AQUACULTURE USING COLD OTEC WATER
byThomas
H. Daniel,LaboratoryDirector
The Natural Energy Laboratory ofHawaii
P.O. Box 1749
Kailua-Kona, Hawaii 96745
ABSTRACT
The unique 2000 f t deep seawater pipeline installed
a t theNatural Energy Laboratory ofHawaii
(NELH)
suppliestheonlycoldseawateravailableinlarge
volumes anywhere i n thetropics.
Not onlydoes the low temperature of thecold
OTEC processpermitthe
seawaterrequiredforthe
tropicalculture of species normally found onlyin
colder areas, i t a1 so allows inexpensive yet precisetemperaturecontrolthroughout
even anopen
high
culture system. The deepwateralsocontains
concentrations of the dissolved inorganic nutrients
essential to p l a n t growth, whiletheneartotal
absence of pathogens,plants and particulates makes
the water particularly
well suited for the culture
of sensi tive organisms and also for the development
of pure c u l t u r e s t r a i n s .
THE NATURAL ENERGY LABORATORY OF HAWAII
- A BRIEFHISTORY
The Hawaii State Legislature founded theNatural
Energy Laboratory ofHawaii
( N E L H ) in 1974. The
enabling legislation set aside
322 a c r e s a t Keahole P o i n t on the Big Island ofHawaii
(Fig. 1)
forresearch i n t o renewableenergy resources and
also established a Managing Board of S t a t e , County
and Universityofficials t o oversee i t s development.
b
Lana:
of<-%
n
HAWAII
1284
From 1974 t o 1979, theFederal DepartmentofEnergy
(DOE) sponsored some experiments onOceanThermal
EnergyConversion (OTEC) which wereperformed a t
NELH by researchers from various universities.
D u r i n g the same years, acomprehensive permitting
program established all the permits necessary for
performing researchonshore and offshore a t NELH.
Mfni-CTEC, t h e w o r l d ' s f i r s t n e t
power-producing
OTEC plant, operated successfully under state
and
privateindustrysponsorship
i n NELH's offshore
researchcorridor i n l a t e 1979.In
the same year,
construction began on the Seacoast Test Facility
(STF), a j o i n t state/DOE project aimed a t providing
laboratory facilities for studying
OTEC processes.
Only asmall portion of thefederal money earmarked
so the
f o r STF construction ever materialized,
state increased its contribution
and applied
"creativeengineering" t o construct an operating
laboratoryforaboutone-halftheoriginal
planned
$16 millioncost.Thislaboratoryhas
met o r exceeded a l l of the goals originally set for the
full scale facil ity.1
The S t a t e o f Hawaii operates NELH t o encourage
research , development and comnercial ization of
a l t e r n a t e energy and relatedtechnologies.Since
Hawaii by i t s e l f does n o t have sufficient financial
or human resources t o perform the needed research,
t h e s t a t e ' s goal i s t o provide a f a c i l i t y where
others from b o t h thepublic and private sectors can
perform theexperimentation.
I t i s planned t h a t
thefacilitywill
soon become self-supporting from
user fees.
The DOE remains the major user of NELR f a c i l i t i e s ,
now providingabout 60%of theoperationalfunding.
The s t a t e has made e f f o r t s t o broaden the NELH
supportbase by encouragingthe i n i t i a t i o n of a
range of new projects i n aquaculture and related
f i e l d s sponsored by bothgovernment and industry.
The s t a t e l e g i s l a t u r e hasrecognizedthepotential
of these new p r o j e c t s , f i r s t by establishing "commercialization" as a legitimate goal of NELH and,
most recently, by i n i t i a t i n g t h e development of the
HawaiiOcean Science and Technology (HOST) P a r k
adjacent t o NELH. Laboratoryusers can now plan on
b o t h pilot scale comercial operations
on land
leased from NELH and eventualexpansion t o l a r g e r
f a c i l i t i e s i n the HOST Park.
