Guam Fish Aggregating Device programme

S e s s i o n 2 - Technologie cles DCP
Guam Fish Aggregating Device p r o g r a m m e
Andrew Torres
Government of Guam, Department of Agriculture, Division of Aquatic and Wildlife Resources,
1 9 2 Dairy Road, Mangilao, Guam, USA 9 6 9 2 3 - [email protected]
Abstract
Installation and maintenance of FADs by the Government of Guam began
in 1979, initially with f u n d i n g from the Salstonstall-Kennedy Act
through the Pacific Tuna Development Foundation. Current funding
for the G u a m FAD project is provided through the D i n g e l l - J o h n son/Wallop-Breaux Sport Fish Restoration programme, a Federal Aid
Project funded by taxes collected on the purchase of fishing equipment
and motorboat fuels nationwide. There are now sixteen operational
FAD sites in Guam's waters. At a cost of approximately US$ 10,000 per
system, concern for the rising costs of replacing and maintaining FAD
systems has prompted the Department of Agriculture's Division of
Aquatic and Wildlife Resources (DAWR) to investigate alternative FAD
maintenance strategies and system design. Several cost-cutting measures being considered include the use of reliable solar-powered navigation lights to reduce the number of maintenance trips required, and
switching to a newer generation of lighter, more durable buoys and
mooring systems. Average time on station for a DAWR FAD system is
nearing two years. Interestingly, in most cases where an errant system is
recovered, the failure in the mooring system was observed to occur at a
depth from 35 to 500 metres. These observations have led to speculation that additional protection of the mooring line down to 500 m
may result in doubling the average time on station of most FAD systems.
Background
Strategically located at 13°2S'N-144°47'E, G u a m is the westernmost
territory of the United States and the largest and southernmost island
of the Mariana Archipelago in the Western Pacific Ocean. Shaped like
a footprint, the island is about 48 km length with a width ranging from
6 to 19 kilometres. It has a total area of 4 5 1 sq. k m and a population
of approximately 133,000 people (1990 census), the highest densities
being concentrated in the northern and central sections. The climate
is tropical marine, generally warm and humid with little temperature
variation, moderated by northeast tradewinds. There are two distinct
seasonal patterns: a dry season that usually occurs from January to June,
and a rainy season from July to December. Offshore fishing activity
typically peaks during the summer doldrums when sea conditions are
calmest.
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S e s s i o i i 2 - FADs t e c h n o l o g y
Centrally situated on the western leeward coast, the Agana Boat: Basin
serves as the island's primary small-boat launch to fishing areas off the
central and northern leeward coast, as well as the northern banks such as
Rota and Icebox banks. Situated to the south, the Merizo Pier, Umatac
Boat Ramp and Agat Marina serve as launch points to the southern
shores and banks like Mile, Galvez, Stu, Baby, Santa Rosa, and W h i t e
Tuna banks. The Agat Marina in particular, located between the Agana
Boat Basin and the Merizo Pier, provides trailerecl boats from the
northern and central portions of the island a closer and more convenient
launch site to southern fishing grounds. Plans to construct two additional boat ramps at presently undeveloped eastern launch sites such as
Ylig River and Inarajan Bay are currently being considered. If completed,
the new boat launches are expected to lead to a significant increase in
fishing effort on the eastern windward side of the island.
T h e estimated n u m b e r of vessels participating in the pelagic troll
fishery has steadily increased from 119 in 1980 to 4 3 8 in 1998. A
wide majority of the fleet is comprised of vessels less than 8 metres in
length and typically owned by recreational-subsistence fishermen who
fish part-time and occasionally sell their catch. A smaller segment of
the fleet, approximately 6%, consists of charter vessels that are berthed
primarily at the Agana and Agat marinas (Anon., 1998).
Annual pelagic landings have varied widely over the years, ranging
between 158 and 393 metric tons for the period between 1980 and 1998.
