICS. It resulted from an overlap of the Southern developing countries into the domain of the Euro-Asiatic great powers. Bearing in mind that both alliances are centered on the geostrategic space of the Indian Ocean and the South Atlantic, South Africa´s South Atlantic strategic potential in tandem with Brazil is of extreme importance. It is possible to differentiate two steams in the transatlantic ties: the Afro-Latin and the trans-Mediterranean.  It is also relevant to place the role of Angola in the African continent as a possible influence in South Atlantic´s dynamics, given due importance to the Lusophone ties which are represented by CPLP.


Author(s):  
Mehrdad Shokoohy

AbstractThe ex-Portuguese town of Diu on the island with the same name off the south coast of Saurashtra, Gujarat, is one of the best-preserved and yet least-studied Portuguese colonial towns. Diu was the last of the Portuguese strongholds in India, the control of which was finally achieved in 1539 after many years of futile struggle and frustrating negotiations with the sultanate of Gujarat. During the late sixteenth and seventeenth century Diu remained a main staging post for Portuguese trade in the Indian Ocean, but with the appearance of the Dutch, and later the French and British, on the scene the island gradually lost its strategic importance. The town was subjected to little renovation during the nineteenth century while in the twentieth century Diu was no more than an isolated Portuguese outpost with meagre trade until it was taken over by India in 1961. As a result, unlike the other former Portuguese colonies in India – Daman and Goa – Diu has preserved most of its original characteristics: a Portuguese colonial town plan, a sixteenth-century fort and a number of old churches, as well as many of the eighteenth and nineteenth-century houses.


2021 ◽  
Vol 13 (14) ◽  
pp. 2817
Author(s):  
Tengfei Xu ◽  
Zexun Wei ◽  
Shujiang Li ◽  
Raden Dwi Susanto ◽  
Nyoman Radiarta ◽  
...  

The southern coast of Java is known as one of the most productive fishing grounds for tuna, feeding by nutrient-rich water along the coast caused by the subsurface water upwelling. This primary productivity can be evidenced by the high sea surface chlorophyll-a concentration (SSC). Based on satellite remote sensing products, we investigate the multi-scale variability in SSC along the Sumatra-Java coast. The results show that seasonal variability of SSCs is primarily due to monsoon-driven upwelling and rainfall in the Indian Ocean and Indonesian seas sides of the Sumatra and Java Islands, respectively. Local Ekman pumping plays a secondary role, while rainfall input to the ocean has little effect. Coastally trapped Kelvin waves and mesoscale eddies are responsible for the intraseasonal SSC anomalies in regions along the south coast of Java and off the Sunda and Lombok Straits, respectively. The interannual variability in SSC is caused by the anomalous upwelling related to the Indian Ocean Dipole. There was a weak increasing trend of ~0.1–0.2 mg/m3 per decade, above the global averaged trend, which may be related to enhanced local Ekman pumping. These analyses provide an overall description of SSC variations based on satellite observations; however, further investigations based on in situ observations are needed to achieve better quantification.


2011 ◽  
Vol 11 (7) ◽  
pp. 1769-1781 ◽  
Author(s):  
H. Delatte ◽  
L. Bagny ◽  
C. Brengue ◽  
A. Bouetard ◽  
C. Paupy ◽  
...  

1922 ◽  
Vol 59 (5) ◽  
pp. 200-212
Author(s):  
Robert R. Walls

Portuguese Nyasaland is the name given to the most northern part of Portuguese East Africa, lying between Lake Nyasa and the Indian Ocean. It is separated from the Tanganyika territory in the north by the River Rovuma and from the Portuguese province of Mozambique in the south by the River Lurio. The territory measures about 400 miles from east to west and 200 miles from north to south and has an area of nearly 90,000 square miles. This territory is now perhaps the least known part of the once Dark Continent, but while the writer was actually engaged in the exploration of this country in 1920–1, the Naval Intelligence Division of the British Admiralty published two handbooks, the Manual of Portuguese East Africa and the Handbook of Portuguese Nyasaland, which with their extensive bibliographies contained practically everything that was known of that country up to that date (1920). These handbooks make it unnecessary in this paper to give detailed accounts of the work of previous explorers.


1876 ◽  
Vol 9 (1) ◽  
pp. 147-154
Author(s):  
A. H. Schindler

The part of Belúchistán now under Persian rule is bounded upon the north by Seistán, upon the east by Panjgúr and Kej, upon the south by the Indian Ocean, and upon the west by Núrámshír, Rúdbár, and the Báshákerd mountains.This country enjoys a variety of climates; almost unbearable heat exists on the Mekrán coast, we find a temperate climate on the hill slopes and on the slightly raised plains as at Duzek and Bampúr, and a cool climate in the mountainous districts Serhad and Bazmán. The heat at Jálq is said to be so intense in summer that the gazelles lie down exhausted in the plains, and let themselves be taken by the people without any trouble.


2012 ◽  
Vol 06 (02) ◽  
pp. 1250010 ◽  
Author(s):  
ANAWAT SUPPASRI ◽  
FUMIHIKO IMAMURA ◽  
SHUNICHI KOSHIMURA

In the Indian Ocean and the South China Sea, many hundreds of thousands of lives have been lost due to tsunami events, and almost half of the lives lost occurred following the 2004 Indian Ocean event. Potential tsunami case scenarios have been simulated in these regions by a number of researchers to calculate the hazard level. The hazard level is based on a variety of conditions, such as the tsunami height, the inundation area, and the arrival time. However, the current assessments of the hazard levels do not focus on the tsunami risk to a coastal population. This study proposes a new method to quantify the risk to the coastal population in the region that includes the Indian Ocean and the South China Sea. The method is simple and combines the use of readily available tsunami data, far-field tsunami simulation models to determine the regional risk and global population data. An earthquake-generated tsunami was simulated, following an earthquake that had a magnitude larger than 8.5 Mw and occurred along a potential subduction zone. The 2004 Indian Ocean event seemed to be a "worst case scenario"; however, it has been estimated that a potential tsunami, occurring in a coastal region with a high population density, could cause significantly greater casualties.


2021 ◽  
Vol 58 (2) ◽  
pp. 68-100
Author(s):  
Manbir Singh, Dr. Jasdeep Kaur Dhami

The Indian Ocean woven together by transmission of trade, commands the control of majority of the world’s cargo ships, one third of the worlds cargo traffic and two thirds of total world’s oil shipments. The main aim of this paper is to analyse Real GDP, Imports and Exports of Indian Ocean RIM Association Member Nations. Time period of the study is from 1980 to 2019.  Indian Ocean Rim Association for Regional Cooperation (IOR-ARC) contributes 11.7 per cent share in world exports, in case of member nations highest share is of Singapore 2.1 per cent  followed by India and UAE 1.7 per cent, Australia 1.5 per cent, Thailand and Malaysia 1.3 per cent. Indonesia, South Africa, Bangladesh, Oman, Iran, Islamic Republic of, Sri Lanka the share in world exports is less than 1 per cent.  


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