25 Feb, 2008

In a column of warm blue water, these lithe and shining creatures swim in formations.

Last week was a difficult time on the coast of KwaZulu-Natal, South Africa. The rivers were full after heavy rain inland, sending red-brown water gushing into the sea. This played havoc with visibility in the water, making any sub-surface filming impossible.

Today, when I arrived at the launch site at Rocky Bay, a 10m (33ft) swell was pounding the sandbanks. I managed to convince a competent skipper to negotiate the surging mayhem, and with a bit of teeth-clenching we cleared the walls of water that had claimed a dive boat the day before.

A much better surprise awaited us. The water over Aliwal Shoal was a luke-warm blue. We plunged into the water column above the reef in the Castle area, and were immediately joined by a loose gang of blacktip (or blackfin) sharks (Carcharhinus limbatus).

These sharks are usually frenetic in their investigation of divers and anything vaguely edible, but today they were quite relaxed. This may have been the warm water, but I had the feeling that the lack of shark activity last week had something to do with their lack of energy. It was almost as if these creatures were settling again on Aliwal after some social upheaval last week.

The sharks spent most of the time swimming in loose formations over and around me, and only the odd individual came in for the classic “flick” of the tail.

I’d gone out today to find tiger sharks, which we hadn’t seen for some time, but apart from a small female early in the day we didn’t have any contact.

The blacktips are a more than adequate substitute. They are one of the more elegant elasmobranches, using their lithe features to propel themselves through the water column, their skin reflecting the sun in a matte shine.

– by Graeme Duane, Earth-Touch crew © Earth-Touch

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