Dive Africa Sharm

Waves of sleep wash over seagulls

2011-06-09T06:06:00.000-07:00

As darkness falls and thoughts turn to slumber, waves of sleep wash over seagulls huddling against the elements.
This is not poetry, but a discovery made by a scientist who has been studying sleep in bird colonies.

He found that seagulls learn from each other when it is safe to nod off, resulting in "waves of sleep" passing through seagull colonies as the birds enter differing states of vigilance. This is the first time such behaviour has been documented. The work is reported in the journal Ethology.
Like many other species, seagulls open and close their eyes periodically while sleeping. That allows them to monitor what is going on around them while they are resting.

"But not to the extent that they could if they were awake," explains Dr Guy Beauchamp of the University of Montreal, Canada.

So sleeping is risky, as it makes the birds vulnerable to predators. Yet, until now, it has not been clear what information seagulls use to decide when to sleep. For example, do they base the decision on their own experiences, or do they monitor what other seagulls are doing?
If many birds are sleeping, that may be a sign that it is safe to nap; equally, if few are sleeping, a seagull may decide that it will be more vulnerable to attack if it is asleep while more vigilant group members are awake.

Dr Beauchamp investigated this puzzle by studying how the sleep patterns of seagulls (Larusspp) change over time at loafing sites in the Bay of Fundy, New Brunswick, Canada. He noted how often individual birds slept within a colony over fixed periods of time.

"Sleeping is easy to score because gulls usually sleep with their bills tucked into their [feathers]. Every minute or two, I calculated the proportion of sleeping birds in the group."

These counts revealed that gulls with more alert neighbours opened their eyes more often while sleeping.

"So seagulls do pay attention to what their neighbours are doing, and adjust their sleep pattern accordingly," he reported.
What is more, as the gulls tended to copy the behaviour of their neighbours, Dr Beauchamp recorded waves of sleep passing through the colony, with the proportion of sleeping gulls rising and then decreasing through time.

"It was not obvious if temporal waves would occur. They are predicted to occur when copying is important, but it had never been documented before," he says.

Dr Beauchamp's results add weight to a growing view among biologists that vigilance in animals is a social phenomenon. Individual animals adjust their behaviour - for example by deciding when to sleep - according to their own perception, but also in response to information gleaned from the behaviour of their companions. Such behaviour then leads to a collective phenomenon, in this case waves of sleep.

Sea turtles' migration mystery is 'solved’

2011-06-09T06:05:00.000-07:00

Until now, how species such as loggerhead sea turtles manage to migrate thousands of miles across oceans with no visual landmarks has been a mystery.

Now researchers from the University of North Carolina believe they have found the answer. Loggerhead sea turtles appear to be able to determine their longitude using two sets of magnetic cues. It is the first time this ability has been shown in any migratory animal. This research is published in the journal Current Biology.
Suprising discovery
Although several species of turtles are known to use magnetic cues to determine latitude, it was believed that this wasn't possible for longitude. However, the loggerhead turtles have managed to surprise researchers by developing a method that involves using the strength and angle of the Earth's magnetic field.
Nathan Putman, the lead author of the research, emphasised that "the most difficult part of open-sea navigation is determining longitude or east-west position. It took human navigators centuries to figure out how to determine longitude on their long-distance voyages".
Loggerhead hatchlings, however, are able to manage this feat as soon as they reach the sea from their nests. On reaching the sea, the hatchlings are able to establish the correct course to the open ocean. The young loggerheads then spend several years successfully navigating complex migratory routes over thousands of miles of ocean.
Loggerhead Sea Turtle

Scientific name: Caretta caretta
Loggerheads in the North Atlantic cover more than 9,000 miles
Loggerheads are found in the Atlantic, Pacific and Indian oceans.
Considered "endangered" by the International Union for the Conservation of Nature (IUCN).

To carry out the research loggerhead hatchlings from Florida were placed in circular water containers and tethered to electronic tracking systems to monitor their swimming direction. The hatchlings were then exposed to magnetic fields which replicated the fields they would come across in two locations on the same latitude but different longitude along their migratory route. The turtles reacted to each magnetic field by swimming in the directions that would, in the real location, take them along their circular migratory route. The researchers say this shows that the hatchlings are able to determine longitude using information from the magnetic field.
Nathan Putman explains that "along the migratory route of loggerheads, nearly all regions are marked by unique combinations of intensity (field strength) and inclination angle (the angle that field lines intersect the surface of the Earth). Thus, turtles can determine longitudinal position by using pairings of intensity and inclination angle as an X, Y coordinate system".
Possible applications
Dr Kenneth Lohmann, director of the laboratory where this research was carried out, said the research "not only solves a long-standing mystery of animal behaviour but may also be useful in sea turtle conservation".

The research might even have a role to play in the development of human navigational technologies, according to Nathan Putman.

"There may be situations where satellite might not be available, where this system of using two aspects of a magnetic field could be very useful".

Sharks Need You!

2011-06-09T05:59:00.000-07:00

With all the media hysteria regarding the recent shark attacks around Sharm el-Sheikh, it is easy to forget that several of these magnificent and misunderstood marine creatures are threatened by extinction. If ever an animal needed a publicity agent, it’s the shark. Of the 490 known species, only 12 are dangerous to humans yet 20 face extinction and the number is increasing. We’re more likely to eat a shark than be eaten by one, isn’t it time we gave Jaws a break?
Great White Shark (carcharodon carcharias) The film Jaws brought the great white star status but also fuelled demand for great white shark products, strange though it may seem to use an animal's dental work as an ornament. Peter Benchley, the author of the book, prior to his death was prominent in the campaign to stop the practice of shark finning but conservationists are still concerned that the film perpetuates the idea that the only good shark is a dead one.