THENELHCOLDMATER
PIPE
The i n i t i a l STF d e s i g n c a l l e d f o r i n s t a l l a t i o n o f
t h r e e3 2 in. p o l y e t h y l e n ep i p e s :
a m i l e - l o n gd e e p
p i p e f o r c o l d w a t e r , a n e a r s h o r e p i p e f o r warm
s u r f a c ew a t e ra n da 7 d i s c h a r g ep i p ef o ro f f s h o r e
d i s c h a r g ea f t e re x p e r i m e n t s .T h e s ep i p e sw e r e
t o r u n t h e 380 f t f r o m t h e s h o r e l i n e t o
a pump s t a t i o na tt h el a b o r a t o r yt h r o u g h at r e n c he x c a v a t e d
t o 8 f t b e l o ws e a l e v e l .T h et r e n c h
was n e c e s s a r y
s i n c e a s t a t i c head i s r e q u i r e d o v e r t h e i n t a k e
p i p e sa n dt h e
pumps t o p r e v e n t pump c a v i t a t i o n
c a u s e db yt h es u c t i o nh e a dd e v e l o p e di ns u c k i n g
t h r o u g h a m i l e - 1 ong p i p e . 2
When f u n d i n g was reduced,engineersdeveloped
a
c h e a p e r" i n t e r i m "s y s t e m ,w h e r et h ep i p e sr u nu p
o v e rt h es e a - c l i f fa tt h es h o r e l i n e .T h i sd e s i g n
n e c e s s i t a t e st h ei n s t a l l a t i o no ft h ed e e pw a t e r
pumps o f f s h o r e t o p r o v i d e t h e r e q u i r e d s t a t i c h e a d .
The s u r f a c e w a t e r p i p e f o r t h i s i n t e r i m s y s t e m
was
i n s t a l l e d as p a r t o f t h e Phase I c o n s t r u c t i o n o f
500 GPM pumps
t h e STF i n 1980. I t sf o u ro n s h o r e
provide a totalcapacityof
2000 GPM, and w a t e rh a s
been pumped t h r o u g ht h es y s t e mc o n t i n u o u s l ys i n c e
J u l y o f 1981.
Nhen i t became c l e a r t h a t DOE f u n d i n g f o r t h e
r e m a i n d e r o f t h e STF w o u l d n o t m a t e r i a l i z e , t h e
s t a t et o o kt h ei n i t i a t i v ea n di n s t a l l e dt h ei n t e r i m c o l dw a t e rs u p p l ys y s t e m ,u s i n gC a p i t a lI m p r o v e m e n tP r o . i e c tf u n d se a r m a r k e df o ra a u a c u lt u r e .P i D e
__
..
\ * b o t t o ma n c h o r
i n s t a l l a t i o n was c o m p l e t e d i n December1981,and
thesystembeganpumpingcoldseawater
i n February
1982.Deepseawaterhasflowedonshorecontinuousl y s i n c e i n i t i a l pumpingproblemswere
rectifiedin
A u g u s t 1982.
F i g u r e 2 shows t h ed e s i g no ft h e
12 i n .d i a m e t e r
J. van
NELH i n t e r i m c o l d w a t e r p i p e l i n e p r e p a r e d b y
R y t i n o f Makai Ocean E n g i n e e r i n g i n Waimanalo,
H a w a i i .T h eo f f s h o r ep o r t i o n ,
made f r o ms l i g h t l y b u o y a n th i g hd e n s i t yp o l y e t h y l e n e ,
i s h e l d on t h e
b o t t o mw i t hc o n c r e t ea n c h o r s
down t o t h e 500 f t
d e p t h ,b e l o ww h i c ht h eb o t t o md r o p so f fm o r es t e e p l y . From t h a t 500 f t t r a n s i t i o np o i n t ,t h ep i p e
f l o a t s i n a b u o y a n tc a t e n a r y down t o t h e 2000 f t
d e p t hw h e r el a r g eb a t t l e s h i pa n c h o r sh o l dt h ei n The pump s t a t a k ea b o u t 100 f t o f ft h eb o t t o m .
tion,locatedinabout
30 f t o fw a t e ra p p r o x i m a t e l y
100 f t o f f s h o r e , c o n t a i n s t h r e e h o r i z o n t a l l y - m o u n t e di n - l i n es u b m e r s i b l e
pumps a r r a n g e d i n p a r a l l e l .
Power f o r t h e pumps comes througharmoredcables
f r o ms h o r e .
E x p e r i m e n t a lr e q u i r e m e n t sd i c t a t e dt h a tt h ec o l d
w a t e r pumps n o t d i s s o l v e i r o n i o n s i n t o t h e w a t e r .
