Sardine run

The Sardine Run is driven by a combination of oceanographic conditions. Each winter, a narrow band of cold water from the Agulhas Bank pushes northward along the eastern coast of South Africa. Sardines are cold-water species, and this band of water creates a corridor, allowing them to migrate into subtropical waters where they would not normally be found. This migration is believed to be primarily for spawning, though the exact biological triggers are still being studied.

As the massive shoals of sardines move along the coast, they become increasingly concentrated, especially when they encounter offshore reefs or headlands. This concentration makes them highly vulnerable to predation. Predators, including thousands of common dolphins (Delphinus delphis), various shark species, and large schools of game fish, converge on these shoals. The dolphins play a crucial role in herding the sardines into tight, defensive formations known as 'bait balls'.

Once a bait ball is formed, it becomes a feeding frenzy. Dolphins, sharks, and game fish take turns darting into the dense mass to feed, while thousands of Cape gannets (Morus capensis) dive from above, creating a spectacular aerial display. Bryde's whales (Balaenoptera edeni) may also be seen lunge-feeding through the shoals. This coordinated attack from above and below is a hallmark of the Sardine Run, showcasing complex predator-prey interactions on an immense scale.

Participating in a Sardine Run liveaboard trip offers a unique opportunity to witness one of the planet's most dramatic marine spectacles. These specialized expeditions are designed to track the sardine shoals, often relying on spotter planes to locate the bait balls. Once found, divers and snorkelers are deployed from rigid-hulled inflatable boats (RHIBs) directly into the action, allowing for close encounters with bait balls and the myriad predators they attract.

Liveaboards for the Sardine Run provide flexibility and comfort, enabling divers to spend more time in the prime hunting grounds compared to daily shore-based operations. They also typically offer a higher number of potential interactions over the course of a trip. Guests can expect early mornings and potentially long days at sea, as the search for the elusive shoals can be challenging and requires persistence. The conditions can be unpredictable, with success largely dependent on sardine movements and weather.

Divers undertaking a Sardine Run liveaboard should be experienced, comfortable with open ocean diving from RHIBs, and prepared for dynamic conditions. While scuba diving is possible, many of the most intense interactions occur close to the surface, making snorkelling equally thrilling. The experience is not solely about diving; it encompasses the entire ecosystem, from birdlife to whales, offering an immersive wildlife adventure that extends beyond typical reef diving.

Myth: The Sardine Run happens every year in the exact same way. Fact: While the Sardine Run is an annual event, its intensity, exact timing, and precise location can vary significantly from year to year. Oceanographic conditions, such as water temperature and current strength, play a crucial role, making each year's run unique and somewhat unpredictable. Some years are more prolific than others, and it requires flexibility from operators.

Myth: You are guaranteed to see massive bait balls on every dive. Fact: The Sardine Run is a wild, natural event, and there are no guarantees. Locating bait balls requires extensive searching, often with the aid of spotter planes, and rapid deployment. Divers might spend significant time searching, and interactions, while potentially spectacular, can be brief and intermittent. Patience and realistic expectations are essential.

Myth: It's primarily a scuba diving event. Fact: While scuba gear can be used, many of the most dynamic interactions with bait balls and predators occur closer to the surface, making snorkelling an equally, if not more, effective way to experience the run. Rapid entry and exit from RHIBs, as well as the quick movement of bait balls, often favour free-diving or snorkelling over full scuba setups.

Myth: The sardines are migrating to spawn in the warm waters of KwaZulu-Natal. Fact: Research suggests that the sardines migrate northward into the cooler, upwelling currents off the Wild Coast for spawning, rather than the warmer surface waters. The main population centre for Sardinops sagax is in the cooler Agulhas Bank, and the northward run is a peripheral event for a portion of the population.