Great whites mature late and have few young and they are caught as bycatch as well as being deliberately targeted.

Studies have shown that great whites are declining, both in number and size.

They are protected in some areas, but even if they are, the conservation measures are not always enforced with much vigour.
Basking Shark (cetorhinus maximus) The basking shark is the second largest fish in the world. It is often seen in British coastal waters. Certain sub-populations, especially those in the North Pacific and North-east Atlantic, have been seriously overfished in recent years. The basking shark has a particularly large dorsal fin, which may be its downfall at a time when the demand for shark fin soup is increasing.

Basking shark numbers have been falling rapidly because of over-exploitation in some areas. There are real concerns that populations will never recover because the fish mature so slowly and have such a low reproductive rate.

In November 2002, basking sharks were added to Appendix II of the Convention on International Trade in endangered species (CITES). This means that basking shark products can only be sold with special permits. They've been protected in waters within 20 km of the British coast for some time.
Whale Shark (Rhincodon typus)
Whale sharks are gentle giants and are particularly vulnerable because they move slowly and close to the surface. Like their name-sakes, they are targeted by harpoon fisheries because their meat and fins fetch a high price on the international market. Even back in 1999, a single whale shark fin was on sale in Beijing for £11,000.

~Paradoxically, whale sharks could play an important role in eco-tourism because they are no threat to humans and are safe to swim with. There is a growing interest in them among the dive community. In November 2002, whale sharks were added to Appendix II of the Convention on International Trade in endangered species (CITES). This means that whale shark products can only be sold with special permits.

Basking shark numbers have been falling rapidly because of over-exploitation in some areas. There are real concerns that populations will never recover because the fish mature so slowly and have such a low reproductive rate.

In November 2002, basking sharks were added to Appendix II of the Convention on International Trade in endangered species (CITES). This means that basking shark products can only be sold with special permits. They've been protected in waters within 20 km of the British coast for some time.
Whale Shark (Rhincodon typus)
Whale sharks are gentle giants and are particularly vulnerable because they move slowly and close to the surface. Like their name-sakes, they are targeted by harpoon fisheries because their meat and fins fetch a high price on the international market. Even back in 1999, a single whale shark fin was on sale in Beijing for £11,000.

~Paradoxically, whale sharks could play an important role in eco-tourism because they are no threat to humans and are safe to swim with. There is a growing interest in them among the dive community. In November 2002, whale sharks were added to Appendix II of the Convention on International Trade in endangered species (CITES). This means that whale shark products can only be sold with special permits.

Sand Tiger (Odontaspididae)
The sand tiger inhabits coastal waters and lives in isolated populations that don't mix. They are now threatened by fishing activity, including spear fishing and beach meshing.

Populations in Australia and South Africa have been studied and are showing a marked decline. Sand tigers are protected in Australia but even there, there is little sign of recovery.

Endangered Species

A major problem with assessing the status of the world's shark populations is finding them. Many sharks species are rarely seen. The IUCN Red List lists numerous sharks that can't yet be categorised because we simply don't know enough about them.

Many more sharks species that are not yet endangered could be soon if current trends continue. A number of 'lower risk' classifications are considered to be 'near threatened' or 'conservation dependent'. Similarly, many species classified as 'vulnerable' are more at risk in some areas than the category would imply. Here are just a few of them.

Ganges Shark The Ganges shark (Glyphis gangeticus) is found in the Ganges river area in estuarine and inshore waters. Our sum knowledge of them has been derived from three ancient museum specimens. This species is critically endangered. It should not be confused with the bull shark (Carcharhinus leucas) which is also sometimes called the Ganges shark.

Borneo Shark The Borneo shark is classified as endangered. Once again, it is found inshore and in coastal areas and has not been widely studied. It is threatened by a rise in shark fisheries in the region.

Smoothback Angel Shark You might think that a good strategy for sharks would be to head for the depths, but you'd be wrong. The smoothback angel shark is a bottom-dwelling species found off Brazil in the waters of the western South Atlantic shelf. Here the species is being depleted by bottom-trawl fisheries. The problem is made worse by the fact that the smoothback angel shark is particularly slow to mature - young sharks are caught before they have a chance to breed.

Speartooth Shark Other shark species listed as endangered include the rare speartooth shark that is at risk from increased coastal development in the Indo-Pacific region which is rapidly destroying its coastal and river habitat.

Whitefin Tope Shark The whitefin tope shark is also struggling for survival in the overfished waters around the Philippines. Its range is extremely restricted and there is no recent information.

What Can You Do?

Eat shark-friendly fish! Campaign for the fishing industry to change their practices and reduce the amount of bycatch they take.
Support ecotourism – responsible tourism can help to save some of the world's most endangered species. Choose a shark watching trip that puts money directly into conservation and make sure the company has a clear animal welfare policy.
Don't be tempted to try shark's fin soup and avoid shark meat unless you are sure it comes from a managed shark fishery. Challenge restaurants that serve shark products.
Don't buy cosmetic products that contain squalene (an oil extracted from shark livers). Eco-friendly alternatives can be sourced from 'green' outlets.
Investigate wildlife charities and pressure groups you may like to support.
Find out more about sharks. Read books, get in touch with conservation organisations and search the internet for information. The more informed you are, the more you will be able to help.
Draw attention to the plight of sharks. Tell your friends and family about the situation.