S i n c ef i b e r g l a s so rp l a s t i cl i n e ds u b m e r s i b l e
pumps
w e r eu n a v a i l a b l e ,
316 s t a i n l e s s s t e e l was s p e c i f i e d
f o ra l w
l e t t e dc o m p o n e n t s .
Pump performancehas
n o ty e tm e ts p e c i f i c a t i o n s ,d u et om a n u f a c t u r e r
i n e x p e r i e n c ew i t h SS c a s t i n g s . Non-316 SS compone n t sh a v ea l s ob e e nr e p e a t e d l yd i s c o v e r e d ,i ns p i t e
o fc e r t i f i c a t i o n st ot h ec o n t r a r y .W i t ht h et h r e e
pumps now i n s t a l l e d ,t h es y s t e mp r o d u c e su pt o
1100
..
200
ELEVATION
dnn
7""
'\
Concrete anchors
600
800
1001
L
1200 a
aJ
1400 n
2000
F i g u r e2 .T h e
'm a x .c u r r e n t
location
P i p eM a t e r i a l s :
No V e r t i c aEl x a g g e r a t i o nO f f s h o r e
- H i g Dh e n s i t Py o l y e t h y l e n e
Onshore - PVC
D i a m e t e r - 12 i n .
NELH C o l d w a t e rP i p e l i n e
1285
COLD WATER PROPERTIES
GPM. Two
new
pumps
planned f o ri n s t a l l a t i o n i n
September1985 willtogetherprovidethe
1300 GPM
designcapacity of the system. One of thepresent
pumps will remain installed as a
backup.
A regular sampling program has been maintainedfor
the three years that cold water has
beenpumped, as
part of the DOE-sponsored OTEC experiments. Weekly
surface and deepwater measurements of s a l i n i t y ,
a l k a l i n i t y , pH, dissolved oxygen, dissolved nut r i e n t s (NO3,PO4,& SiO3),totaldissolvednitrogen
and phosphorus, totalorganiccarbon,
and total
suspendedsolidssupplement
daily measurements of
temperature and hypochlorite concentration.
for instalThe NELH s t a f f hasdevelopedtechniques
ling and removing thecoldwater
pumps in most wave
and currentconditions from asmallboat.Maintenance becomes impossible, however, d u r i n g extreme
wave conditions which occur 20 t o 30 daysperyear.
In s p i t e of t h e f a c t t h a t system f a i l u r e s tend t o
coincide w i t h extreme conditions, hard workand a
generous amount o f good luck have permitted nearly
continuous operation for more than three years.
TableI summarizes t h e r e s u l t s of these measurefrom traditional oceanoments. As waswe11-known
graphic data, the
deep water i s s i g n i f i c a n t l y enrichedoverthetropicalsurfacewater
i n the dissolvedinorganicnutrients
which areessential t o
plant growth. The intaketemperature of thecold
waterstayswithintherange
of 5.5OC - 6.5"C
The temper(42.4"F - 43.7"F) throughouttheyear.
ature delivered on shore is a function of the flow
a t 500 GPM thetemperature is
rateinthepipe:
about 10°C (50°F) , a t 1000 GPM i t i s approximately
7.5OC (45.5"F).
The polyethylenepipessurvivedthelarge
waves
generated by Hurricane Iwa i n November 1982, b u t
damage t o the armored electricalcablesresulted
in
severalshort-duration pump outagesoverthe
ensuing two months. No flow interruptions exceeding
two hoursoccurred a f t e r t h a t u n t i l l a r g e
waves
againbrokethe
armored power cablesinJanuary
1985. A 37 houroutage a t t h a t timepermitted
i n s t a l l a t i o n of new specially designedcaged-armor
cables which shouldensurecontinuousoperationas
l o n g as the pumps operate and the pipeline remains
intact.
Three properties of thecoldwater
ularlyusefulforaquaculture:
1) Coldness - Not onlydoes thecoldwaterpermit
the culture of plants and animals which couldnot
otherwisetoleratetropicaltemperatures,
i t also
provides a simple,accurate and cost-effective
throughout
meansof year-roundtemperaturecontrol
a culturing system. Control of therate of water
The NELH coldseawater system i s believedto be the
only one i n the world which continuouslybrings
pureocean water from 2000 f t deep i n the sea to
shoreforexperimentation
and comercialventures.
Planning i s underway foradditionalpipelinesto
be
i n s t a l l e d a t NELH by b o t h industry and government.
