Winter is coming ... and so are those sexy sardines

Something sexy happens after the Indian Ocean runs colder than 21º — if you're a sardine, that is. Having spent eight hours in that water, I don't get it. But it must be something that gives billions of sardines the gees to spawn in the Agulhas Bank, where the warm Indian Ocean and the cold Atlantic clash, and  swim up along the east coast towards Mozambique.

It's called the sardine run and scientists don't quite know why it happens — only that it does from late May through July. And only if the water is cold. 

It's one of those miracles in Africa — like the Great Wildebeest Migration — where the locals are indifferent but the tourists flock to see what they call the “Greatest Shoal on Earth”. As it passes Port St Johns in the Eastern Cape, another apex predator is added: divers.

They come from all over the world to experience this phenomenon, a bucket-list ocean safari right on our doorstep.

It was with this background that I embarked on my first free-diving experience with Offshore Africa, a sardine-run specialist operator based in Port St Johns.

For five weeks a year, the operator takes divers out into the Wild Coast and it's such a popular event that many of the seats for the 2023 run have already been taken. 

Offshore Africa is run by PADI divemaster and commercial skipper Rob Nettleton and master scuba diver trainer and shark-awareness instructor Debbie Smith. Between them, the couple have more than 30 years’ experience. I had none when I arrived on a Sunday in July but Smith reassured me that it would be OK as she fitted my 5mm-thick wetsuit on for the next day's 6.30am launch. 

I woke up at the Port St Johns River Lodge, convenient because it's where Offshore launches its boats. It was a Monday in the middle of the run — and freezing cold. 

It took me 20 minutes to get the wetsuit back on in the morning. There's an art to it and, as a novice, I haven't yet learnt the secret. I was also given little wetsuit bootees — probably because Smith felt sorry for me — and a beanie. 

I was joined by another journalist — a diver who (of course) had his own gear. We were the only South Africans going on the tour. 

Nettleton said only 5% of their clientele were local tourists, the rest came from any and everywhere. In two inflatable boats were divers from Spain, the UK, the US and Bahrain.

On board was skipper Clive Mortimer and guide Rogan Borrill, oxygen cylinders, fins and goggles and — my personal favourite — a huge cooler box with coffee and hot chocolate and the biggest lunch I've ever seen (because, of course, we were going to be on the ocean for eight hours).

We sat on the inflatable side of the boat and held on — with our feet. 

A skilled skipper is needed to get through the Umzimvubu River mouth — the Wild Coast is dotted with boats and shipwrecks.

But before we got out to sea, the lazy river offered an exquisite morning view. Forests and mountains. A fish eagle above us and the honk of a Trumpeter hornbill.

The day before I was able to see the remarkably untouched coastline from the company's  fire-engine red, fixed wing Sling aircraft. Pilot Brad Isaacson takes passengers above the sardines, which glint like silver foil on the surface of the water.

Another spectacle and happy coincidence is the humpback whale migration from cold Antarctica to their warm breeding grounds off Mozambique, Tanzania and Madagascar. Flying above them is an incredible experience, even better if you spot a newborn calf. Isaacson also works as a spotter, guiding the boats to the action. But back to the boat.

“HOLD ON,” Borrill warns as the boat navigates the waves. 

Once it successfully launches, he's on his feet arching his back, head to the sky as he whoops and woos into the wind, fist clenching a shark prodder in the air like Poseidon with his triton. This is the mood for the rest of the day.

Once we get to open water, the mission begins: Find a baitball. Borrill is in and out of the boat like a seal looking for the action in the water.

According to the SA National Biodiversity Institute, sardines are schooling fish that use the vibration in the water to alert the other fish about what is happening. They all move at the same time, forming a giant swarm.

They do this because they are on the bottom rung of the food chain — as they run they are followed by apex predators: sharks, dolphins and whales stalk them from below and above, torpedoes of Cape gannets and Cape cormorants rain down like bullets. 

The fish huddle together to create a long, shimmering bus. But at every turn the possibility exists that a dolphin can cut through them like a knife slicing off a piece of bread, called a bait ball. In a small group, the sardines can be easily separated and picked off.

Once a baitball is created the predators swoop in — the common dolphins work together to herd and confuse the fish, nearby the predators wait and grab what comes to them as sardine stray.

This is what the divers are after, the frenzy of sharks, dolphins, whales and other creatures stalking for a chomp of fish. 

Borrill has leapt off the boat again. “Alex, let's get you in here and used to the water,” he calls from the pea soup. I'm a good swimmer usually, but am suddenly drowning. The man-seal takes my hand and shows me a dolphin swimming under us. I'm hooked, but it's time to get moving.

Propelled by our guide, I fly through the air and onto the side where I can wriggle back onto the boat. Imagine the sound of rubber squeaking, panting and swearing. Finally, I'm on board — the man-seal has somehow beaten me to it, his fins off and his beard already drying.

It's a “super average day” I'm told as a pod of 12 humpback whales swims by, close enough for me to see their eyes blink. Birds are dropping like bullets into the water, beaks first at full speed. I'll sit here and eat my chocolate.

I'm not allowed a weightbelt in case they never see me again. The result is that I am constantly driven by pressure to the surface, popping up like a cork. 

At last, a baitball. We dive back in and swim towards the shimmering fish. As we bob on the water, Borrill says: “Watch out for sharks.”

“What?” I reply. I link arms with him and lift my feet so they can't nibble my toes. The visibility is bad, they could be anywhere — and they probably are. 

The show begins. Dolphins — six. They split up in pairs and, in unison, the dance begins. Two dive in the air and onto the ball as another pair dive below. The fish scatter and come back together just in time to be parted by another pair.

The senses are heightened. You can hear the whistles and clicks from the mammals, my skin is cool, the arm squeezing Borrill is warm and the hairs prickle against the wetsuit. A taste of salt. We're bobbing on open ocean. It's sheer terror, like the feeling of looking over Bloukrans bridge before a bungee. I imagine the sharks seeing me and me not seeing them. I start to feel nauseous.

I've swallowed too much seawater. At least, that's what I say as I lose my breakfast over the side of the boat. 

There is a camaraderie among divers. I remind them of their first dive and they regale everyone with stories of the amazing oceans they've swum. We warm up to a huge lunch. The jovial atmosphere is taken back to the lodge, where strangers have become friends and a long table becomes a banquet of supper. 

OFFSHORE AFRICA

1. Offshore Africa offers ocean safaris and ocean photographic trips on their vessels Offshore I and Offshore II. You can book packages with them for this year's run — and more — at offshoreportstjohns.com. 
2. If you're after an adventure that's a little more subdued, the company also offers the 24-seater Bobalong barge for a relaxing cruise along the Umzimvubu River. Hiking trips are available, Waterfall Bluff is particularly beautiful with a series of waterfalls, one of which fall directly into the ocean. It is one of only two waterfalls in South Africa that fall directly into the ocean and only 19 such waterfalls worldwide.

• Patrick was a guest of the Eastern Cape Parks and Tourism Agency. See visiteasterncape.co.za