Landings consist almost entirely of "mahi-mahi" (Coryphaena hippurus),
wahoo (Acanthocybium solandri), skipjack tuna (Katsuwonus pelamis),
yellowfin tuna (Thunnus albacares), and Pacific blue marlin (Makaira
mazara). Other landings, to a m u c h lesser extent, include rainbow
runner (Elagatis bipinnulata), barracuda (Sphyraena barracuda), "kawakawa" (Euthynnus affinis), dogtooth tuna (Gymnosarda unicolor), and
shortbill spearfish (Tetrapterus angustirostris) (Anon., 1998).
A t t e m p t s to establish reliable annual estimates of the percentage of
the total harvest of pelagic fish attributed to FADs, as well as the percentage of total trolling effort spent working FADs, have been made in
the past. However, the results are not conclusive due in part to varying
survey methodologies and the inherent difficulties in establishing when
a vessel is, or is not, actually working a FAD. There is also the concern
of whether a fish caught in the vicinity of a FAD was truly affected by
the presence of that system or purely coincidental. This may be the case
given the number of FAD sites in the Guam programme today, the area
they affect, and the close proximity of the sites. In general, DAWR
remains satisfied with the effectiveness of its FADs and does not depend
on yearly creel survey results to justify continuation of the programme.
For this reason, collection of harvest and effort data around FADs during
offshore creel surveys was discontinued in 1993.
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S e s s i o n 2 - Technologie cles DCP
Guam's involvement with FADs began in 1979 alter the G u a m Department of Agriculture's Division of Aquatic and Wildlife Resources
(DAWR) received a US,f 21,500 grant from the Salstonstall-Kennedy Act
through the Pacific Tuna Development Foundation (PTDF) to construct
and deploy several FAD systems. From L9S0 to 1982, development of
the DAWR FAD project continued utilizing Dingell-Johnson (DJ) Sportfish Restoration f u n d i n g after the initial PTDF award was depleted.
The project then went through a period of relative inactivity between
1983 and 1985 as no new FADs were constructed or deployed after the
last of the first generation FADs came off station in 1983. In 1.986, the
project was reactivated and became permanently funded through the
DJ-funcled Fisheries Development programme.
Funding
DAWR's ability to continue to operate an extensive FAD programme over
the years with little to no local f u n d i n g has been made possible with
federal grants through the Dingle-Johnson/Wallop-Breaux Sportfish
Restoration Act. Enacted in 1950 and amended in 1984, this federal
legislation captures a percentage of the annual excise taxes collected
nationwide on the manufacture, importation and sale of fishing equipment and motorboat fuels. The Etnds generated are then apportioned
to eligible State and Territorial fish and wildlife agencies to strengthen
their ability to restore and manage fish and wildlife resources to effectively meet the consumptive and non-consumptive needs of the public
for these fish and wildlife resources. Approximately US$ 2.8 billion has
been apportioned to State and Territorial fish and wildlife agencies
since 1952 (US Fish and Wildlife Services Basic Grants Management
Course, Oct. 19-22, 1998). G u a m and other insular US territories
receive 1/3 of 1% of the total a m o u n t of money collected annually,
which has yielded approximately US® 7 0 0 , 0 0 0 for G u a m each year for
the last several years. O f the US$700,000 G u a m receives annually,
approximately US$ 50,000 (7%) is appropriated each year to the DAWR
FAD project. From 1986 to 1998, over US$ 620,000 have been spent to
establish and maintain the sixteen-site FAD programme that exists today.
History
1979-1983
Type I raft design
The earliest DAWR FAD system utilized a first-generation Type I raft
design that consisted of three foam-filled 200-liter drums held together
inside a welded steel frame (fig. 1). The upper exposed portion supported
a small tower with a radar-reflector and navigation light. A 30-kg
concrete counterweight extended directly beneath the raft. The mooring
system began with a bridle chain attached to the raft that allowed the
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S e s s i o i i 2 - FADs t e c h n o l o g y
counterweight to swing through freely. The bridle chains joined together
below the counterweight and continued clown on a single length of chain
another 18 metres. Sixteen-millimetre polypropylene line then extended
clown from the end of the bridle chain to the seafloor where it was
attached to another 18-m section of chain. This last section of chain
was then shackled to a 900-kg cement block anchor.
