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Status Of the Marine Environment Report (SOMER) - Sultanate of Oman Country Report to UNEP Regional Seas Programme / ROPME Sea Area (RSA)

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"MRMEWR (2003) Status Of the Marine Environment Report (SOMER) - Sultanate of Oman Country Report to UNEP Regional Seas Programme / ROPME Sea Area (RSA). Ministry of Regional Municipalities, Environment and Water Resources (MRMEWR), Muscat. 106 pp Working Group: Mendonca V, Jupp B, Al-Jabri M, Al Muzaini M, Al-Sariri T
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National Report
on the State of the Marine Environment
(SOMER 2003)
Ministry of Regional Municipalities, Environment & Water Resources
Sultanate of Oman
MRMEWR (Ministry of Regional Municipalities, Environment & Water
Resources) - Oman. 2003. National Report On the State of the Marine
Environment. Marine Pollution and Coastal Zone Management Section/
Ministry of Regional Municipalities, Environment & Water Resources.
Muscat, Sultanate of Oman. 96 pp.
Ministry of Regional Municipalities, Environment & Water Resources
Sultanate of Oman
http://www.mrmewr.omantel.net.om
For further information please contact:
Directorate General of Environmental Affairs
Environmental Inspection & Control Department
Marine Pollution & Coastal Zone Management Section
Tel. (++968) 692411
Fax (++968) 692462
Email: maljabri@hotmail.com
This report was prepared by:
Vanda Mendonca
Barry Jupp
Musallam Al Jabri
Thuraya Al Sariri
Mohamed Al Muzaini
Tomo Shoji
And approved by:
Mohamed Al Areimi
Mohamed Al Muharrami
Ibrahim Al Ajmi
Ministry of Regional Municipalities,
Environment & Water Resources
Sultanate of Oman
State of the Marine Environment
Country Report for ROPME
March 2003
Ministry of Regional Municipalities,
Environment & Water Resources
Sultanate of Oman
National Report
On the State of the Marine Environment
March 2003
MRMEWR (Ministry of Regional Municipalities, Environment & Water
Resources) - Oman. 2003. National Report On the State of the Marine
Environment. Marine Pollution and Coastal Zone Management Section/
Ministry of Regional Municipalities, Environment & Water Resources.
Muscat, Sultanate of Oman. 96 pp.
Ministry of Regional Municipalities, Environment & Water Resources
Sultanate of Oman
http://www.mrmewr.omantel.net.om
For further information please contact:
Directorate General of Environmental Affairs
Environmental Inspection & Control Department
Marine Pollution & Coastal Zone Management Section
Tel. (++968) 692411
Fax (++968) 692462
CONTENTS
I.INTRODUCTION ………………………………………………………… 1
II. GENERAL INFORMATION ……………………………………………. 2
A. Description of physical-geographical features of the coastal area, and the
marine environment ………………………………………….. 2
B. Socio-economic structure of the Sultanate of Oman ……………. 7
C. Meteorological and oceanographic characteristics of the marine
environment ………………………………………………………. 10
III. HISTORICAL CONTEXT ……………………………………………… 15
IV. RESOURCE EXPLOITATION …………………………………………. 17
A. Exploitation of living marine resources ………………………….. 17
1. Fisheries …………………………………………………… 17
2. Aquaculture ………………………………………………… 20
B. Exploitation of non-living resources ………………………………. 21
1. Mineral and fossil fuels …………………………………….. 21
2. Water resources …………………………………………….. 23
3. Touristic resources …………………………………………. 23
V. OCEANOGRAPHIC CHARACTERISTICS …………………………… 24
A. Meteorological conditions and physical oceanographic
characteristics …………………………………………………. 24
1. Winds, storms, etc. …………………………………………. 24
2. Bathymetry, currents, waves, upwelling, temperature, salinity,
oxygen, etc. ………………………………………………… 25
B. Geological oceanography and sedimentary characteristics ………. 27
C. Chemical oceanography ………………………………………….. 28
D. Biological oceanographic characteristics …………………………. 29
1. Major habitats ………………………………………………. 29
1.1. Wadis ...……………………………….…………….. 29
1.2. Khawrs, tidal inlets, and sabkhas …………….…..…. 29
1.2.1. Khawrs …………………………………… 29
1.2.2. Tidal inlets ……………...…………………. 29
1.2.3. Sabkhas ……...…………………………….. 30
1.3. Rocky, sandy, and muddy tidal flats ……...………… 30
1.4. Coral reefs …………………………………………… 31
1.5. Mangroves …………………………………………... 31
1.6. Seagrass beds and seaweed beds ……………………. 31
1.7. Marshes and halophytes …………...………………… 32
2. Major biodiversity ………………………………………….. 32
2.1. Intertidal organisms ………………………………….. 32
2.1.1. Flora ………………………………………….. 32
2.1.2. Fauna ………….………………………………. 33
2.2. Subtidal organisms ……………………………………. 34
2.2.1. Phytoplankton ………………………………… 34
2.2.2. Zooplankton …………………………………... 34
2.2.3. Pelagic and benthic organisms ……………….. 35
Fish ……………………………………….. 35
Sea snakes …………………………………. 35
Corals ……………………………………… 36
2.3. Seabirds ……………………………………………….. 40
2.4. Protected/endangered organisms …………………….. 42
2.4.1. Marine turtles …………………………………. 42
2.4.2. Cetaceans …………………………………….. 43
Humpback whale
(Megaptera novaeangliae) ………….
46
Indo-Pacific dolphin (Sousa chinensis) …… 46
Conclusion ………………………………… 47
VI. ANTHROPOGENIC ACTIVITIES ……………………………………... 48
A. Land-based activities ……………………………………………… 48
B. Sea-based activities ……………………………………………….. 51
VII. MAJOR ACIDENTS AND OTHER EPISODIC EVENTS ……………. 53
A. Oil spills and leaks, tanker accidents, war and war remnants …….. 53
B. Unusual population growth phenomena …………………………... 53
1. Euthrophication …………………………………………….. 53
2. Red tides and harmful algal blooms (HABs) ……………….. 54
C. Massive mortalities of marine organisms …………………………. 55
1. Harmful algal blooms (HABs) ……………………………... 55
2. Upwelled hypoxic waters ………………………………….. 55
3. Other natural impacts ………………………………………. 57
4. Human impacts …………………………………………….. 58
VIII. MARINE CONTAMINATS AND THEIR EFFECTS …………………59
A. Types, concentrations and distribution of contaminants in waters, biota and
sediments (and the Marine Pollution Monitoring Programme)
……………………………………………………….. 60
1. Oil pollution on beaches ……………………………………. 61
2. Heavy metals in intertidal sediments and biota …………….. 62
3. Seawater quality ……………………………………………..64
B. Natural seepage ……………………………………………………. 65
IX. PREVENTION AND CONTROL MEASURES ………………………... 66
A. Policies …………………………………………………………….. 66
B. International arrangements and legislation ………………………... 67
1. Environmental strategies and administration ………………. 67
2. Environmental legislation ………………………………….. 68
C. Remedial actions ………………………………………………….. 74
1. Monitoring and assessment of habiata condition …………... 74
Marine Pollution Monitoring Programme ………………….. 75
Air and Noise Monitoring Programme ………………….….. 75
Water Pollution Monitoring Programme …………………… 76
Chemical Substances Monitoring Programme ……………... 76
2. Remediation …………………………………………………76
Artificial Reefs ……………………………………………... 76
Beach and Reef Cleanup Project …………………………… 78
Mangrove Restoration Projects …………………………….. 78
Sea Turtle Monitoring Programme ………………………… 80
X. THE NATIONAL (REGIONAL) OVERALL ASSESSMENT OF
THE STATE OF THE MARINE ENVIRONMENT
…………………………. 81
A. The present condition of the marine environment ………………… 81
B. Trends in the state of the marine environment ……………………. 81
C. New challenges ……………………………………………………. 81
REFERENCES ……………………………………………………………… 84
ACKNOWLEDGEMENTS
The Marine Pollution & Coastal Zone Management Section of Environmental
Inspection & Control Department, Directorate General Environmental Affairs,
Ministry of Regional Municipalities, Environment & Water Resources, in
charge for preparing this report, wishes to thank all governmental authorities,
private companies, and non-governmental organizations, which have
collaborated by providing information, especially:
- Noise & Air Pollution Section, Environmental Inspection & Control
Department, Directorate General of Environmental Affairs, Ministry of
Regional Municipalities, Environment & Water Resources;
- Waste Management & Water Pollution Section, Environmental
Inspection & Control Department, Directorate General of Environmental
Affairs, Ministry of Regional Municipalities, Environment & Water
Resources;
- Chemical Substances Department, Directorate General of
Environmental Affairs, Ministry of Regional Municipalities,
Environment & Water Resources;
- Pollution Control & Combat Department, Directorate General of
Environmental Affairs, Ministry of Regional Municipalities,
Environment & Water Resources;
- Environmental Planning & Permits Department, Directorate General of
Environmental Affairs, Ministry of Regional Municipalities,
Environment & Water Resources;
- Department of Biodiversity, Directorate General of Nature
Conservation, Ministry of Regional Municipalities, Environment &
Water Resources;
- Department of Wildlife Protection, Directorate General of Nature
- Conservation, Ministry of Regional Municipalities, Environment &
Water Resources;
- Department of Conservation Planning, Directorate General of Nature
Conservation, Ministry of Regional Municipalities, Environment &
Water Resources;
- Directorate General of Water Resources, Ministry of Regional
Municipalities, Environment & Water Resources;
- Food & Environmental Monitoring Centre, Ministry of Regional
Municipalities, Environment & Water Resources;
- Ministry of Transport & Communications;
- Directorate General of Fisheries Wealth, Ministry of Agriculture &
Fisheries;
- Marine Science & Fisheries Centre, Ministry of Agriculture & Fisheries;
- Ministry of National Economy;
- Oman LNG;
- Petroleum Development Oman, PDO;
- Oman Bird Records Committee; and
- Oman Whales & Dolphins Research Group.
I. INTRODUCTION
The Sultanate of Oman occupies the north-east to south-east corner of the Arabian
Peninsula, between latitudes 16º 40' and 26º 20' North and longitudes 51º 50' and 59°
40' East. Coastlines border the Gulf and the Gulf of Oman in the North and the
Arabian Sea in central and southern regions, whilst the land borders the United Arab
Emirates, Saudi Arabia and Yemen in the north-west, central and southern regions,
respectively (Figure 1.1). Its coastline extends over 3,000 km, from the Strait of
Hormuz to the border with Yemen, including the main islands, which are Masirah
Island in central Oman coast (Sharquiyah Region), and the archipelagos of the
Damaniyats and of the Al Hallaniyats, respectively in the Gulf of Oman in the north
(Al Batinah Region), and in Al Hallaniyah Bay in the south (Dhofar Region).
The extensive coastline of the Sultanate of Oman has shaped the culture, economy
and history of the country and its people. Even today, when geological resources,
mostly oil and natural gas, are the main factors for the regional economies in the Gulf
region, marine resources are still very important.
This report provides an updated review of the state of the marine environment in the
Sultanate of Oman, and includes information made available mostly after 1999, as the
situation before that has been described in the previous report on the state of the
marine environment (MNR-Oman, 1999). Where it is felt useful, earlier literature has
been quoted to give background information.
Figure 1.1. The position of the Sultanate of Oman
in the Arabian Peninsula, and the Administrative
Regions of the Sultanate of Oman.
II. GENERAL INFORMATION
A. Description of physical-geographical features of the coastal area,
and the marine environment
The geomorphology of the Sultanate of Oman shows exceptional variety. High
mountains are mainly concentrated both in the north (Musandam Mountains, Northern
Mountains) and south of the country (Dhofar Highlands), separated by the Central
Plateau (sand and gravel plains), whilst sand deserts and salt lakes are located in the
interior, with exception of the Ramlat Al Wahibah (Figures 2.1, 2.2). The Northern
Mountains are separated from the Central Plateau by the Northern Foothills and Plains
Area (Alluvial Plains). Both the Batinah coast in the north and the Dhofar coast in the
south are Coastal Plains. In the eastern central Oman, areas surrounding the Masirah
channel and including many several small islands and Masirah Island are mainly low
rock outcrops and the Huqf Area, an escarpment which contains geological features of
both national and international importance. The Damaniyat Archipelago is a group of
nine uninhabited main islands named D1 to D9, from east to west, parallel to the
Batinah Coast, less than 100 km north of Muscat, in the Gulf of Oman. The islands
are characterized by limestone rocks and ancient corals, and surrounded by rocky
outcrops and coral reefs (Figures 2.3, 2.4). Both Masirah Island and the Al Hallaniyat
Islands, in the Arabian Sea, have high mountain areas (Figures 2.5 to 2.8).
Figure 2.1. Satellite image of the
Sultanate of Oman (MRMEWR-
Oman, 2002a).
Figure 2.2. Topography of the Sultanate
of Oman (MWR-Oman, 1991).
Figure 2.3. Map of the Damaniyat
Islands (D1 to D9, from east to
west), Gulf of Oman.
Figure 2.4. D4 Island, Damaniyat
Archipelago, Gulf of Oman, during the
seabirds nesting season.
The ancient Oman landscape shows the crustal movements, erosion and deposition,
which occurred here over many millennia. Today, the Sultanate of Oman is mostly
desert area, with no rivers although it has some wadis, but the climate has varied
dramatically over its geological history. Ancient glacial deposits have been
discovered in the interior showing that at least twice, the Arabian continent was at
latitudes closer to the South Pole. In opposition to that, at the summit of Jebel Shams
(Oman’s highest mountain), there are marine fossils, which once lived in a shallow
tropical ocean (Figure 2.9). Coal also occurs, suggesting the presence of ancient
forests. Finally, fossil fuels (oil and natural gas) also occur in the country as result of
ancient proliferous life environments.
According to a review by Hanna (1995), the geology of Oman has been controlled by
the geology of the large ocean Tethys, which opened up and lasted for about 190
Million years, a remnant of which comprises the Gulf of Oman. Oman was also a part
of the Gondwanaland, which was made up of continental crustal rocks over 700
Million Years old. The Sultanate of Oman was also close to the South Pole and
covered by ice. When Oman drifted to north, the melting ice formed sediments which
were deposited underwater. These are found in Wadi Bani Kharus, Wadi Mistal and
in all the Jebel Akhdar Windows (a window is basically a large hole through which it
can be seen the underlying rock strata. Then the sea encroached over the land, and
black limestones were deposited above the glacial sediments. Following the melting
of the ice, the sea level rose and the climate changed to a warmer environment as
Oman moved northwards from the South Pole. Stromatolites (ancient algae) formed
many of the rocks above the glacial sediments, and are seen also in the Jebel Akhdar
Windows. About 300 Million Years ago, Oman was again close to the South Pole,
and experienced another Ice Age, which resulted in the Al Khalata glacial sediments
in Huqf (in the Carboniferous-Permian Age).