Special Offer

2011-03-02T10:05:00.001-08:00

Urchin Mantis Shrimp

2011-02-26T09:21:00.000-08:00

One of our favourite sites around Sharm el-Sheikh is Shark’s Bay. At first glance it seems little more than a vast tundra of rocks and sand. On closer inspection though it has a lot to offer, especially if you enjoy macro. One of the most exciting discoveries we have made there recently is a small colony of urchin mantis shrimps. Admittedly we didn’t know what creature we’d stumbled upon until we’d compared our photos to others on the Internet but even before we were able to positively identify the shrimps, we knew we’d spotted something a little rare and unusual. The shrimp has a telson (in laymans terms, it’s arse) that resembles a rock-boring urchin which it blocks the entrance to its cavity (lair) to avoid detection (both from predators and divers). We only initially noticed the shrimps because one just happened to move whilst we were photographing the coral it inhabits. On the same day we saw an eagle ray which is enough to make most divers happy, yet this 30mm shrimp was the highlight of the dive.

Common name: Urchin Mantis Shrimp

Functional type: Smasher

Range: Central Pacific and Hawaii to Western Indian Ocean

Habitat: Coral reefs, reef walls

Depth: 10–50 m

Home: Cavities in hard substrates, often large worm tubes; juveniles in coral rubble

Diet: Unknown; has been found eating crabs, gastropods and other species of mantis shrimp

Size: 8–80 mm

Color: Yellow, orange or more typically red with while spots, while spots form band running across carapace and raptorial meri, no prominent meral spot; telson spines white

Distinguishing Characters: Bilobed eyes; spined telson that mimics an echinometrid urchin

Activity: Crepuscular, rarely leaves cavity; often seen blocking entrance with telson

Aquarium Requirements:

Temperature: 22–28° C

Salinity: 33–35 PSU

Cohabitants: Unknown; will eat small prey, almost never leaves cavity

Aquarium size (adult): 20 l

Aquarium substrate: Requires tight-fitting, long narrow cavity, either pvc pipe or in rubble

Suitability for Aquarium: Good; needs stable water parameters; not active but usually can be seen looking out of cavity entrance; use of unusual telson that mimics urchin is interesting

Availability: Rare; occasionally can be specially ordered from collectors in Hawaii; while common at 20–30 m, because of the nature of their cavities, E. guerinii are extremely difficult to collect alive.

To visit our original webpage click here

Shark's Bay - Love it or Loathe it

2011-01-07T01:45:00.000-08:00

Okay, with dive sites such as Shark Reef, Thomas Reef or Ras Umm Sid to choose from, why would anyone in their right mind say "One of my favourite dive sites is Shark's Bay"?

You'll probably never see hundreds of snappers there, or a shiver of sharks, and no wrecks (except for sun-wizened dive guides), so why, oh why! (do girls love horses?), would anyone cite Shark's Bay as one of their favourite dive sites?

For a start, it's an excellent spot for a night dive, teeming with crustaceans, echinoderms and cephalopods. Shark's Bay is predominately made up of hard corals (and sand) so can look ... without wishing to sound too harsh ... dreary in the daytime but at night all these corals (or at least the polyps) come out to feed. It's also an excellent place for photography, with lots of macro and little currents. It is quite easy to spend 90 minutes on a dive and not drop below 8 meters.

Secondly, admittedly you have to look a little harder in the daytime, but Shark's Bay has a very healthy population of stonefish and scorpionfish (devil, bearded, and smallscale). Yeah, I know, these are the 'ugly bastards' of the fish world and not to everyones taste and, if that's you, there are plenty of 'pretty fish' such as butterflyfish, angelfish, gobies, blennies, anthias and anemones (including at least two pink anemones).

And there's not just the small things there either. Admittedly not a regular basis, I've also seen here whale sharks, a leopard shark (just the one), eagle rays, mantas, fantail rays, honeycomb rays (or leopard rays) and, of course, the bluespotted ray. I also know guides who have seen guitarfish and oceanic white tips.

I've seen robust ghostpipefish (there has also been sighted ornate ghost pipefish), juvenile starry puffers (which look like swimming olives), juvenile yellow-mouthed morays and juvenile coral hinds.
The reason for these, I think, is there is very little current action in Shark's Bay which is why it is such a popular place for training dives too.

My favourite spot in the whole area is the glassfish pinnacle (28m) but don't look for it on the dive site maps as it seems, amazingly, to have been overlooked. Here you will find a very healthy pinnacle with a large pygmy sweeper colony protected by several red-mouthed groupers. On the pinnacle itself you can find numerous types of shrimps and a very active cleaning station, while usually somewhere at the base of the pinnacle you can find a couple of resident scorpionfish. Often you'll also come across a large malabar grouper that likes to stop at the aforementioned cleaning station and, while it is being cleaned, is quite happy for you to 'float' next to it (usually at all other times the fish won't have anything to do with you).

Shark's Bay also hosts, I believe, the two fiercest anemonefish in the whole of the Northern Red Sea. On a sandy plateau at about 14m, you come to a very nice coral head (often with two large morays inside it) and next to this is a bubble anemone inhabited by some seriously aggressive fish. If you believe anemonefish don't have teeth (which I've actually heard some dive guides say), spend a few minutes near this anemone and then tell me they don't have teeth. I swear these fish are reincarnated sharks.

Best time to dive Shark's Bay? Obviously at night, but before 8AM is equally good (i.e. before the day boats arrive to ferry all those divers and snorkelers to the Strait of Tiran) as is an hour before sunset (once all those day boats have deposited their guests back on terra firma).

Love it? Loathe it? It's all the same to me; Shark's Bay is one of my favourite dive sites.

