The Red Sea and the Gulf of Aden (RSGA) region is well-known globally for its distinctive marine and coastal biodiversity, significance to international maritime transportation, and unique economic, historical, and social significance. Rich biodiversity has been fostered by the RSGA ecosystems, which have a relatively high proportion of endemic species. There are a number of sites and species in this area which require global conservation merit.
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean that lies between Africa and Asia. It is a narrow body of water that stretches 1,200 miles (1,930 kilometres) southeast from the Suez Canal, Egypt, to the Bab el-Mandeb Strait, which links it to the Arabian Sea via the Gulf of Aden. From a geological perspective, the gulfs of Suez and Aqaba (Elat) must be considered as the northern extension of the same structure. To the west, the sea divides the coasts of Egypt, Sudan, and Eritrea and to the east, the coasts of Saudi Arabia and Yemen. It is connected to the south through the Gulf of Aden and the Bab el-Mandeb Strait. The Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez are located to its north. It is underneath the Red Sea Rift, which is part of the Great Rift Valley. The Red Sea has been one of the first large bodies of water mentioned in the recorded history. During 2000 BCE, it played a significant role in the Egyptian maritime commerce. By about 1000 BCE, it was being used as a water route to India for trading purposes.
The surface area of the Red Sea is approximately 1,69,000 square miles (4,38,000 square kilometres) with a length approximately of 1,400 miles (2,250 kilometres); a width of 221 miles (355 kilometres) at its widest point; and an average depth of 1,610 feet (490 metres). It reaches to a maximum depth of 9,970 feet (3,040 metres) in the central Suakin Trough. About 40 per cent of the Red Sea is shallow with less than 330 feet depth (less than 100 metres) and about 25 per cent is less than 164 feet (less than 50 metres) deep.
Some of the hottest and saltiest waters of the world could be found in the Red Sea. It is one of the most extensively used and busiest waterways in the world, carrying maritime traffic between Europe and Asia, due to its connection to the Mediterranean Sea through the Suez Canal. The Red Sea was named from the colour changes that were observed in its waters over the years. It is typically deep blue-green in colour; however, on rare occasions, the sea water turns reddish brown due to the extensive blooms of the algae, namely Trichodesmium erythraeum.
A huge part of the rift (a break in the Earth’s crust) valley in the continental crust of Arabia and Africa has been partially occupied by the Red Sea. This break in the crust is part of a complex rift system. The East African Rift System, which forms the great Wadi Aqaba-Dead Sea-Jordan Rift, extends southwards through Ethiopia, Kenya, and Tanzania for nearly 2,200 miles and northwards for more than 280 miles from the Gulf of Aqaba. It also extends eastwards for about 600 miles from the southern end of the Red Sea to form the Gulf of Aden.
The Red Sea valley also cuts through the Arabian-Nubian massif. The Red Sea is considered a relatively new sea and its trough has apparently formed in at least two complex phases of land motion. Africa started to move away from Arabia some 55 million years ago. About 30 million years ago, the Gulf of Suez and the northern portion of the Red Sea began to open up. The second phase, which formed the trough in the Gulf of Aqaba and the southern portion of the Red Sea valley, started around three to four million years ago. This motion is estimated as amounting to 0.59 to 0.62 inch (15.0 to 15.7 mm) per year, and has been proceeding further.
The Arabian-Nubian massif was a continuous central mass of Precambrian igneous and metamorphic rocks. The outcrops of it have formed the rugged mountains of the adjoining region.
The Red Sea receives scanty rainfall and no water enters the Red Sea from rivers; however, evaporation loss is made up by an inflow through the eastern channel of the Bab el-Mandeb Strait from the Gulf of Aden. The Red Sea region is home to five main categories of natural resources: (i) heavy metal deposits in the bottom oozes of the Atlantis II, Discovery, and other deeps; (ii) petroleum deposits; (iii) evaporite deposits; (iv) sulphur; and (v) phosphates. None of the heavy metal deposits has been exploited. The countries bordering the sea, however, have exploited the natural gas and oil reserves to differing degrees.