Figure 2.5. Map of Masirah Island,
Arabian Sea
Figure 2.6. Jebel Suwayr, south
Masirah Island.
Figure 2.7. Map of the Al Hallaniyat
Islands (from east to west: Al Qibliyat,
Al Hallaniyat, As Sawda, and Al
Hasikiyat), Arabian Sea
Figure 2.8. Mountains on Al
Hallaniyat Island.
Gondwanaland then began to fragment into separated continents as it moved
southwards during the Permian and Mezsozoic. The Afro-Arabian plate moved
southwards from Eurasia and the Tethys Ocean began to open as a consequence, and
intervening ocean crust (ophiolite) was formed. Sediments were deposited on the
ocean floor and above submarine volcanoes, limestones (Oman exotics) were
deposited. By then, the continental shelf of Arabia was covered by the shallow Tethys
Ocean, and limestones were deposited in a reducing environment, responsible for
changing in the limestone to grey colour (Hajar Super Group, found on Jebel Shams
and along wadis crossing Jebel Akhdar, Saih Hatat and Jebel Nakhl Wadi Bani
Kharus, Wadi Sahtan and Wadi Bani Awf), and containing many marine fossils. As
the American plate moved away from Africa, the Atlantic Ocean began to open,
making Africa to move northwards, and resulting in the closure of the Tethys Ocean,
pushing marine sediments (Hawasina) and ophiolite landwards, until it was emplaced
above the shallow marine limestone of the Hajar Super Group. After the
emplacement, the rock complex was exposed above sea level. Dinosaur remains,
turtle bones and fossil wood found in these conglomerates, indicating a dominant
tropical environment similar to that of East Africa. Then, between 65 2 Million
Years ago, Oman was once again drowned by a warm and shallow sea, visible in the
yellow Tertiary limestones, also rich in fossils (mainly molluscs, corals and
echinoderms). This period was also characterized by a drop in sea level, resulting in
the deposition of coal (in Jebel Jaalan, Al Khoud and Muscat area). The mountains
were formed as a result of major earth movements between the Oligocene and the
Miocene, although they were initiated during the uplifting of the ophiolite and deep
ocean sediments.
According to Le Metour et al. (1995), the configuration of the present-day Oman
coastline along the Gulf of Oman and the Arabian Sea reflects fluctuations of both
Figure 2.9. Geology of the Sultanate of Oman
(MWR, 1991)
climate and sea level during the Quaternary (i.e. the last 1.8 Million Years). Although
Oman and the Middle East as a whole were not influenced directly by the great
Quaternary glaciations, effects of related major falls in sea level are observed. Thus,
15,000 Years ago, at the end of the most recent glaciation, the mean global sea level
was 100 m lower than that of the present-day. The coastline was then several tens of
kilometers off the current coastline. A significant part of the present-day shallow and
fairly flat continental shelf was at this time dry land, and Aeolian sand dunes
developed as a southward extension of the Wahibah Sands, and river channels which
can still be discerned. In contrast, during the Tertiary (about 5-2 Million Years), the
sea level was higher than at present. Marine coastal erosion cut into the Eocene
limestone forming flat terraces and coastal cliffs along the eastern slopes of the Oman
Mountains bordering the Gulf of Oman. Such features are clearly visible between
Quriyat and Ras Al Hadd, inland from the present-day coastline where five main
stepped levels exist, with increasing altitudes of 15m, 50m, 110m, 150m and 190m,
respectively, representing the successive coastline positions from the end-Tertiary
(Pliocene) to the recent Quaternary. However, the uplifting and creation of the Oman
Mountains began in the Miocene (about 16 Million Years ago).
The continental shelf of Oman is narrow along the Gulf of Oman and the Arabian Sea,
bounded by a relatively steep continental slope which descend towards the abyssal
plain at a depth of 3,000 m or more. Sediments from the Gulf of Oman are usually
unstable and subject to gigantic submarine slides. The deep ocean floor is made up of
abyssal plains (Figure 2.10). Several well-defined oceanic domains border the north,
the southeast and the south of Oman. To the north is the Oman Basin and the Gulf of
Oman, bounded to the north by the gentle continental slope of Makran. To the
southeast is the Owen Basin of the Arabian Sea, bounded to the east by the submarine
mountains of the Owen Fracture Zone. To the south, is the northeast part of the Gulf
of Aden, bounded by another submarine mountain chain, the East Sheba Ridge, a
relatively young segment of mid-oceanic ridge.
Figure 2.10. The North Indian Ocean, and its
major Dorsals, Basins and Fractures.
Oman
Tropic of Cancer
ARABIAN SEA
Arabian Basin
INDIAN OCEAN
Owen Fracture
Carlsberg Dorsal
Maldives Dorsal
Somalia Basin
Along the Oman coastline, the 200 m bathymetric varies significantly from one area
to another, and it is best developed along the southeast coast between Ras Al Hadd
and Hasik, where it reaches a width of 100 km (Figure 2.11). The islands of Masirah
and of the Al Hallaniyat Archipelago protrude from this shelf. Between Ras Al Hadd
and Ras Sawqirah, the shelf edge line is almost linear, oriented NNE-SSW. Further
south, the shelf runs E-W towards Hasik in Dhofar, incorporating the Al Hallaniyat
Islands. Along the coastline of the Sultanate of Oman, supratidal environments
(between the levels of mean high tide mark and the mark of the highest spring tide)
includes coastal sabkhas (Figure 2.12).
Figure 2.11. 200m bathymetric in the NW Indian
Ocean (adapted from Schott, 1993).
Supratidal Intertidal Subtidal
Bathyal
Figure 2.12. Schematic representation of marine depositional
environments (adapted from Le Metour et al, 1995).
Abyssal
B. Socio-economic structure of the Sultanate of Oman
According to mid 2000 estimates, the population of the Sultanate of Oman comprised
about 1.8 millions individuals Omanis and 0.6 millions expatriates giving a total of
2.4 million, most of which live in urban areas (Figure 2.13).
The population density of the Sultanate of Oman is 6.5 ind./km2 (spread on 309,500
km2 of area), and most are of Islamic religion, with some expatriates being either
Hindus or Christians. The official language is Arabic, although English is widely
spoken.
In 1999, life expectancy was 72.5 years, birth rate increase was 2.8%, and 616,829
boys and girls (aged 6-18 years) were receiving education at various schools in the
Sultanate of Oman.
Spending on medical care in 1998 was about 3.5% of the GDP, health expenses per
capita was US$150, and the Ministry of Health accounted for 6.2% of the total
government spending. Social security is also in place to combat poverty (Table 2.1).
0.652
1.826
(growth rate
= 2.4%/year)
33%
66.2%
28.3%
71.7%
Figure 2.13. Socio-economic indicators (ME-Oman, 2002)
(millions
individuals)
Table 2.1. Health indicators in the Sultanate of Oman in 1998 and 1999
(MRMEWR-Oman, 2002b).
Although fisheries, agriculture and livestock have been traditionally important for the
economy of the Sultanate of Oman, currently the economy relies mostly on mineral
wealth, especially oil (with production of about 956,000 barrels/day), and natural gas,
although agriculture and fisheries continue to contribute to the Gross Domestic
Product (GDP), which is about 6 million Omani Rials (Table 2.2). Other less
represented industries (Table 2.3) also play an important role, especially by providing
source of income for many employees.
Table 2.2. Domestic and National Saving in Millions Omani Rials (ME-Oman, 2002).
Items
1999
2000
2001
GDP at Market Prices
6,040.6
7,639.2
7,668.4
Final Consumption Expenditure
4,440.5
4,580.5
4,996.2
Gross National Income
5,763.6
7,351.2
7,427.4
Indicators
1999
2000
Hospitals
54
54
Hospital
beds
5,049
5,049
Health
centers
117
116
Doctors
3,061
3,143
Dentists
201
237
Pharmacists
435
395
Nursing staff
7,453
7,525
Birth rate
per 1,000
29
30
Death rate
per 1,000
3.7
3.6
Infant
mortality per
1,000
18
17.6
Life
expectancy
at birth
72.2
72.5
Life
expectancy
for Males
71.8
72.3
Life
expectancy
for Females
74.2
74.3
Table 2.3. Industrial projects in the Sultanate of Oman from 1990 to 2000
(MRMEWR-Oman, 2002b).
International
Classification
Industrial Activity
Number of
registered
establishments
Total
investment
(thousand
Rials
Omani)
31
Foodstuff, beverages, tobacco
224
93,672,4
32
Yarning, weaving, cloth and
leather
41
18,573,9
33
Wood and wood products
including furniture
140
4,589,6
34
Paper and paper products,
Printing and Publication
29
13,556
35
Chemicals, chemical products, oil
products, plastic and glass
72
77,669,3
36
Mining of non-mineral raw
material products
308
86,494,4
37
Basic mineral industries
14
5,540,8
38
Mineral products
274
43,317,7
39
Other industries
18
6,257,2
Confirmed oil reserves are estimated at 5.8 billion barrels, confirmed natural gas
reserves are estimated at 24.4 trillion cubic feet, and copper reserves are estimated at
about 15 million tons (MRMEWR-Oman, 2002b).
Cultivated land is estimated at 70,000 ha distributed as follows: Batinah Region and
the capital area (50.6%), Interior Oman (12.6 %), Sharquiyah Region and Jaalan
(10.4%), Dhahirah Region (8%), Southern Region (5.9%), the remaining areas
(12.5%). In view of the importance of the agricultural sector in providing food, the
government provides support for this sector in all development plans, and efforts are
also made to restrict food imports, as far as possible through the following steps:
improvement of productivity per acre, increase in cultivated area and number of
livestock, improvement of marketing of agricultural produce, achievement of some
sort of integration between agricultural areas, enhancement of research and
agricultural extension, provision of production inputs, pest control, and provision of
subsidy to farmers. Agro-industries are considered important factors in agricultural
development because they help to maintain agricultural produce, and this in turn,
increases return for farmers and consumers in particular and the national economy in
general.
Regarding livestock, the Sultanate of Oman has about 299,000 heads of cattle,
979,000 heads of goat, 344,000 heads of sheep and 119,000 heads of camel.
Fish stocks in the Sultanate of Oman are estimated at 4.7 million tons. The Sultanate
of Oman has a unique geographical composition that consists of a 3,165 km long
coast bordering the Arabian Gulf, the Gulf of Oman and the Arabian Sea. This marine
convergence makes fishing the main traditional activity since the dawn of Omani
history.
C. Meteorological and oceanographic characteristics of the marine
environment
The climate of the Sultanate of Oman varies greatly as it includes areas in the Strait of
Hormuz (Musandam Peninsula), Gulf of Oman and the Arabian Sea. However, two
distinct seasons occur: winter, from November to April, and summer, from May to
October. In summer, the Inter-Tropical Convergence Zone usually moves towards the
Arabian Peninsula, so that the Southwest Monsoon (locally known as khareef)
primarily affects the extreme south and southeast of Oman.
Mean annual temperatures are typically between 26 ºC and 29 ºC throughout the
lowland area of the Sultanate. The capital Muscat, has a mean annual temperature of
about 30 ºC, and daily maximums above 40 ºC during three or more months in
summer (Figure 2.14). In lowland areas, mean monthly temperatures generally range
between about 20 ºC and 36 ºC, and diurnal temperatures range tend to be 6-8 ºC
greater in the central desert areas.
Although most precipitation in the Sultanate of Oman falls as rain, isolated hailstorms
sometimes occur, and in the highest mountains such as Jebel Shams and highlands of
Jebel Akhdar, snow sometimes occurs above 3,000 m during winter months (MWR-
Oman, 1991).
Daily sunshine is about 10 hours, with the exceptions of mountainous areas and the
khareef-affected south, which experiences very little sunshine between mid-June to
mid-September.
Figure 2.14. Typical climate of the
Sultanate of Oman (MWR-Oman, 1991).
Wind velocities tend to be moderate throughout the country, typically averaging
between 2 and 3 m/s (at 2 m above ground level) for lowland areas. These wind
velocities do not vary greatly during the year, except as a result of occasional
cyclones, mostly originated in the Indian Ocean entering the Arabian Sea quite
regularly (Figure 2.15). Tropical cyclones occur most frequently from May to
November, and up to an average of 13 cyclones/month were registered for June, over
a period of 20 years. Few of these cyclones cross the coast of the Arabian Peninsula,
and not all of those cross the Oman coastline.
Rainfall varies from <50 mm in central Oman to >300 mm in the Northern
Mountains, and total rainfall varies widely from year to year. Nevertheless, the
Sultanate of Oman is generally arid to extremely arid in some regions. In winter, the
weather in the Arabian Peninsula is influenced by extra-tropical circulation systems,
which bring rainfall to eastern parts of Oman, especially Jebel Akhdar mountains.
During summer, tropical systems originating over the Arabian Sea yield significant
khareef rainfall in some areas, especially the extreme south of Dhofar. According to
MWR-Oman (1991), four principal mechanisms are responsible for most of the
rainfall in the Sultanate of Oman:
1. Cold frontal troughs, associated with eastward-moving extra
tropical depressions, many of which are originated over the North
Atlantic Ocean or Mediterranean Sea. These troughs are most
common in the Oman region during winter and early spring.
Typically, they bring extensive middle-level cloud ahead of the
troughs and may bring quite steady rain to the northern parts of the
country. They may even cause areas of patchy rain in central and
southern Oman where cooler air behind the troughs undercuts
warmer air advected northeastwards from eastern Africa. Rain-
producing disturbances may sometimes form in this region of
convergence (the Oman Convergence Zone), and move
northeastwards towards southern Iran.
Figure 2.15. Tracks followed by cyclones
across the Arabian Sea (MRW-Oman, 1991).
On the other hand, advection of a deep layer of cold air southeastwards
from central Asia to Oman across the Arabian Gulf can cause particularly
heavy rain. The layer evaporates considerable moisture and becomes very
unstable. Such conditions appear to occur about three times on average
each year. Frontal systems are absent during summer because the upper
troposphere circumpolar westerly flow, with its embedded subtropical jet
stream, has by then been replaced by tropical easterlies on the southern
flank on the south Asian Monsoon anticyclone or ridge.
