Sharks have a reputation for being dangerous killers regularly attacking and killing swimmers. The chances of being killed and eaten by a shark are relatively small, but this is not the case for our underwater fiber-optic cables, so necessary for the flow of data around the world. Sharks seem to be attracted to these vital communication links.
Dan Belcher, Google’s product manager, announced that the company was starting to re-enforce some of its cables, including the trans-Pacific cable, by covering them in a material similar to Kevlar.
What is the attraction for the sharks?
Sharks use small detectors called ampullae Lorenzini, which are found the snout and allow them to sense electromagnet fields in water. These tiny organs, which resemble freckles, can detect even the smallest changes to the electrical fields and this helps them to locate prey, to move around and now to detect our cables. The Director of the Florida Program for Shark Research, George Burgess, notes that the electromagnetic fields from these wires are very attractive to some sharks.
It is interesting to note that the older copper cables don’t have the same attraction. One theory is the emissions given from the fiber-optic cables confuse the shark because they are similar to signals from fish. By updating these cables, both the sharks and the cables will be protected.
These problems have been continuous since the 1980s. In 1985 it was reported that shark teeth had been discovered in a cable near the Canary Islands. It is not only sharks, but other wildlife, fishing vessels and seismic activity that are responsible for at least 50 repairs on these lines each year.
The new $300 million system which will connect the US with Japan will include these new reinforced cables. This will increase the internet speed to 60 terabytes each second.
Maybe the sharks are just doing this to improve their public reputation.