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HAWAIIAN FISH AGGREGATING BUOYS
Department of Land and Natural Resources
A Dingell-Jolmson Federal Aid in Fish Restoration Project;
Artificial Fish Shelter/Fish Aggregating System Development and Operation

Status Report January 1983

In 1980 the Department of Land and Natural Resources (hereafter  referred to as “Department^”), with strong support from Governor George Ariyoshi and the State Legislature, established a unique Statewide Fish Aggregating Buoy System. The primary objectives of the system, which is operated by the Department I s Division of Aquatic Resources, are to increase the harvest efficiency of our· commercial and recreational fishers and the enhancement of fishing opportunities in Hawaii. In April1980, the Department deployed 26 fish buoys in waters around the main Hawaiian Islands and since then an estimated 4 million pounds of fish have been "produced" by the buoy for the local fishers. When deployed in suitable areas the buoys are capable of attracting and holding, for varying Periods of time,  fishes such as' ahi (yellpwfin and bigeye tunas) , aku (skipjack tuna) , mahimahi (dolphinfish), ono (wahoo) , opelu (mackerel) and billfishes. The buoys have helped to increase the State's annual fish landings, to reduce the time fishers spend searching for fish schools, and to decrease costly fuel consumption by the fishing vessels.

The system is presently in the fourth year of a five-year project which is scheduled to end in June, 1984. Hawaii I s fishers have strongly supported the system and consider it a high priority project that should be continued. The Department intends to examine alternative means of managing and funding the operation of the fish buoys after the project is completed.

Background

Fish aggregating buoys are man-made floating objects (flotsam) placed (anchored or free floating) in the ocean to attract and concentrate certain pelagic fishes. Fish buoys have been used in the Philippines, Japan Sea, Mediterranean Sea, and in other areas of the world. Filipino fishers use large bamboo rafts called "payaos" in their tuna purse seine fishery. As much as 200 metric tons of tuna have been reportedly caught in a single purse seine set around payaos. Japanese fishers use bamboo fish buoys called "tsuke"; elsewhere, fishers use materials such as palm and coconut fronds, cork slabs to fabricate their buoys.

Why do fish buoys aggregate fish? Scientists have offered a number of' hypotheses on this subject. Larger fishes may be attracted to food such as smaller forage fish and plankton gathered around the buoy. Shelter, reproductive spawning substrate, a "station" where fishes can have parasites removed by "cleaner fishes" are' all plausible explanations for the enormous fish attracting power of the buoy. It may simply be serving as a point of reference in the open ocean environment.

Establishment of Hawaii's Fish Aggregating Buoy System

The use of fish aggregating buoys in Hawaiian waters began in 1977 when the Honolulu Laboratory (Southwest Fisheries Center) of the federal National Marine Fisheries Service, with funds from the Pacific Tuna Development Foundation, installed a few experimental fish buoys off Oahu, Lanai, and West Hawaii. Aku catches of 5-10 tons were reported frequently around these buoys; the largest catch was over 15 tons. The aku pole-and-line fishing vessels used less bait enabling them to make more fishing trips Per week. Also sports fishers averaged 200 pounds of rnahimahi per boat per day atone experimental buoy.

Following this successful demonstration of fish buoys in Hawaiian waters, in 1979 Governor Ariyoshi proposed establishing an .innovative statewide system of fish aggregating buoys in State waters. This was part of the State's fisheries development effort to help revitalize the fishing industry and increase its 5fQrtsfishing opportunities. In response, the State Legislature appropriated funds to the Department for developing and implementing a Hawaiian fish aggregating buoy system. Also, supplemental funds were obtained fran' the Federal Aid in Sport Fish Restoration (Dingell-Johnson) Marine Development Program administered by the U. S. Fish and Wildlife Service.

In April 1980 the Department designed and fabricated 26 fish buoys and placed them around the main Hawaiian Islands (Figure 1) at distances of 5-25 miles offshore and in depths of 1,200-6,000 feet. 'Ihe average depth of a buoy site was 2,880 feet.

