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The Underwater Kingdoms of Somalia | Picture Gallery

11039 Views 5 Replies 3 Participants Last post by  juzme123

Dugong - Africa's most endangered creature.

Somalia is home to a large number of birds, over 700 species, and boasts over 170 species of mammals. It's also home to a variety of marine life. The endangered dugong, also known as the 'sea-cow', is among the aquatic fauna found living along the eastern coastline. The dugong is a shy, placid, herbivore that forages for sea-grass. Other common marine animals include manta rays, great hammerhead sharks, black marlin, and shortfin mako sharks. - Source
Study on Marine life around Berbera:

The marine environment off Berbera is very productive. Seaweeds flourish in many areas in the inshore region and wind-generated water movement promotes their growth as well as the transport and breakdown of algal detritus in the system. Large shoals of fish were observed in the region and these provide food for numerous dolphins, a further indication of high productivity. The seaweed beds, associated detritus and climatic energy subsidy make a contribution towards the productivity of the area. Further study would be needed to establish the importance of seaweed production relative to that derived from upwelling.

The coastline is relatively straight and consists mainly of beaches; very small rocky promontories occur only in a few localities. A raised fossilised seabed backs many of the beaches. The dunes behind the beaches are generally low and sparsely colonised by xerophytic grasses and shrubs, as is the coastal plain. A high dune field, which is almost devoid of vegetation, occurs in one locality and arid rocky mountains are found at three sites.

At the time of the study, the beaches had a clear monsoon storm berm above the present high water mark. The latter was littered with seaweed, some coral fragments and large numbers of shells, particularly shells of gastropods occupied by scavenging hermit crabs. Remarkably little pollution was found. Ghost crabs were prolific on some beaches.

The subtidal sandy substratum appears to be relatively sterile. Seaweed detritus had accumulated in the sand ripples in certain areas and a single concentration of holothurians was found next to one reef. However, very few observations were made on the sand substratum because of time constraints and this environment may be inhabited by burrowing organisms such as bivalves. No evidence of their presence was found in beach litter.

As stated, rocky shores were sparse. The intertidal zone had a clear band of Saccostrea cucullata, some whelks (Nerita sp.) and grapsid crabs. No corals were observed in the subtidal region, which was also sparsely vegetated with few algae, probably because of surf energy. Reefs were found between 1-10 m and appeared to originate from fossilised beach rock. They thus appear to represent a submerged coastline and were patchy.

The coral communities on the reefs varied considerably in their condition. All had been affected by bleaching to some degree. The shallow reefs (1-2 m) to the west of Berbera were slightly bleached and those <1 m appeared to have died from tidal exposure. The shallow reefs to the east of Berbera were far more severely affected by bleaching and, in many instances, had suffered nearly total mortality and become both encrusted and accreted by coralline algae. Montipora stellata had commenced recolonisation of these areas.

Deeper reefs (2-5 m) were in better condition. Patchy reefs subject to considerable sedimentation were dominated by sediment tolerant faviids, while more established reefs were dominated by Porites spp. and plate Montipora spp. Astreopora myriophthalma was conspicuous on the deepest reefs (5-10 m) and manifested recovery from crown-of-thorns (COTS) predation. Three COTS were found on one reef. A total of 69 species of scleractinian coral, 11 species of alcyonacean (soft) coral and two species of fire coral were found during the survey. Other reef organisms encountered during the field work were sparse and included only five Panulirus versicolor, two specimens of two species of anemones, five specimens of Tridacna spp. and various sponges, ascidians, holothurians, echinoids, crinoids, molluscs and zoanthids.

Seaweed were widespread in patches on hard substrata, both in the inshore area and in deeper water (<10 m) that is sedimented to a varying degree. Their prevalence on substrata which would otherwise appear more suitable for corals is probably due to a combination of physico-chemical factors. These would include the levels of turbidity and sedimentation that were observed, as well as the nutrient enrichment emanating from these factors and regional upwelling. A range of green, brown and red algae were recorded. Sheets of Zoanthus sansibaricus and a number of sponges were associated with the deeper algal beds.

Reef fish were diverse and the presence of large schools of fish as well as an abundance of large fishes indicated a relatively unexploited resource and pristine environment. The diversity of reef fish was greatest in the coral reef environment and substantially lower in areas with a rocky or sandy substratum and in algal dominated assemblages. However, the abundance of fishes, including juveniles, in the latter environment was higher. The reef fish community differs considerably from that of the eastern Arabian Peninsula to the north, and the fish communities of eastern Africa to the south and the Red Sea to the west.

Large shoals of pelagic fish were conspicuous. Pelagic fishes observed at sea included schooling tuna (e.g. bonito), carcharinid sharks and whale sharks.

Small cetaceans are abundant in waters off Somaliland. A total of 35 sightings of five species of dolphins (common, spinner, spotted, bottle-nose and humpback dolphins) were recorded during the survey. More than 20 species of sea and shore birds were recorded but, in the case of gulls and terns, these were not as numerous as anticipated, particularly as feeding aggregations over shoaling fishes.

Evidence of turtle nesting was found on beaches distant from Berbera. A total of 36 nests was the highest density encountered along a five km stretch of coast. Turtle remains and sightings at sea suggested that green turtles and hawksbill turtles are the commonest species in the area, while a single loggerhead turtle was seen at sea. The major threat to turtles arises from the opportunistic harvest of green turtles which includes incidental gill net entrapment. Natural threats to the eggs include the flooding of nests and the likelihood of egg consumption by land mammals. Humans apparently collect turtle eggs during the Southwest Monsoon season.

The extensive lagoon at Khoor Shoora is bounded by a fringe of Avicennia marina. It is characterised by clean sediment, clear water and prolific seaweed growth; there appeared to be little freshwater input. Little evidence of timber extraction was found and very little appears to be used as firewood. The fauna in the area included a number of birds, abundant juvenile fishes and mud crabs.

