The KwaZulu-Natal sardine run of southern Africa occurs from May through July when billions of sardines – or more specifically the Southern African pilchard Sardinops sagax – spawn in the cool waters of the Agulhas Bank and move northward along the east coast of South Africa.

The run, containing millions of individual sardines, occurs when a current of cold water heads north from the Agulhas Bank up to Mozambique where it then leaves the coastline and goes further east into the Fisherman are sometimes observed singing songs while hauling in the fishing nets in typical South African style.

In terms of biomass, researchers estimate the sardine run could rival East Africa's great wildebeest migration.

Genomic and transcriptomic data indicate that the sardines participating in the run originate from South Africa's cool-temperate Atlantic coast.

[4] These are attracted to temporary cold-water upwelling off the south-east coast, and eventually find themselves trapped in subtropical habitat that is too warm for them.

A band of cooler coastal water and the occurrence of Natal Pulses and break-away eddies make it possible for sardine shoals to overcome their habitat constraints.

The presence of eggs off the KwaZulu-Natal coast suggests that sardine stay there for several months and their return migration during late winter to spring is nearly always unnoticeable because it probably occurs at depths where the water is cooler than at the surface.

Once the sardines are rounded up, sharks (primarily the bronze whaler), and birds (like the Cape gannet), and Bryde's whales take advantage of the opportunity.

[6] 2005 records: In June and July 2005 the avian and mammal predators included Bryde’s whale (Balaenoptera edeni), African penguin (Spheniscus demersus), Cape cormorant (Phalacrocorax capensis), which were predominantly found in the cooler southern part of the region.

Peak sardine run activity occurred within 4 km of shore at the northward limit of a strip of cool water (<21 °C) stretching along the East Coast.

International and domestic divers join local tour operators on sardine run diving expeditions.

Both local and international tourists are attracted to the spectacle and are provided with opportunities to participate in activities such as dive charters and boat based predator viewing tours.

[11] The Sardine Run Association (www.thesardinerunassociation.org) has been formed to provide a link between tour operators, tourists, non-governmental organisations, scientists, and local and national governments.

Thousands of Cape gannets and dolphins were seen in a continuous line of about 6 km between Brazen Head and just north of the Umtata River.

[16] Rough seas (with waves up to 4.7 m) caused by strong winds associated with a cold front kept the sardines from the shore on 23 June 2011.

The main shoal was still suspected to be off the Eastern Cape coastline,[17] with a report of some sardines still seen near Port St Johns on 22 and 23 June 2011.

Cape gannets and other seabirds were seen "plunging from considerable heights" to catch the sardines, especially on the South Coast.

The group of divers had encountered a pocket of sardines when a 3 m long dusky shark bit Mr Stanchi on his left leg and hands.

Mr Stanchi managed to free himself from the shark, and was treated on the diving boat before being transported to Rocky Bay, where medics stabilised him.

Mr Stanchi had been wearing split fins with black and grey stripes, and this may have looked like a small shoal of fish to the shark.

[29] A strong cold front hit South Africa towards the end of July, causing land surface temperatures to drop below 10 °C over much of the country.

[31] The cold front caused swells of up to 4 meters on the KwaZulu-Natal coast and a 25 to 30 knot wind with rough sea conditions.

[32] A ship called the Phoenix ran aground at Salt Rock, Ballito on 26 July 2011 because of the rough conditions.