ICPC: Sharks No Threat to Subsea Cables

The International Cable Protection Committee (ICPC) has responded to a rediscovered YouTube video of a shark biting a subsea cable which caused a media storm back in August 2014.

According to some commentators, the video signified that worldwide telecommunications were under attack by sharks because submarine fibre-optic cables are the backbone of the global Internet.

ICPC said it has reviewed records of cable faults worldwide, and together with an assessment of the video, concluded that much of the media hype was incorrect.

According to ICPC, sharks and other fish were responsible for less than 1% of all cable faults up to 2006. Since then, no such cable faults have been recorded.

“Information about the YouTube video is sparse, but it appears to have been produced in 2003 as part of a marine survey. In 2010, the video was uploaded to YouTube by an individual named Sudmike, but that person has not been traced. The video received wide media exposure in the summer of 2014 during the annual “Shark Week” in the US, when the number of views approached 1 million.

Expert advice suggests the cable was attacked by a six-gill, blunt nose shark (Hexanchus griseus), which took one bite and swam away. The cable sustained no obvious external damage and is unlikely to have suffered internal damage.

It is also unclear if the cable is a fibre-optic telecommunications or an electrical power system.” ICPC said in a press release.

ICPC says that studies reveal a marked decline in the number of cable faults caused by fish bites including those of sharks.

That marked reduction in faults is consistent with improved cable design and other measures to protect cables such as burial beneath the seabed. The negligible amount of fish bite damage contrasts strongly with ships’ anchoring and fishing activities, which account for 65-75% of all cable faults. Other faults relate to natural phenomena, such as subsea landslides and ocean currents (less than 10%), cable component failure (5%) and “cause unknown” (10-20%). It is unlikely that shark bites are masked in the “cause unknown” category, because bites leave evidence in the form of teeth imprints or actual teeth embedded in a cable’s sheathing.

The first recorded shark bites of a deep-ocean fibre-optic cable occurred off the Canary Islands in 1985 to 1987. These pioneering systems were damaged by small sharks biting through cable’s polyethylene sheath. Testing by Bell Laboratory scientists showed the culprit was the deep-dwelling, crocodile shark (Pseudocarcharias kamoharai) that occupied water depths of 1060-1900m. Those events led to design improvements of the cables’ protective sheathing that effectively eliminated the problem, ICPC said.

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