46 unmanned systems
inside
January/February 2016
MARINE AQUACULTURE-MARICULTURE
Photos courtesy of Y. Olsen and the United Nation's Food and Agriculture Organization
and InnovaSea
to believe that that's going to be any different
going forward."
The world's appetite for fish is driving growth
in aquaculture and that growth is likely to ac-
celerate, Kite-Powell said, but many of the real-
ly good, near-shore locations for new operations
are either already being farmed or are being
used for other things. For that reason he sees
marine production moving further away from
the coast to open ocean farms, a new form of
offshore aquaculture called mariculture.
But where will these farms be located and
what kind of technology will they need?
The Goldilocks Problem
While the potential for mariculture is vast, cer-
tain environmental conditions are necessary for
an open ocean farm to be successful.
"I call it the Goldilocks problem," Kelly said.
"When you go offshore, if you look at water
depth—you can be too shallow, you can be too
deep, you can be just right. If you look at cur-
rent—you can be too slow, you can be too fast,
you can be just right. And the issue on current
is that you need a certain amount of current for
water exchange (to supply) dissolved oxygen.
If you have too much current they (the fish)
spend all their energy fighting the current and
not growing."
There are some 190,000 square kilometers of
the world's oceans that are particularly suited
to open ocean aquaculture, according to a 2013
study by the United Nation's Food and Agri-
culture Organization. To get to that number
researcher James Kapetzky started with the
world's exclusive economic zones (EEZ), that
Sea cages and longlines
with oyster ropes for
offshore mariculture
A diver works on a fi sh enclosure.
Source: NOAA (2011).
A UN report
details the areas
suitable for
mariculture.