PARAMETER
Table 1. WATER QUALITY DATA - NELH WARM AND COLD SEAWATER SYSTEMS
(Weekly Sampl es 1982-84)
Ut4 IT
WARM SEAWATER SYSTEM
COLD SEAWATER SYSTEM
RATIO WARM:COLD
max .
mean
min.
mean
-
28.0
82.4
24.3
75.7
-
-
-
35.05
34.33
34.71
34.29
-
8.35
8.02
8.24
7.55
-
NO3 + NO2
u w t / '1*
0.50
0.05
0.17
39.62
1:230
NH4
wat/l
0.76
0.20
0.47
0.34
-
p04
Si1 icon
ug-at/l
0.34
0.03
0.15
3.00
1:20
vg-at/l
11.52
1.80
3.46
77.58
1: 22
Total Diss.
Nitrogen
ug-at/l
7.84
2.51
4.12
42.16
1: 10
Total D i ss.
Phosphorus
ug-atll
0.66
0.19
0.35
3.03
1:9
1.20
0.51
0.91
0.58
-
Temperature
( i n Lab)
Salinity
PH
"C
O F
O/OO
Total Org.
Carbon
*microgram-atoms/liter
1286
make i t partic-
-
f l o w ,m e r e l yb yo p e n i n go rc l o s i n gv a l v e s ,p e r m i t s
maintenance o f a n yt e m p e r a u r eb e t w e e nt h ei n p u t
c o l dw a t e r( a l w a y sl e s st h a n
10°C)and
t h ea m b i e n t
a i rt e m p e r a t u r e( a l w a y sa tl e a s t
22°C).Temperai n t h i s way even i n open o r
t u r e sc a nb em a i n t a i n e d
s h a d e - c l o t h - c o v e r e dt a n k so r a c e w a y s N
. o t et h a t
b ym i x i n gt h ed e e pw a t e rw i t ha p p r o p r i a t ea m o u n t s
oftheflowingsurfacewateralsoavailableat
NELH, l a r g ev o l u m e so fs e a w a t e ra ta n yt e m p e r a t u r e
between 10°C and 24°C (50°Fand75°F)canbeobtainedyear-round.
2 ) N u t r i e n t s - The h i g h n u t r i e n t l e v e l s o f t h e c o l d
d e e pw a t e rp r o v i d et h eo p p o r t u n i t yf o rr a p i dg r o w t h
r a t e s i n m a r i n ep l a n t s - e i t h e r f o r p l a n t p r o d u c t i o n o r as f o o d f o r d e s i r a b l e a n i m a l s .
-
3) Purity
S i n c et h ed e e pw a t e r
comes f r o m w e l l
below tine p h o t i c z o n e , v i a b l e p l a n t c e l l s a r e
s c a r c e ,a l l o w i n gt h ec u l t u r eo fp u r es t r a i n so f
a l g a ew i t h o u tc o s t l yf i l t r a t i o n .B a c t e r i aa n d
o t h e rp a t h o g e nl e v e l s
i n t h ed e e pw a t e ra r ea l s o
e x t r e m e l yl o w ,p e r m i t t i n gc u l t u r eo fv e r ys e n s i t i v e
a n i m a l a r v a ls t a g e s
i n therawseawater.
AQUACULTURE
RESEARCH
PROJECTS
FOR
OTEC
BY-PRODUCTS
B o t hr e s e a r c ha n dc o m m e r c i a la q u a c u l t u r ep r o ' e c t s
havebeenconductedusingNELH'scoldwater.jThis
s e c t i o nd e s c r i b e sr e s e a r c hp r o j e c t s ,i n c l u d i n g
t h o s ew h i c hr e q u i r ev e r yl a r g ev o l u m e so fw a t e r ,
s u c ha sw o u l db ed i s c h a r g e df r o ma no p e r a t i n g
OTEC
p l a n t . Such p r o j e c t sm i g h tp r o v ev e r yp r o f i t a b l e
i nc o n j u n c t i o nw i t ha n
OTEC p l a n t
evenenough t o
s i g n i f i c a n t l yi m p r o v et h eo v e r a l le c o n o m i cv i a b i l i ty o f t h e OTEC process - b u t a l o n e t h e y m i g h t w e l l
beunable t os u p p o r tt h et r e m e n d o u sc a p i t a li n v e s t m e n tr e q u i r e df o ri n s t a l l a t i o no ft h er e q u i r e dc o l d
watersupplysystem.