The buoy locations were based on input received from Hawaii's fishing community during statewide public meetings held in October 1979.

Since 1980 the State has tried three surface fish buoy designs: tire design, pentasphere design, and more recently, a single-sphere design.



The first buoys were fabricated from discarded 1500-pound sugar cane tournahauler tire carcasses filled with polyurethane foam. The tire buoys were found to be unwieldy and by late 1980, these were replaced with the second generation pentasphere buoys. The pentaspheres were made from surplus Navy sphere buoys and weighed 800 pounds. Although much lighter than the initial tire buoys, the pentasphere buoys had a drag problem that placed tremendous strain on the mooring line under strong current conditions.



In October 1982 the Department constructed three single-sphere fish buoys and with assistance of the federal research ship, FRS Townsend Cromwell, of the National Marine Fisheries Service, they were deployed off Maui ("M") and east Hawaii ("G" and D"). The single-sphere buoy has minimum surface current drag and has about 3 ,000 pounds of buoyancy.

The average cost of the buoys (tire, pentaspheres, single-sphere) ranges from approximately $4,000-$6,000 each for construction, deployment, and maintenance. The mooring line is about 60% of the total cost of a buoy.
The Department also experimented with a subsurface fish buoy which was installed off Kaneohe, Oahu till September 1981. It was a 58-inch diameter steel sphere placed about sixty-feet under the ocean surface. It was believed that this buoy should have a longer, maintenance-free operating life by not being exposed to the harsh ocean surface currents and storms, and it would allow for unrestricted passage of transiting surface vessels. The Kaneohe subsurface fish buoy remained on station for 14 months. In the future, additional subsurface buoys may be deployed in a cluster pattern to create "fish aggregating areas" around the Hawaiian Islands.

Buoy Fish Catch Results
Fishers reported making over 8,000 fish buoy trips (average number trips to each buoy = 71). They also reported 1,759 (20%) no-catch buoy trips. Although 1,578,970 pounds of fish were reportedly caught at the buoys as of December 1982, the actual amount of fish landed probably exceeded four million pounds based on discussions with the fishers and from known unreported catches made at the buoys.

The dominant fish caught at the buoys were: aku (678,912 pounds, 43%), ahi (536,401 pounds, 34%), mahimahi (120,989 pounds, 8%), and bi11fishes (176,692 pounds, 11%). These fish comprised 96% of the total reported catch.

The approximate breakdown in fish landed by major gear type around the buoys were: pole-and-line = 704,267 pounds (45%); trolling = 628,044 pounds (40%); hand line = 229,790 pounds (15%).

Cost: Benefit ratio of 1:3.5 was estimated for the buoy system. The Department spent a total of $454,207 (federal funds = $340,655 and state funds = $113,552) for developing, operating, and maintaining the unique fish buoy system. Accrued benefits of the buoys were estimated at $1,578,969 based an a one-dollar per pound value of fish reportedly caught at the buoys. However a cost:benefit ratio as high as 1:8 ($454,207:$3,179,449) may not be unrealistic considering the discrepancy between reported and actual catches, and if fuel savings and recreational benefits were included in the rough economic analyses of the fish buoy system.

Fish Bouy Losses
Although the buoys have proven to be successful and are extremely popular with the fishing ccmmunity, a major problem confronting the system is buoy losses. Since their initial installation in 1980 the buoy loss rate is about 60%, the recovery rate is arormd 41%. The average "life span" of the buoy is approximately nine months (range= 2-18 months)
Currently there are 14 buoys on station (including the recently acquired OTEC buoy) and 12 stations without buoys.


Fish buoy losses have been attributed to strong current, winter storm, corrosion of metal hardware on the mooring line, unsuitable buoy location (e.g. pinnacle), nun-in with tugboat towline and submarine, and fish bite. Hurricane Iwa that hit the main Hawaiian Islands on November 23, 1982 removed two fish buoys and overturned three. Fishing vessels tying onto the buoys (resulting in mooring line fatigue and breakage of the line) have also been implicated as causes of buoy losses.