2. Tropical cyclones, moving in from the Arabian Sea, which are
originated over the Arabian Sea or more rarely India or even the
Bay of Bengal. Tropical cyclones are relatively rare visitors to
Oman, but can bring heavy rainfall to the southern and eastern
coasts. Tropical cyclones have been observed in all of the months
from May to December, occurring on average about once every
five years in Dhofar, but only once in ten years in Muscat.
3. On-shore southwesterly monsoon winds, which occur during June
to September, linked to the surface flow over the Arabian Sea. This
flow is dominated by the strong circulation which feeds the south
Asian Monsoon circulation. A small off-shoot of this flow mixes
with another air stream originating over the Gulf of Aden and
brings extensive stratiform clouds and frequent drizzle to the
Dhofar coast (and known as khareef). Only a very narrow strip of
coast between Masirah Island and Aden is usually affected by this
on-shore monsoon flow.
4. Occasional penetrations of the shallow monsoon winds further
inland towards the United Arab Emirates can also trigger scattered
convective showers, particularly over the mountains in the East. As
a result, in the Salalah area, particularly on the Jebel Dhofar, the
summer is characterized by high humidity, low potential
evaporation and semi-persistent fog during June and July, which is
intercepted by vegetation and other surfaces. The average rainfall
on Jebel Qara is as high as 500 mm a year on the summit and 100
mm nearer the coast. The Najd region, on the lee side of Jebel Al
Qara from the prevailing monsoon direction, receives only 50 mm
on an average annual basis.
5. Finally, convective rain storms, associated with localized cells of
strong convection, can develop at any time of the year.
Development of these cells, which are up to 100 km, is favoured by
advection of cooler, moist air at middle levels within cold pools,
especially those moving within the circumpolar westerlies. Such
circumstances are most frequent in spring and autumn.
Alternatively, the movement of a cold front into a convectively
unstable area may have similar effects. Sea breezes can also trigger
isolated convective storms. Strong convection is particularly
favoured when these circulations interact with mountainous areas.
Average annual rainfall is 100 mm with 80% (7,585 km2) of it evaporating and 5%
(474 km2) lost to the sea, leaving 15% (1,422 m2) for aquifer recharge. Water
resources consist of surface water (rain/aflaj/springs) which account for 35% of total
water consumption, and 65% is ground water. Although small quantities of surface
water run through the high wadis of the northern mountain area, most of it mainly
runs during rain storms, reaching the sea or any interior lowland area, for which dams
have been built to keep this water for groundwater recharge. Mountains witness the
highest rate of rainfall, which recharges groundwater in Al Batinah, Musandam and
the foots of the interior mountains. Rain that falls away from the interior mountains is
considered an important source of on-the-spot recharge in areas of interior Oman.
Seasonal rain that falls on the southern mountains is an annual resource for
groundwater recharge in the Salalah Plain and in the Najd, but storm events over the
Najd are the source of recharge of shallow groundwaters.
In the central desert areas, average annual relative humidity is only about 40%,
however in the north it tends to be about 60%, and does not vary greatly throughout
the year. The south is the most humid region of the country with an average of about
70% humidity and particularly high levels have been registered in areas of southern
Oman affected by the khareef (Southwest Monsoon).
Annual evapotranspiration varies between regions, being on average 3,000 mm/year
in the interior, 2,100 mm/year on the Batinah coast, and on the Salalah Plain, which is
affected by the Southwest Monsoon in summer, it is about 1,700 mm/year. High
summer temperatures and low humidity in coastal regions, such as the Batinah and
Salalah Plains reduces mean evapotranspiration to less than 10 mm/day.
The Southwest Monsoon or khareef
The south-east coasts of Oman facing the Arabian Sea are subject in summer to the
Southwest Monsoon (SWM) driven by heating of the Tibetan Plateau which creates
low pressure zones in Asia relative to the Indian Ocean. Pressure differences set up
strong (>10 m/s) low level winds which blow from June to September (maximum
development in July-August) parallel to the Arabian Sea coast developing, with
Ekman transport, one of the most intense coastal upwelling regions in the world .
The sea-surface temperature drops and the air mass moving over it cools below its
dew point, forming bands of fog and low cloud which move inland. Moisture-laden
air is driven up the slopes of Jebel Qara (mean altitude: 850 m) to condense as mist
precipitation both on the ground and on vegetation. This adds to, and may exceed,
precipitation from cyclonic storms so that mean annual rainfall for Qairoon Hariti
(altitude: 878 m) is 247 mm (Fisher, 1994) but total precipitation in the Dhofar
Mountains may exceed 500 mm/yr. In contrast, Salalah (altitude: 20 m) on the coastal
plain receives 110 mm of rainfall annually (Fisher, 1994).
The south-facing jebel-front tends to reflect the north-ward-moving monsoon winds
upwards and through the gaps in the jebel, giving rise to both orographic rainfall,
often as drizzle, and occult (condensation) precipitation as fog. According to MWR-
Oman (1991), records from Salalah and Qairoon Hariti show that the SWM rainfall
represents 60% of the total amount for Salalah and 75% at Qairoon Hariti. During the
SWM, on average 4 rain days/month are observed in June and September in both
areas, but in July and August, Salalah has 20 rain days/month and Qairoon Hariti has
23 rain days/month. Regarding precipitation, Salalah has on average 4-8 mm/month
and Qairoon Hariti has 60-80 mm/month, reflecting the importance of the SWM to
recharge the mountain limestone aquifers, which supply both the coastal plain and the
interior groundwater, and generates abundant vegetation, which supports a dense
grazing stock, especially between July and October. This precipitation on the
escarpment runs off as the seasonal springs and also percolates into groundwaters
which feed, via underground channels, the headwaters of the coastal lagoons (khawrs)
which are of high conservation value. Large numbers of tourists are attracted to the
Dhofar region during the khareef, which occurs at the same time as the hottest season
elsewhere in the Arabian Peninsula.
III. HISTORICAL CONTEXT
Oman’s periods of prosperity have stemmed from its geographical position,
seamanship and trading acumen. The history of Oman as a seafaring nation dates back
at least to the 3rd Millennium BC when copper smelting in Magan lead to active
trading with Dilmun and Mesopotamia. A second phase of sea trade occurred in the
1st Millennium B with the trade in spices (frankincense, myrrh, balsam) with the
Mediterranean and Africa, especially from the port of Samhhuram near Salalah.
Frankincense became crucial to the religious rites of almost every people in the
known world, including the temples of Egypt, Jerusalem and Rome, and made the
South Arabians the wealthiest people on earth, well into the 6th Century.
Qalhat on the north coast near Sur was the 2nd Century base of Malik bin Fahm of the
Azd tribe. In the Islamic era Sohar became a major entrepôt of the area at the
crossroads between China and India to the East, Iraq to the Northwest and the Red
Sea and East Africa to the Southwest. Arab sailors brought in cargoes of silks,
camphor and ceramics and exported cargoes of linen, cotton and metalwork. Links to
India brought supplies of teak for shipbuilding.
Whilst the 10th Century was the “golden age” of Sohar, the 13th and 14th Centuries
saw the rise of Dhofar based on the coastal towns of Mirbat and Al Baleed. Arab
seamen controlled a virtual monopoly of the spice trade. Total maritime orientation
lead to the rise of Qalhat, Sur and Muscat. Omani sailors operated the most long-lived
sea route of the mediaeval world. European powers, starting with the Portuguese in
the 16th Century then later the English, exerted more influence bringing technological
advances in shipbuilding. A striking feature of Oman’s history has been the interplay
between the interests of the Interior and those of coastal towns. Many benefits of the
revival of agriculture combined with maritime trade were seen during the Ya’ruba
dynasty (1624-1748) when the fleets of Sultan bin Saif became dominant in the
western Indian Ocean. In 1650, Sultan bin Saif expelled the Portuguese, making the
Sultanate of Oman the oldest independent state in the Arab world. The capture of the
garrison at Mombasa in 1698 lead to Omani ascendancy in East Africa.
The ascendancy of Ahmad bin Said Al Said, who reigned from 1744 to 1783 has
meant almost 260 years under the Al Saids. Sayyid Sultan had a primary interest in
the coffee trade. Sayyid Said bin Sultan (1807-1856) expanded greatly the Arab
influence along the East African coast. He spent most of his life in Zanzibar
developing the export potential of cloves and other crops and consolidating trading
along the Cape route between the Atlantic and India.
These eras in history were possible due to the early pioneering of sea routes, the
navigation skills and sailing methods of Omani sailors and skills in shipbuilding. A
key factor was knowledge of and exploitation of the monsoon systems. Thus the boum
or baghlah dhows would leave Sur and Muscat in the early Northeast Monsoon (mid
to late-November), turn to the south and reach Mombasa, Pemba and Zanzibar by
Mid-February. Two months of trading would occur, then the ships would leave
Zanzibar on the first signs of the Southwest Monsoon in mid-April. They would reach
Muscat by May before the intense SW Monsoon would start.
It is noteworthy that the geographical location of Oman meant accessibility to trading
nations in Asia and Africa with the ports providing convenient calling places on the
East-West trading routes. This has seen a recent revival with the current drive towards
coastal industrialization in Sohar and Salalah Ports, the development of coastal
structures such as large power and desalination plants at Barka, the OLNG Plant at
Qalhat near Sur as well as the development of numerous fishing harbours around the
coast.
In 1970, HM Sultan Qaboos bin Said became the current ruler of the Sultanate of
Oman, and, in developing the country, Sultan Qaboos has shown an acute desire to
preserve as much as possible of Oman’s traditional character and historical legacy,
while concerned with technology, sustainable development, environmental issues and
conservation of its biodiversity.
IV. RESOURCE EXPLOITATION
A. Exploitation of living marine resources
1. Fisheries
The richness and diversity of the fish resources in the Sultanate of Oman may be
attributed to several factors such as the country’s diverse coastal habitats, huge
economic zone (300,000 km2), wide climatic spectrum, and its unique geographic
location in the Northwest Indian Ocean with strong upwelling zones. In fact, the seas
off the coast of the Sultanate of Oman are among the most highly productive areas of
the world in terms of primary and secondary production (e.g. Milliman and Smith,
1998, 1999, 2000, 2001).
Over a five-year period, from 1996 to 2000, the average annual production of fish and
shellfish landed in the Sultanate of Oman was 115,202 tons. The most recent available
data is for the year 2000, a particularly good year for the fishing industry (Figure 4.1),
with small pelagic fish (especially sardines, anchovies and Indian mackerel), and
demersals (especially emperors and groupers) playing an important role (Figures 4.2 -
4.3). Out of the total catch, 384 tons have been classified as “unidentified fish”.
Fisheries Landing (120,421 tons)
in the Sultanate of Oman in 2000
Figure 4.1. Fisheries in the Sultanate of Oman in 2000
(source: MAF-Oman, 2002a).
Demersal Fish
28% (33,294 tons)
Large Pelagic
Fish
23% (27,543 tons)
Small Pelagic
Fish
43% (51,539 tons)
Sharks & Rays
3% (3, 891 tons)
Crustaceans
1% (834 tons)
Molluscs
2% (2,936 tons)
Large Pelagic Fish Landings in the Sultanate of Oman in 2000
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
Yellowfin tuna
Longtail tuna
Kawakawa
Stripped bonito
Frigate tuna
Skipjack
Other tunas
King fish
Queenfish
Barracuda
Cobia
Sailfish
Large jacks
Others
Catch (tons)
Small Pelagic Fish Landings in the Sultanate of Oman in 2000
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
Sardines Indian oil
sardine Anchovies Indian
mackerel Needlefish Mullets Jacks Others
Catch (tons)
Demersal Fish Landings in the Sultanate of Oman in 2000
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
Ribbonfish
Emperors
Seabreams
Groupers
Croakers
Sweet lips
Snappers
Jobfish
Rabbitfish
Catfish
Others
Catch (tons)
Figure 4.2. Bony fish landings in the Sultanate of Oman in 2000 (MAF-Oman, 2002a).
Figure 4.3. Cartilaginous fish, crustaceans and molluscs landings
in the Sultanate of Oman in 2000 (MAF-Oman, 2002a).
Shrimps
432 tons
Lobster
402 tons
Cuttlefish
2891 tons
Abalone
45 tons
Sharks (3,651 tons)
Rays (240 tons)
Sharks and rays landings
in the Sultanate of Oman in 2000
Crustaceans landings
in the Sultanate of Oman in 2000
Molluscs landings
in the Sultanate of Oman in 2000
In the Sultanate of Oman, the Ministry of Agriculture and Fisheries has taken a
number of steps to conserve fish stocks while at the same time developing
commercial fishing and preserving the livelihood of traditional fishermen. These
include restricting the fishing for lobsters and abalone. Closed seasons are from April
to August for shrimp and from 16 December to 14 October for lobsters and abalone.
Other species have no closed season (Table 4.1).
Table 4.1. Fishing craft and closed seasons for fishery resources in the Sultanate of
Oman (MAF-Oman, 2002a).
Resource
Fishing craft and gear
Closed season
Demersal Fish
Handline, fish traps and
trawling
Nil
Large Pelagic Fish
Gillnets, drift gillnets,
longline
Nil
Small Pelagic Fish
Beach seines, gillnets, cast
nets
Nil
Sharks and Rays
Hook and line, trolling
Nil
Shrimp
Nets
Apr-Aug for shrimp
Crustaceans
Traps, cast nets
16 Dec-14 Oct for lobster
Molluscs
Diving, spears
16 Dec-14 Oct for abalone
Other measures include the regulation of size of nets and equipment used for fishing
activities, as well as no-take areas, and specification on depths, quantities, and species
caught. Inspectors, assisted by the Royal Air Force of Oman and Royal Oman
Police/Coastal Guard patrol the area of jurisdiction of the Sultanate of Oman, and
monitor commercial fishing vessels (MAF-Oman, 2002a). Commercial fishing is
limited to 15% of the total catch and, within Oman’s territorial waters, foreign vessels
need a licence for commercial fishing.
The small pelagic fishery is seasonal in Dhofar, peaking between October-February,
and discontinuing during June-September. Fishing in Muscat and Al Batinah regions
occurs all year round.
The large pelagic fishery forms the mainstay of Oman’s fisheries, with
Scomberomorus commerson, Thunnus tonggol, Thunnus albacares accounting for
nearly half of the total catch. The fishing season for S. commerson and T. albacares
occurs between September-December and February-April, whereas the fishing season
of T. tonggol occurs between May to late June.
Demersal fishery stocks are distributed all along Oman’s coast, and are exploited both
by artisanal and commercial fisheries. This fishery can occur at any time of the year,
including for many shallow water species. Nevertheless, the most represented familes
are: Serranidae, Sparidae, Lethrinidae, Haemulidae, Sciaenidae and Nemipteridae.