See our Shark's Bay Photo Gallery

The Oceanic Whitetip Shark "Carcharhinus Longimanus"

2011-01-07T01:24:00.000-08:00

Sightings of oceanic whitetip sharks at certain dive sites in the Central & Southern Egyptian Red Sea became a common occurrence in the late 1990s/early 2000s. Found off-shore in tropical and subtropical seas around the globe, they are normally cruising the upper layers of their open-ocean habitat in search of food.
They are easily recognisable sharks, with their broad, large, rounded first dorsal fin, wing-like pectoral fins, and conspicuous colour markings on practically all fins (see fig. 1). These markings do not only identify them on the species level, they also allow for easy identification of individuals.

In October 2004 a photo-identification study of oceanic whitetip sharks was initiated that continues until today (see http://hepca.us1.list-manage.com/track/click?u=96f527b0a31776324930823d5&id=15aa959f6a&e=bb0a582a97).u=96f527b0a31776324930823d5&id=15aa959f6a&e=bb0a582a97).

Collecting underwater images of these sharks led to a species catalogue containing the individual markings as well as sighting histories of close to 550 identified oceanic whitetip sharks to date.
Taking a closer look at these documented sightings, certain residency and movement patterns have emerged over the last 6 years. The hotspots for oceanic whitetip sightings have been Daedalus Reef, Brother Islands and Elphinstone, with clearly fewer sightings reported from St Johns, Fury Shoals, and South Sinai. Aside from the occasional encounter in spring and summer, the clear majority of these sharks are seen from late September to early December. Most of the oceanics approaching dive sites, dive boats and humans are ranging from ~1.5 m to ~ 2.2 m total length.
On occasion, individuals have become residents of a certain site or area for months at a time, but a more typical pattern is a short stay during one season with a 15-40% chance of resighting in following years.
Single individuals are seen over several years on a regular basis, proving the suitability of the natural markings used for this research (see example in figure 2).

Fig. 2: Underwater images of the dorsal fin (right side) of individual 506, an adult female oceanic whitetip, from 2004 – 2010. The reef where the respective picture was taken is given underneath the information on month and year (© longimanus-project)

Very few animals reaching (or even almost reaching) the reported maximum size for the Red Sea (2.5 - 3 m) have been documented throughout the last 6 years. A total of eleven individuals were identified from the species catalogue before November 2010. Table 1 gives details on where and when these large sharks were photographed.

Table 1: List of the larger oceanic whitetip sharks documented on photographs collected since October 2004.

Figure 3 shows the different body proportions identifying these large specimens, even without accurate measurements being available.

Fig. 3: Proportion of different oceanic whitetip sharks from the Egyptian Red Sea. Top: juvenile, middle: slender adult, and bottom: large adult.

Behaviour towards humans:

The Egyptian Red Sea is THE place worldwide to observe oceanic whitetip sharks underwater. Unlike some of the other shark species in the area, which are easily intimidated by human presence, they are self-confident and inquisitive. This notorious boldness – often wrongly interpreted as aggression – results in close and memorable encounters for thousands of divers every year.
Throughout the last 6 years a few incidents of oceanic whitetips biting humans in the water were reported from the Central & Southern Egyptian Red Sea. Most of these cases could be linked to illegal feeding and/or baiting activity from liveaboards and all of them involved snorkelers.
No serious incidents with divers have been reported.
Baiting and feeding predators can cause changes in their behaviour. As a consequence, interactions with them might become more unpredictable and potentially dangerous.

Guidelines for diving with sharks in the Red Sea:

Remember, you are entering the realm of highly evolved and perfectly adapted open-ocean predators, who should be treated with respect and caution. While the risks in diving with sharks are minimal, following certain behavioural rules helps to avoid potentially stressful or even dangerous situations.

Feeding and baiting sharks is illegal across the Egyptian Red Sea! Do not enter the water if there is any sign of this kind of activity in the vicinity.
Only enter the water if you are comfortable with the situation and confident that you can stay calm.
Avoid any quick, jerky or erratic movements.
Be aware that you are most vulnerable on the surface. So descend promptly after entering the water and watch your buoyancy throughout the dive.
Try to avoid quick ascents, especially with a shark right below you.
If you want (or need) to leave the water, do so in a calm and orderly fashion.
Most shark species that are inquisitive enough for close approaches are found in open water, not along the reef. Staying next or retreating to the reef should help avoid a close encounter. If conditions allow it, surface next to the reef and wait to be picked up by zodiac.
Do not try to touch or in any way harass any shark. This includes not closing off an escape route for sharks you find underneath overhangs, in caves or crevices in the reef wall.
Do not be alarmed by a shark calmly circling you; just make sure you turn with it and keep it in sight
Stay alert and look around you from time to time to see if another shark is approaching you from behind/underneath/above. As predators, sneaking up on unknown objects is part of their natural behaviour.
Generally, sharks are more reluctant to closely approach groups of divers than single ones.

Scientific Outlook:

The Oceanic Whitetip Shark is the only Red Sea shark species, for which any kind of scientific data is available. Using the presence of divers and the widespread use of underwater digital cameras, the collection of underwater images has proven to be a useful tool for the study of these ocean-going predators.
These efforts to collect photographs and videos will be intensified, reaching out to visitors to the Red Sea and encouraging them to make their footage available to the study.
Additionally HEPCA is funding a pilot tracking project fitting oceanic whitetip sharks with satellite tags. These tags will hopefully provide introductory information unavailable from purely photo-ID based studies, such as dive profiles and geolocation tracks. Subject to future funding, a more extensive study will be conducted, focussing on identifying critical habitats of the species, e.g. reproductive areas and nursery grounds.
To address the lack of data available for other Red Sea shark species, a monitoring program is planned involving diving professionals as qualified volunteers. Further details on these projects are available at www.hepca.com/longimanus-red-sea-shark-id.aspx.

