A portrait of a Scalloped Hammerhead shark

Daedalus Reef — Where the Hammerheads wander

9 min readMay 10, 2018

This article originally appeared in my Blog on my Website in May 2018.

The Hammerhead shark is one of those animals that everyone knows, no matter if you’re into diving or not. It is all over the place, from children's books, comics, and cartoons down to great images, and various adventure/wildlife multi-media content including documentary TV shows and movies. One of the easy-to-get places from Europe, where encounters with Hammerhead sharks are common is Daedalus Reef in the Red Sea, Egypt.

A story about Scalloped Hammerhead sharks and Daedalus Reef.

For more shark photos take a look at my Sharks and Ray gallery as part of my Website.

In December 2019, they have been upgraded from Endangered to Critically Endangered as the overall population trend is in Decline.

Hammerhead

Hammerhead sharks are named due to the unusual and unique shape of their head, called cephalofoil, which is flat and has a hammer-like shape.

The key reason why the head is shaped like a hammer is to improve vision and sensory capability.

Their eyes are positioned on the sides of the head and this gives them 360 degrees of vision in the vertical plane. This means that they can at any given time see what is above and below them.

This specific shape contributes to the distribution of their electroreceptors (Lorenzini ampules) over the wider area which allows them to look for their prey more efficiently. This is like they have a bigger antenna built into their heads when compared to other sharks.

For each Hammerhead species, the head comes in a slightly different appearance and based on it some of the Hammerhead species got their common names.

They have a very small mouth compared to body size and often feed off the bottom. Their excellent sensory capability allows them to find prey under the sediment at the bottom such as stingrays.

Overall, their size can range from 1 to 6 meters, depending on species, age, and sex. Color varies depending on species and location while bellies are always white which allows them to camouflage themselves and sneak onto prey that is below them.

Scalloped Hammerhead shark from above in the deep waters

Unlike other sharks, Hammerhead sharks usually swim in schools that can be very small with a dozen of them up to large ones that have hundreds and even thousands of sharks. Young ones since on their own are always kept together for safety and can be found in schools only while adults can also be found on their own. Like any other shark, when the sun goes down they become solitary predators and get into feeding mode.

They typically reside in warm waters close to the coast and continental shelves. During the summer they look for cooler waters and migration happens, but in some cases, this also means that they stay in the same place but just go deeper.

The most famous places to encounter large schools of Hammerhead sharks are Cocos Islands in Costa Rica, Malpelo Island in Colombia, and the Galapagos Islands in Ecuador. All these places are very remote places and accessible only by the very small amount of liveaboards that operate in those specific areas. Specific local regulations also apply.

Scalloped Hammerhead

The scalloped hammerhead with its scientific name Sphyrna lewini is the most common. They are named Scalloped due to the “scalloped” front edge of their hammer-shaped head.

It typically comes in olive, bronze, or light brown color with a white belly. The edges of the fins are usually darker on young animals but become lighter as they grow older.

Scalloped hammerhead can be found all around the globe in the coastal regions of tropical, subtropical, and moderate climate zones, which means between roughly 40 degrees north and south of the equator. Most often they can be found up to 25 meters of depth but they can dive down to 300 meters. Males typically stay deeper compared to females.

It is a very large shark, though not as large as the Great Hammerhead. Males are typically long between 1.5 and 2 meters while females on average are 2.5 meters long. Females can easily grow more than 4 meters in length.

They feed mostly on fish such as sardines, herring, and mackerels. Occasionally they also feed on squid, octopuses, and stingrays. Large Scalloped Hammerhead sharks also eat small-sized shark species such as Black Tip Reef sharks.

Groups of scalloped hammerheads prefer staying in regions that have pinnacles or sea mountains which reach from great depths practically to the water’s surface.

Silhouette of Scalloped Hammerhead deep down

How To Act

They are not considered as dangerous and are normally they’re not aggressive toward humans. Some of the registered accidents can be contributed to murky waters and confusion.

As with most sharks, bubbles are the key obstacle between you and a close encounter with a scalloped hammerhead. Therefore, make sure your breathing is highly controlled and you and your diving buddies do not produce a wall of bubbles in front and around you. One way to manage bubbles is also to keep a bigger distance between each other than you would normally do. Finally, save some bubbles to manage too close of an encounter if you need to.

While diving with a small school of scalloped hammerheads we noticed that the school registres us from far away while they’re deeper and then sends an “envoy” to assess the situation and identify should the school approach us or not.

Swimming fast toward the “envoy” and being ecstatic about it would typically make him go away very quickly and that also means no encounter with the school at all. So, keep calm and maintain distance toward this one Hammerhead and that will make sure the entire school will most probably and very soon appear. They will just come up from the depth to around 25–30 meters and allow for close passes.

They like strong currents such as next to Wolf and Darwin Islands in Galapagos where one needs to manage a big physical effort related to breathing to get close to them. One of the strategies is to find a cover from the currents next to or in-between big underwater rocks or use a reef hook which will allow for an easy stay in the strong currents with no significant effect on breathing. Here one can see schools of hundreds or thousands.