-
T h en e x ts e c t i o n
w
i
l d e s c r i b ec o m m e r c i a lp r o j e c t s
w h i c hg e n e r a l l yu s el e s sw a t e rp e rp o u n do fp r o d u c t
so t h a t , e s p e c i a l l y f o r i n t r i n s i c a l l y v a l u a b l e
speon t h e i r
c i e s , t h e y may p r o v e e c o n o m i c a l l y v i a b l e
own. Such p r o j e c t se i t h e ru s es u c hs m a l l
amounts
o fw a t e rt h a tt h e yc a np r o d u c ec o m m e r c i a la m o u n t s
o fp r o d u c tu s i n go n l yr e s e a r c hv o l u m e so fw a t e r ,o r
t h ep r o d u c tv a l u ei sg r e a t
enough so t h a t p i p e l i n e
i n s t a l l a t i o n c o s t s become a c c e p t a b l e .
SALMON
AND
TROUT
- When t h e c o l d s e a w a t e r f i r s t
became a v a i l a b l e e a r l y i n
1982, D r . A. F a s t o f t h e
H a w a i iI n s t i t u t eo fM a r i n eB i o l o g y( H I M & )o b t a i n e d
f u n d i n gf r o mt h e
UH SeaGrant (UHSG) programandthe
s t a t eD e p a r t m e n to fP l a n n i n ga n dE c o n o m i cD e v e l o p ment (DPED) t oc o n d u c t an i n v e s t i g a t i o n i n t o t h e
p o s s i b i l i t yo fg r o w i n gs a l m o n
a n dr a i n b o wt r o u ti n
t h ec o l dd e e pw a t e r .T h i sp r o j e c tc o n t i n u e d
t h r o u g ht h ee n do f1 9 8 4 ,a n di n d i c a t e ds i g n i f i c a n t
p o t e n t i a lf o rg r o w i n gt h e s ef i n f i s hi nt h et r o p i c s .
Rainbow t r o u t ( S a l m ok i s u t c h )w e r ea l r e a d yb e i n g
g r o w ns u c c e s s f u l l yi nf r e s h w a t e ri nH a w a i i ,
and
t h e ya d a p t e dw e l lt ot h ec o l ds e a w a t e ra t
NELH. By
m a i n t a i n i n gh i g hf l o w so fa e r a t e dw a t e r ,t h er e s e a r c h e r sw e r ea b l et ok e e pn e a r l y
400 l b s . o f f i s h
a1 i v e i n each600-gal 1o n f i b e r g l a s s t a n k .
Eggs
werehatched i n f r e s h w a t e r a n d t h e
fry r a i s e d t o
thesmoltificationstage,afterwhichtheywere
t r a n s f e r r e dt oc o l ds e a w a t e rw h e r et h e yg r e wr a p i d l y as " s t e e l h e a d " .
E x p e r i m e n t sw i t hs a l m o n ,b o t h" K i n g "( C h i n o o k
O n c o r h y n c u st s h a w y t s c h a )a n ds i l v e r( c o h o
k i s u t c h ) , i n i t i a l l y g a v el o ws u r v i v a lr a t e s
when
thefishweretransferredfromfreshtosaltwater.
R e c o g n i z i n gt h a te n v i r o n m e n t a li n f l u e n c e s
on t h e
smol t i f i c a t i o n p r o c e s s w e r e p o o r l y u n d e r s t o o d , D r .
GordonGrau i n i t i a t e d a s e p a r a t ee x p e r i m e n tt o
on
s t u d yt h ee f f e c t so fp h o t o p e r i o da n dt e m p e r t u r e
t h e smol t i f i c a t i o np r o c e s s .I n i t i a lr e s u l t si n d i c a t et h a tp h o t o p e r i o dh a sl i t t l ee f f e c t ,b u tt h a t
lowertemeraturesdecreasethetimebefore
smol tification.
0.
4
I nf u r t h e re x p e r i m e n t sw i t hm a t u r eb r o o dt r o u t ,t h e
r e s e a r c h e r sm a n i p u l a t e dt h et e m p e r a t u r ea n dp h o t o p e r i o dt oc o n v i n c et h ef i s ht o
spawn i n seawater.