Facts about the Sharm El Sheikh incidents November / December 2010:

Between Tuesday, November 30th, 2010, and Sunday, December 5th, 2010, five swimmers were attacked by shark(s) off the South Sinai Coast, between North of Naama Bay and Ras Nasrani.
The first two victims, two Russian women, were attacked in short succession in the early afternoon on Tuesday while swimming off the beach. Both suffered multiple bites resulting in serious injuries. Minutes before one of these attacks, divers photographed a large adult female oceanic whitetip shark and observed it approaching one of the swimmers on the surface.
The following day, two men (one Russian, one Ukrainian) were attacked – again in short succession close to the beach around midday – a few kilometres north of the area of the first attacks. One of the victims was bitten once resulting in minor injuries, the other again suffered multiple bites and serious injuries. No video or photograph has been available of this attack or the involved shark.
As a consequence, all diving, snorkeling and other watersports activities were suspended in the Sharm El Sheikh area, with the exception of Ras Mohamed National Park.

By Thursday afternoon/night, pictures of two captured (and killed) sharks were published by officials, showing one male shortfin mako shark (Isurus oxyrinchus) and one female oceanic whitetip shark. Comparing their natural markings and body proportions, it could be concluded immediately, that the caught oceanic was not the same large female that was photographed at the site of the first attacks.

This large female was observed and filmed by divers in Ras Za'atar (Ras Mohamed National Park) on Friday, December 3rd, 2010, around midday. It showed the typical inquisitive behaviour of this shark species; no aggression was reported.
The information, that the shark implicated in the first 2 attacks was seen in Ras Mohamed was made available to officials immediately.
On that same day, exploratory dives had been carried out by dive professionals along the Sharm El Sheikh coast without encountering any other sharks.

All restrictions on water-activities were lifted and the beaches re-opened on the morning of Saturday, December 4th, 2010.

On Sunday, December 5th, 2010, around midday, a German swimmer was attacked by a shark in Garden Bay. She died on site due to the severity of her injuries. A picture taken on the surface during the attack shows the same large female oceanic whitetip shark that had been observed during Tuesday's attacks, and interacting with divers in Ras Za'atar on Friday. Again, individual markings were used to verify her identity.

All beaches were immediately closed again, and at the time of writing, only dive professionals and experienced divers have been allowed in the water, with further restrictions in place in the area of the attacks. These divers have been asked to report back any shark activity in the area.

On Tuesday, December 7th, 2010, around midday, underwater photographs taken in Ras Mohamed by some of these divers again show the large adult female oceanic whitetip shark (from Tuesday, Friday & Sunday) interacting with divers at Yolanda/Shark Reef.

Conclusion:
A single large female oceanic whitetip shark has been observed at the site of 3 attacks on swimmers off Sharm El Sheikh, with eye-witness reports available for two. She is still in the general area, and – for the last 8 days – followed a pattern of traveling between the area of the attacks North of Naama Bay to Ras Mohamed National Park and back within 2-3 days.
The severity of the attacks and the amount of human tissue taken (and potentially swallowed) indicates a clear deviation of the normal behaviour of an oceanic whitetip shark. Instead of briefly grabbing for testing or tasting purposes, this female apparently considers human swimmers as a potential food source.

For further information & questions please contact:

Dr. Elke Bojanowski
Biologist and initiator of the longimanus-project
sharks@hepca.com

To submit underwater images of Oceanic Whitetip Sharks, please go to
http://www.longimanus.info/rss_upload/upload.html

Shark incident off Southern Sinai

2011-01-07T00:19:00.000-08:00

Short summary of the events:On November 30th, 2010, two snorkelers were attacked by a shark off a beach just north of Naama Bay, both suffering serious injuries. Photographs taken minutes before the 2nd attack show a fully grown oceanic whitetip shark (Carcharhinus longimanus), that closely circled divers before approaching and eventually attacking a swimmer on the surface.On December 1st, 2010, a third swimmer was attacked just a few kilometres north of the previous incidents; no photographic material is available from this event.Reports of a fourth attack were later corrected, stating that the injuries to the hands of the swimmer involved were sustained by contact with corals rather than from the bites of a shark.

As a first response, the Ministry of Tourism suspended all water activities for the Sharm El Sheikh area, with the exception of Ras Mohamed National Park, until the evening of December 3rd, 2010.Additionally, National Park Authorities attempted to capture the shark(s) believed to be involved in the attacks. As a result, two individual sharks were caught on December 2nd, one mako shark (Isurus oxyrinchus) and one oceanic whitetip shark.

Comparing the photographs of the oceanic whitetip shark responsible for the 2nd attack with the images of the captured oceanic whitetip shark, it is clear that they don't show the same individual.

Hesham Gabr, the chairman of the CDWS (Chamber of Diving and Watersports), has condemned the random catching of sharks in the area. In agreement with HEPCA, both organisations would have preferred a more graded response to the unfortunate events. No attacks on divers have been reported from any of the dive sites in the Egyptian Red Sea, making the closure of all diving activities an unnecessary and extreme measure. While we fully appreciate the difficult and sensitive situation after such an unusual string of attacks for the tourism sector, the random catching and killing of large oceanic sharks in the area does not help to mitigate the problem; additionally it sends the wrong message that people entering the water are generally in danger of being attacked by sharks.Such attacks are extremely rare and in the past have often been connected to illegal fishing and feeding activities.

We therefore welcome the efforts of the CDWS today, sending out volunteering dive professionals and registered CDWS members to monitor and observe the Sharm El Sheikh dive sites for any shark activity. These divers were encouraged to document any shark sightings by taking underwater images, so that we will be able to verify and potentially identify any oceanic whitetip sharks still present in the area.

