THE WATERS THAT WASH South Africa's east coast are home to both tropical fish species and those that prefer cooler temperatures. The warm Mozambique Agulhas stream flows south from the Equator, moderating the climate year-round and creating a sub-tropical habitat to the north.
As important, though far more irregular, is the winter counter-current, the Benguela.This carries richly nourishing colder waters from the depth of the ocean and feeding fish migrations from Cape Town waters towards Mozambique.
Most famous of these is the Sardine Run. In winter millions of sardines leave the Southern Agulhas Banks and cover some 600 miles to reach plankton off KwaZulu-Natal. Here Sodwana Bay Nature Reserve is renowned for its many exciting coral reefs, offering a great diversity of seascapes, flora and fauna.
South of Durban and close to Umkomaas we find Aliwal Shoal, South Africas most popular dive site. It is known for its raggedtooth sharks but also increasingly tiger sharks, blacktips, hammerheads and the rare Zambezi or bull shark.
Protea Banks lies in the south of KwaZulu-Natal. Pelagic life is the main attraction, with schools of yellowtail, kingfish, tuna and barracuda attracting a variety of top predators, including an especially large Zambezi population.
Further south, Transkeis Wild Coast is a relatively untouched haven, a land lost in time, though increasingly tourists and wildlife enthusiasts turn up in June and July to experience the Sardine Run there. All year round there is something happening off KwaZulu-Natal.

hspace=5 FEBRUARY
Sightings and close encounters with tiger sharks are more frequently reported. The blunt snout and distinct grey barring or vertical rows of spots on the upper flanks of these animals make them easy to recognise, though these markings do fade with age and may be very light or absent in adults. Tiger sharks have become used to divers and sometimes come close enough to nose camera dome-ports, as in this picture of a 3.5m female.

hspace=5 MARCH
Tiger shark sightings continue but you can also see other sharks. The blacktip (Carcharhinus limbatus) has a pointed snout and a slightly stouter body than the similar spinner shark. Most of the fins other than the anal are black-tipped and maximum size is around 2m. Blacktip sharks move around between the tigers but they are much faster and sometimes speed up when something catches their attention. Unlike tiger sharks, they rarely savage the bait.

hspace=5 APRIL
Its hard to get good shots of sharks because they dont get close enough to the camera, but this month the number
of sharks seems to increase, perhaps because they are preparing for the Sardine Run, are curious or simply more accustomed to divers. Photographers looking for action photos or any diver looking for an extra charge of adrenaline can see many sharks in the water at once. I have seen 30 or more, some coming very close, which they are more likely to do if you wear light-coloured fins or suits.

hspace=5 MAY
Around the end of the month the Wild Coast starts to attract tourists eager to experience
the Sardine Run. This spectacular annual phenomenon triggers a banquet of gigantic proportions, with hundreds of dolphins, sharks, seals and other predators following the shoals of sardines for an easy meal. The sardine shoal can be miles long, sometimes resembling a marine monster. Like the herring and anchovy, the sardine (Sardinops sagax) is a primitive fish with a short life-cycle and fast growth - it can reach a length of of 23cm in two years.

hspace=5 JUNE
The action builds as the sardines head north. Dolphins are the most numerous underwater predators and with each pod containing 300/500 specimens, more than 20,000 animals may get involved. The arrival of common dolphins in Eastern Cape waters announces the imminence of the exodus. Using their click language, they position themselves under the sardine shoal and push them up to the surface.

hspace=5 JULY
Diving from the sky like military aircraft into the chaotic waters below, thousands of Cape gannets join the party. The height from which they dive depends on the depth of the fish. If they are at 5-10m, the birds may dive from as high as 30m. They can dive to about 5m and then swim down a further 3m or so to catch the sardines.

hspace=5 AUGUST
Humpback whales (Megaptera novaeangliae), first spotted during the Sardine Run, continue migrating north from their summer feeding grounds off Antarctica to their winter calving and mating grounds off Mozambique. Their journey may take them up to 5000 miles. Humpbacks feed mainly on krill and small schooling fish but dont feed off KwaZulu-Natal. They swim at less than 7mph, though they can reach speeds of up to 15mph, and often perform spectacular leaps out of the water. Imagine being on a RIB when a 45-tonne cetacean breaches close by!

hspace=5 SEPTEMBER
Raggedtooth sharks or raggies (Carcharias taurus) come to KwaZulu-Natal waters to mate from July to November. They have heavy bodies, an average length of 1.5 to 2m (maximum 3.7m), a short pointed snout and small eyes, and tend to inhabit shallow coastal waters. Raggies can be found in caves such as Cathedral and Raggie at Aliwal Shoal and Protea Banks and up to southern Mozambique, feeding on fish and small sharks. Their ferocious-looking teeth give the species its common name but these sharks are harmless to divers. They tend to move further north after the Sardine Run but can be seen year-round.
hspace=5 OCTOBER
Bottlenose dolphins are the largest of the beaked dolphins, with an average length of 3m. Their short, stout beaks are marked by a crease where they meet the forehead. A thousand or so live along the coastline and these are the dolphins most commonly seen in inshore waters, often swimming behind the surf-line in pods of 10-50 individuals. They feed on small fish and cephalopods, which they detect and pursue using sonar pulses. These dolphins dont seem to be particularly dependent on the sardine shoals.

hspace=5 NOVEMBER
You can dive with a huge array of fish species at this time of year, including the potato cod grouper (Epinephelus tumula) as well as turtles, sharks and manta and other rays. Pods of dolphins and whales are frequent visitors. Often depths between 6-18m are sufficient for marine-life watchers.

hspace=5 DECEMBER
KwaZulu-Natal waters can be dived all year round, and December is summer in the southern hemisphere. Visibility varies from 5 to 40m, and the water temperature in summer is 24C-plus (and in winter no colder than 19C). This is a good time to see solitary cape fur seals (Arctocephalus pusillus), the only seals likely to be seen in southern African waters. These large animals have brown coats and pointed ears and feed on small schooling fish as well as cephalopods and crayfish, diving as deep as 200m for six or seven minutes at a time. Seals are important as prey for great white sharks.