In an on-going effort to reduce the buoy loss rate, the Department has retained the services of consultant engineers and is working closely with the University of Hawaii to study fish buoy and mooring/anchor designs. Table 2 presents a list of characteristics for a durable and economical fish buoy.

In order to prevent buoy losses caused by human-related activities, on May 28, 1981, Governor Ariyoshi signed Act 80, SLH 1981 authorizing the Department to promulgate an administrative rule governing the use of the fish buoys. A draft rule (Chapter 73, Title 13 entitled: "Fish Aggregating Devices") was prepared with guidance from the Hawaii Fisheries Coordinating Council. Essentially, proposed Chapter 73 is intended to prevent losses and damages to the buoys as well as prevent buoy use conflicts. It prohibits any person from attaching, mooring or tying a boat or other watercraft to the buoy. Also it would be unlawful to board, damage, remove or destroy any fish buoy except as permitted by the Board of Land and Natural Resources (or its authorized representative) for maintaining, operating, repairing, or monitoring the fish buoys. Following the Governor's approval, statewide public meetings/hearings were held on the rule. Subsequently the proposed Chapter 73 was adopted by the Board of Land and Natural Resources for promulgation and was submitted to the Governor for approval to implement it.



Proposed Additional Buoys in Hawaiian Waters
Because of the high demand for the buoys by the fishing community, the Department is planning to construct and install additional fish buoys around-the main Hawaiian islands during 1983. Twenty-six (26) new buoy sites (Figure 1) have been proposed based on statewide public meetings held one-year ago.

The construction and installation of the proposed additional buoys will require approvals and clearances from the various governmental agencies such as the U.S. Coast Guard, U.S. Army Corps of Engineers, U.S. Navy, and Department of Land and Natural Resources.
As part of the State's fisheries development effort, the installation of fish buoys in the Northwestern Hawaiian Islands area is being considered.
OTEC is an acronym for Ocean Thermal Energy Conversion. The OTEC-l project (a test ship-facility developed by private contractors under the Federal Department of Energy funding) was initiated in late 1980 and moored approximately 20 miles southwest of Kawaihae Harbor, Island of Hawaii.


While OTEC-l was in operation, its surface/subsurface buoys served as effective fish aggregators "producing" at least one million pounds of fish for the West Hawaii fishing community. During 1982 the Department of Energy terminated the OTEC-l project because of lack of funds and intended to retrieve its buoy/mooring system including a cold water pipe. Recognizing that removal of the OTEC-l buoys would be a tremendous loss to the fishing community and the State, inquiries were made to the Department of Energy as to the Department's possible
acquisition of the system. As a result, on October 27, 1982, the OTEC-l buoys and mooring were transferred to the Department, with approval from the Board of Land and Natural Resources, from the U. S. .Department of Energy via Argonne National Laboratory and The Research Corporation of the University of Hawaii. The OTEC-l cold water pipe assembly was transferred to another agency.

The OTEC surface buoy was reconditioned at Kawaihae Harbor and later, with the kind assistance of the Navy's U.S.S. Conserver, it was redeployed on station. Currently the OTEC surface/subsurface buoy operates as part of the Department's fish aggregating buoy system.

Baitfish Trials at a Fish Buoy
During 1982 the Department arranged live bait sea trials, using cultured Mexican topminnows produced at the Maui County baitfish facility, by an aku fishing vessel at fish buoy "E" off Hilo, Hawaii. These trials were to determine the effectiveness of topminnows as live bait for aku pole-and-line fishing at the buoys. About 3,000 pounds of small aku and bigeye tuna were taken from the buoy during a 2-hour period using 100 pounds of topminnow baitfish. The results of these initial trials
indicated a high potential of using cultured baitfish at the buoys to increase its fish aggregating effectiveness. Additional sea trials using topminnows at the buoys are being considered by the Department.
 

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