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Mon, 25 January 2010

The Ocean Correspondent for the Save our Seas Foundation (SOSF), Cheryl-Samantha Owen, summarises the official investigation into the shark attack, and adds relevant insights based on cumulative findings by the SOSF White Shark Research Project after thousands of hours in the field studying these apex predators.


Shark attack could not have been avoided

The fatal shark bite that took place at Fish Hoek earlier this month could not have been avoided, according to the City of Cape Town. The City’s official review of the incident puts to an end any speculation and incorrect perceptions around the incident, and suggests it was most likely a combination of factors that contributed to the attack.

Ocean conditions

The water and weather conditions on the day dramatically reduced the likelihood of seeing white sharks in the area. The review, conducted by the city’s head for environmental policy and strategy, Gregg Oelofse, stated, “Conditions for shark spotting at the time of the attack were not ideal, as indicated by the raised Shark Spotters black flag. There was a high wind speed of 69km per hour, which resulted in high chop conditions and intermittent cloud cover.”

Location

Mr. Loyd Skinner was swimming, and not standing as previously reported, about 100 metres away from the shoreline when the shark approached him. This was significantly further out into the bay and in deeper water than any of the other estimated 12 to 15 bathers in the water at the time. In addition, eyewitnesses reported a large school of fish in close proximity to where Mr. Skinner was swimming at the time of the attack. Fish are a large part of the white shark’s diet, and prey availability seems to be the primary reason for white sharks venturing close to shore. SOSF white shark scientist Alison Kock has frequently recorded white sharks hunting schools of yellowtail at the surface in False Bay, and in line with this summer’s increase in shark sightings have also been reports of an abundance of baitfish in the area. On this occasion the white shark was most likely drawn to the warmer in-shore waters to hunt the nearby school of fish or larger fish predating on the school. Alison suggests that the shark was already in feeding mode, with its heightened senses stimulated when it came across Mr. Skinner swimming in the bay on his own. 

Rare type of attack

All indications are that the shark suddenly emerged from deeper water, where it was not visible beforehand and attacked within seconds. The report states that had the shark spotters on duty seen the shark prior to the attack there would not have been any time to warn the bathers before the shark attacked. The type of attack witnessed here was predatory in nature, but these kinds of attacks are extremely rare. The vast majority of shark attacks are not fatal.

White sharks have evolved over millions of years to predate on fish, other sharks and marine mammals such as Cape fur seals. The ocean is not our natural habitat and because humans did not evolve in the water alongside sharks we are not on sharks’ menus. “White sharks, however, are opportunistic predators, and very occasionally under a certain rare combination of factors they bite people,” states SOSF white shark scientist Alison Kock.

All shark bite incidents have their own set of unique circumstances and different behaviours apply to different species of sharks. According to Alison each shark attack results from the unique combination of certain factors, which include: location, time of the attack, species of shark involved, behaviour and activity of the shark, size of the shark, behaviour and activity of the person, environmental and biological factors.

White sharks hunt most of their prey using the element of surprise. When predating on Cape fur seals in False Bay, for example, white sharks launch themselves from depths below the seals as they leave or return to Seal Island.  They also choose the early morning or late afternoon hours for their ambush when the light intensity penetrating the water is low and the seals are less able to see them.

White sharks in-shore

White sharks are present along South Africa’s Western Cape shores all year round, with a higher number of white sharks moving closer to shore during the summer months (between October and April), a pattern that has most likely been going on for decades. In fact, most white sharks that were hunted in the 1960’s and 1970’s in Cape Town waters were hunted in the summer along the stretch of coast between Strandfontein and Strand. The first fatal shark attacks recorded in False Bay were from Simon’s Town area in 1900 and 1901.

Almost every day of the summer white sharks swim along the inshore waters of False Bay and other areas in the Western Cape, often immediately behind the backline of breakers. The waves from Muizenberg to Glen Cairn are often populated with hundreds of surfers and body boarders. If white sharks viewed humans as part of their prey attacks would be a daily occurrence, not only along the backline but also much closer to the beach, and we would have no choice but to stay out of the water completely.

There is a risk factor associated with almost any activity, including driving to the beach, making toast or even sitting on a chair, and swimming in the ocean is no different. The ocean is one of the last wildernesses on our planet and entering it is not without inherent risk. No “shark safety method” is 100 per cent effective. In fact, no safety method for anything is 100 per cent in the ocean. Rogue waves happen, rip currents catch people unawares, some of the ocean’s smallest creatures can be the most venomous, and hazardous waste can cause diseases. There is always a risk. The aim for each individual is to be responsible for their actions and whenever possible minimize those risks.

•    Swim in a group
•    Do not swim in an area where sharks have been spotted
•    Do not swim beyond the breakers
•    Do not swim when there is fish activity in the area (look out for birds and dolphins feeding at the surface as a clue for high fish activity).

The SOSF white shark research project is studying the behavioural ecology of white sharks in the Cape’s waters and much of the information available in this article comes from information collected by the research team spending thousands of hours in the field studying these apex predators. Through this research we hope to gain a better understanding of what the driving forces are behind the movements of white sharks. Great white sharks are a naturally occurring species in South African waters and as such they remain part of our landscape. The SOSF white shark research project and the Shark Spotters will continue to monitor the movements of white sharks and issue alerts, such as that issued prior to the attack on the 12th January, when there is an increase in shark sightings.

For more information or to donate to the Great White Shark Research Project please visit www.saveourseas.com 

 

Comments  

 
Andrew Keet
+2 #4 Andrew Keet 2010-02-18 17:16
For more information on sharks, take a look at this local site devoted to them. www.sharks.org.za
 
 
Andrew Keet
0 #3 Andrew Keet 2010-02-18 17:14
For more information on sharks, take a look at this local site about sharks. www.sharks.org.za
 
 
Stuart7777
0 #2 Stuart7777 2010-02-14 05:01
I'm not for starting a war..
But if its him or me, it will be me..
 
 
predator
-5 #1 predator 2010-01-25 15:49
how can you tell a surfer to stay out of the ocean.
bring on the dynamite... the war begins.

If a lion walks down the street are you going to leave him alone and let him prey every once in a while on humans, no bag and to the zoo with him.

think the ecologists being paid need to start showing results... or look for another job? pro surfer? :-O
 
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