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Re: fiber-optic cables


Howard Teas <[log in to unmask]>


Scientific forum on fish and fisheries <[log in to unmask]>


Sun, 12 Mar 2000 20:56:22 -0900





text/plain (1 lines)

Although my experience with fiber-optic cables is limited so far, I have
been working on the marine science portions of an EIS for a fiber-optic
cable for over a year. The process of laying one is pretty straight
foreward. Whenever the cables are laid in less than 1500 m water depth it
must be buried, if possible. The cable goes down to the bottom, where a
plough towed behind the ship digs a 2 m deep trench and positions the cable
to drop to the bottom of it. This is, of course, only on soft bottoms.
The plough, working with natural sorting, covers the cable with up to 2
meters of sediment after burial.

The cable is laid directly on rocky substrates. There is enough weight in
a cable to keep it on the bottom when laid dorectly on rocky bottoms, so it
doesn't hang in the water column, unless crossing a very steep canyon.
Even then it will work its' way to the3 bottom of most variations.

At least in the US, fishermen, as well as any other interested parties, are
welcome at several points in the process to comment on the project or point
out conflicts. All comments must be addressed in the final EIS.
A problem arose for the GCI fiber-optic cable laid down the coast from
Alaska to Washington last year. Fishermen ignored the public process until
the cable-laying ship entered a narrow straignt to lay a connecting cable
in to Juneau. Black cod fishermen reacted strongly to what turned out to
be non-existent problems. I would like to stress here that they refused to
be a part of the process until the ship arrived to start laying the cable.

Since fiber-optic cables use light, not electricity, there is no potential
for EMF stresses. The sheath is non-toxic, so it is not likely to cause
problems. Whales are not likely to be found in the immediate area of cable
laying operations, due to the disturbance and noise, so I really doubt
there is likely to ba a conflict with them. The biggest effect is likely
to be an increase in hard substrate along deeper (<1500 m) sections of a
cable. It is likely to provide substrate for any deep dwelling epifauna
in areas dominated by soft bottom habitat.

Bottom line is we really couldn't find problems beyond localized
disturbances during ploughing. The local benthic feeding fish populations
are likely to do well shortly after passage of the plough.

Howard Teas
Anchorage, AK

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