Yellow Fin Warning

Pierre de Villiers, Cape Town surfing pioneer, shaper and veteran spearo

Once when spear fishing at southwestern reefs (off Cape Point) with my mate Duncan, he had a very heavy experience. The water was full of pelagic fish and sharks, and while I was able to spear fish and get away with it, he was getting seriously harassed by sharks. Eventually, while fighting a big yellowtail, he got rushed by a great white intent on a bite.

It totally ignored his struggling yellowtail. This is very unusual. Nothing gets a shark more excited than a fish on a spear. By luck and instinct, he escaped serious injury. Now all this time I was 30 metres or so from him and I had seen sharks only on the edge of my viz. Duncan was rattled and shouting for backup and I noticed as I was swimming towards him that from a distance (before I began to make out his shape) I could saw the yellow flick of his fins winking at me  - flash - flash - flash. Every time he kicked, the blade bent and flicked back, and the yellow tip flashed. There was no other word to describe it. The sharks could not leave them alone.

We are both convinced that the yellow blades were the problem. I notice the majority of boogers use two-tone fins. Most are seriously bright and many are yellow. I try to tell them but I mostly only connect in the water so I’m keen for you to pass it on. Anyway, I’ve had it on my mind for a while now please let me know how this info can help.

Alison Kock, shark scientist and world authority on the white shark

We know that sharks see contrasting colours very well. I've seen the same thing happen myself a few times with both black and brightly coloured fins, one incident involving a white shark, the other with makos, blues, and tiger sharks, the blues in particular like nipping at a person's fins, and I've also observed them show what seems to be increased interest to brightly coloured fins. My own anecdotes come from myself and my husband's shark diving experiences (he is a spearfisherman turned underwater cameraman), and our own rules are to wear all dark colours while diving with sharks of any species, making sure neck, wrists and ankles are covered and there are no contrasting colours on our wetsuits or any other gear e.g. silver, white or yellow on a dark colour that can be mistaken for fish or simply just be of interest to a shark. One of the questions in the South African Shark Attack Incident Report asks about any jewellery worn by the victim for this very reason too, namely shiny objects worn which a shark may mistake for fish.

However, I think a lot also has to do with the action the fins are making. I have seen sharks show particular interest in people who dive or swim erratically in the water (e.g. fast and frequent finning), versus others who are calmer, fin slower and are more relaxed in the water regardless of what colour their fins are. But, having said that based on my own experiences (not scientific evidence) I don't wear brightly coloured fins or strong contrasting colours when diving with sharks. Another anecdote is that underwater cameramen like using brightly coloured underwater housings, like yellow and silver because they get a lot of interest from the sharks and thus some great footage, and yet another interesting observation is how attracted some species of shark are to the flashing strobes of underwater cameras.

How applicable these observations are to surfers or boogie boarders who are right at the surface and thus silhouetted against the light background I'm not sure. I think the actual finning action as seen by a shark from below would be worthy of investigation regardless of colour. From our observations at Seal Island with white sharks and seal decoys we know that sharks treat stationary decoys very differently to ones that are moving. Relatively speaking most sharks approach the stationary decoy slowly from below versus the full out breaching behaviour that is seen when the same decoy is moving while towed behind a boat. Similar behaviour is seen with seal prey. A dead seal lying at the surface is usually approached slowly from below, while healthy seals swimming fast trying to avoid being predated upon are attacked using the ambush strategy, fast and explosive. Thus, the main difference being again the movement involved. Some people have likened it to dogs chasing cars, a stationary car not so interesting...a moving car much more so.