In 1979, three Type I FAD systems were constructed at a cost of approximately US$ 3,000 each. One system was deployed off Facpi Point, another off Maputo Point, and the third held as a replacement system.
Several deployments were conducted using a Coast Guard vessel at no
cost to the Government of Guam.
The average lifespan of the Type I system was 66 clays. Actual time on
station ranged from a m i n i m u m of 7 clays to a maximum of 94 days.
f6)
6 volt self-contained anchor light (floating)
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S e s s i o n 2 - Technologie cles DCP
Type II tyre raft design
In 19SO, the Type II foam-tilled tyre buoy was incorporated into the
FAD programme (fig. 2). This raft design was comprised of one largediameter (1.6-m) (oam-fillecl tyre with two smaller foam-filled tyres
attached. The same mooring tackle and navigational configuration
were utilized as the Type I. Five of the Type II systems were constructed
in 1980 at a cost of approximately US$2,500 each.
The average lifespan of the Type II FAD was approximately 79 clays. Actual
time on station ranged from a m i n i m u m of 15 clays to a maximum of
142 days.
Figure 2
Type II FAD.
Si
Type III "small-tyre" raft design
Four Type III rafts were constructed and deployed in 1981 (fig. 3). This
raft design used a smaller tyre casing (1.2-m) in the construction of the
raft and thus was referred to as the "small-tyre" FAD raft. Additional
modifications included use of 19-mm three-strand polypropylene line, a
1:1.13 scope ratio, 12-mm chain below the raft, stainless-steel cable to
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S e s s i o i i 2 - FADs t e c h n o l o g y
Figure 3
Light
Type III FAD.
Radar-reflector
.Thimble
ft- Swivel
Garden hose
. covering
• Three 1 / 2 " cable clips
.Welded shackles
g;
200'
5 / 8 " stainless-steel cable
Stainless
ball bearing
swivel
Regular
swivel '
•/Thimbles
No
shackle
Three 1 / 2 " cable clips
e hose covering
- 2 0 0 0 lb each
rebar reinforced
c e m e n t block
Attracting
material
5 0 ' 9 / 8 " chain
P
Ball bearing
swivel
Thimble splices
are w o r m e d
first, then spliced
and choaked
All splices, w o r m i n g
and clioaks are coated
with minimum 2 layers
of rubber contact c e m e n t
t o prevent unravelling
and to stiffen
attach to the mooring block, fiberglassecl or welded shackles, stainless-steel
ball bearing swivels, and splices that were whipped and double-coated with
thick rubber contact cement. Each Type III FAD system cost approximately US$3,900 to construct.
One of the four small-tyre systems promptly sank after being deployed
due to the anchor settling into deeper water than the mooring system
was designed to handle. This system aside, the other three Type III
systems performed fairly well by remaining on station for an average
of 369 clays. Actual time on station ranged from a minimum of 226days
to a maximum of 640 days.
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S e s s i o n 2 - Technologie cles DCP
1987-1995
Surplus channel marker nun and can buoys
In 1987, DAWR adopted a second-generation FAD system design similar
to that being used in the State of Hawaiian FAD programme during that
same period. However, rather than using a spherical buoy, the G u a m
FAD p r o g r a m m e utilized surplus US Coast Guard channel marker can
and nun buoys (fig. 4). From 1987 to 1989, FAD project activity primarily
concentrated on acquiring system components and contracting necessary
services for preparation and deployment of FADs. Actual deployment
of the first five of these systems did not occur until 1990.
As recommended in the South Pacific Commission H a n d b o o k no. 24,
"Design improvements to Fish A g g r e g a t i n g Device mooring systems
in general use in Pacific Island Countries" (Boy & Smith, 1984), the five
nun and can buoy FADs described above incorporated the catenary loop
concept to prevent the mooring line from rising to the surface. Another
four such systems were deployed in March, 1992. However, rather than
310
S e s s i o i i 2 - FADs technology
using the single 9 0 0 - k g anchor block recommended by SPC, DAWR
instead continued use ol the two-block system in order to deplete an
existing inventory of 6 8 0 - k g anchors. T h e last two sets of n u n and can
buoy FADs with double-block anchors were deployed in December,
I 9 9 2 , at the Cocos Island and Facpi Point sites.