2. Aquaculture
Intensive aquaculture on a large scale does not exist yet in the Sultanate of Oman, but
two cage fish-farms are operational and several companies have applied recently for
environmental permits particularly for shrimp farms. In Oman, any company wishing
to conduct aquaculture exploitation must apply for permits both to the Ministry of
Agriculture and Fisheries and to the Ministry of Regional Municipalities,
Environment and Water Resources. Strict regulations are necessary in order to avoid
the introduction of diseases that have caused catastrophic losses among aquaculture
industries and ecological problems alike, especially whenever there is introduction of
non-indigenous species that, once escaping to the natural environment, cause
imbalances in complex food webs, affecting entire ecosystems. The Master Plan
organization for the implementation of aquaculture in the Sultanate of Oman include
legislation and integration of the approval process, environmental monitoring, aquatic
disease management, and development plan (MAF-Oman, 2002b). Potential species
for aquaculture exploitation in the Sultanate of Oman include finfish, shrimps and
crabs, oysters and clams, abalone and several seaweeds (Table 4.2).
Table 4.2. Possible cultured species in the Sultanate of Oman (MAF-Oman, 2002b)
Taxonomic
group
Scientific name
of species
English
common
name
Arabic
common
name
Remarks
Finfish
Epinephelus spp.
Groupers

-
Finsfih
Several species
Seabreams

Tested
Finfish
Siganus oramin
Rabbitfish

-
Finfish
Stromateus niger
Pomfret
-
Finfish
Acanthopagrus cuvieri
Sobaity

Tested
Finfish
Several species
Mullets

Being
currently
tested
Crustacean
Penaeus indicus
Shrimp

tested
Crustacean
Penaeus semisulcatus
Shrimp
-
Crustacean
Scylla serrata
Crab


-
Mollusc
Perna virids
Mussel

-
Mollusc
Perna picta
Mussel
-
-
Mollusc
Saccostrea cucullata
Rock oyster


tested
Mollusc
Pinctada sp.
Pearl oyster

-
Mollusc
Anadara sp.
Cockle
-
-
Mollusc
Paphia gallus
Clam
-
Mollusc
Mercenaria sp.
Clam
-
-
Mollusc
Haliotis mariae
Abalone

tested
Mollusc
Pecten erythraeensis
Scallop

-
Seaweed
Gracilaria canaliculata
tested
Seaweed
Hypnea sp.
Red seaweed



tested
B. Exploitation of non-living resources
1. Minerals and Fossil Fuels
The mineral sector has a vital role in the process of economic development in the
Sultanate of Oman regarding the contribution to the national income, creation of work
opportunities and development of labor skills. Mineral raw materials (copper,
manganese, gold), coal, industrial rocks and building materials (silica sand, marble
and limestone) are relatively abundant in the Sultanate of Oman (Table 4.3).
Table 4.3. Mineral production (metric tons x 1000, except for gold, which is in Kg) in the
Sultanate of Oman from 1998 to 2000 (MRMEWR-Oman, 2002b).
Mineral/rock
1998
1999
2000
Marble
166
188
148
Limestone
1,902
3,809
3,497
Gypsum
165
180
132
Salt
14
11
12
Chromite
30
26
15
Gold (kg)
569
884
1,029
Building Materials
11,242
15,682
22,448
The relatively large stock of oil in The Sultanate of Oman has played a great role in
supporting development efforts, by taking away the pressure from other natural
resources such as forests, which used to be the major source of fuel. The Sultanate
encourages the rational and wise utilization and management of non-renewable
resources, which are subjected to depletion due to over consumption. The Sultanate
also insists on investing revenues accruing from this sector in developing other
productive sectors that do not depend on oil such as agriculture, fisheries and tourism.
By the end of 2001, the actual net oil reserve was estimated at about 5,800 million
barrels, during the period 1996-2000, the average daily production of crude oil and oil
condensers was estimated at 913,000 barrels, and it is expected to increase that figure
to about 980,000 barrels in the Five-Year Plan for 2001-2005 (MRMEWR-Oman,
2002b). Finally, it is pertinent to refer that the oil sector’s contribution to the national
net production during 2000 was 49%, but it is planned to reduce this figure to 35%
during the 6th Five-Year Plan/ 2001-2005. The Sultanate uses and saves oil revenues
for sustainable development by transferring the oil revenues derived from the over
$15 increase for a barrel during the 5th Five-Year Plan and the $18 increase in the 6th
Five-Year Plan to a special fund known as the Reserve Fund. These financial policies
are expected to form governmental savings that could reach about $25 billion by
2020, providing financial resources for the development programmes designed for
future generations in exchange for the amount of the main non-renewable natural oil
wealth consumed by the present generation.
Gas is the second most important source of energy and financial source for
sustainable development programmes, and by the end of the year 2001, the confirmed
net reserve of gas was estimated at 24.4 trillion cubit feet. The total production in
2000 was 146,000 million cubic feet, which is equivalent to 400 million cubic feet per
day.
With the increase in average family income, among Omanis, the use of wood and
kerosene in generating power for domestic purposes has been replaced by the use of
gas and electricity. Therefore, the Government of the Sultanate of Oman adopted a
policy to reduce emission of greenhouse effect resulting gases from diesel-fired
stations of power generation or desalination plants as follows:
transferring from the use of diesel to natural gas, and
rational use of natural gas to generate power and operate desalination
plants.
2. Water Resources
The availability of potable water has been a limiting factor for the success of human
settlements in the Sultanate of Oman. Traditionally, the Aflaj channels and wells
provided the water demanded by the country. Currently, aflaj systems provide
approximately 35% of the water demand of the country, but problems related to the
arid climate, saline intrusion into groundwater tables, and desertification, led the
governmental authorities to invest in desalination plants, and treatment of wastewater,
either for reuse (Table 4.4), or before discharging into the sea. Desalination plants
have been established both in urban and rural areas, and currently over 320 Sewage
Treatment Plants (STPs) in the Sultanate of Oman, half of which in the Muscat area.
Desalination Plants have been established and managed by the Ministry of Housing,
Electricity and Water, and the Ministry of Regional Municipalities, Environment and
Water Resources, whilst STPs are under the Ministry of Regional Municipalities,
Environment and Water Resources. The capacity of STPs in the Sultanate of Oman
ranges between 815,000 m3/day, and in 2000 have produced 37.446 million m3 of
treated water. The Sultanate has a specialized environmental monitoring system to
implement laws and regulations to ensure protection of water resources from
pollution. Oman’s annual production of solid waste is estimated at 909,040 t/year, and
there are 350 Waste Disposal sites countrywide, mostly for food and organic products
(53.226%), but also for glass (6.342%), plastic (12.405%), metal (6.329%), paper and
cardboard (12.698%). Hazardous waste management is expected to be tendered for
privatization.
Table 4.4. Discharge and re-use of treated water in 2000 (MRMEWR, 2002a).
Use
Quantity
Irrigation
28.2 million m3
Industry
229,000 m3
Aquifer discharge
8.6 million m3
Discharge into the sea
387,000 m3
3. Touristic resources
Traditionally, touristic activities have been limited, but a number of mechanisms
including the construction of new hotels and resorts have been promoted over the last
decade or so, and especially eco-tourism has been widely advertised.
V. OCEANOGRAPHIC CHARACTERISTICS
A. Meteorological conditions and Physical Oceanographic
characteristics
1. Winds, storms, etc.
Coasts of Oman are affected by strong seasonal winds. The low pressure area that
develops over the Tibetan plateau (30º N) during heating in spring (May) and the high
pressure system over the ocean cause winds to flow as the summer Southwest
Monsoon (Prell, 1984). This starts up in May and runs maximally in the summer from
June to September. The winds are from the southwest at extremely high velocities (>
10 m/s). They blow under pressure gradients between the Indian Ocean and the Asian
continent and run parallel to Arabian Sea coasts. This creates one of the most intense
coastal upwellings in the world due to Ekman transport of surface water offshore
(Currie, 1992). The upwelling of nutrient-rich subsurface waters, combined with high
flux of iron-rich Aeolian dust to a tropical ocean receiving intense (saturating) solar
radiation results in a sustained, high rate of primary productivity exceptional in
magnitude among offshore ocean regions. Further offshore the strongest tropospheric
jet known (Findlater Jet) runs at 1 km altitude with the surface expression called the
“Somali Jet”:
The winter Northeast Monsoon runs maximally from December to February with
transition periods in March- May. During the NE Monsoon atmospheric high
pressures form over most of Asia, whereas low pressures are found over most of the
Indian Ocean (Saager, 1994). The Indian Ocean is protected against the full, cold NE
winds by mountain ranges (Himalayas, Hindu Kush, Iran) so relatively moderate, cool
dry air blows over the northern Indian Ocean, leading to cooling and evaporation of
surface waters. These NE winds, which have modest speeds of ~ 0-10 m/s, are weaker
and more variable than the SW Monsoon airflow. Using cores from century-old
colonies of massive Porites coral in coastal waters of southern Oman, Tudhope et al.,
(1996) found, from coral coring /isotope exchange data obtained near Mirbat, Dhofar,
that there is a strong correlation between coral skeletal 18O and SSTs in the NE
Monsoon probably due to the more uniform oceanographic conditions (but not winds)
compared to the heterogeneous nature of Sea Surface Temperatures (SSTs) during the
SW Monsoon. Further, they showed trends towards increasing NE Monsoon SST
through the period 1973-1991 (~ 0.5 C/decade), perhaps linked to warming by Indian
Ocean El Nino/Southern Oscillation (ENSO) events.
Occasional tropical storms and cyclones occur mainly along Arabian Sea coasts. Thus
a severe cyclone crossed Masirah in June 1977 with wind gusts to ~64 m/s and 431
mm rainfall in 24 hours. In a review of frequencies and tracks of cyclones over the
Arabian Sea, Murty and El-Sabh (1984) stated that they occur predominantly in the
premonsoon months of April-May and in the postmonsoon months of September-
December. Cyclones traverse the Arabian Sea generally in an east-west direction and
hit the south coast of the Arabian Peninsula. DGCAM (1998) listed 17 cyclones (wind
Force 12, >34 m/s) that crossed the Omani coast between 1890-1996 and these
usually hit the coast between Masirah and Salalah.
2. Bathymetry, currents, waves, upwelling, temperature, salinity , oxygen etc.
Musandam coasts are bordered by steep rocky headlands and fjord-like valleys
providing an extensive rocky sublittoral with rich and varied coral reefs. Along the
Gulf coast of Musandam near-surface (top 20 m) currents run in a predominantly NE
(55º) direction as part of a large counter-clockwise gyre/cyclonic flow in the southern
Gulf. Recent data (December 1996 March 1998) show the average near-surface
flow runs to the northeastward out of the Arabian Gulf. This predominant outflow to
the southern part of the Strait of Hormuz is dominated by the wind and runs at 12 15
cm/s with peaks of 40 cm/s from about October to February. There appears to be a
weak residual inflow in the reverse SW (220º-230º) direction in February to April.
The Strait of Hormuz is only 56 km wide at its narrowest point with the trough
deepening to more than 100 m through the Strait. The bathymetry of the northwestern
part of the Gulf of Oman shows a narrow shelf with the 200 m isobathymetric curve
running at 20 to 25 km offshore. Over half this sector is in 500 m depths with a deep
basin over 3,000 m in central parts of the Gulf of Oman.
The continental shelf along Arabian Sea coasts is wide in parts with the 200 m
bathymetric contour extending 100 km off Ras Sharbitat. The Gulf of Masirah is a
large, shallow part of the shelf showing an important “warm pool” effect (Glynn,
1993; Mohan and Siddeek, 1996). with entrained waters in Ghubbat Hashish and off
Barr Al Hikman experiencing SSTs of 27º-28 ºC in July/August when the rest of the
Arabian Sea coasts experience SSTs of usually much less than 25 ºC. The shelf is
narrow along the Mirbat peninsula, with the 200 m bathymetric contour in places only
10 km offshore, with the area around Sadh is regarded as a centre of intense
upwelling. There are extensive shallow waters in Kuria Muria (Halanniyat) Bay
beyond Ras Hasik.
The currents of the Gulf of Oman are complex but a feature of the winter/spring N.E.
monsoon is the presence of a clockwise gyre in the western end of the Gulf of Oman
and an anti-clockwise gyre in the eastern end. These gyres pull out an upwelling cold-
water spout out from the Iranian coast. These surface features are visible in AVHRR
satellite imagery (Reynolds, 1993). Shetye et al. (1994) and McCreary et al. (1996)
show flows of surface currents running along the Gulf of Oman coasts to the north
and northwest during December and January in the Northeast Monsoon. At the
Batinah coast there is a divergence of currents at Wudam with flow to the northwest
above Wudam to the U.A.E. border, and flow to the southeast between Wudam and
Ras Sawadi (Dobbin, 1992).
Data are sparse in the outer Gulf of Oman. Flagg and Kim (1998) showed currents
have a tendency for weak (10 - 30 cm/s) northerly flows along the Ras Al Hadd to
Muscat area from approximately January to July. Currents at Qalhat (OLNG Plant)
run mainly parallel to shore in WNW to ESE directions in August to December with a
weak tidal signature. The headland at Al Galilah to the north-west of the OLNG site
provides shelter from stronger offshore south-westerly oceanic currents so flows close
inshore are characteristically weak. Current velocities in the Qalhat area are low of the
order of 20 cm/s with typical monthly maximum near-surface current in the range 25
to 40 cm/s with 99.5% of measurements being less than 30 cm/s (Wimpey Env.,
1995). Peaks have occurred at various times with the highest recorded 1:100 year
near-surface current velocity of 65 cm/s in November 1994 and 44 cm/s in July 1995.
The flow along this coast running to the southeast from August to December adds to
the strong northeast flow of the Ras Al Hadd Jet during the SW Monsoon (Flagg and
Kim, 1998).
The important winds along the Gulf of Oman are the NW (Shamal) winds which run
all year-round but bigger storms can be associated with winter NE Monsoon (NEM
winds na’shi) in December-February. The largest waves can be expected with storms
from the NE.
The tides are typically greater in amplitude in the Gulf of Oman region than they are
along the Southern coast of Oman. The Gulf of Oman has a typical tidal range of 0.9
to 1.8 m with a maximum range of 3 m. The tidal regime of Omani coastal waters is
predominantly of the mixed, semi-diurnal type. At spring tides, the tide tends towards
a more semi- diurnal character. At neap tides, the tidal curve takes on a marked
diurnal inequality.