According to an ongoing study of oceanic whitetip sharks in the Egyptian Red Sea, only 11 individuals resembling the size and proportion of the shark responsible for the 2nd attack have been documented throughout the last 6 years. All these sightings were from remote areas such as Daedalus, Brother Islands or the St. Johns plateau. 10 of these sharks were photographed by divers only on one occasion, and – to our knowledge – did not approach any humans or human activity afterwards.These observations support the idea, that the string of attacks is the result of a single individual behaving in a highly atypical way.

Both HEPCA and CDWS call for calm in this unprecented and difficult situation, and appeal to tourists and professionals to follow well-known behavioural guidelines recommended in areas where sharks might be present.·

- Do not fish, feed or bait any marine animal.
- Do not enter the water if any of these activities occur in the vicinity.·
- Stay calm! Avoid any quick, jerky or erratic movements.·
- If you want or need to leave the water for any reason, do so in a calm and orderly fashion.

For more detailed guidelines on diving with sharks in the Egyptian Red Sea, feel free to contact sharks@hepca.com.

Recent Sightings

2010-10-03T06:17:00.000-07:00

As always, we've had some very good sightings this last month. The sighting that caused the most excitement (and envy) was some dolphins at the Thistlegorm. Greg and two very, very lucky guests spent 7-10 minutes with 7 bottlenose dolphins during the end of their first dive on the wreck. Not a bad way to make a safety stop. Gordon Reef has provided us with some cool moments: Sameh and his guests saw a manta and two eagle rays there, Maria with her guests saw two white tip reef sharks, two eagle rays and some schooling barracudas and Sean had three white tip reef sharks (probably why the area is known as the shark pool). Still in the Strait of Tiran, Greg found a leopard shark at Woodhouse Reef and Richard found two green turtles. In the Ras Mohammed National Park, Maria and her guests saw a thresher shark at Marsa Bareika and spent 20 minutes with a large manta at Ras Za'atar. At Shark & Yolanda Sean found a honeycomb whip ray resting at the back of Shark Reef. We don't get excited about just the large critters either, Sean found an urchin mantis shrimp in Shark's Bay and swears it's the best thing he's seen all year.

Water temperature is about 26-27 degrees Celsius, and the air temperature is still in the mid 30s. We've changed the clocks (the fourth time this year!) so the evenings come fast now. Not that this is a problem, it just means you can start your night dives a little bit earlier now.

Hammerhead Shark

2010-10-03T06:10:00.000-07:00

Hammerhead Shark from Cigdem Cooper on Vimeo.

The hammerhead sharks are a group of sharks in the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a "hammer" shape called a "cephalofoil". Most hammerhead species are placed in the genus Sphyrna; some authorities place the winghead shark in its own genus, Eusphyra. Many, not necessarily mutually exclusive, functions have been proposed for the cephalofoil, including sensory reception, maneuvering, and prey manipulation. Hammerheads are found worldwide in warmer waters along coastlines and continental shelves. Unlike most sharks, hammerheads usually swim in groups (called ‘shivers’). Some of these schools can be found near the Cocos Islands by Costa Rica

The nine known species range from 0.9 to 6 m (3.0 to 20 ft) long. The average hammerhead shark weighs about 500 pounds, but some may grow up to 1000. All the species have a projection of their face on all sides of the head that gives it a resemblance to a flattened hammer.
It was determined recently that the hammer-like shape of the head evolved to enhance the animal's vision. The positioning of the eyes give the shark good binocular vision, as well as 360-degree vision in the vertical plane, meaning they can see above and below them at all times. The shape of the head was previously thought to help the shark find food, aiding in close-quarters maneuverability and allowing sharp turning movement without losing stability. However, it was found that the unusual structure of its vertebrae allowed it to make the turns correctly, more often than its head. The hammer would also shift and provide lift.
Hammerheads are one of the most negatively buoyant of sharks. Like all sharks, hammerheads have electroreceptory sensory pores called ampullae of Lorenzini. By distributing the receptors over a wider area, hammerheads can sweep for prey more effectively. These sharks have been able to detect an electrical signal of half a billionth of a volt. The hammer also allows the nostrils to be placed farther apart, increasing its ability to detect chemical gradients and localize the source.
Hammerheads have disproportionately small mouths and seem to do a lot of bottom-hunting. They are also known to form schools during the day, sometimes in groups of over 100. In the evening, like other sharks, they become solitary hunters.
Hammerheads are notably one of the few animals that acquire a tan from prolonged exposure to sunlight. Tanning occurs when a hammerhead is in shallow waters or close to the surface for long periods.

Since sharks do not have mineralized bones and rarely fossilize, it is their teeth alone that are commonly found as fossils. The hammerheads seem closely related to the carcharhinid sharks that evolved during the mid-Tertiary Period. Because the teeth of hammerheads resemble those of some carcharhinids, it has been difficult to determine when hammerheads first appeared. It is probable that the hammerheads evolved during the late Eocene, Oligocene or early Miocene.
Using mitochondrial DNA, Andrew Martin constructed a phylogenetic tree of the hammerhead sharks that showed the winghead shark as its most basal member. As the winghead shark has proportionately the largest "hammer" of the hammerhead sharks, this suggests that the first ancestral hammerhead sharks also had large hammers.

The hammerhead sharks exhibit a viviparous mode of reproduction with females giving birth to live young. Like other sharks, fertilization is internal with the male transferring sperm to the female through one of two intromittent organs called claspers. The developing embryos are at first sustained by a yolk sac. When the supply of yolk is exhausted, the depleted yolk sac transforms into a structure analogous to a mammalian placenta (called a "yolk sac placenta" or "pseudoplacenta"), through which the mother delivers sustenance until birth.
In 2007, the bonnethead shark was found to be capable of asexual reproduction via automictic parthenogenesis, in which a female's ovum fuses with a polar body to form a zygote without the need for a male. This was the first shark known to do this.