It is challenging to navigate in the Red Sea. There are a few natural harbours on the shorelines of northern half of the Red Sea. The coral reefs grown in the southern half have limited the navigable channel and blocked certain harbour facilities. However, in the 20th century, the Red Sea was the focus of extensive scientific investigation, especially after World War II. Researchers have been focused and a great deal of attention is being paid to comprehend the geologic structure of the Red Sea while examining its chemical and biological properties.
Gulf of Aden
The Gulf of Aden serves as a natural sea link connecting the Arabian Sea with the Red Sea. It is between the shores of Arabia and the Horn of Africa, and is named after the seaport of Aden, which is located in southern Yemen. It narrows into the Gulf of Tadjoura to the west, and the meridian of Cape Guardafui (51°16’ E) defines its eastern boundary. In terms of oceanography and geology, it covers an area of around 2,05,000 square miles (5,30,000 sq. km), extending to the eastern boundaries of the continental shelf beyond the island of Socotra to the south and the Kuria Muria Islands to the north. Its mean width, measured from north-northeast to south-southwest, is 300 miles (480 kilometres), while its total length is 920 miles (1,480 kilometres), measured from east-northeast to west-southwest.
The Gulf of Aden is a deepwater gulf of the Indian Ocean between Yemen in the north, Arabian Sea in the east, Djibouti in the west and Guardafui Channel Socotra and Somalia to the south. With 21,000 ships passing through the gulf each year, the waterway is a part of the vital Suez Canal maritime route which connects the Mediterranean and Arabian Seas in the Indian Ocean. The gulf is part of a complex water structure. Gulf waters, via the Bab el-Mandeb Strait, flows into the Red Sea. This compensates for the water loss due to evaporation in the Red Sea. The monsoon winds and eddies complicate the gulf’s flow pattern. The surface layer has high salinity.
The dominant relief feature of the gulf’s terrain is the Sheba Ridge, an extension of the Indian Ocean ridge system, which extends along the middle of the gulf. The spreading of the seafloor away from the Sheba Ridge axis is the main geologic formation factor of the gulf. The African continent and the Arabian Peninsula initially split along their present margins about 35 million years ago. They have since drifted apart in a direction parallel to the gulf’s faults. The Aden Ridge, which is an active oblique rift system located in the Gulf of Aden between Somalia and the Arabian Peninsula to the north, has been widening about 15 millimetres every year.
The marine life of the Gulf of Aden is rich. Seasonally variable upsurge of waters in the coastal zone provides the surface layer with a substantial supply of nutrients. This helps in the production of abundant plankton. In the areas of upheaval, sardines and mackerel are found in abundance. Dolphin, tuna, billfish, and sharks are some of the main open-sea fishes found in the region. Apart from this, the gulf provides a breeding ground for sea turtles and rock lobsters. Despite a lack of large-scale commercial fishing facilities, the coastline supports many isolated fishing towns and villages.
The Gulf of Aden plays a crucial role in the global economy as a shipping route, particularly for transporting oil from the Persian Gulf. The Gulf of Aden is crossed by about 11 per cent of the world’s seaborne petroleum as it passes to local refineries or the Suez Canal. The main ports along the gulf are Aden, Balhaf, Bir Ali, Al Mukalla, and Shokra in Yemen; Djibouti city in Djibouti; and Zeila, Berbera, and Bosaso in Somalia.
The Gulf of Aden is one of the world’s busiest shipping routes. Despite that since the late 2000s, the gulf evolved into a hub of pirate activity. By 2013, attacks in the waters had steadily declined due to active private security and international navy patrols. The Federal Government of Somalia (FGS) is, however, concerned over the lack of capacity to manage Somali maritime space effectively, whose vulnerability has been highlighted by piracy. Though not fully suppressed by the navy patrolling, piracy is still seen as a dormant threat in the region and a part of it is attributed to the problems with unregulated fishing by foreign vessels in the Somalian waters. India receives imports of around US$ 50 billion and sends exports of around US$ 60 billion through this region, annually. Due to this, and for the sake of protecting the trade of other countries, India keeps a warship escort in this area.
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