OPEN OCEAN AQUACULTURE IN HAWAII
by Charles E. Helsley
SOEST, University of Hawaii at Manoa
Published in the March Issue of Hawaii Fishing News.
For the past four years, the University of Hawaii and the Oceanic Institute have
been engaged in research into the feasibility and environmental acceptability of Open
Ocean Aquaculture in Hawaii.
I would like to convey to your readers some results from
News magazines and newspapers have recently published a series of articles that
imply that aquaculture has deleterious consequences on the environment.
Indeed, like all
things, adverse interactions can occur and have been documented in some parts of the
world where over-development, or development without adequate understanding of the
environmental consequences, has had negative impacts. This was the reason that
environmental monitoring was made a part of Sea Grant’s support for our Hawaii Open-
Ocean Aquaculture Demonstration Program (HOARP) that was begun 4 years ago.
The initial goals of HOARP were (1) to learn whether or not open ocean
aquaculture could be done in Hawaii, (2) if it was feasible, to ask whether the technology
was mature enough to warrant the investment in time and effort to develop a farm, and
(3) to determine whether the associated environmental impacts to the seafloor,
surrounding water, and other nearby elements such as reefs were sufficiently small to be
acceptable to the people of Hawaii.
We learned that, indeed, it was feasible to grow a
local fish in offshore cages, that the technology was mature enough to withstand the
rigors of our rough offshore waters, and that the environmental impact was virtually nil.
I will elaborate on each of these elements of our work in the paragraphs that follow.
After examining several sites, we chose to do our work at a site about 2 miles off
Ewa Beach on Oahu.
It was not that this was necessarily the best site, but it was out of
the main shipping lanes, it was an adequate one with a sandy bottom where we could
deploy anchors, and it was one that was accessible on a daily basis from the University of
Hawaii’s marine support base in Honolulu harbor.
The Oceanic Institute and the UH
entered into agreements to pursue the work in the fall of 1998 and research permits from
the State were requested and received.
We ordered an OceanSpar 3000 cage, a fully
submersible cage built by a firm in the Seattle area, in the fall of 1998 and began growing
some 90,000 fingerlings at the OI facility in Waimanalo in February 1999.
The cage was
assembled and deployed in March and by the end of April we had some 50,000 to 70,000
fingerlings in the cage.
We began harvesting the moi in the cage in September 1999 and
continued until the end of October when the cage was empty (approximately 50,000 fish
Throughout the 8-month effort, we made observations of the seafloor,
sampled the water around the cage, and monitored the health of the nearby reef (about _
We saw nothing!
No change at all.