Hammerhead sharks are known to eat a large range of things, including fish, other sharks, squid, octopus, and crustaceans. Stingrays are a particular favorite. They are also known to eat their own young.

It's official - Stonefish are from Space!

2010-08-31T05:07:00.000-07:00

NASA has confirmed what many divers have believed for a long time - stonefish (Synanceja verrucosa) are not of this world!

NASA boffin Issac Einstein Asimov told reporters that, using the Hubble telescope, they had located the home galaxy, named 'Tadpole Galaxy', of the

stonefish.

"It's amazing!", enthused an excited Mr Asimov, "The larvae of the fish are spawned in the Tadpole Galaxy and then, once they reach a suitable size for

space travel, ejected from the galaxy in search of an aquatic world such as our own."

The scientists are unsure whether the fish have specific destinations in mind once they start their travels, or if and how they send postcards back home.

It also explains why the stonefish are so damn ugly and perpetually sad. In the first case it is due to travelling through the coldness of space, before being roasted

via planetary entry and then plunged into, often, cold water. As for their perpetually sad countenance, they are simply homesick.

It also explains why most divers do not see small stonefish, they simply burn-up on entry in to a planet's atmosphere.

Celebrate this amazing discovery by playing 'Hungry Space' via the following link - http://www.freeworldgroup.com/games/hungry_space/index.html

UNDERWATER PHOTOGRAPHY ETIQUETTE

2010-08-29T15:12:00.001-07:00

Etiquette for Photographers

Respect the Environment
Taking a good photo is no excuse for damaging the environment. This is where underwater photographers are most vulnerable to criticism. Unfortunately there are a lot of divers out there who, before they fine tune their buoyancy control, rush out and buy an underwater camera. Adding a camera and strobe affects buoyancy! Once the eye is glued to the viewfinder, depth perception and peripheral vision are reduced enough so that even a skilled and concerned diver might accidentally bump into coral. In addition, underwater photography generally requires close proximity to the subject in order to maximize colour and detail. Get too close, catch a bit of surge, get bumped by another diver and accidents happen. Photographers who truly care about the reef will learn and practice buoyancy control. Unfortunately, there are also callous photographers who are willing to damage the reef in pursuit of a photo. You've probably seen them, lying on coral to take a photo of an anemone, holding on to a piece of coral to steady themselves, or exhorting their buddies to sit on part of a wreck for a “great group photo”. It’s possible they don’t know better but, in this age of eco-enlightenment, not likely. We know the reef is a finite resource, very susceptible to damage and slow to recuperate, no one should be allowed to trash it purposely, whether in pursuit of tropical fish for the aquarium, food for the table, or even photos for a Facebook album. Doing so is criminally wrong. If you see divers doing so, have a word with the dive guide - not the divers themselves.
Play Nice
Ever wonder why in some photos Spanish Dancers are “dancing” yet the ones you see on dives are always sitting on corals? The reason is usually the photographer has picked up the dancer and thrown it in to the water column to get the dancer to dance. Moving and harassing marine life for the sake of a photo is wrong. Photos of purposely inflated pufferfish or divers handling turtles show a lack of respect for sea life and the marine environment. These photos shouldn't be taken, and certainly should not be rewarded by being published or considered in photographic competitions.
Be Considerate
Just because you hold a camera doesn't mean you can dislodge a non-photographer diver away from something they’re looking at. If you see a diver observing something of interest, wait from a respectful distance and approach for the shot when the other diver has finished.
Dive Safe
Don't ignore dive safety in pursuit of a photograph. Remember – Diver first, photographer second. Too often photographers will dive too deep, stay too long, and perform careless zigzag profiles, all because that's where the pictures are.
Be Appreciative
Taking photographs under water is a privilege, not a right. Toting cameras below does not bestow upon the photographer any special status or rights. Whatever one's underwater interests, all divers should enter the water with an ample supply of humility and an appreciation of one another and this special place we are allowed to visit.
Etiquette for non-photographers
Be Knowledgeable
All contact is not necessarily bad contact. There are portions of the reef, particularly bits of rubble or algae-covered rocks, that are unaffected by careful finger or fin placement. Kneeling in the sand patches is certainly reef-friendly, so long as a photographer doesn't erupt in a cloud of detritus leaving the bottom, thereby silting the very coral reef you so admired a moment before. Before assigning guilt, make sure the photographer is actually in damaging contact with live coral. Sometimes the perspective of distance gives a false illusion of eco-terrorism.
Be Understanding
Not everyone on a dive boat understands the value or the fragility of photographic equipment. The photographer bears the responsibility of keeping the gear on a dedicated camera table or somewhere out of the normal flow of traffic. Other divers on boats bear the responsibility of not dropping their equipment on dome ports, housings and strobes. Also remember “wet & dry” areas, and don’t go flinging saltwater droplets from wetsuits or hair as the photographer is changing batteries or lenses. A little space for photographers and their gear is essential.
Be Sensible
Use common sense with underwater encounters. If you see a photographer carefully stalking some elusive critter, don't swim nearby. Just the sound of your regulator may scare the subject away. If you see a photographer setting up a wide-angle shot on a vertical wall, don't swim directly beneath. Your exhaust bubbles will inevitably rise exactly where they shouldn't.
Be Forgiving

Just because you see an unattended camera on the bottom; don't assume you've struck it rich. Photographers can't change film or batteries under water, so occasionally they will carry more than one camera or strobe on a dive. Don’t just take what you find, there could be a photographer in the area who’s very upset that you’ve just swam with his/her second camera.
Be Careful

The rinse bucket is no place for carelessness. This precaution is for photographers, non-photographers and Divemasters. Too often, camera floods or dome damage occurs at the end of the dive in the rinse bucket. When multiple camera systems are placed in the rinse tank simultaneously, cords entwine framers and abrasive arms and trays inevitably bounce on delicate ports. Pulling one system out pulls something else off and a flood ensues. The goal is to displace salt water with fresh water immediately, and to that end, a brief but thorough rinse is all that's required.

