South Africa's SardineText and photos by Claudia Weber-Gebert Run & the Interaction of Predators 17 X-RAY MAG : 96 : 2020 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO travel Sardine Run Hundreds of long-beaked common dolphins and flocks of gannets pursue the sardine swarms during Sardine Run (above); Gannet gulps down a sardine (right) This natural spectacle takes In some years, however, the Sar- place almost every year on dine Run is not observed. During these years, it was thought that the eastern coasts of South the Sardine Run did not take Africa and Mozambique—the place due to climatic conditions. so-called “Sardine Run.” To But just because one cannot this day, the reason why it see it on the surface does not mean that the sardines are not occurs cannot be precisely migrating. It is quite possible that defined. There are various this migration then takes place scientific theories, but some at greater depths and/or farther of them contradict each away from the coast. coast of South Africa. Towards the end of the summer in the Southern other. Factors involved in this, “Normal case” scenario Hemisphere, the speed and strength the world’s largest migra- Here is a rough summary of what of the Agulhas Current decreases. tion of South African sardines happens during a normal year: The This gives the Benguela Current the Agulhas Current brings warm water opportunity to transport cold water in (Sardinops ocellatus), include from the Indian Ocean along the a narrow strip along the continental the two major ocean cur- eastern coast of Africa. The Benguela shelf on the eastern coast of Africa rents—the Agulhas and the Current, which pushes cold water to the KwaZulu-Natal coast and to Benguela—plus wind speed northwards from the Antarctic to the push off the Agulhas Current. The sar- Cape, is averted by the warm water dines, which prefer the colder water, and rain as well as air and of the Agulhas Current at the Cape follow this cold and nutritious current water temperatures. and thus flows along the western in huge masses to the KwaZulu-Natal Dense schools of South African sardines form the world's largest migration each year duing the Sardine Run PREVIOUS PAGE: Bryde's whale and dolphins hunting and feediing on sardines 18 X-RAY MAG : 96 : 2020 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO travel coast and Mozambique. statements about it. Years of studies at beginning at These swarms of sardines can be sev- several locations would have to be car- the Cape and eral kilometres long and are clearly visible ried out simultaneously to get a better passing along from an airplane as long as they are not overview. And what happens at greater the entire too deep below the surface of the water. depths in the water column is sometimes southeastern Such a large source of prey attracts a hidden from the viewer. coast. Already huge number of predators, which benefit in January, from this wealth of food. These predators Migration timeline one can see include dolphins, whales, sharks, seals, and characteristics the sardines in penguins and various seabird species such When we speak of the Sardine Run, we the region around the Cape and False main objective of the Sardine Run is prob- as Cape gannets and Cape cormorants. are mostly referring to the events that Bay; from February to May, they are in ably only sardine reproduction, because However, depending on environmental take place off the KwaZulu-Natal coast the region of Algoa Bay and East London; not all sardines take part in the migration. factors, there are different variants in the from June to July. But that is actually the and only from May to July are they off Sardine Run’s usual scenario. Research- end of this animal migration. The sardines the KwaZulu-Natal coast. Sardine spawn- The predators ers who observe this natural event can begin to move towards the KwaZulu- ing has also been observed in the water, Long-beaked common dolphins (Del- Cape gannet (above); Dense school of sar- therefore only make limited scientific Natal coast and Mozambique in January, which has led scientists to believe that the phinus capensis) make up the largest dines (top left); South Aftican coast (right) 19 X-RAY MAG : 96 : 2020 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO travel number of predators. These dolphins reach a maximum length of 2.5m and are very agile, which gives them a big advantage in the Sardine Run. Bottlenose dolphins are rarely observed, and resident groups do not participate here; however, bot- tlenose dolphins passing by can sometimes be found at bait balls. In the early months of the year, Bryde’s whales (Balaenoptera brydei) are the largest predators in the southern coastal regions. Occa- sionally, one can also find the some- what smaller Antarctic minke whales (Balaenoptera bonaerensis). From June to July, humpback whales (Megaptera novaeangliae) and southern right whales (Eubalae- na australis) are present in the north- found in the Sardine Run: cop- related is still unclear. Orcas also ern coastal areas. But the hump- per sharks, mako sharks and dusky only come because of the dolphins. back whales are on a completely sharks. Great white sharks can also It has been observed though, how different migration, namely towards be spotted; however, they are not orcas hunt the dolphins by isolating warmer waters, where they will mate interested in the sardines, but in the individuals from their pods. Other and give birth to their calves. But dolphins and seals. marine mammals that prey on the when the opportunity arises, the sar- Sometimes, small groups of orcas sardines include Cape fur seals, dines are a nice find for them. appear, usually during a full moon which only appear in small groups Three shark species can also be phase. How these two things are near bait balls, shooting through the Bryde's whale feeding (above); Cape fur seals (left); Long-beaked common dolphins and gannets (top) 20 X-RAY MAG : 96 : 2020 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO travel Sardine Run Snorkellers watch hundreds of dolphins (above) corralling sardines into a bait ball (right), as Cape gannets feed on sardines pressed at the water's surface or jumping into the air to escape predators (left). 15m to catch ing frenzy! You go out on a rubber boat the sardines. for a few kilometres and you do not see The Afri- much at first—sometimes even nothing— can penguin perhaps just a few birds flying somewhere (Spheniscus or waiting on the surface of the water. It The adventure begins when you see all demersus)— may be quite disappointing at first, but the gannets flying in the same direction swarm with great speed and underwater also known as the “jackass penguin” it is actually a good sign. Because when in large numbers. Now it starts, because acrobatics. because of its donkey-like cry—also takes nothing is going on, the event is at this this means that the dolphins have started As for seabirds, Cape gannets and part. They can reach a speed of 25km/h point probably concentrated somewhere to drive the sardines. It is the long-beaked Cape cormorants should be mentioned underwater. Unfortunately, they are now else. And now it is time to follow the signs common dolphins that come together, first among the avian predators. While a endangered as a species. One hundred and find this place! coordinated from all directions to drive larger variety of seabirds can be observed years ago, their eggs were sold as a deli- The gannets and cormorants are a and hunt the huge swarm of sardines. at the sardine swarms, the large brown cacy, and their manure was removed good indicator. Are they still sitting on We were able to follow a pod of boobies and Cape cormorants are the from the islands and shipped to England. the water in groups or are they flying in approximately 100 to 200 dolphins, which predominant species represented. The nests of the penguin colonies on St. a certain direction? And is there dolphin were heading towards the open sea The sardines themselves measure Croix Island were completely destroyed. activity somewhere on the water’s sur- at a rapid pace, followed by seabirds approximately 25 to 30cm in length. They Today, there are several stations on the face? It is hard to see when the waves that plunged into the water again and are too big and too heavy for smaller sea- South African coast that take care of are coming at you. From the boat, you again, catching individual fish. And more birds to catch, since the birds would then injured penguins. can see for about 3km. It means look- and more dolphins came from all direc- have to fly several kilometres back to their ing out on all sides and identifying and tions—all in all, about 1,000 dolphins were young with the prey. This leaves the sar- Observing the Sardine Run interpreting the variations on the water’s involved in the chase, swimming at great dines almost exclusively reserved for large And now a bit about the adventure: It is surface. The search can sometimes take speeds even farther out in open sea. birds. Gannets are able to dive down to pure madness for the observer—a feed- several hours! The water seemed to be boiling.