Submarine cables: Preserving the Mid-Atlantic’s telecommunications superhighway

An integral part of this system is undersea cables ― a network of thousands upon thousands of miles of infrastructure that crisscrosses the Mid-Atlantic seabed from North America to Europe.

"Undersea cables have been in the ocean since before the U.S. Civil War," said Bob Wargo, President of the North American Submarine Cable Association. "The first telegraph cable across the Mid-Atlantic was installed in 1858."

The first telegraphs were capable of transmitting six to eight words per minute. Today, trans-Atlantic undersea cables with flashy names like the Emerald Express run from Long Island to Dublin with data delivery capacity of 60 terrabytes per second. These cables cost upwards of $200 million to $500 million to build, and are often jointly funded by a consortium of telecom companies. One of the highest densities of undersea cables is across the northern Atlantic Ocean between the U.S. and Europe, where there are currently 19 active submarine telecommunication cables that land in the Mid-Atlantic region.

“Somewhere between 95 and 99 percent of all international telecommunications travels on undersea cables,” Wargo said.

Whereas cables lie on top of the ocean floor in the deep seas, cables crossing the more shallow continental shelf waters are armored and buried roughly one to two meters below the seafloor to protect them from damaging activities.

However, the submarine cable industry has made great improvements in minimizing cable damage caused by fishing activity in particular through directly working with commercial fishermen to share data on cable locations (known as “route position lists”) and providing compensation for fishing gear that becomes snagged on cables.

"There is a longstanding tradition amongst the cable industry -- and it’s actually part of international law ― that if a fisherman sacrifices his gear to protect a submarine cable, we replace his gear," Wargo said.

However, Wargo noted there is still some work to do mitigating conflict with other ocean uses.

"We’ve had cables that have been broken by sand dredging [for beach replenishment] and, in the recent past, we’ve had dredge vessels show up very close to cable landings without any input from either the dredger or the folks who had contracted the dredge," Wargo said. "The fact of the matter is that there have always been conflicts and you have to work them out."

Recently, the undersea cable industry made a major step forward in providing more accurate and reliable data to depict the locations of active or “in-service” cables for the purposes of ocean planning.  The North American Submarine Cable Association (NASCA), whose membership includes telecom giants such as Verizon, Sprint and AT&T, worked with NOAA to share a comprehensive database of cable locations (known as “route position lines”) owned by NASCA members on the Marine Cadastre website.

The new NASCA data identifies “in-service” versus “out-of-service” cables and includes the cable name and owner information.  It is important to note that NASCA members include the majority ― but not all ― of private operators of submarine cables, so a small number of submarine cables in the Mid-Atlantic are not represented in these data. 

Within the context of ocean planning, the submarine cable industry is interested in developing minimum buffers between cables and other uses like fishing, anchoring and dredging. However, at this point, their main goal is to continue operating business as usual, Wargo said.

"The goal is for us to be able to do what we’ve done for 100 years or more," he said. "The Portal can show other industries where we are. Hopefully they can plan to avoid us early in the process rather than us needing to react when a project is sited directly over a cable landing or impinges upon some other part of the cable off shore."

The NASCA submarine cable data will make accounting for this vital infrastructure possible in all ocean planning efforts going forward.