The most significant oceanographic feature of Arabian Sea coasts of Oman is the
summer upwelling driven by the Southwest Monsoon. The onset of this system is a
remarkably regular annual event beginning within a few days of 24 May (Smith et al.,
1998a) creating one of the five most intense coastal upwellings in the world (Currie,
1992; McCreary et al., 1996; Morrison et al., 1998). The strong southwesterly winds
drive currents parallel to Arabian Sea coasts with cold (21 ºC) and low salinity (35.5 -
35.7 ‰) water upwelled onto the continental shelf from depths of about 150 m. This
northeastward flowing coastal current runs from April/May to September with a
maximum current velocity of 45 cm/s in June with the heading to the northeast. The
upwelling runs maximally in the summer from June to September. The coastlines of
Yemen and Oman are the most affected by the SW monsoon in summer (Sheppard et.
al., 1992).
The winter Northeast Monsoon runs maximally from November to February. During
the NE Monsoon atmospheric high pressures form over most of Asia, whereas low
pressures are found over most of the Indian Ocean (Saager, 1994). The Indian Ocean
is protected against the full, cold NE winds by mountain ranges (Himalayas, Hindu
Kush, Iran) so relatively moderate, cool, dry, continental air blows over the northern
Indian Ocean, leading to cooling and evaporation of surface waters. These NE winds
are weaker and more variable than the SW Monsoon airflow. In the Arabian Sea
currents are weak without showing a very distinct pattern with peak strength in
January when surface currents of < 22 cm/s run to the southwest.
There are large seasonal variations in Sea Surface Temperatures (SSTs) along
Arabian Sea coasts as well as strongly contrasting thermal environments in the Gulf
of Oman and Arabian Sea coasts of Oman (Glynn, 1993). Low temperatures in
January are a result of convective cooling during the Northeast Monsoon. In both seas
SST increases from March to June with maximum mean temperatures in June (29 C).
Thereafter the largest differences in SSTs between the Gulf of Oman and Arabian Sea
coast occur during the summer months of June to September. Then the maximum SST
in the Gulf of Oman may reach 32 C, with sporadic and often rapid drops in
temperature. By contrast the monsoon-induced upwelling along Arabian Sea coasts
causes a sudden decrease to seasonal minima (23-24°C, often <20 C) in July to
September. There is a post-monsoon warming and by November temperatures of 27
°C occur off all of Oman coast. In deep water, at 1,000 m. temperature ranges from
8.3 °C to 9.4 °C from October to May, but during the SW monsoon, the range is 8 °C
to 13 °C. At 3,000 m, water temperature is 1.8 °C (Wooster et al., 1967).
Surface salinity shows a general gradual decrease from N to S. Salinity is greater than
36.5 in the Strait of Hormuz, whilst off the SE coast values rarely fall below 35.75
(Wooster et al., 1967). Water mass exchange through the Strait of Hormuz in
summer results in a tongue of Gulf water at 200 m with a temperature of 20-21 ºC,
salinity above 37.5 ‰ and a thickness of almost 200 m. These mesopelagic layers also
have a slightly elevated oxygen content. There is some evidence of a drop in salinity
along Arabian Sea coasts as the SW Monson season progresses probably due to
advection of low-salinity waters by the Somali Current (Morrison et al., 1998).
B. Geological oceanography and sedimentary characteristics
There are three coastal regions in Oman bordered by different bodies of sea:
1. The Arabian Gulf coastline on western shores of the Musandam
Peninsula
2. The Gulf of Oman coastline from Musandam to Ras Al Hadd
3. The Arabian Sea coastline from Ras Al Hadd to the border with
Yemen
Geomorphological features vary in these three regions from the deep, fjord-like bays
of Musandam, to the flat alluvial plains with deposited sand and gravel material in
wadis (watercourses) along the Batinah coast and the mixed Arabian sea coastlines
with alternating rocky shores, sandy beaches, sabkha (saline mud flats) and khawrs
(coastal lagoons).
The Musandam Peninsula is the most northern region of Oman, and is separated from
the main portion of the country by part of the United Arab Emirates. The Musandam
Peninsula has a coastline in either side of the Strait of Hormuz, facing on one side the
Arabian Gulf, and on the other the Gulf of Oman. Both areas of the coastline have
rocky shore and rocky walls, which extend steeply to 40 m depth, and wadi valleys
(Sheppard and Wells, 1988).
The Batinah Plain is a flat alluvial plain with deposited sand and gravel material in
wadis running down from the northern edges of the Al Hajar range of the N. Oman
Mountains. The alluvial fans, deposited on a bedrock of Tertiary limestone, supply
terrigenous, dark sand to the coastal beaches. There appears to be input of weathered
ophiolite accounting for high levels of nickel and chromium in subtidal sediments at
Ras Sawadi. There is erosion at the edges of these alluvial fans and deposition of
sediments in areas in between the edges. The coastline consists largely of beaches
which are almost continuous from Barka to Khatmat Milahah with occasional bedrock
and, in places, the fine grained sand extends out as shoal areas to 2 km offshore.
Beaches are backed by a raised beach ridge with low dunes and associated halophytic
vegetation. In the more eroded northern section the beaches are backed by a cobble
ridge or, where erosion is greatest, by a steep erosion scarp.
This long shoreline is dissected by wadi-mouths which form khawrs or coastal
lagoons with or without mangrove trees and usually with a sand bar. These areas are
associated with high ecological conservation value. In addition, there are areas of
sabkha (salt flats) with associated halophytic vegetation. The sabkhas are composed
by unconsolidated carbonate sediment with minor amounts of quartz and other
minerals, and salt content estimated at 4-5 % (Le Metour et al., 1995).
Sandy beaches are the predominant feature of the coastline bordering the Arabian Sea
and this coastline is predominantly a soft substrate environment (Sheppard et. al.,
1992). Sands are predominantly carbonate with some quartz and are light in colour.
These beaches are subject to wave action particularly during the SW monsoon and
have smooth, convex profiles. Sandy beaches may be backed by rock cliffs, coastal
dune systems (in the Wahiba Sands area), extensive sabkha (at Barr Al Hikman) or
sand-gravel plains (along the Sahil Al Jazir) or interrupted by coastal lagoons and
khawrs, tidal inlets and cliffed coasts.
The continental shelf is generally narrow along the Arabian Sea coast with some
wider areas off Ras Sharbatat to Masirah Island. The bottom is sand-covered,
primarily of terrigenous or aeolian derivation. Sediments of terrigenous origin
(predominantly from Aeolian transport of quartz and carbonate-rich dust from the
Arabian peninsula) cover the Arabian Sea continental slope down to about 2,750 m.
Red clay deposits cover a large part of the basins below 4,000 m. The balance is
covered by calcareous ooze (Le Metour et al., 1995).
C. Chemical oceanography
The Arabian Sea develops an extremely well-developed oxygen minimum zone
(OMZ) with < 0.2 ml oxygen/l from 200 m to 1,000 m depths (Swallow, 1984). This
is due to the intense microbial decay of high levels of organic matter formed during
the upwelling as well as the semi-enclosed nature of the northwestern Arabian Sea.
Stirn et al, (1993) suggested that the low oxygen concentrations (3.5 ml/l) they
recorded in sub-surface waters may arise from the advection of this hypoxic water
into shallow areas of the shelf and which may cause occasional fish mortalities in this
region.
Surface values of nutrients are high in the Gulf of Oman due to monsoonal upwelling,
with surface phosphate levels over 1.0 µM and nitrate levels of 8.8 µM found in
February and March (Brewer et al., 1978). Waters around the Daymaniyat Islands
appear to be oligotrophic and may be part of an area of stagnant water from an inner
gyre.
During the SW Monson upwelling coastal waters along the Dhofar Region, where the
shelf is only a few km wide off Sadh, become eutrophic with nutrient levels in excess
of 20 M nitrate-nitrogen and 2 M phosphate-phosphorus found between July to
mid-October. These high levels of nutrients, along with the low temperatures (<20 C,
minimum of 15.9 C in August near Sadh), account for dense nearshore blooms of
phytoplankton (maximum >20 g chlorophyll a/l) and the annual development of
dense beds of macroalgae along Arabian Sea coasts (Savidge et al., 1990).
During the NE Monsoon North of 20 in open sea the surface cooling leads to vertical
convection that deepens the upper mixed layer, enhances the nutrient supply to this
mixed layer, and results in phytoplankton blooms in the northern Arabian Sea (Banse,
1994). There is likely to be some dampening coastal effect, however, reducing
windspeed and resulting in less mixing and evaporative cooling immediately adjacent
to the Oman coast (Tudhope et al., 1996). At its peak strength in January the mixed
layer in the northern Arabian Sea deepens to more than 100 m and nutrient
concentrations are higher than 11 µM Nitrogen. At its peak strength in January the
mixed layer in the northern Arabian Sea deepens to more than 100 m and nutrient
concentrations are higher than 11 µM Nitrogen (Morrison et al., 1998). This leads to a
well-defined spring bloom of phytoplankton in the northern basin of the Arabian Sea
in February, March and April (Banse, 1994; McCreary et al., 1996). Surprisingly high
phytoplankton productivities (1-2 gC/m2/day) were found offshore in the NE
Monsoon in this region (Smith et al., 1998a).
Much recent information on physical, chemical and biological oceanography of the
Arabian Sea, including some Stations near the Oman coast, has been generated during
the 1994-1996 Joint Global Ocean Flux Study (JGOFS) Expedition (Milliman and
Burkill, 1999; Milliman and Smith, 1998; 1999; 2000; 2001).
D. Biological oceanographic characteristics
1. Major habitats
1.1 Wadis
Flat alluvial plains around the coast have wadis (watercourses) which if may run
down from interior mountain ranges and then fill with deposited sand and gravel
material during infrequent rainstorms. No major rivers are found in the Sultanate of
Oman. Wadi systems enhance conditions for expansion of terrestrial communities of
fauna and flora by the occasional nutrient flows into these coastal ecosystems.
1.2. Khawrs, Tidal Inlets and Sabkhas
1.2.1 Khawrs
These are coastal lagoons with or without mangrove trees usually at the mouth of
wadis and separated from the sea by a sand bar. There are several on Barr Al Hikman
of high conservation value as wader and migratory bird feeding areas (Clarke et al.,
1986). The khawrs of the Salalah Plain are important reservoirs of biodiversity
including waterbirds, fish, invertebrates and macrophytes including reeds. Four
khawrs support mangrove stands.
1.2.2 Tidal inlets
These are tidally inundated channels. Clarke et al., (1986) found tidal inlets to be less
common than coastal lagoons. Tidal inlets tend to be larger than coastal lagoons,
measuring up to as much as 14 km in length. Several inlets lie parallel with the
shoreline behind sandbars, through which eroded channels admit tidal flows. Several
tidal inlets support mangroves and should be protected. The tidal inlets at the E coast
of the Barr al Hikman and at the west side of the Ghubbat Hashish flooded only
during spring tide have different characteristics. Being dry almost through out the
year and without any vegetation due to their extreme salinity, they resemble
faunistically the sabkhas and are used only by very few species.
1.2.3 Sabkhas
Sabkhas (saline mud flats) are supratidal coastal evaporites, where minerals evaporate
from solution as a result of evaporation of water, and are common in coastal areas of
the Arabian Peninsula, being composed of unconsolidated carbonate sediment with
minor amounts of quartz and other minerals (Sheppard et al., 1992). The coastal
sabkha plains generally lie above the high tide level and slope gently seaward at
approximately 0.4 m per km and at their inland margins they abut rock outcrops, sand
dunes or debris fans (Akili and Torrance, 1981). On the peninsula of Barr Al Hikman
there are extensive areas of recent and ancient sabkha covered with salt crusts as well
as a large sabkha to the west of Filim. These have a salt content estimated at 4-5%
where there is recent inundation by spring tides twice a year, whereas the salt content
is much more than 5% without recent connection to the sea (Wiedleplan, 1992).
Animal and plant life is almost impossible on these saline, arid environments except
for microbial mats of cyanobacteria and halobacteria (Ehrlich and Dor, 1985;
Friedman and Krumbein, 1985).
1.3 Rocky, sandy and muddy tidal flats
Large sections of the coast of Oman are characterized by sandy shores (over 300 km
of the Batinah Plain, sandy bays in the Muscat to Ras Al Hadd coast and much of
Arabian Sea coasts) with rocky shores predominant in Musandam, Muscat and parts
of the Dhofar coast (Figure 5.1).
Figure 5.1. Major sandy and rocky tidal flats
along the coasts of the Sultanate of Oman.
Coastal cliffs and escarpments are characteristic of the Jazir coast of Al Wusta region,
and in Dhofar. Coastal desert sands are only found in Sharqiyah, north of the Masirah
Channel. Most rocky shores along the Gulf of Oman suffer from high air temperatures
and desiccation effects and complete exposure to the full force of any rough weather.
Exposed limestone platforms along Dhofar coasts develop high diversity and biomass
during and after the SW Monsoon.
Southern beaches, subject to strong wave-action during the summer SW Monsoon, are
more wave-dominated, with smoother convex profiles and with the water table lower
on the shore than northern beaches. Almost the entire northern end of Ghubbat
Hashish bay is composed of tidal mud flats with low diversity but high abundance.
1.4 Coral reefs
In the Sultanate of Oman, major coral growth is restricted to four areas: the
Musandam Peninsula (Arabian Gulf coast); the rocky shores, bays and islands in and
adjacent the Muscat area (Gulf of Oman, with surface water temperatures ranging
from 22-32 ºC); the straits, shallows and shores west of Masirah Island, and some
isolated sheltered locations in Dhofar and the Al Hallaniyats, Arabian Sea (Sheppard
and Wells, 1988). The coral reefs running parallel and 1 to 5 km off the southern edge
of Barr Al Hikman are unique in that they form the largest continuous reefs in Oman.
Other parts of the coast of the Sultanate of Oman, either lack corals or have limited
growth of small, scattered colonies, due mainly to the absence of suitable substrate
(e.g. along the sandy Batinah coast), or to seasonal upwellings of cold water on the
Arabian Sea coast.
1.5 Mangroves
The indigenous black mangrove Avicennia marina (the only species found in Oman)
with its associated biota is collectively called the mangal ecosystem (Mann, 1982).
The position of the mangrove areas, between the terrestrial and marine provinces,
makes these ecosystems an important ecological transition zone. In many areas of the
Sultanate of Oman, especially in the Dhofar region, mangals are also growing in the
khawrs. Mangroves provide nursery areas, as well as refuge and breeding areas for
birds and other marine and terrestrial wildlife. Furthermore the mangroves contribute
nutrients to the coastal marine waters and food and shelter to the large schools of fish-
fry that can develop in the channels.