School of scalloped hammerhead from the above deep down

Environmental Status

Their shark fins are highly valued and they are being increasingly targeted in some areas in response to increasing demand for shark fins while at the same time a by-catch on bigger scale fishing.

Depending on the type of hammerhead, IUCN has categorized them in different ways.

Great and Scalloped Hammerhead sharks are per IUCN Red List assessed overall as Critically Endangered.

In 2013, Hammerheads were added to Appendix II of CITES, bringing shark fishing and commerce of these species under licensing and regulation.

In December 2019, they have been upgraded from Endangered to Critically Endangered as the overall population trend is in Decline.

The species is caught globally as a target and bycatch in pelagic commercial and small-scale longline, purse seine, and gillnet fisheries, and is retained for the meat and fins. The Scalloped Hammerhead has undergone steep declines in all oceans, with some signs of stabilization and possible recovery in response to management only in the Northwest Atlantic and Gulf of Mexico. The weighted global population trend estimated median reductions of 76.9–97.3%, with the highest probability of >80% reduction over three generation lengths (72.3 years), and is therefore assessed as Critically Endangered A2bd.

How and where to find them

Part of my encounters with Scalloped Hammerheads was limited to the Red Sea, specifically, the southern part. All such encounters took place during the series of Alex Mustard’s Underwater Photography Workshops that were all about Oceanic Whitetips and they were held each year in early November.

I am talking more about these trips in my previous blog post on Oceanic Whitetips: The Red Sea — Home of the Oceanic Whitetips.

School of Scalloped Hammerhead sharks from the above deep down

Daedalus Reef

Daedalus Reef, also known as Abu Kizan is an off-shore reef in the Red Sea, Egypt positioned around 90–100 kilometers east of Marsa Alam, almost halfway to Saudi Arabia.

The reef has a shape of a submerged reef table. It is approximately 450 meters long and 100 meters wide. The reef wall drops from 30–40 meters to a depth of 500 meters.

Inside the reef, there is a small artificial island that hosts a lighthouse constructed in 1863 that was later rebuilt in 1931. Lighthouse can be visited and is a unique opportunity in the Red Sea to step out of the liveaboard and do something different.

Reef walls are packed with abundant growth of hard and soft coral as well as standardly amazing Red Sea marine life. But, pretty much everyone here comes for the sharks.

Daedalus Reef is one of the most famous scuba diving locations in the Red Sea due to the possibility to experience an encounter with sharks, especially with a school of scalloped hammerheads.

Scalloped hammerheads can be found all around the reef throughout the year. In summer they would tend to stay deeper in cooler waters so the probability of the encounter is smaller, but not impossible. The northern tip of the reef is where most of the encounters take place.

Dives on which you will meet scalloped hammerheads are all in the blue. For this, you need to be an experienced and well-patient diver since you could spend easy 20–40 minutes in the blue and see nothing. Many of the dives end with no encounter at all, so it could be maybe disappointing. This is why it is important to keep coming and repeating the same dive in the blue and be patient on each of the dives.

Other shark types can also be seen here as well, such as Oceanic Whitetip, Gray Reef, Silky, and Trasher sharks. The most commonplace to see them is the southern plateau.

Mantas are not uncommon, but not standard. In all my trips I have seen only one.

The only way to get here is to book a liveaboard with a route that includes this amazing reef on its itinerary. To get the best out of it and to maximize your chance to have an amazing encounter with any type of shark and definitely to see a school of scalloped hammerheads is to stay there for a few days and some liveaboards offer this option on their itinerary. Or just keep coming many times for a day.

Manta Ray showing up at the beginning of a dive at Daedalus Reef

Key Takeaways

If you would like to get some sort of takeaway from this story and write down some action points while getting ready for your next trip to the Red Sea, think about these things:

The easiest way to meet scalloped hammerheads is on the Red Sea liveaboards running the southern route that visit Daedalus Reef.
You need to be patient and not scare the first hammerhead you see since you might miss the entire school if he goes away.
Scalloped hammerheads are sensitive to bubbles, so control your breathing.
Be prepared to go deep, down to 40 meters, so think about what gas mixture you’re breathing.

References

Photos and videos used in this article were created by me on three different liveaboard trips in the Red Sea throughout 2014, 2015, and 2016.

My tools of the trade under the water are Nikon D700 DSLR camera with Nikkor AF 16mm f/2.8D fisheye, Sigma AF 15mm f/2.8 EX DG fisheye, and Nikkor AF-S 16–35mm f/4.0G lenses inside Sea & Sea underwater housing with Sea & Sea YS-250 PRO underwater strobes.

Above the water, I am a big fan of the Fujifilm XT-10 camera in combination with Fujinon XF 23mm f/1.4 R lens.

Video material is also created by me using the GoPro camera on the same trips.