August 2010: Recent Sightings

2010-08-29T15:05:00.000-07:00

Summer in Sharm el Sheikh

Shoals of twin-spotted snappers off the wall at Shark Reef, schooling barracudas in the blue at the front of Yolanda Reef, hammerheads in the Strait of Tiran and angry titan triggerfish; it can mean only one thing - Summer has finally arrived! The air temperature is now well in to low 40s and the water a balmy 26-27 degrees Celcius, so it's definitely time to put away your longsuit and time to see if your shorty still fits after it's winter hiatus. It's also definitely time to be drinking liking a fish (and we're refering to H2O not Sakara).

We’ve had some good sightings over the past few weeks: white tip reef sharks and leopard sharks at Gordon Reef, more white tips at Jackfish Alley as well as black tip reef sharks, whale sharks at Ras Nasrani, fantails at Ras Ghamila and Marsa Bareika, hammerheads at Thomas Reef (well one anyway), mantas at Shark Reef and Tower, grey reef sharks at Ras Gomaa, spotted eagle rays just about everywhere, and green turtles at Ras Ghamila at the back of Yolanda Reef. If there is such a thing as the"best time" to be diving around Sharm, then it is probably now.

Fish of the Month: Stonefish

2010-08-29T05:09:00.000-07:00

Stonefish (Synanceja verrucosa)

Length: up to 0.4 m
Distribution: Pacific and Indian Ocean, ranging from the Red Sea to Great Barrier Reef

Synanceja verrucosa is a fish species, sometimes lethal to humans, which is known as the reef stonefish or simply stonefish. They are carnivorous ray-finned fish with venomous spines that lives on reef bottoms, camouflaged as a rock. They are the most venomous known fish in the world.

The average length of most stonefish is about 30-40 centimeters. The largest Stonefish ever recorded was 51 centimeters long. It has a mottled greenish to mostly brown colour which aids in its ability to camouflage itself among the rocks of many of the tropical reefs. It eats mostly small fish, shrimp and other crustaceans.

Like the shark family, stonefishes do not possess a swim bladder and swim by thrashing their tail in a side-to-side manner. However, divers rarely see a stonefish swimming (which has given rise to the often stated and incorrect statement that "stonefish can't swim") as they are usually found motionless on the coral or floor. Unless severely frightened, a stonefish will prefer to move by walking on its pectoral fins.

Its main habitat is on coral reefs, around dull coloured plants, near and about rocks, or can be found dormant in the mud or sand.

The Reef Stonefish is the most venomous fish in the world. Its dorsal area is lined with 13 spines that release venom from two sacs attached to each spine. Its venom causes severe pain with possible shock, paralysis, and tissue death depending on the depth of the penetration. This level can be fatal to humans if not given medical attention within a couple of hours. Immediate first aid treatment requires immersion of the affected limb in hot water, ensuring that it is not so hot that skin damage may occur. The immobilisation of venom at penetration site by tourniquet or firm constrictive bandaging is no longer recommended.

The venom consists of a mixture of proteins, including the hemolytic stonustoxin, the neurotoxic trachynilysin and the cardioactive cardioleputin; an antivenom is available.

The venom is protein based, and it can be (partially) denatured by the application of a very hot compress to the injury site. Some relief can be gained from infiltrating the wound with a local anaesthetic. This is a temporary measure to reduce localized pain and shock. Medical aid must be sought at the earliest opportunity. Typically, surviving victims suffer localized nerve damage occasionally leading to atrophy of adjoining muscle tissues.

There have been unproven reports of osteo-arthritic sufferers experiencing improved mobility and reduction in joint pain following envenomation episode. The responsible agent has not been identified.

The pain is said to be so severe that the victims of its sting want the affected limb to be amputated. The poisonous sting of Scorpion Fish and Lionfish are said to deliver almost the same level of pain.

Gordon Reef, Strait of Tiran by Sean Cooper

2010-08-13T00:37:00.000-07:00

Gordon Reef is the first of four reefs lying in a north-east line in the Strait of Tiran and is easily identified by the wreck of the Louilla, a Panamanian cargo ship, that ran aground on the reef in 1981. The "classic" dive here runs along the north side of the reef, however the reef on the southern and western side is, for me, far prettier, more pristine and has a lot more variation.

My favourite dive here (which can be done as a fixed mooring dive or drift dive), starting from one of the westerly moorings, takes you east to the drop-off where you encounter numerous giant sea fans. From here, proceeding in a south-westerly direction, you follow a large extensive plateau (approixmately 24m), skirting around the outside of what is known as the Amphitheater (a large circular sandy depression). In this area you generally find hundreds of schooling bannerfish, numerous twin-spotted snappers and trevally (orange-spotted and barred). If you are fortunate, you may encounter turtles, large rays (such as the spotted eagle ray) or even sharks (such as the leopard shark, grey reef shark or white tip reef shark). Eventually the plateau turns north leading you back to the mooring area (a sandy area full of fire corals as well as a pile of cables and metal bars). If conditions are favourable, you can continue the dive as a drift along the western side of the reef which has an extensive area of pinnacles.