The most important khawrs with associated mangrove communities along the Batinah
coast are at Khawr Nabr (< 1.5 km2), Khawr Shinas (~ 6 km2) and Khawr Kalba (3.6
km2 inside Oman). The stands of Avicennia marina around Mahawt Island on the
Arabian Sea coast are of great conservation interest. The island is 3 km wide and 4
km long situated 3.5 km offshore from Filim. It has one of the best mangrove forests
in Oman which covers 60% of the island (Al Muharrami, 1994). The estimated area of
mangrove here is 162 ha.
1.6 Seagrass beds and seaweed beds
Along Oman coasts, and especially the southern Oman coasts (Dhofar region),
Arabian Sea, over 230 taxa of macroalgae (seaweeds) have been identified for the
post-monsoon season (Wynne and Jupp, 1998; Jupp, 2000). During the summer
months, in the coasts of the Arabian Sea, upwellings triggered by the southwest
monsoon fuel dense growth of phaeophytes dominated by Nizamuddinia zanardinii
and Sargassum spp. Some plants may reach nearly two metres in length in
approximately four months and they grow from the upper sublittoral to a depth of
about 10-15 meters.
1.7 Marshes and Halophytes
On the saline coastal plains (altitude 0-20 m), the Halopeplis perfoliata and Cyperus
conglomeratus community is common and, except for occasional trees of Prosopis
cineraria and Acacia tortilis, no others occur (Ghazanfar, 1991). A 1991 survey of
Ghubbat Hashish, Barr Al Hikman and Masirah Island, found different vegetation
types including psammophytes (sand hillock-forming plants, e.g. Zygophyllum
qatarense), halophytes (salt-tolerant plants, e.g. mangrove Avicennia marina),
submerged aquatics (Ruppia marina, Najas maritima) and lichens. More than 120
species of flowering plants and 16 species of lichens were recorded. Various transects
were mapped across sabkha and other habitats. Along borders of sabkha a 30-500 m
wide belt of succulent halophytes was found with species such as Halopeplis
perfoliata, Limonium stockii and Haloxylon salicornia (Wiedleplan, 1992).
Halophytes cover large portions of the dimaniyat Islands, providing nesting grounds
both for seaterns Sterna spp. and hawksbill turtles Eretmochelys imbricata
(Mendonca, 1999).
2. Major organisms
2 1. Intertidal living organisms
2.1.1 Flora
Tidal mud flats in khawrs and enclosed bays such as Khasab may have growths of
algae such as Chaetomorpha, Enteromorpha and Rhizoclonium. Rocky shores from
Ras al Hadd to Dhofar develop a rich and dense intertidal macroalgal flora from June
onwards as a result of cold, nutrient-rich waters generated by the strong southwest
monsoon upwelling from June to October. These seaweeds are dominated by species
such as Jolyna laminarioides, Melanothamnus somalensis, Gelidium sp., Solieria
robusta and Ulva fasciata. Species may survive in Dhofar until December/January
when they die off.
Four species of seagrass have been found in Oman, dominated by the smaller species
Halodule uninervis and Halophila ovalis with occasional beds of the larger species
Syringodium isoetifolium and Thalassodendron ciliatum (Jupp et al., 1996). Mean (77
g dry wt/m2) and maximum (177 g dry wt/m2) biomass of Halodule uninervis was
found in intertidal zones, with increased biomass of Halophila with depth. Biomass
data off the west coast of Masirah Island are lower than for other sites in Oman (Ras
Suwadi), the Gulf and the Red Sea due to factors such as lower sea temperatures and
increased turbidity during the SW Monsoon. Seagrasses of the area form important
diet for the endangered green turtle Chelonia mydas and the Masirah Channel was
identified by Ross (1985) as a major feeding ground. They also provide important
habitat for fish and crustaceans such as the commercially significant Penaeus
semisulcatus in Ghubbat Hashish bay (Mohan and Siddeek, 1996). Sparse beds with
occasional drift plants of Halodule and Halophila occur along the Batinah coast but a
dense bed of Halodule uninervis in the southwest ‘notch’ of Jabal Add, Ras Sawadi
was studied in 1995/96with a mean biomass of 178 g dry wt/m2, maximum biomass
of 296 g dry wt/m2, and mean shoot density of 12,406/m2 (Jupp, unpub.).
The only extant mangrove species occurring in the Sultanate of Oman is the highly
saline-tolerant Avicennia marina, but Rhizophora stylosa and Lumnitzera racemosa
were artificially transplanted by the Japanese in the early 1980s (T. Shoji, pers.
comm., 2002). R. stylosa pollen was later found in sediment samples dating from the
late Holocene, indicating that this species colonised the area at that time (Lezine et
al., in press). The stands of Avicennia marina around Mahawt Island are of great
conservation interest. The island is 3 km wide and 4 km long situated 3.5 km offshore
from Filim. It has one of the best mangrove forests in Oman which covers 60% of the
island with tree heights reaching 10 metres.
2.1.2 Fauna
A total of 58 species of intertidal fauna has been recorded from Oman's beaches,
dominated by polychaetes, crustaceans and molluscs (McLachlan et al., 1996). Some
of these animals are new to science such as large oligochaetes and species richness is
higher than similar beaches elsewhere. On the tidal mud flats at the northern end of
Ghubbat Hashish bay there is a surface film of benthic diatoms fed on by enormous
numbers of shells, with 7,200/m2 individuals of Cerithidea cingulata reported by
Wiedleplan (1992). Endofaunal filterfeeders were common in these sediments as well
as crabs with 1,520/m2 Ocypode crab burrows.
Mangrove forests are critical marine habitats acting as a genetic reservoir since they
provide a nursery ground harbouring juvenile stages of commercially important fish
(e.g. mullet) and penaeid shrimp. A faunal survey of mangals (PCDEG-Oman, 1992)
revealed more than 100 fish species, more than 100 species of molluscs (gastropods
and bivalves), more than 40 spp. of crustaceans (crabs and shrimps), and many birds,
reptiles and insects. The mud crab Scylla serrata and often huge numbers of the snail
Cerithidea cingulata and the horn shell Terebralia palustris are important animals. In
addition, mangroves provide a refuge and breeding area for birds (gulls, terns,
flamingoes) and the three northern mangal khawrs, Khawr Kalba, Khawr Shinas and
Khawr Nabr, support the only known populations of the endemic, rare (possibly
endangered) Arabian white-collared kingfisher Halcyon chloris kalbaensis (Salm and
Jensen, 1991). Some 92 species and a total number of 7,859 birds have been recorded
at Khawr Shinas in the last 20 years (Oman Bird Records Committee, 1993). Large
wildlife includes over 200 bird species, 3 turtle species and 4 mammal species
(PCDEGD-Oman, 1992; Al Saady, 2001; Shoji, 2002).
Many of the flat, rocky outcrops of the Batinah coast suffer heavy scouring and
support little attached life. At sites like Ras Sawadi there is more diversity and rocky
intertidal fauna includes the large barnacle Tetraclita squamosa and the rock oyster
Saccostrea cucullata. Rocky shores near Sur have low diversity with around 8
molluscs recorded; mussels (Modiolus sp.), rock oyster (Saccostrea cucculata),
periwinkles (Nodolittorina sp.), limpets (Nerita sp., Patella sp.), shells (Cypraea sp.,
Thais savigny) and chitons (Acanthopleura sp.). Brittle stars, barnacles, crabs, fish
(Goby sp) and serpulid worms have also been found.
The biodiversity and endemicity of rocky shore fauna along Arabian sea coasts is high
presumably due to the rise in nutrients and productivity due to the seasonal upwelling.
Thus the great importance of Masirah Island is recognised for its diverse and
abundant mollusc fauna (Bosch et al., 1995). Rocky shores of Dhofar are dominated
by winkles Nodolittorina spp., rock oyster Saccostrea cucullata, barnacles e.g.
Tetraclita squamosa, limpets Patelloida spp., the mussel Perna picta and grazing
crabs, especially Grapsus albolineatus.
2 2. Subtidal living organisms
2.2.1 Phytoplankton
Very little is known about plankton communities in the Gulf of Oman. Unpublished
data off Muscat show high levels of phytoplankton chlorophyll in winter/spring
dominated by diatom blooms (e.g. Coscinodiscus, Skeletonema). A feature of this
region is the occurrence of red tides dominated by dinoflagellates (e.g. Ceratium,
Noctiluca). Late summer and early autumn nutrient enrichments give blooms which
means that there is continuously high primary productivity.
As far as species composition of the phytoplankton of Arabian Sea coasts more data
are available. In the US JGOFS study, diatoms dominated the area of coastal
upwelling during the SW Monsoon and picoeucaryotic algae increased nearshore
during upwelling (Campbell et al., 1998; Garrison et al., 1998). Burkill et al., (1993),
however, found that the cyanobacterium Synechococcus, which contributes a major
component of picoplankton, was present in concentrations at a nearshore station off
Ra's Al Madrakah in September-October an order of magnitude lower than at offshore
stations. Further data on phytoplankton found in the Gulf of Masirah are given in
Stirn et al, (1993) with records of diatoms (Nitzschia, Thalassiosira, Cyclotella spp.)
and dinoflagellates (Pyrocystis, Gymnodinium, Prorocentrum spp.). Studies in
November 1999 around Masirah Island (Planes and Galzin, 1999) have identified 44
genera of phytoplankton and microphytobenthos. These included 23 genera of
diatoms (Biddulphia, Chaetoceros, Rhizosolenia etc.) and 18 genera of dinoflagellates
(Amphidinium, Dinophysis, Ostreopsis, Prorocentrum etc.).
2.2.2 Zooplankton
Little is known about zooplankton in the Gulf of Oman. Zooplankton along the
Arabian Sea coast was studied at one nearshore station off Ras Al Madrakah, when
the highest biomass was found in the SW Monsoon (Smith et al., 1998b). Copepods
are more than an order of magnitude more abundant nearshore during the SW
Monsoon than during the NE Monsoon. In the upper layer of the Arabian Sea, at least
231 species of copepod have been identified (Lane et al., 1998). Calanoid copepods,
especially Calanus carinatus, dominate upwelling areas off Oman, significantly
impacting phytoplankton populations and are, in turn, important prey items for macro-
invertebrates. These in turn support the very productive rich mesopelagic fish
communities found along Arabian Sea coasts affected by the strong SW monsoon
system.
Medusae, ctenophores, salps and siphonophores are particularly abundant after
upwelling events. Pelagic molluscs species known to occur in Omani waters are
detailed by Bosch et al., (1995).
2.2.3 Pelagic and benthic organisms
Fish
Over 1,000 species of fish (and invertebrates) have been identified from Omani
waters. Al-Abdesalaam (1995) describes 280 species (and invertebrates) with
emphasis on commercial species. Demersal fisheries of the Arabian Sea, Gulf of
Oman and the Gulf include over 350 commercial fish species (Siddeek et al., 1999).
Randall (1995) describes 930 coastal fishes from shelf areas, excluding deep-sea
fishes, flying fishes and lanternfishes.
The predominant pelagic species in the Gulf of Oman include the most important
commercial fish in Oman, the Spanish Mackerel (kingfish) Scomberomorus
commerson and tunas (Thunnus albacares, T. tonggol), the scad Decapterus russelli,
sardines Sardinella longiceps and others in the 20 to 100 m depth range.
Commercially important demersal species here include croakers (Sciaenidae),
snappers (Lutjanidae), jacks (Carangidae), barracudas (Sphyraenidae), and emperors
(Lethrinidae).
The butterflyfish are important coral reef fish and an endemic butterflyfish new to
science Chaetodon dialucus has been described from reefs at Barr Al Hikman. In the
Gulf of Masirah, the maximum biomass of pelagic fish is found in September and
October following the SW monsoon. The following dominant species Sardinella
longiceps (43.1 %) Trachurus indicus (42.6 %) Decapterus russelli (15.1 %) and a
small frequency of Rastrelliger kanagurta and Selar crumenophthalamus (0.1 %)
were found in the 15 m to 200 m depth zone (Thangaraja et al., 1995).
Coral reefs, seagrass and macroalgal beds in the area provide important nursery
habitats and feeding grounds for many fish. Nearly 200 fish species were recorded in
a recent survey (Planes and Galzin, 1999) in Masirah with the most abundant fish
being damselfish Pomacentridae. The most diversity was seen in wrasses Labridae (25
spp.), then Pomacentridae (18 spp.) and the parrotfish Scaridae (12 spp.).
Observations included very large numbers of dead triggerfish Blistidae, probably due
to anoxic conditions. Further, the fish fauna here shows a high level of endemism,
with isolation and lower diversity than the Indian Ocean. These findings have been
ascribed to limitations imposed by the seasonal upwelling, which maintains a barrier
of cold water along the coast confining the fish fauna.
Sea Snakes
At least nine species of sea snakes belonging to the family Hydrophiidae occur in the
Sultanate of Oman (Gallagher, 1990). These are Enhydrina schistosa, Hydrophis
cyanocinctus, H. lapemoides, H. ornatus, H. spiralis, Lapemis curtus, L. viperina (=
Praescutata viperina), Microcephalophis gracilis (= Hydrophis gracilis), and
Pelamis platurus.
Corals
Corals (Order Scleractinia) form very diverse ecosystems with reefs harbouring 3,000
or more species of animals. Reef-building corals require clean water primarily for
photosynthesis by their symbiotic zooxanthellae. There are only four principal areas
of coral growth along the Oman coasts:
1. the khawrs and fjords of the Musandam Peninsula
2. the Capital Area coast (with the Daymaniyat Islands) to Ras al Hadd,
3. the south-west coast of Masirah Island and shores west of the island,
4. the Dhofar area from the Al Hallaniyat Islands to Salalah.
In none of these areas are coral reefs highly developed. Coral growth is generally
restricted to those areas where they can grow directly on a rock substratum and in
protected bays sheltered from wind and wave action, and where the bottom is
relatively flat and turbidity is relatively low. Most of Oman’s coastline is unsuited to
coral growth. The exceptions to this are well-developed reefs with a variety of coral
species in the Daymaniyat Islands and reefs made by the growth of a single species of
Montipora in the Gulf of Masirah southwest of Masirah Island and south of Barr al
Hikman (Coles, 1995).