Theeggsandspermwerethen"milked"fromthe
femalesandmalesandmixedtogether
i nf r e s h w a t e r .
These f e r t i l i z e d eggs e x h i b i t e d h i g h e r s u r v i v a l
r a t e st h r o u g ht h es m o l t i f i c a t i o ns t a g et h a nh a d
been o b t a i n e di np r e v i o u se x p e r i m e n t se l s e ~ h e r e . ~
NOR1 - A n o t h e r p r o j e c t i n i t i a t e d i n t h e s p r i n g
of
1982 w i t h UHSG and DPED f u n d i n gg r e wt h e
seaweed
" n o r i "( P o r p h y r a %)
u n d e rt h ed i r e c t i o no f
D r . R.
Spencerand
F. Mencher.The
n o r i ,w i d e l yu s e di n
JapanandHawaii
f o rw r a p p i n g" s u s h i " ,g r e ww e l l
u s i n g a m i x t u r e o f warm s u r f a c ea n dc o l dd e e ps e a w a t e rR
. e s e a r c h e r se x p e r i m e n t e dw i t hv a r i o u s
temp e r a t u r e sa n dp h o t o p e r i o d s ,a n dc o n c l u d e dt h a t
g r o w t hi sb e s tv e r yn e a rt h ec o n d i t i o n s
i n the
i n JapanG
. r o w t hr a t e so f
h a r b o r sw h e r en o r gi r o w s
a b o u t 35% i n c r e a s e i n w e i g h t p e r d a y w e r e a c h i e v e d
forthefirst
15days
i n a t u m b l e - c u l t u r eu s i n g
r a p i dw a t e rf l o wa n db u b b l e da i r .M o r et h a n
600gms
drywgightpercubicmeterwereharvestedafter39
days.3Japaneseresearchersare
now i n v e s t i g a t i n g
c o m m e r c i a ln o r ic u l t u r ep r o s p e c t sa t
NELH.
MAINE LOBSTER - BeginninginSeptember1982,
Sand e r sA s s o c i a t e s ,a ne l e c t r o n i c s
companyheadquart e r e d i n Nashua, New Hampshire,performed a one
yearpilottestoftheirproprietaryprocessfor
g r o w i n gM a i n eL o b s t e r
(Homarus a m e r i c a n u s )w i t h
p a r t i a sl p o n s o r s h i pb y
DPED. U s i n gm i x t u r e so f
d e e pa n ds u r f a c es e a w a t e rt oc o n t r o lt e m p e r a t u r ea t
d i f f e r e n ts t a g e so fh a t c h i n ga n dg r o w t h ,t h e ys u c c e s s f u l l yg r e wt h ea n i m a l sf r o m
eggshatched i n
H a w a i ti oa d u l t s .S a n d e r sd e t e r m i n e dt h a t h eh i g h
costofthematerialsandthe
manpower r e q u i r e d
make t h e p r o c e s s u n p r o f i t a b l e a t t h e p r e s e n t l e v e l
o fw h o l e s a l el o b s t e rp r i c e si nH o n o l u l u ,
so t h e
p r o j e c t was t e r m i n a t e d a f t e r oneyear.6
OYSTERS - O y s t e r s( C r a s o s t r e a sp.) i m p o r t e d f o r a
d e f u n c t p r o j e c t a r e now beinggrownby
NELH s t a f f .
I n i t i a la t t e m p t st oc u l t u r ev a r i o u ss t r a i n so f
a l g a et of e e dt h eo y s t e r sm e tw i t hm i x e ds u c c e s s .
R e c e n t l y ,r a p i dg r o w t hh a sb e e na c h i e v e db yf e e d i n g
t h eo y s t e r sw i t hd i a t o m sb e i n gf i l t e r e df r o mt h e
a b a l o n ef a r m ' sk e l pt a n k s .T h i ss u c c e s sh a s
1 ed t o
t h ei m p o r t a t i o no fo t h e ro y s t e ra n dc l a ms p e c i e s
f o rs i m i l a re x p e r i m e n t s .
Though c o m m e r c i a l - s c a l e
1287
growoutof thesemollusks i n the tropics may require too much water and i n f r a s t r u c t u r e t o be economicallyviable, i t doesappear that the purity of
the deep water may provideidealconditionsfor
commercial hatcheryoperations.
