There is a local proverb in South Africa: Aloe vera blossoms, sardines come. Between May and July, billions of sardines migrate north from the Argalls Shoal, Africa's southernmost tip, all the way north to Durban, South Africa's third-largest city, covering a total length of about 1,000 kilometres. Locals have given this natural wonder a name: sardine run.
Migrating schools of sardines are about 7 km long, about 2 km wide and up to 30 m deep, like a giant black belt, clearly visible in the shoals.
Sardine migration route map. South Africa's marine environment is unique, surrounded by the Atlantic Ocean and the Indian Ocean on three sides, where cold and warm currents meet. Generally speaking, in the winter of the southern hemisphere, when the icy currents of antarctica invade from south to north along the Coastline of South Africa, forming a narrow strip of cold water, the cold-water-loving sardines begin their annual migration.
The necessary route for sardines to migrate: the "Wild Coast" of St. John's Harbour in South Africa. Facing the Indian Ocean, warm and humid air currents often hover here, and the wild coast is gloomy and violent. This is the destination of the trip to Chinese dive photographer Song Gang and his two companions Zhang Xuan and Hu Yeyang. Every season, the port town is home to whale watchers and divers from all over the world.
Sardines prefer to live in the huge shoals of the ocean's surface, and although they are small, they are one of the largest fish families in the ocean, accounting for nearly 25% of the world's fish production in terms of numbers alone, making them one of the most economically valuable fish for human beings.
Despite its small size, sardines are an important part of marine food networks, providing a rich source of protein for many marine birds, cephalopods, sharks, marine mammals (including dolphins and cetaceans), and large fish (including sailfish and tuna). So, as such a huge piece of bait passes majestically along south Africa's east coast, thousands of dolphins and sharks, as well as tens of thousands of South African, are watching the shore, waiting for this annual marine feast.
An imposing army of dolphins. Dolphins have an absolutely dominant role in the entire process of encircling and suppressing sardines. Schools of sardines are often discovered by dolphins with sonar detection systems, mainly Delphinus capensis and some bottlenose dolphins (Tursiops aduncus). As many as thousands of dolphin legions were highly motivated, and groups of three or five jumped out of the sea to the battlefield.
A group of long-snouted dolphins are working together to divide and surround the sardine school into "bait balls". If a migratory school of sardines is likened to a giant train, the dolphins will unite to push a carriage out. These clever sea elves drive sardines from the bottom of the sea to the surface before dividing the school into giant bait balls.
Sardine bait balls can reach diameters of up to 10-20 meters, but have extremely short lifespans, rarely lasting more than 10 minutes. Once dolphins have successfully divided and surrounded sardine bait balls, other marine life such as sharks, South African and Brinell's whales have the opportunity to take advantage of them.
During the sardine feast, the follow the dolphins closely, and the dolphins drive the sardines to the surface, which is within the depth of the boobies' diving. They fly 30 meters above the surface of the water, and once they find their prey, they fold their wings and face down, like a meteor splashing into the blue sea, and the huge sound generated when entering the water can stun fish swimming about 1.5 meters below the water surface.
are natural swimmers and divers, and their fishing skills are very high. Underwater, use their wings and webbed feet to draw water, bite the fish, swallow the fish underwater, and then surface.
The boobies' steedine-eating techniques are highly ornamental, and the overwhelming swoop down from high in the air like smoke-pulling fighter jets.
Sharks are excellent hunters, they are too lazy to eat one by one, and when they see the opportunity, they open their blood basins and rush through them.
Sharks are constantly shuttling through the "bait ball" and eating very happily.
The strategy of swordfish hunting is relatively simple, but they are very good at arranging the speed of attack. They will slowly rush towards the sardines until the school of fish is under physiological stress, and once the sardines are injured or disoriented, the sailfish uses its pointed mouth to stab into the sardines.
The Brinzewals whale is a rather mysterious species of whale in the Great Blue Ocean, first named after The Bruce Whale, which was first named by Johan Bryde, a Norwegian whaling entrepreneur. Because there is no accurate research results on the details of its activities and mating habits, it is called "the most unknown and most distinctive whale".
Brinell whales are sleek and predatory. When dolphins drive sardines to sea level, agile Brinell whales will open their mouths and swallow the sardines along with the seawater at the densest point of the population. Other hunters around wait for the whale to leave at any time so that they can enjoy the cold heat left behind by its feast.
Off the east coast of South Africa, which is also a migratory route for many whales, the currents flowing through it are like a maritime highway, and whales and children travel between the warm South Pacific Ocean and the rich Antarctic waters.
In this sardine "feast", human beings have also benefited a lot. For impoverished and backward South Africa, especially along the southern coastal region of KwaZulu-Natal, sardine migration is nature's most generous gift. It forms a small-scale seasonal coastal purse seine fishery that provides additional protein to the locals' diet.
On the shoals off South Africa's east coast, citizens are working together to tow ashore purse seines filled with sardines. Above the shoals, dense are swooping down, trying to get a piece of the human purse seine fishing. In an era of increasing depletion of fishery resources, the South African sardines remain surprisingly rich in fisheries and are the mainstay of the economy of many of the local coastal areas.