Various surveys have examined the diversity of Oman’s corals compared to the great
Indo-Pacific distribution with more than 82 genera and over 580 species (Veron,
2000). Maximum species diversity is seen in the warm tropical seas surrounding the
Indonesia-Philippines archipelago with decreases in all directions from this central
point. Oman is relatively distant from this center of maximum diversity, and fewer
types of corals exist along Oman's coast than in most areas of the tropical Indian and
Pacific Oceans. Although high coverages of reef corals can be found in Oman, the
number of coral types is suggested as low with surveys in Oman waters in the 1980’s
and early 1990’s suggesting between 70 and 90 reef coral species and about 50 genera
(Sheppard, 1986; Salm and Sheppard, 1986; Sheppard and Salm, 1988; Sheppard and
Wells, 1988; IUCN, 1991; Salm, 1993; Coles, 1995). The traditional view of low
diversity and low endemicity of Oman’s corals may change with more survey effort,
previous misidentifications and recent indications are that over 100 species may exist
(an estimated 104 species can be listed from, for example, distribution maps generated
from previous reports by Veron, 2000). An update on coral diversity presently being
carried out shows coral communities in northern Oman showing high levels (10%) of
endemicity (M. Claereboudt, pers comm., 2002). The occurrence of the most common
genera by region as known by the mid-1990’s is shown in Table5.1:
Table 5.1. List of coral genera by Region in the Sultanate of Oman (Green and Keech,
1986; Salm and Sheppard, 1986; Salm, 1993; Sheppard and Salm, 1988; Coles, 1995).
Family Genus Musandam Muscat Masirah-Gulf Dhofar
ThamnasteriidaePsammocora + + + +
Astrocoeniidae Stylocoeniella + + 0 +
Pocilloporidae Pocillopora + + + +
Stylophora + + + +
Seriatopora 0 0 0 +*
Madracis + + 0 +
Acroporidae Astreopora + + + +
Acropora + + + +
Montipora + + + +
Agariciidae Pavona + + + +
Leptoseris 0 + 0 +
Gardineroseris 0 0 0 +
Siderastreidae Siderastrea + + + +
Pseudosiderastrea + + + +
Anomastrea + + + +
Coscinaraea + + + +
Poritidae Porites + + + +
Porites (Synaraea) + + 0 0
Goniopora + + + +
Alveopora + 0 + +
Favidae Favia + + + +
Favites + + + +
Goniastrea 0 0 0 +
Platygyra + + + +
Leptoria 0 0 0 +
Montrastrea 0 0 0 +
Plesiastrea + + + +
Leptastrea + + + +
Cyphastrea + + + +
Echinopora + + + +
Rhizangidae Culicia + + 0 0
Phyllangia + + 0 +
Oculinidae Galaxea 0 + 0 +
Parasimplastrea + + 0 +
Merulinidae Hydnophora + + + +
Mussidae Blastomussa + + 0 +
Symphyllia + + 0 +
Acanthastrea + + + +
Pectiniidae Echinophyllia + + + +
Oxypora + + 0 +
Caryophylliidae Euphyllia 0 0 0 +
Paracyathus + + 0 +
Polycyathus + + 0 0
Heterocyathus 0 + + +
Caryophylliid + 0 0 0
Dendrophylliidae
Balanophyllia + + 0 0
Rhizopsammia + 0 0 +
Dendrophyllia + + 0 +
Tubastraea + + 0 +
Turbinaria + + + +
Heteropsammia 0 + + 0
Tubiporidae Tubipora 0 0 0 +
Milleporidae Millepora 0 0 0 +
Stylasteridae Stylaster 0 0 0 +
___________________________________________________________________________
(0 - not recorded; + - recorded; * Seriatopora caliendrum recorded by Sheppard and Salm (1988) is
probably Stylophora pistillata exhibiting similar growth form; 1 total excludes the coralline alcyonarian
Tubipora and the two hydrozoans Millepora and Stylaster).
The Musandam shoreline is exposed to waves and rock boring animals so substrates
for coral settlement are unstable except at the heads of khawrs which are not subject
to sedimentation. Air temperatures within the khawrs soar during summer months,
exposing corals to temperatures that are probably the highest in Oman waters, and
cause stress to corals that may approach or exceed their tolerance limits. Nevertheless
good coral growth can be seen particularly around Goat Island (Salm, 1993),
The Capital Area, including Muscat, area extends from the Ras Sawadi and the
Daymaniyat Islands on the west to Ras Abu Daud on the east and includes some of
the best growth of hard corals and development of coral reefs that occur in Oman
(Coles, 1995). At the Daymaniyat Islands, southern shores and sheltered embayments
on northern shores have formed substantial patch and fringing reefs, growing up from
the original rock base. Abundant coral growth extends to up to 20 m depth, in water
that has the highest clarity of any coral growing area in Oman. There are massive
Porites colonies, Acropora colonies and large stands of Pocillopora on rubble
substrates.
Coral along the Muscat coast is generally sparse on exposed shorelines which face
eastward and northward. Coral coverage on these exposed areas tends to be
dominated by two species of soft corals Sinularia spp. and Sarcophyton sp. Where
reefs do exist, they are generally small with abundant and contiguous growth of one
or two dominant coral species forming reefs only a few meters thick. However, reef
development exceeds that found in both the Musundam and the Dhofar areas,
suggesting that conditions in Muscat waters are the best suited of any in Oman to
long-term coral growth and survival. Bandar Jissah and Bandar Khayran provide the
greatest areas of high coral cover and well developed reefs in sheltered habitats. There
are the following main types of reefs found here;
Fringing reefs dominated by Porites and fringing reefs dominated by
multilayer stands of tabular and ramose Acropora spp. Well developed
only in sheltered sites of Cemetery Bay, Bandar Jissah and Bandar
Khayran.
Framework reefs almost exclusively built by often huge (~ 3 m high)
and old (> 200 years) colonies of Porites lutea, P. compressa and
subdominant species of Platygyra and Symphyllia.
Patch reefs dominated by Pocillopora damicornis (e.g. Daymaniyat
Islands, Fahal Island, Muscat Island, Cemetery Bay, Bandar Jissah,
Bandar Khayran and Ras Abu Daud), with few small scattered colonies
of other corals, particularly around the periphery. These reefs are
present in relatively sheltered environments, have high live coral cover
(>80%), and are essentially monospecific in composition, with in
general a maximum framework thickness of 2-4 m, although 6-8 m has
been recorded.
Fahal Island is a very important site for coral growth in the Muscat area being a centre
of high coral diversity with an overall total of 41 genera recorded, the highest coral
diversity of all sites studied in the Sultanate (Salm, 1993). This high diversity is
ascribed to the variety of substrate, depths and exposures to waves and currents in the
vicinity of the island. In addition to the important fringing reefs such as the banks of
Pocillopora damicornis on the South side and mixed coral reefs with high live coral
cover of more than 60% in North Bay, there are three sites near Fahal Island of
unusual interest;
Three deep rock outcrops near Fahal Island at depths of 17 25 m, 20 35 m and 22
42 m. These are the only known sites of three azooxanthelate genera Madracis,
Phyllangia and Rhizopsammia.
Where the limestone strata of the mainland protrude from silt as ridges at 15 m is the
type location of the new species Acanthastrea maxima (Sheppard and Salm, 1988)
and the new genus Parasimplastrea (Salm, 1993).
The silty substrate between Fahal Island and the mainland is the only location so far
of the motile Heteropsammia cochlea.
Generally, coral abundance decreases further east from the Capital Area as the effects
of wave turbulence become more dominant. Corals and incipient reefs are found at
Ras Abu Daud and Qalhat, but most areas southeast to Ras al Hadd have little coral
cover.
Coral communities between Qalhat and Sur have been mapped by consultancy
companies in 1995 and 2001 with the following 7 sublittoral zones identified;
Zone 1: Limestone platform with algal turf
Zone 2: Limestone platform with occasional coral colonies
Zone 3: Soft coral dominated limestone platform
Zone 4: Acropora dominated limestone platform
Zone 5: Acropora dominated spur and groove reef
Zone 6: Porites/limestone boulder community.
Zone 7: Sand
Zone 6 was the only community type which formed coral reef structures in the local
area with most reefs described as healthy, dominated by Acropora table colonies
some reaching 3 m in diameter with a cover of 60 100%. Coral colonies include
Acropora clathrata (some impacted through local construction), Acropora
valenciennesi and Acropora valida. Also present, though not in the same abundance,
are colonies of Platygyra daedalea and Pocillopora damicornis. Natural impacts
included predation by the Crown of Thorns Starfish Acanthaster planci and storm
damage with deeper (812 m depth) colonies overturned by heavy wave action. Of
great conservation interest in this area was the discovery in 1996 of communities of
the rare Fungiid mushroom corals Cycloseris sp. and Diaseris fragilis recorded near
Sur in the 19 m depth zone.
South of Ras al Hadd to the Gulf of Masirah the nearshore environment is entirely
sedimentary and corals are absent.
The northern fringes of the Gulf of Masirah with water depths less than 20 meters
include some coastal habitats of high conservation value including the proposed
Nature Reserves of Barr Al Hikman and Masirah Island (Clarke et al., 1986; Salm,
1989; Weidleplan, 1992). Thus the largest area of true coral reefs in Oman runs along
the southern edge of Barr Al Hikman where the cabbage coral Montipora foliosa
(Montipora Oman foliosa?) forms spectacular reefs of many square kilometres (Salm,
1993) running parallel and 1 to 5 km off the southern edge of Barr Al Hikman. These
are unique in that they form the largest continuous reefs in Oman. Lying in the lee of
Masirah Island protected from ocean swells, the reef has formed a solid framework
formed almost entirely by Montipora foliosa. Some colonies are up to 4 metres in
diameter and these unique reefs are of exceptional value for scientific research.
Another factor of importance here may be the persistence of warm pools of water with
SSTs of 27º-28 ºC off Barr Al Hikman during the SW Monsoon. The Al Hikmani
tribe, with fishing rights in the area, have a self-imposed policy of prohibiting fishing
on these reefs so there is little human impact. Coral colonies within Ghubbat Hashish
bay occur around Abb Island, at Ra’s Shajarat, south of Ra’s Abana and on small rock
assemblages east of Mahawt Island (Weidleplan, 1992). There is no true reef
development with species of various genera reported (Acropora, Favia, Favites,
Montipora, Pocillopora, Stylophora). Few corals and no developed reefs survive on
the east side of Masirah Island, which is subjected to heavy wave turbulence and
seasonal upwelling in the summer which greatly reduces temperatures along the east
shore of the island compared to the west shore. Recent studies of corals of Masirah
Island and Barr Al Hickman by G. Paulay and S. Wilson in Planes and Galzin (1999)
indicate 60-70 species with some endemism. Identifications are tentative with, for
example, further studies to be made on Montipora Oman foliosa?.
The predominantly sedimentary environment of the coastline from south of Masirah
Island to Al Hallaniyat Bay precludes coral development. From this area southward
the 800 km Dhofar coast and the Al Hallaniyat Islands provide rocky surfaces and
habitat for a variable coverage of reef corals and limited reef development. However,
the dominant environmental factor affecting marine life in this region is coastal
upwelling of deep, cold water that results form the southeast monsoon winds blowing
from May to September. Corals growing in this region must therefore contend
annually with water temperatures that drop below 18 °C during summer months and
must compete with blooms of macroalgae that respond to the high nutrients that arise
during upwelling This unstable physical environment and macroalgal competition
undoubtedly restricts the growth and development of corals and coral reefs from what
would otherwise be achieved. Despite these restrictions 52 reef forming coral species
have been reported for the Dhofar region, less than for the Muscat Capital Area, but
one species more than for the Musandam, At least five species of reef corals, one hard
alcyonarian (organ pipe coral) and two hydrozoans (fire coral and Stylaster) exist in
Dhofar but are not found elsewhere along the Oman coast, probably due to the
relative proximity of Dhofar to the Red Sea where these varieties are relatively
abundant.
Live coral coverage is maximum in the AI Hallaniyat Islands and east of Marbat
where cover can range up to 99% of available substratum. Small reefs up to 3 m thick
can be found in these areas. Available coral habitat diminishes toward the PDRY
border, especially west of Al Mughsayl where steep cliffs extend only a few meters
into the water to a sand bottom. The primary coral growing areas for the region are
further east where relatively sheltered bays occur at Marbat, Wadi Zead and Sadh.
2.3 Seabirds
Most records on Oman avifauna are either for terrestrial or coastal birds. Very little is
known for the offshore birds of Oman. The Oman Bird Records Committee lists all
records carried out by themselves, and very few other publications, e.g. Ballance et al.
(1996). However, it is well known that Oman has a very rich avifauna because of its
strategic geographical position for migrating birds, travelling between the Palaearctic
and Afrotropical regions. Many migrant birds (more than 80 species) overwinter on
offshore waters, islands, coastal cliffs, shores, khawrs and mangals. Such habitats are
productive and provide food for large numbers of waders, shorebirds and seabirds.
Offshore islands are breeding grounds for seabirds and birds of prey, especially the
Daymaniyat Islands with at least 6,000 pairs of terns (Sterna spp.), at least 500 pairs
of sooty gulls (Larus hemprichii) and at least 19 pairs of sooty falcons (Falco
concolor) (Mendonca et al., in press a), and the Al Hallaniyat Islands with at least
5,000 pairs of masked booby (Sula dactylatra) and at least 5,000 pairs of Socotra
cormorants (Phalacrocorax nigrogularis) (Mendonca et al, in press b).
Oman’s coastal zone supports huge numbers of wintering and migrating birds, and of
breeding and non-breeding bird species (Eriksen, 1998, 2000). Midwinter counts by a
modest number of observers covering only a fraction of the coastline give a total of
mid-winter population of 300,000-500,000 waterbirds, belonging to 90110 species,
most of which are shorebirds identified at a single site the Barr al Hikman, opposite
Masirah Island. Recent records suggest that the globally endangered slender-billed
curlew Numenius tenuirostris winters in this area regularly in significant numbers.
Other waterbirds which winter in especially large numbers are as follows:
- More than 80% of the world population of sooty gull Larus hemprichii
(34,000 ind.),
- More than 50% of the flyway populations of great knot Calidris
tenuirostris (1,200 ind.); bar-tailed godwit Limosa lapponica (55,000
ind.), and sandwich tern Sterna sandvicensis (50,000 ind.);
- More than 10% of the population of the subspecies lesser sand plover
Charadrius mongolus atrifrons (9000 ind.); and
- More than 10% of the flyway or biogeographical populations of
Western reef heron Egretta gularis (3,000 ind.), Eurasian oystercatcher
Haematopus ostralagus (12,000 ind.), little stint Calidris minuta
(17,000 ind.), dunlin Calidris alpina (60,000 ind.), common black-
headed gull Larus rudibundus (45,000 ind.), slender-billed gull Larus
genei (55,000 ind.) and great crested tern Sterna bergii (7,000 ind.).
