Sardine run in full swing along KwaZulu-Natal coast

Posted by David Henning on 29 June 2021

Every year, one of the largest migrations in the world occurs when millions of sardines form shoals that migrate up South Africa’s east coast, causing fishermen and wildlife to scurry for the shore.

There are the familiar scenes of fishermen on the beaches hauling in nets filled with fish soon after the message gets out about the greatest shoal on earth. Sardines (Sardinops sagax) live out their lives in large shoals in the surface layers of the ocean. Although the fish are small, they compromise almost a quarter of the world’s fish by weight.

Sardines are cold-water fish, occurring in areas of cold ocean upwelling: a phenomenon where deeper, cooler nutrient-rich water currents emerge to the surface when they strike shallow coastal areas. For this reason, sardines are usually found in the colder waters of South Africa’s west coast.

Sardines don’t live long, usually not more than three years. But in their short lifespan, they produce thousands of offspring. The main sprawling grounds are the Agulhas banks off of the southern coast, where adults tend to gather for a prolonged breeding season from spring to early summer.

Their eggs are released into the ocean and taken up by currents, left to fertilise as they drift westward with the current to the nutrient-rich waters off the west coast. After maturing on the west coast, they are strong enough to venture against the current, forming dense shoals that migrate along the east coast, where the water is cooler in water, with the upwelling near the shoal.

It is this natural phenomenon that facilitates the mass migration along South Africa’s coastline, offering a significant food source, for humans and the wildlife which all descend upon these shoals, forming the famous “sardine run”.

 

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The shoals are easy food, a buffet for the ocean’s predators. Surrounding pods, regular visitors are sharks, dolphins, whales, seals and other predatory fish.  Recently, a 207kg shark was caught off a shoal in Pumala beach.

Sean Schimper from Plan D Scuba offers diving tours and had some amazing sights and footage from the recent dives, mentioning that from the boat they saw a shoal of about 5000 dolphins.

Diving near a shoal comes with its risks but provides a one-of-a-kind wildlife encounter as it is a feeding frenzy, where animals like sharks and whales are trying to devour as much as they can.

But by keeping a safe distance, experienced divers can take in a whole other world, seeing the hive of activity below. Sean says that when diving near the shoals, the sharks are not interested in the divers, you just have to make sure you stay out of their way. Watch the video below to see raining seagulls taking their share of the fish.

Sean managed to catch some underwater footage of his dive. Although diving conditions weren’t the clearest, he managed to catch a lot of action.

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This annual migration is under threat with current climate change and the associated warming of the oceans. Sardines occur in water at 19°C and below, so with rising ocean temperatures, the east coast may become inhospitable for the sardines. This will have a cumulative effect on the other wildlife that regularly feed on these migrating shoals as well as on humans, where these fish are the livelihoods for many subsistence fishermen.

A daily report on the sardine run by ASFN Fishing, commented that from early in the morning of 29 June, shoals could be sported all over the KwaZulu Natal coast, with an early net being pulled in at Sezela beach.

Also read:  

Sardine Fever takes over KwaZulu-Natal

Pictures: Flickr Commons






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