Marine resources are used only on a small scale in the study area, canoes being used to set a limited number of 7, 15 and 30 cm stretch mesh size gill nets. Handline fishing was observed on one occasion. Sharks are especially targeted in these operations with only the valuable fins being landed; this is largely due to a lack of refrigeration.

Turtles appear to be harvested opportunistically, both by jigging and harpooning at sea and through the capture of nesting turtles. Both fishermen and nomadic herdsmen are probably responsible for the latter; herders have temporary shelters and animal pens on certain beaches. - Source
Berbera's eco-tourism and marine life pictures:

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Fish living in dark caves still feel the rhythm of life

By Leila Battison - 10 September 2011

Millions of years of evolution in the dark have led to this Somalian cavefish losing its eyes, scales, and pigmentation.

A blind, cave-dwelling fish in Somalia knows what time it is, but its "day" is twice as long as ours. Most animals have an internal body clock, or circadian rhythm, that lasts around 24 hours and is modified by the light-dark cycle of a day.

But an international team, whose research is published in the open access journal PloS Biology, shows that certain blind cave fish have a circadian rhythm that lasts almost two days.

The cavefish, Phreatichthys andruzzii, has evolved for nearly two million years in the isolated darkness of caves beneath the Somali desert.

Professor Nick Foulkes, of the Karlsruhe Institute of Technology in Germany, said that this particular species was chosen "because it was such an extreme example, having been isolated from a day-night cycle for so long".

In the course of its evolution it has lost its eyes, colouration and scales, having no need for them in the pitch-black of an underground cave system.

But it appears that the absence of day and night has caused a much more profound change in the fish's life rhythm.

Light sensitivity

The internal body clock of most mammals is slightly longer than 24 hours, although it is unique for each person and is modified by light.

"If we look again at them in a few million years, they may have no trace of a circadian rhythm” -Nick Foulkes, Karlsruhe Institute of Technology
This is most obvious to us when we travel across time zones, as jet lag is caused by the delay in our circadian rhythm synchronising with the new daylight times.

On a smaller scale, the body clock can be measured by the switching on and off of certain "clock genes" at different times during the day. This happens automatically daily, but is synchronised with the day-night cycle through exposure to light.

Light is detected primarily by the eyes, but most cells in the body have some reaction to light levels. In non-mammalian animals, such as fish, these "peripheral" detectors play a more important role.

This means that, even though the cavefish have lost their eyes over the course of evolution, their bodies should still be able to react to changes in light.

When comparing the reactions of the circadian rhythm of the cavefish to those of a "normal" zebrafish, however, the blind fish showed none of the responses to external light changes that the zebrafish did.

After two million years in the dark, the cavefish have no need to react to the light, and their body clocks have permanently changed to reflect this.

Alternative triggers

But these blind fish do still have a body clock, which can be reset by triggers other than light. Feeding the fish at regular times showed that both the zebrafish and the cavefish responded by resetting their circadian rhythms.

Furthermore, when the cavefish were left to reset their clock according to their natural rhythm, the researchers found that their "day" is 47 hours long.

Professor Foulkes said that this was "possibly linked with food availability, or we could have caught them in the process of losing their clocks. If we look again at them in a few million years, they may have no trace of a circadian rhythm".

The team plans to investigate whether this gradual loss of body clock is a common feature among all species of fish living in perpetual darkness.

LOL, there is some truth to it though, even historic heritage from as recent as the 15th century lies submerged beneath Somalia's coast, there is no telling what sea-encroachment did to B.C era lost cities like Opone, Malao, Essina, Sarapion, etc.

After the 2004 tsunami hit India, a whole historic city, completely intact, was found there.
Somalia's Milky sea, the largest in the world

Satellites capture first glimpse of ‘milky-sea’ glowing-water phenomenon

By Steven Miller and Steven Haddock

Rare glowing-water effects known as ‘milky seas’ are generally attributed to bacterial bioluminescence, but their causes are still a mystery. Low-light satellite measurements have now provided the first overview of a milky sea, observed off the Somali coast and spanning ~15,000km2. The findings offer new hope for learning about these extraordinary displays.

‘Milky seas’ are rare nocturnal events where the ocean gives off a radiant glow that is reminiscent of a snow field and bright enough to read by. Witnessed over the centuries by mariners crossing the Indian Ocean, milky seas have been associated more with legends of the sea than scientific knowledge.

More recently they have been attributed to bacterial bioluminescence, but their cause, distribution, and role remain mysteries. In particular, the environmental circumstances supporting the seemingly unrealistic bacterial populations needed to produce milky seas have been a topic of debate in the microbial ecology community for decades. Some evidence points to bacterial colonization upon surface slicks of organic matter, but observations of milky seas under higher wind conditions (where slicks would break apart) challenge this hypothesis.

One point of consensus is the fundamental importance of additional in situ observations to help understand the cause of these elusive macro-scale processes. The problem has always been finding a practical way to locate them. Satellite sensors represent a previously unexplored tool for this study.

Perhaps surprisingly, the night-time hours feature a rich diversity of visible light, both natural (moonlight reflection, lightning, fires, and aurora) and artificial (cities). The Defense Meteorological Satellite Program6 (DMSP) series of military weather satellites carries the operational linescan system (OLS). This instrument is capable of detecting very weak light sources (roughly one million times fainter than the solar disk). Despite this sensitivity, the OLS cannot detect the more common bioluminescence events associated with disturbed-water (breaking waves, ship wakes) due to their, typically small, extent. However, the steady, widespread glow of milky seas makes them a better candidate for OLS detection. -- Source
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