In addition to that, substantial numbers of the following waterbirds occur in the
winter, but estimates of the total flyway populations are not yet available, and the
exact significance of the counts cannot yet be judged, although they are obviously
important: grey heron Ardea cierea (1,500 ind.), kentish plover Charadrius
alexandrinus (5,000 ind.), broad-billed sandpiper Limicola falcinellus (5,000 ind.),
Eurasian curlew Numenius arquata (3,000 ind.), common redshank Tringa totanus
(14,000 ind.), great black-headed gull Larus ichthyaetus (3,000 ind.), yellow-
legged/herring gull Larus cachinnans, also known as L. argentatus (6,500 ind.), and
Caspian tern Sterna caspia (1,700 ind.)
Two other seabird species, the Persian sheerwater Puffinus persicus and the Jouanin´s
petrel Bulweria fallax may only breed in Oman, and have been observed nesting on
Al Hallaniyat islands (Eriksen, 1998). In addition to that, huge feeding concentrations
of seabirds occur in the upwelling off the Oman’s Arabian Sea coast during the
summer, many species being non-breeding visitors from the southern oceans and
Antarctica.
2.4 Protected/Endangered organisms
2.4.1 Marine turtles
Of the total seven species of marine turtles in the world, five species are found in
Oman. Four species nest in Oman coasts and islands, especially in the Arabian Sea,
which support nesting populations of worldwide importance. The four nesting species
are loggerhead turtles Caretta caretta, green turtles Chelonia mydas, hawksbill turtles
Eretmochelys imbricata, and olive Ridley turtles Lepidochelys olivacea. A fifth
species, leatherback turtles Dermochelys coriacea only feed in the area. All these
species are mentioned in the IUCN Red Data Book either as “endangered species” or
as “critically endangered species” (Baillie and Groombridge, 1996).
The Sultanate of Oman is the only country in the area with sea turtle populations of
worldwide importance, respectively for loggerheads on Masirah Island, greens at Ras
Al Hadd, and hawksbills on the Daymaniyat Islands (Ross and Barwani, 1981;
Meylan and Donnelly, 1999).
At least 30,000 annual female loggerhead turtles nest on Masirah Inland (Ross and
Barwani), and between 6,000-13,000 annual female green turtles at Ras Al Hadd
(Salm, 1991a; Baldwin and Al Kiyumi, 1999). The Daymaniyat Islands also provide
very dense nesting grounds for 250-1,000 annual female hawksbill turtles on the 1.5
km of beaches (Mendonca et al., in press a; Al Kiyumi et al., in press a; Al Kiyumi et
al., in press b; Al Saady et al., in press a; Al Saady, in press b). Oman is also the only
country in the Arabian area where olives (estimated at around 150 annual females,
Salm, 1991a) have been observed to nest on beaches of the Masirah channel.
Seagrasses of the area form important diet for Chelonia mydas and the Masirah
Channel was identified by Ross (1985) as a major feeding ground.
Until recently it was believed that the population on Europa Island in the
Mozambique Channel, with 6,000 annual nesting females of green turtles was the
most numerous in the Indian Ocean, but numbers at Ras Al Hadd have exceeded those
(Baldwin and Al Kiyumi, 1999; Al Kindi et al., in press; Mendonca et al., in press c).
The Al Hallaniyat Islands, further south in the Arabian Sea, also provide nesting
grounds for at least three turtle species (Mendonca et al., in press b; Mendonca et al.,
in press d; Mendonca et al., in press e). In the nearby mainland, in the Dhofar region,
the four sea turtle nesting species have been identified in large numbers, especially
loggerheads and greens (Salm, 1991a; Mendonca et al., in press b). Near Marbat,
Hino Island also holds an important colony of sooty gulls Larus hemprichii and of
green turtles (Mendonca et al., in press f).
Tagging programmes of sea turtles in the Sultanate of Oman started in 1977 and tag
returns of loggerheads show that turtles tagged on nesting grounds in Oman migrate
to feeding grounds further north in the Gulf of Oman, Arabian Gulf and to the coasts
of Pakistani, and further south to the Yemeni coasts. Tag returns of greens show that
turtles tagged in Oman move further north to the Gulf of Oman and Arabian Gulf,
further south to the Yemeni coasts, Gulf of Aden and even the Red Sea coast. A tag of
a green turtle was also returned from the Maldives. Tag returns from Oman also show
that a green turtle tagged on nesting grounds in Socotra Island died in Oman waters.
Interestingly enough, a green turtle coming to nest at Ras Al Hadd had a tag from
Saudi Arabia. No tag returns are available for the other species (Al Saady et al., in
press a; Al Saady et al., in press b).
2.4.2 Marine Mammals
Aside from a single record of an elephant seal (Mirounga leonina), which was
discovered on a Dhofar beach in 1989, the only marine mammals known to regularly
occur in Omani waters are cetaceans. Dugongs (Dugong dugon) may occasionally
stray into Omani waters in nearshore environments of the Arabian Gulf off
Musandam, but there are no confirmed records of this species in Oman.
To date, 3 species of mysticeti (baleen whales) and 15 species of odontoceti (toothed
whales, dolphins and porpoises) have been confirmed to occur in Omani waters (see
Table 5.2). Additional species, which are unconfirmed but may occur, include the
finless porpoise (Neophocaena phocaenoides), which is found in the Arabian Gulf
and may stray into nearshore areas of Musandam. There are also unconfirmed reports
of fin, sei and minke whales (Balaenoptera physalis, borealis and acutorostrata).
Although some of these observations were recorded by reliable sources, they are not
supported by photographic evidence. Historic whaling data and recent genetic
analysis of tissue samples collected from live and beach-cast specimens of
Balaenoptera sp. suggest that the Bryde’s whale (Balaenoptera edeni) is the only
species of this genus that can be confirmed at this time for Omani waters. Further
study is required to explain the apparent morphological variation observed in this
species (large range of sizes, and lack of three rostral ridges in some specimens) in
Oman.
The waters of Oman are part of the Indian Ocean Whale sanctuary, and ongoing
research is revealing the importance of Oman’s waters as breeding and feeding
habitats for a number of species. Results of recent research, as well as past surveys
are stored in the Oman Cetacean Database (OMCD), which, since the 1970’s has been
housed in the Oman Natural History Museum and maintained by local scientists on a
volunteer basis.
Records include data collected during extensive beach surveys (Gallagher 1991a, b;
Salm 1991b, 1992; Collins et al., 2002), sightings during seismic surveys (Baldwin,
1997; Baldwin et al., 1999; Wilson 1999), and boat-based cetacean surveys (Ballance
et al., 1996; Minton et al., 2002). Although these records provide a preliminary
indication of the species that inhabit Oman’s waters and their possible distribution,
knowledge of abundance or local ecology is still extremely limited.
Table 5.2 includes the species that have been recorded in the region, along with
information on their IUCN Red list status. Two species of special interest, the
humpback whale (Megaptera novaeangliae) and the Indopacific humpback dolphin
(Sousa chinensis), are discussed in greater detail below the Table;
Table 5.2. Cetaceans occurring off the Sultanate of Oman (updated from Baldwin et al., 1999)
Baleen whales (Mysticeti)
Common name
Scientific name
Red List
status/category
*
Coastal/
Offshore
**
Notes
Bryde’s whale
Balaenoptera edeni
DD
C/O
Most commonly sighted
baleen whale in the Gulf
of Oman, also observed
in Arabian sea coastal
waters
Blue whale
Balaenoptera
musculus
LR:cd
C/O
First confirmed record
from Hallaniyat Islands
from whaling vessel in
1868. Recent sightings in
Muscat (Nov 1997, Nov
1999) and Dhofar (Feb
2001)
Humpback
whale
Megaptera
novaeangliae
VU/A1 ad
C
See text for more
information.
Toothed whales (Odontoceti)
Common name
Scientific name
Red List
status/category
*
Coastal/
Offshore
**
Notes
Rough-toothed
dolphin
Steno bredanensis
DD
O
Calvaria found at Ras
Madrakah and stranding
of 3 individuals together
with Tursiops sp. in Sur
Jan 2002.
Indo-Pacific
humpback
dolphin
Sousa chinensis
DD
C
See text for more
information.
Risso’s dolphin
Grampus griseus
DD
O
Regularly observed
offshore (depths >1000m)
in groups of 5-20.
Occasional large groups
of over 100. Sometimes
in mixed groups with
Tursiops sp.
Bottlenose
dolphin
Tursiops truncatus/
Tursiops aduncus
DD
C/O
One of the most
commonly reported
species in Arabian Sea
coast of Oman, often seen
nearshore. Usually seen
in groups of <50, but
some large groups
offshore.
Pantropical
spotted dolphin
Stenella attenuata
LR: cd
O
Infrequent live sightings.
Spinner
dolphin
Stenella
longirostris
LR: cd
C/O
Frequently observed in
the Gulf of Oman, with
fewer confirmed
sightings in the Arabian
Sea. Often occurring in
mixed groups with
Delphinus capensis.
Striped dolphin
Stenella
coeruleoalba
LR: cd
O
Only one record of
remains at Ras al Hadd
Common
dolphin
Delphinus capensis
LR: lc
C/O
Frequently sighted in
Gulf of Oman and
Arabian Sea coastal
waters. Often occurring
in large (300-1000)
groups, and in the Gulf of
Oman, often associated
with Stenella longirostris.
Melon-headed
whale
Peponocephala
electra
LR: lc
O?
Known only from a
damaged calvaria form
Hallaniyat islands.
Pygmy killer
whale
Feresa attenuata
DD
O?
Only one confirmed live
sighting offshore from
Ras Markaz, and one
complete specimen found
on beach in Qurm.
False killer
whale
Pseudorca
crassidens
LR: lc
C/O
Live sightings and beach
stranded specimens in
both Gulf of Oman and
Arabian Sea.
Killer whale
Orcinus orca
LR:cd
O
Almost all live sightings
are of groups of 1-8 more
than 20km offshore.
Some recent nearshore
sightings in the Capital
area and Daymaniyat
Islands.
Cuvier’s
beaked whale
Ziphius cavirostris
DD
O
Few confirmed live
sightings from Ras ar
Ruways, Mirbat and the
Hallaniyats. Several
skeletal remains.
Sperm whale
Physeter
macrocephalus
VU/A1bd
O
Most observations are
more than 20 km offshore
in water greater than
1000 m depth. Groups of
up to 20, more commonly
1-3 indiv.
Dwarf sperm
whale
Kogia simus
LR:lc
O
Known only from three
records of beach-cast
specimens, including two
skulls and partial
skeletons entangled in
fishing nets near Ras al
Hadd.
*Red List status taken from the Red List database at the Internet site
http://www.wcmc.org.uk/species/animals/.
EN Endangered, VU Vulnerable, LR:nt Lower Risk: Near Threatened, DD:
Data Deficient, LR:lc Lower Risk: least concern (i.e. not on the Red List).
** Coastal/Offshore status is based on known habitat preferences for these
species throughout the world. Due to the bathymetry of the Southern coast of
Oman, where the 1000m contour line/continental shelf is sometimes within
5km of the coast, some “offshore” species may occur closer to shore.
Species of particular interest
Humpback whale (Megaptera novaeangliae)
An increasing body of evidence supports the theory that the humpback whales of the
Arabian region are non-migratory, residing in Arabian waters year-round, a
phenomenon which is unique for a species that performs long seasonal migrations
from the polar feeding grounds to tropical breeding grounds elsewhere in the world
(Mikhalev, 1997; Baldwin, 2000; Minton et al., 2002). Upwelling of cold nutrient rich
water along the Arabian Sea coast supports populations of prey species such as
sardines and euphausiids, which are believed to provide a continual food supply for
the whales (Papastavrou and Van Waerebeek, 1998). Research to date confirms that
whales off the coast of Oman adhere to a Northern Hemisphere breeding cycle
(Mikhalev, 1997; Minton et al., 2002). Observations of small calves and singing
males (associated with breeding), indicate that the Kuria Muria bay and the Gulf of
Masirah may be particularly important for this population’s reproduction.
Observations of feeding behaviour in the Gulf of Masirah and along the Dhofar coast
also confirm the importance of Oman’s waters as feeding grounds for this and other
species of cetacean. Genetic comparison of skin samples from humpback whales off
the coast of Oman with those from breeding populations in the Southern Indian Ocean
indicate that while there are some shared characteristics, at least two maternal
lineages have been proven to be unique to Oman (Rosenbaum et al., 2002a).
There are 8 recorded incidents of live entanglement of humpback whales in fishing
gear. Furthermore, a number of whales found floating dead at sea, or stranded on
beaches show evidence of interaction with fishing gear. The species’ preference for
shallow coastal waters, susceptibility to entanglement in drift and gill nets, breeding
status in Omani waters and IUCN Red list categorization as “vulnerable” make it one
of the key species to consider in management and conservation efforts in the Arabian
Sea. Although we know much less about other species of baleen whales in Omani
waters, there is reason to believe that they too might make use of the productivity of
the region for both feeding and breeding. Further research is needed to better
understand the habitat use, ecology, conservation status and population identity of this
species in Oman.
Indo-Pacific dolphin (Sousa chinensis)
Baldwin (2000) reviews the status of this species in Arabia, with a focus on data from
Oman. The majority of records of this species in Oman are of beach-cast specimens,
many of which show evidence of fisheries interactions. The species is known to feed
in very shallow coastal waters and is often observed from shore (perhaps explaining
the predominance of sightings of this species despite a lack of boat-based survey
work). It’s preference for shallow nearshore waters make it particularly susceptible to
entanglement in fishing gear and disturbance from coastal development (pollution,
dredging, land reclamation, beach degeneration, erosion, construction,
boating/shipping traffic, noise pollution etc.) and it should be a priority focus for
conservation efforts.
Preliminary results of genetic analysis show that there may be significant differences
between humpback dolphin populations along Oman’s coastline (Rosenbaum et al,
2002b). However a larger sample size, and more extensive analysis are required to
better understand the relationship between dolphins sampled in different sites in
Oman and those throughout the rest of the Indian and Pacific Oceans. The species is
classified as “data deficient” in the IUCN Red list, and more research is needed to
determine its distribution, abundance and ecology in Oman, as well as the severity of
threats to their well-being.
Conclusions
Although there is still much to be learned about cetaceans inhabiting Omani waters,
there are many indications that it is a very rich and productive area, which supports at
least 20 cetacean species. There is mounting evidence that at least two of the recorded
species may represent unique and discrete Arabian populations, whose protection
should be a priority in any future conservation efforts. Preliminary and opportunistic
results of research show that fisheries interactions are a frequent cause of mortality
among coastal cetaceans, including bottlenose dolphins (Tursiops sp.), common
dolphins (Delphinus capensis) and spinner dolphins (