- Dr. Murray Dailey,incooFeration
GIANT
CLAMS
w i t h the WaikikiAquarium, has begun a project w i t h
private and grant funds u s i n g the deep water a t
NELH to grow giant clams (Tridacna %)
imported
from Palau.Theseclams
haveeconomic potential
both f o r their meat and f o r t h e i r s h e l l s which, a t
various stages of growth, have usesranging from
earringstobathtubs.Sincetheysubsist
on algae
whichgrow symbiotically w i t h i n their bodies, they
require no food beyond the sunlight and nutrients
necessaryforplant
growth. The i n i t i a l phase of
t h i s p r o j e c t , beginning i n August 1985, includes
research t o determine the e f f e c t s of thefollowing
variables:(1)thenutrient-richwater,
( 2 ) colder
temperatures,(3)flowrate,(4)
l i g h t spectrum and
( 5 )s p a t i a ld i s t r i b u t i o n .
CURRENT COMMERCIAL DEEP WATER AQUACULTURE
PROJECTS
ABALONE - In May 1984, HawaiianAbalone Farms (an
a f f i l i a t e of MontereyAbalone Farmsof California)
signedalong-termlease
f o r 21.3 acres of land
adjacent t o the NELH compound andbegan development
of a "Commercial Demonstration Module" of an abalone(Haliotusreferens)productionfacility.This
culminated more than two years of research a t NELH
which indicated the suitability
of the deep cold
waterforabaloneculture.
TheCompany has since
moved i t s productionoperations fromMonterey to
Kona and clearedthelandforthedemonstrationmodule. They arepresentlyinstallinga
new coldwaterpipewith
t h e i r own funding, and plan t o
marketabalonesoon.
Thiscompany's research hasdemonstratedtheuseful
properties of the deep cold water for aquaculture
of marinemollusks.
The purity of thewaterpermits successfullarval growout w i t h o u t expensive
waterpurification.
The high l e v e l s of dissolved
inorganic nutrients i n the deep waterproviderapid
growth r a t e s and high proteincontent i n b o t h the
microscopicdiatomsthemollusks
consume as larvae
which
and i n the g i a n t kelp(Macrocystispyrifera)
they eatasadults.Sincethe
deep wateris always
colderthanrequiredforthevarious
growth stages,
temperature can be maintained i n a l l systems by
control1 ing water flow.
MICROALGAE - Cyanotech Corporati on ofWoodinvi 11e ,
Washington has recently constructed large
raceways
on land leased a t NELH f o r t h e c u l t u r e of various
marinemicroalgae.
Initialproductionincludes
Spirulina,aprotein-richmicroalga
in g r e a t demand
asahealth
food supplement. Though Spirulina is
normally grown i n freshwater, Cyanotech s c i e n t i s t s
havedevelopedtechniques
f o r growing i t i n NELH's
pure nutrient-rich deep seawater. Thecompany is
a l s o growing other microalgae w i t h very h i g h concentrations ofBeta carotene, a vitamin A precursor
w i t h a recently-discovered ability
t o preventcertaintypes of cancer.Futureplansincludedevel-
1288
opmentof other pharmaceuticalproducts
croalgae.
from m i -
The microalqae grow i n oval raceways, some u p t o
550 f t 1 ong by50 f t wide, w i t h the water circulated by large paddlewheels..
The deepseawater i s
intentionally warmed to the higher temperatures
needed f o r optimum algal growth during i t s slow
passagethrough
thepipestotheraceways.
Once
production i n eachraceway i s i n i t i a t e d , t h e o n l y
waterrequired is toreplaceevaporationlosses.
The high nutrient content of thewater, i t s extreme
purity and the h i g h sun1 i g h t a t Ke-ahole Point (the
highest solar insolation measured a t sealevel i n
the U.S.), combine toprovideideal
growth condit i o n s f o r t h e s e rnicroalgae.
COLD SEANATER AGRICULTURE!
A t the instigation
of NELH Board ChairmanJohn
Craven, UH investigators have begun research on the
possible use of the cold freshwater which condenses
on thepipescarryingcoldseawatertoirrigate
agriculturalcrops such asstrawberries.
With
funding from UHSG, several bedswere constructed a t
NELH and plumbed withvariouscominations
of coldwater p i p i n g r u n n i n g bothabove andbelow t h e s o i l .