Given the additional complications with loading and deploying twoblock anchoring systems, as opposed a one-block system, the switch was
eventually made to a single pyramid-shaped 1,800-kg anchor after the
last of the 6 8 0 - k g anchors was used (fig. 5). This change resulted in
much less troublesome loading and deployment procedures.
By I993, the average cost to construct and deploy a DAWR FAD increased
to US$ 1.1,500, largely the result of deployments that were charged a
flat rate of US$4,500 per FAD regardless of location. In 1994 and 1995,
the average cost per system was cut a p p r o x i m a t e l y 2 5 % to a b o u t
311
S e s s i o n 2 - T e c h n o l o g i e cles DCP
US$8,400 after another tug company was contracted to conduct the
deployments based on an hourly rate for equipment and services rather
than at a flat rate.
The average time on station for DAWR nun and can buoy FADs was
4 4 6 clays. Actual time on station ranged from a m i n i m u m of 120 clays
to a maximum of 1,320 clays.
1995-Present
Surplus spherical buoys
In 1995, DAWR acquired thirty surplus spherical steel buoys from a
scrap yard in Honolulu to replace the depleted inventory of nun and
can buoys (fig. 6). These buoys are approximately 1.75 metres in diameter
and weigh about 230 kilogrammes. DAWR initially planned to copy
Figure 6
• A m b e r navigation light ( 1 5 f t m )
Spherical b u o y FAD.
3 6 " — 4 " 0 galvanized pipe
115"
6 0 " 0 •'"'••sj
^ u o y ( s s f e t y yellow)
\
• 1 0 0 f t 3 / 4 " o p e n link chain
( 5 0 0 lb)
/
I
7 / 8 " 1 2 - s t r a n d plaited
p o l y p r o p y l e n e line
j
( 3 , 0 0 0 ft)
End-to-end splice
• Eye splice
5 / 8 " 1 2 - s t r a n d plaited
Nylon line ( 1 , 8 0 0 ft)
1 1-3/8" safety shackle 1 each
^
\
Eye splice -
2 1-1/4" safety shackle 1 each
Ô 3 7/8" eye-ancl-eye swivel 1 each
5 0 ft. 3 / 4 " o p e n link chain
( 2 5 0 lb)
^
4 3 / 4 " safety shackle 5 each
6
5 3 / 4 " eye-and-eye swivel 3 each
(îl 6 3 / 4 " Nylite thimble leach
^
7 7/8" Nylite thimble 1 each
312
C o n c r e t e anchor....
S e s s i o i i 2 - FADs technology
Hawaiian FAD buoy modifications that included the welding ol a 1.1 m
length of 1 0 0 - m m d i a m e t e r galvanized pipe on top of the buoy to
serve as the mast for the navigation light, and another length of pipe
below to serve as a counterbalance. However, to simplify modification
of the newly acquired buoys for FAD use, DAWR experimented with using
15 and 30-m lengths of 1 9 - m m link chain to d e t e r m i n e if the weight
of the chain, 129 and 2 5 8 kg respectively, was sufficient to holei the
buoy upright. T h e results were both lengths of chain held the buoy and
light mast w i t h navigation light assembly inserted in a full u p r i g h t
position. Given these results, DAWR was able to forego the additional
modification of welding a length of pipe below the FAD buoy to serve
as a counterbalance. In addition to making buoy modification procedures
less complicated and costly, the absence of the lower l e n g t h of pipe
also made loading and deployment of the buoy less c u m b e r s o m e and
much more convenient.
The average FAD time on station between 1995 and 1998 was approximately 457 clays. However, this figure may have been underestimated
because several annual figures used in the final calculation included
newly deployed FAD lifespans w i t h o u t end dates. Since some of these
new systems eventually r e m a i n e d on station for longer periods, a
recalculation would likely yield an increased average lifespan.
