Aliwal Shoal: Home for sharks, heaven for divers

In South Africa, divers usually have one focus: sharks. They want to know where they can dive with sharks, how to do it ethically, and why sharks flock to the southern tip of Africa. Notorious for its sheer quantity of sharks is Aliwal Shoal, which is nestled into the northeastern part of the country. Experienced divers know that Aliwal Shoal is the best place to see sharks in South Africa.

A perfect geological home for sharks

Aliwal Shoal is a fossilized sand dune and beach rock reef. It is composed of calcium carbonate (the same material as limestone). Some scientists have dated the age of this reef to 2.9 million years old. The shoal was originally a coastline, but when glaciers melted, global sea levels rose. Today, the reef is in the ocean 5 kilometres offshore from the small town of Umkomaas, Kwazulu-Natal, South Africa.


Its geographical location has caused the reef to boast some of the most diverse marine life in South Africa. The Agulhas current moves warmer ocean water from the Indian Ocean along the Eastern Coast of South Africa. Then, it pushes up nutrient-rich water from the depths of the ocean towards reefs like Aliwal Shoal. This, in turn, allows marine life to flourish.

Photo Credit: Katherine Hutchinson

Aliwal sits between the cold-water diving of Cape Town to the south and the tropical waters of Sodwana Bay to the north. The current provides Aliwal with the biodiversity of both regions when predators like sharks follow the fish who follow the food.


Nicki Gibson and Gary Snodgrass have been diving in Aliwal Shoal for 26 years between them and to this day, Nicki gets excited about every dive. When we dove with their dive company, Blue Ocean Dive, she shared that her excitement was because “You never know what you’re going to get!” The marine life changes seasonally, but the divers who frequent the shoal are always surprised by the new and fantastic marine life.

Nicki Gibson and her dog, Trimex

Preserved by Marine Protected Area status

Another reason that Aliwal Shoal has remained a pristine diving location is that it became a Marine Protected Area (MPA) in 2004. The World Wildlife Fund defines an MPA as:


“An area designated and effectively managed to protect marine ecosystems, processes, habitats, and species, which can contribute to the restoration and replenishment of resources for social, economic, and cultural enrichment” (WWF, 2017).

This means that commercial fishing vessels are banned. Commercial fishing vessels damage reefs with harmful practices, industrial projects and other human activities. Due to this protected status diving operators and marine science researchers are required to obtain permits to dive. Generally, dive companies obtain these on behalf of recreational divers.


This has greatly helped the reef’s preservation. Now, future generations will be able to see the site that Jaques Cousteau ranked as one of the world’s best.

The Marine Life

Approaching the dive site from shore is no easy feat. Even with access to a boat, the waves going out of the launch are rough and large – enough to make any experienced diver sick. Even so, the turbulent journey is absolutely worth it.


Depending on what time of year it is, different shark species are present. We were diving during August which meant we saw about ten ragtooth sharks in one dive. These sharks took no mind to the group of divers that were gawking at their teeth. If Rag Tooths were people they would spend a lot of time in an orthodontist’s office.

A Ragged Tooth Shark (Carcharias taurus) - PC: Blue Ocean Dive

Despite it being their breeding grounds, the sharks were lethargic for the most part. Aliwal is known for the large numbers of sharks that are present during dives. One research study found that during Tiger Shark season, there were 4 tiger sharks to one person!



But sharks aren’t the only thing you can see! There is a ton of echinoderm diversity including sea stars, turtles, dolphins and whales. New species are also discovered often. A new species of sponge was discovered here as well as a new species of moray eel. Finally, it’s important to remember one of nature’s most beautiful marine spectacles. Each season from May to July divers can witness the annual sardine run.

Threats to the Reef

Although the MPA has prevented large-scale fishing, it has not stopped smaller scale fishing vessels. This is largely the result of a lack of enforcement by the local and federal governments. The Marine Protected Area is a full 125 kilometres squared (that’s 18.3 km long) and has no coast guard to protect it.


Although they lack a coast guard, the diving community and researchers stand together when they see illegal activity. Dive operators’ boats have chased out invaders and called the police more than once.



Since most small-scale fishing vessels don’t hold any MPA permits they often don’t get targeted as often as the diving operators or researchers. This means that there is often no regulation of their activities, and which puts marine life at risk.



Another danger to the local marine life is the Sappi Saiccor pulp mill. The mill has a pipeline that releases 50°C effluent. Located in Umkomaas, the pipeline is 7 km from the northern shoreline and 23 meters underwater. Some divers say that the discharge affects the visibility on some days.



One final danger is actually caused by divers. Poor diving technique can cause lasting damage to the reef. A poorly guided kick from a fin can damage an entire coral organism. These corals take years to form and are often a highlight for divers. Luckily, this is something that can be resolved with diving protocol and education.

Ongoing work to combat threats to Aliwal Shoal

Firstly, tourist dollars go far in small communities like Umkomaas. By supporting the diving industry here, it helps the preservation of the reef. The money from the MPA permits goes towards maintaining the MPA. Happily, tourism is growing here. Diving companies are trying to keep up with the tourist demand. Blue Ocean, which currently has 41 staff members, is finding that they need to expand and hire more people to keep up.


Significantly, South Africa’s Department of Defense is looking to establish a coast guard. This could drastically curb illegal fishing activities. Without illegal fishing, the reef will continue to thrive and shark diving enthusiasts will be able to enjoy it for generations.

A Honeycomb Moray (Gymnothorax favagineus) happy that a coast guard may be established! PC: Blue Ocean Dive

Furthermore, most diving operators are involved in community projects. Blue Ocean Dive regularly contributes to the community by being part of PADI’s Project Aware. They also partner with other NGOs and do beach cleanups. In addition, Blue Ocean has gotten involved in community projects to provide people with a means of income by teaching them to dive. 


Like most good dive companies, Blue Ocean focuses on teaching good diving technique to avoid collisions with the reef. They are also working to reduce the plastic generated by their on-site restaurant. Lastly, they are one of the few diving operators which don’t offer caged shark diving which is an unethical practice. Although they have not eliminated baited diving, they are working towards a business model without it


So it looks like things are looking up for Aliwal Shoal. With the establishment of a coast guard, it will help reduce the amount of illegal fishing.

Learn More

South Africa’s marine life is both rich and plentiful, though not as well known as its game. For many, however, going diving in South Africa is far cheaper than going on a safari, and just as incredible (if not more!). If you are as desperate to dive ethically with sharks as I was, you can get started by checking out a local company in Umkomaas like Blue Ocean Dive Resort. You come as a guest and you leave as a friend!


To plan your trip, see the rough guide to the different shark seasons:


Sharks in Season

June to November

May to September

November to May

October to March

December to February

December to May

March to Ocotober


Ragged Tooth Sharks (Aliwal Shoal is their breeding ground)

Dusky Sharks

Tiger Sharks AND Bull Sharks (Zambezi)

Hammerhead Sharks

Whale Sharks

White Tip Reef Sharks

Giant Guitar Sharks

Oceanic (Pelagic) Black Tip Sharks




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Smith, D. G. (2002). Enchelycore nycturanus, a new moray eel from South Africa (Teleostei: Anguilliformes: Muraenidae). Zootaxa104(1), 1–6.


If any information is incorrect or needs to be updated, please let us know! Bio on the Go focuses on using the most scientifically accurate and updated information as possible.

Disclosure: We were able to see the magnificent biodiversity of Aliwal Shoal and Ragged Tooth sharks because of the warm hospitality of Blue Ocean Dive Resort.