More sharks, healthier ecosystem

KNYSNA NEWS - Despite the third shark attack along the Eastern and Southern Cape coast in less than a month experts believe that an encounter of this nature is still a rare occurrence.

This after Australian professional surfer Mick Fanning survived a close encounter with a shark while surfing in the JBay Open in Jeffreys Bay on Sunday, July 19.

The shark became tangled in his surfboard leash and knocked him off his board. Fanning managed to kick and punch the shark while trying to get back on his board, before a rescue boat and staff on jet-skis came to his aid. Fanning walked away unscathed.

About three weeks earlier, 19-year-old student Dylan Reddering was bitten by a shark while surfing at Lookout Beach in Plettenberg Bay on June 26, and 19-year-old Caleb Swanepoel lost his leg in a shark attack while body-surfing at Buffel's Bay the next day.

The director of research at Oceans Research in Mossel Bay Enrico Gennari, said although there was always a risk of a shark encounter when in the ocean, most attacks were “a case of mistaken identity”.

Research manager at Shark Spotters (an organisation that conducts research focused on inshore white shark presence and behavioural ecology) Doctor Alison Kock agreed but added that sharks, like other predators, were opportunistic hunters and therefore bites could also be related to investigation, feeding or even social interactions, including defensive or competitive social interactions.

She added that about 70% of white shark bites – like in the recent cases – were bite-and-release instances. in nature.

“Unfortunately a bite can cause major damage. In the rest of the cases sharks do return and bite again. Inside the shark’s mouth are hundreds of sensory organs for taste and touch. Therefore, if a shark bites into an inanimate object like a surfboard or wetsuit it knows that it is not the same texture and taste as a seal or fish or anything else they naturally feed on and can reject it.

"In some cases, sharks can even get a fright if they bite into something hard and it’s not what they expected. I've seen this happen when they bite an outboard motor for example and then quickly swim away. But, this is dependent on individual behaviour.”

Gennari said he believed that the sudden increase in shark activity in the region could be attributed to the annual sardine run and that an increase in food could have caused an increase in these apex predators along the coast.

“This is definitely a possibility, although the sardine run typically only starts near East London and occurs up towards Kwazulu-Natal, it is very possible that there is predator and prey activity associated with the run further south. It is also possible that predators, like sharks travel through that area to get to the sardine run.

"Whatever the reason it is likely that there is a temporary increase in shark activity in that area possibly due to local favorable environmental conditions. It is also important to remember that the Garden Route is a well-known area for shark activity from white sharks, to bronze whalers to ragged tooth sharks and many others,” Kock said.

She added that shark bites was still a rare occurrence, especially in South Africa where there is on average only four shark bites every year. “It usually ranges from zero to eight per year. Last year there were 72 bites – of which only three were fatal – worldwide.”

According to International Shark Attack File – the longest running database on shark attacks – a shark attack was a potential danger that had to be acknowledged by anyone that frequents marine waters, but that this should be kept in perspective as bees, wasps and snakes were responsible for far more fatalities each year.

“Each shark incident is a terrible tragedy, but it is important to remember that sharks play vital roles in our oceans. Sharks feed at the top of the food chain and they feed on a variety of prey from squid, to fish and other sharks to seals, dolphins and even scavenge on dead whales.

"As a result they impact these species in two main ways – they have a direct impact on prey abundance and indirectly they impact prey behaviour for example prey will spend a lot of time trying to avoid being eaten, and the combination of these two effects means that white sharks play a regulatory role in our bay, influencing ecosystem structure and function.

“The presence of sharks, especially those at the top of the food chain is a sign that there is enough food to support them, which suggests a relatively healthy ecosystem. In areas for example, some coral reefs where sharks have been fished out, the ecosystem is less bio diverse and less healthy. Thus, having sharks around is actually a good sign for our ecosystems.”