Indian Ocean rafts
Materials necessary for the construction of ten SPC-recommencled Indian
Ocean rafts were acquired in 1995 (fig. 7). This low-cost, l i g h t w e i g h t
and low-resistance design will eventually be incorporated i n t o the
DAWR FAD p r o g r a m m e once a better end-float is identified or designed
to accommodate the US Coast Guard requirement for a navigation light
on each system. U p until 1999, DAWR relied on 9 - k g battery-powered
navigation lights to meet Coast Guard l i g h t i n g requirements.
The weight and size of these lights make the current SPC-recommended
end-float design impractical in terms of securing and s u p p o r t i n g this
light. N o w that twenty 2.6-kg solar-powered lights have been purchased
by DAWR, it is likely that a reasonably-priced cleepwater spar buoy
system will be purchased to secure and support this m u c h lighter navigation light at a practical height above the water.
FAD sites
There are now sixteen operational sites in the DAWR FAD p r o g r a m m e
(fig. 8). Contrary to the usual practice of setting FADs at least ten miles
apart and at the 1,000-fathom depth contour, the majority of the Guam
FADs are spaced relatively close together and usually at a d e p t h of 500
fathoms. Given the relatively high n u m b e r of recreational-subsistence
vessels in the troll fleet, and their early d e m a n d for more FADs closetto the major launch sites, DAWR gave priority to m a k i n g more FADs
available rather than m a k i n g a few FADs more productive. DAWR also
313
S e s s i o n 2 - Technologie cles DCP
responded to requests for FADs in the more-distant and less-frequented
areas on the eastern windward side of the island and to the north. T h e
Faclian P o i n t and Asiga FADs were thus deployed for those fishermen
favouring the eastern side of the island, while the Pati Point (no. 6) FAD
was installed for those choosing to fish the n o r t h e r n portion of the
island.
DAWR continues to consider additional FAD sites and annually budgets
for the bathymétrie surveys of potential new sites. DAWR thus contracts
a qualified and properly equipped local charter boat company for two
full days of depth sounding services each year. There are several potential
new sites currently being considered which will require appropriate
314
S e s s i o i i 2 - FADs t e c h n o l o g y
Figure 8
FAD sites.
"Number 5"
13-4'1.7'N
"Old NOAA"
13°43.5'N
144"40.8'E
1 000 fa H
"«-«LITE
• 480 la
\
\
\
"Number 4"
13"43.3'N
144"43.3'E
H 600 fa
12 nm
10 nm
"Number 6"
13°42.6'N
6 5 nm
145-016Ï
500 fa |g|
D,J
\
"Number 3"
23°39.9'N
/
400 fa
5 nm
Ritidian Pt.
v
f
/
7 nm
' Uruno Pt,
"N™ber2'
i I S N
13°35.6'N
144°45.6'E
.100 fa |
B a
~ ~
144°40.4'E
, , „ , , tm
410 fa ®
\
4
4
nm
n m
8 nm
X
"Number 1"
13-32.2'N •
144-43.It T
500 fa
\
,/
\
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— - f Maputo Pt.
/
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3 4nm
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-^-"AdelupPt.
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f
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A
y
M
Fadian Pt.
f
Agat Bay
y
"9-Mile"
13°15.1'N
144-28.7'E
500 fa
1
A .
AsigaPt.L
(
y
/
9 nm
/
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1 000 fa
1
Z ' j Umatac
2 . 5 nm \
"Umatac"
13-17.0'N
144°37.0'E
750 fa
5 n m
ç
"Facpi"
f
13°20.4'N
j
144-36.5'E
/
500 fa
/
B - 2 n n i / Facpi Pt.
"Facpi 2"
~~
"Fadian"
13-26.1'N
144-55.3'E
gSOOfa
5 nm
13"17.8'N
-144-51.7'E
I 500 fa
/
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Coco Is.
3 . 5 nm
V
"Cocos"
i3"i2.o'N
144°41.7'E
• 500 fa
p e r m i s s i o n before a FAD can be installed. Conversely, there are a few
existing sites that m a y be e l i m i n a t e d f r o m the p r o g r a m m e because t h e
FADs are reported to be n o n - p r o d u c t i v e , seldom used, f r e q u e n t l y lost
and located in areas that m a k e t h e m more expensive to maintain and
replace.
