• SharkieSophie

Raise the Bar!

Updated: Apr 27

On 26 August 2019, there was an incident in Tuşuco, Turkey, where several sandbar sharks (Carcharhinus plembeus) harassed a team of commercial divers. Thankfully, the bites were non-fatal, but there was concern that the attacks were unprovoked. In these situations it is important to understand what caused the sharks to behave in the way that they did, so that we can strive to avoid it ever happening again.


Sandbar shark with a snorkelled (Image source: www.hawaiiadventurediving.com)

The incident occurred at a fish farm in the Mediterranean Sea, off the southern coast of Turkey. The commercial divers were working to clean and untangle fish carcasses from outside the cages, which were anchored to the sea floor at 20 m depth (Ergüden et al, 2020).


Bitten fin (Ergüden et al, 2020)

At which point 8 sandbar sharks circled them, coming increasingly close, becoming agitated and they took some bites at the divers. They recorded an image of the damage done to a diver's fin; a shark had bitten down on the plastic, but thankfully, the diver was unharmed. Some of the sharks were killed in order to protect the divers (Ergüden et al, 2020).


Sandbar sharks are generally not considered to be dangerous, and snorkelers and divers commonly interact with them in the water without incident. In fact, they are considered one of the safest shark species to swim with!


After investigating the circumstances, a team of scientists concluded that the 'un-provoked' attacks occurred because the sharks were agitated by the presence of excessive amounts of dead and wounded fish around the cages. This effectively acted like "chum" in the water; attracting sharks to the area, in the hopes of finding prey. This kind of behaviour is known as a "feeding frenzy" (Ergüden et al, 2020).


One of the sharks killed to protect divers (Ergüden et al, 2020)

According to the International Shark Attack File of the Florida Museum (the institution responsible for recording and analysing global shark attacks annually) an "un-provoked shark attack" is defined as an 'incident where an attack on a live human occurs in the shark's natural habitat with no human provocation of the shark'. For example, this would include an attack upon a surfer who did not even realise the shark was there or a bite on a swimmer who did not approach the shark. Comparatively, a "provoked attack" is defined as 'when a human initiates interaction with a shark in some way'. This would include when an ocean user harasses a shark; swimming too close or attempting to touch the shark, or when a fisherman handles a shark after bringing it onboard a vessel.


The sandbar shark (Image Source: Instagram user Clark Little)

So, it could be argued that this incident was not unprovoked; the divers were creating a significant shark attractant with their activities. You would not be surprised to be attacked by a lion of you got out of your jeep during a safari and threw zebra carcasses around you!


Of course, I am not criticising the victims and I am very thankful that they were not seriously injured! But, this incident does highlight a serious issue... Our behaviour in the ocean can cause unpleasant incidents with sharks, which, arguably, are not the fault of the shark! They are behaving completely naturally in their habitat! We are the intruders. It does not seem right to me that they should be penalised or persecuted for this.


So, let's improve ourselves! How can we make sure that when we use the ocean, we are doing so as safely and responsibly as possible?

  • If you are using the ocean in a shark-fish area (lucky you!) educate yourself about the local restrictions and protective measures. Check for shark warnings in your area (either online or through signage at the beach) and adhere to local guidelines. DO NOT ENTER THE WATER IF LOCAL AUTHORITIES HAVE ADVISED IT IS NOT SAFE!

  • To be extra sure you are safe when boarding, you can buy SharkShocker devices, which repel sharks to a degree. It is important to note that these devices are in development; some models work better than others and they are not a 100% successful deterrent. You should still always be mindful of local guidelines rather than relying solely on these devices to protect you.

  • If you are interacting with sharks in the water on an organised diving or snorkelling trip, educate yourself about the behaviour of that particular species. You can google this or ask your dive master or another member of the crew. All animals communicate in their own way, but we just have to know how to read their signals. Sharks use body language to communicate; many species dip their pectoral fins as a threat display, some also hunch their backs and swim erratically or exaggeratedly (known as "posturing"). If you observe a shark exhibiting these behaviours, it is warning you to back off or it will attack! DO NOT PANIC! Move away slowly without thrashing and always keep your eye on the shark. DO NOT TURN YOUR BACK.

  • DO NOT FEED WILD SHARKS! It is dangerous to you and other ocean users! There is a lot of evidence that feeding wild animals is also quite bad for their health, as the titbits we give them are not as nutritious as their natural food sources. Over time this can cause the sharks to have increasing poor body condition and become unhealthy.

  • NEVER APPROACH A WILD SHARK! Simple as that! You do so at your own risk. All wild animals are potentially dangerous and we must respect their space and not make them feel threatened by approaching them too closely.




References

Ergüden D, Ayas D & Kabasakal H (2020). Unprovoked non-fatal attacks to divers by sandbar sharks, Carcharhinus plumbeus (Carcharhiniformes: Carcharhinidae), off Tuşuco coast (Mediterranean Sea, Turkey). Annales, Series Historia Naturalis, 30.


By Sophie A. Maycock for SharkSpeak.

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