I n i t i a l r e s u l t s show t h a t s u f f i c i e n t w a t e r condenses from the ambient a i r a t Ke-ahole Point to
provide adequate irrigation for strawberry growth.
grown u s i n g this cold
In addition,thestrawberries
condensedwater consistently have about five times
with
the sugar content of control plants watered
ambienttemperaturetapwater.
Varying theflow
r a t e of thecoldseawateralsoallowscontrol
of
the r o o t temperature of theplants,providingthe
p o s s i b i l i t y of rapidseasonalcyclingforincreased
f r u i t production. The i n i t i a l six-month p i l o t
project conducted i n 1984 demonstrated the usefulness of the coldwater agriculture concept,
and
f u r t h e r work i s plannedsoon.
FUTURE PLANS
Recognizing the significant conunercial possibil it i e s developing from thecoldwaterresearch
at
NELH, t h e s t a t e government has begun developmentof
the Hawaii Ocean Science and Technology (HOST) Park
on 547 acres of land adjacent to the
NELH property.
Park s i t e s , ranging i n s i z e from three acres to 100
or more acres, will be leased to companies w i s h i n g
t o takeadvantageoftheuniquenaturalattributes
of Ke-ahole P o i n t for production of aquacultural,
energy or related products. 7
I n i t i a l l y proposed by the HawaiiHigh Technology
Development Corporation as an appropriate area of
"High Tech" f o r Hawaii, the HOST Park has now
receivedsupport from GovernorAriyoshi and the
l e g i s l a t u r e . Design work is underway, and the
infrastructure (including warm and coldseawater
systems) will be completed in 1986.
In addi tion t o the new p i pel ines planned f o r t h e
HOST Park and f o r HawaiianAbaloneFarms,
DOE i s
presently contracting for final design
of a new 30
i n . p i p e l i n ef o r OTEC research. Each of these
pipe1 ines will give some measureofredundancy
the NELH seawatersystem,providingtheincreased
r e l i a b i l i t y which i s p a r t i c u l a r l y d e s i r a b l e f o r
aquacultureresearch and development.
to
NELH willcontinuetoprovideresearch,
development
and pilot-scale "incubator" facilities for projects
which may eventually expand i n t o t h e HOST Park
f a c i l i t i e s . The capability of combining research
with pilotscaleproduction
makes NELH a unique
site for important stages of
commercial development. New ventures can now utilizetheseunique
advantages, knowing t h a t f u l l - s c a l e devel oprnent may
follow a t t h e HOST Park.
ACKNOWLEDGEMENTS
Chairman John Craven and the other unpaid members
of the NELH Board are largely responsible for the
success of thelaboratory.
The work reportedhere
hasbeenperformed
bymany researchers andcompan i e s , a l l of whom d e s e r v e c r e d i t f o r t h e i r e f f o r t s .
REFERENCES
ILarsen-Basse, J . , e t a1 . , "ClosedCycle OTEC Corrosion and Heat Transfer Studies at the Seacoast
Test Facility - Current Status", Oceans 85Proceedings, This volume.
2ResearchCorporation of the University of Hawaii,
"OTEC SeacoastTestFacility
- Preliminary System
Design Description", Preparea for
Argonne National
LaboratoryContract No. 31-109-38-4406, February,
1980.
3Fast, A.W., e t a1 . , .'Xquacul t u r e Research a t NELH
- 1981-1984",inpreparation
by U H SeaGrant.
4Grau, E . Gordon, e t a l . , "VariationsinThyroid
Hormone Levels and in Performancein theSeawater
ChallengeTest AccompanyingDevelopment in Coho
Salmon Raised inHawaii",presented
atInternational Smol t i f i c a t i o n Workshop, sponsored by E.O.C.,
Stirling,Scotland, 3-6 July 1984, t o be published
inAquaculture i n 1985.
(Porphyra
SMencher, F.M. , e t a l . , "GrowthofNori
tenera) in an Experimental OTEC-Aquacul t u r e System
inHawaii", J . World Maricul.SOC.,14:458-470,
1983.
6SandersAssociates,Inc/ResearchCorporation
Univ e r s i t y of Hawaii,"LobsterAquaculture DemonstrationProject:FinalReport",
December 1983.
7High Technology Development Corporation, "Hawaii
Ocean Science and TechnologyPark:Marketing
and
FeasibilityStudy",Presentedtothe
Hawaii S t a t e
Legislature,January 28,1985.
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