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Session 2 - Technologie des DCP
FAD losses
Fishbite
Between 1994 and 1999, ten FADs that came off station were eventually
recovered. The depth at which the mooring systems failed ranged from 31 m
to 721 m, the average being approximately 150 metres. Interestingly, none
of the systems failed as a result of a faulty splice or a defective piece of
hardware at the top or bottom of the FAD. Fishbite is therefore the
likely cause of the majority of FAD system losses based on the depth of
the breaks in the line, the appearance of the end strands recovered and
the age of the system. T h i s is consistent with studies by Berteaux and
Prindle (1987) that suggest the frequency of fishbite increases as the
geographical location of a deep-sea buoy gets closer to the equator.
According to their data, two thirds of experimental buoys set within
10 degrees of the equator showed signs of fishbite. However, similar
fishbite experiments that compared frequency of fishbites as a function
of d e p t h yielded results that indicated peak activity occurred between
900 m and 1,000 m, which is significantly deeper compared to the 150-m
average d e p t h for G u a m mooring system failures. This is probably due
to regional differences in the fish species likely to bite and damage
mooring lines and their peak activity depths. T h e speculation therefore, is that protection of the mooring system from fishbite clown to
300 m will possibly result in d o u b l i n g the average lifespan of most
FAD systems.
Corrosion and mechanical wear
If fishbite is the p r i m a r y cause of FAD losses, especially in the early
portion of a system's life, corrosion and mechanical wear of hardware
would be the next likely reason as the system gets older. T h i s was the
case between 1 9 9 0 and 1995 when DAWR was still using n u n and can
buoys for its FAD systems. The relative instability of these buoys resulted
in excessive rocking and twisting motions which in turn lead to increased
wear of the upper m o o r i n g hardware.
Onsite underwater p h o t o g r a p h s taken in 1995 of a channel marker
FAD buoy system, in p a r t i c u l a r the then nearly two-year-old Facpi
Point FAD, clearly d o c u m e n t e d the dramatic difference in degree of
wear between the hardware just below the surface and the hardware
3 0 - m clown. Based on the level of wear on the eye-ancl-eye swivel below
the buoy, it was not surprising that these n u n and can buoy systems
broke off station after two to four years. In fact, two such systems, the
Aclelup Point and H a p u t o Point FADs deployed in March 1992, came
off station after 24 and 25 m o n t h s respectively. Two o t h e r similar
systems, the Cocos Island and Facpi Point FADs deployed in December,
1992, broke off after 38 and 4 4 m o n t h s respectively.
DAWR addressed the p r o b l e m of p r e m a t u r e losses elite to corrosion and
mechanical wear of the u p p e r m o s t hardware by s w i t c h i n g to larger
diameter hardware. T h u s , rather than the 1 9 - m m safety shackles and
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S e s s i o i i 2 - FADs t e c h n o l o g y
eye-ancl-eye swivel previously used to connect the buoy to the upper
chain, DAWR now uses a 3 5 - m m or 3 0 - m m safety shackle, followed by
a 2 2 - m m swivel and a 19-mm shackle, to connect: to the 19-mm chain.
Streamlining costs and effort
At a current cost of approximately US$ 10,000 per system, concern for
the rising costs of replacing and maintaining FAD systems has prompted
DAWR to investigate alternative FAD replacement and maintenance
strategies. Several cost-cutting measures include standardization of FAD
site depths and the use of reliable long-life solar-powered navigation
lights to reduce the number of maintenance trips required annually.
Prefabricated 500 and 1,000-fathom mooring systems
Efforts to standardize site depths to 500 and 1,000 fathoms in recent
years have made it possible to maintain an inventory of backup systems
which in turn allows for immediate replacement of a FAD that has come
off station. For example, the Facpi Point FAD recovered on August 2 7 , 1 9 9 6 ,
was redeployed the following clay on A u g u s t 28. In the past, m o o r i n g
systems were essentially custom b u i l t for each site. Considerable effort
and time were required to measure out the lengths of line needed,
before tackling splicing and eventual faking of the mooring system into
the deployment container. These time-consuming procedures are still
necessary for those sites with d e p t h s not equal or close to 500 or 1,000
fathoms. O n the other hand, prefabricated (pre-measured,-spliced anclfakecl) mooring systems boxed and palletized at the factory, have allowed
for readily-available mooring systems that are quite convenient to store,
prepare, load, transport and deploy.
Battery-powered versus solar-powered navigation lights
Prior to 1999, the Guam FADs utilized battery-powered navigation lights
that required replacement every 4 to 6 months. At approximately US$ 250
for each light u n i t and about US$ 150 per battery pack, the estimated
costs over a two-year period would a m o u n t to around US$ 850 for just
the light and batteries. I-Iowever, this figure does not include the cost
of hiring a commercial vessel to transport DAWR staff and e q u i p m e n t
to the FAD site to conduct maintenance procedures. In most cases, light
replacements are m a d e on the same day a FAD deployment in the area
is conducted, and therefore, the need for additional voyages for the sole
purpose of replacing navigation lights are kept to a m i n i m u m . However,
such " m a i n t e n a n c e only" voyages, a l t h o u g h i n f r e q u e n t , still occur
because s c h e d u l e d l i g h t c h a n g e s d o not always coincide w i t h an
u p c o m i n g FAD d e p l o y m e n t . Such t r i p s increase the total cost of
maintaining a FAD with a battery-powered navigation light by approximately US$350 each occurrence.
To address this concern, DAWR acquired 20 solar-powered navigation
lights in 1.999 to replace the battery-powered lights presently in use.
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S e s s i o n 2 - Technologie cles DCP
Costing iess than US$300 each, these lights are p u r p o r t e d to have a
lifespan of up to eight years. If the solar-powered lights meet expectations,
DAWR could realize a significant reduction in the expenses associated
with maintenance of navigation lights because the procedure may be
reduced to annual test inspections and cleaning of bird droppings off
the solar panel on the top of the light.
Recommendations
Improvements to the DAWR FAD p r o g r a m m e in the f u t u r e will focus
on m a k i n g the upper 3 0 0 metres of the mooring system invulnerable
to fishbite and converting to the SPC-recommencled Indian Ocean raft
design to replace the spherical metal buoy presently being used. DAWR
is thus considering use of a 3 0 0 - m length of thick-strand 1 6 - m m , or
thicker, stainless-steel cable to connect directly to the spherical buoy
currently being used. A l t h o u g h this may serve well to m a k e the FAD
less vulnerable to fishbite, it is not certain whether this length of cable
can also serve to replace the N y l o n line in the catenary curve. Another
concern is w h e t h e r t h e t h i c k - s t r a n d cable will alter d e p l o y m e n t
procedures considerably. In addition, DAWR will eventually explore
the possibility of incorporating this length of stainless-steel cable to
string the floats of the Indian Ocean raft.
Other minor improvements include the attachment of plastic strapping
appendages to the upper mooring chain, affixing radar-reflectors to the
spherical buoy l i g h t masts, and a s w i t c h i n g f r o m l a n t e r n - b a t t e r y powered navigation lights to solar-powered lights.
Bibliographic
references
Anon., 199S. Pelagic fisheries of the W e s t e r n Pacific. 1998 Annual
Report. A p p e n d i x 2. Territory of G u a m , Western Pacific Regional
Fishery M a n a g e m e n t Council, Honolulu, Hawaii. Draft Rep., 2-37.
Berteaux H . O . , Prindle B., 1987. Deep-sea moorings fishbite handbook.
Woods Hole Oceanographic Institution, WHO-87-S, Woods Hole,
Massachusetts.
Boy R.L., Smith B.R., 1984. Design improvements to Fish Aggregating Device (FAD) mooring systems in general use in Pacific Island
Countries. SPC, N o u m e a , N e w Caledonia. SPC H a n d b . , 24.
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