TRIAL FISHING SURVEYS FOR SKIPJACK AS AN EARLY DEVELQPMENT OF THE INDONESIAN SKIPJACK FISHERY

M. Unar

Marine Fishery Research Institute Djalan Kerapu 12, Djakarta, .

ABSTRACT

A brief account is given of the early development of the Indonesian skipjack fishery. The skipjack industry in Indonesia has the potential to expand tremendously, especially since the skipjack stock is underutilised and there Is an increasing demand for the raw material in world markets.

A review of the methods of fishing for skipjack indicated that the pole-and- line method appears to be the best means for harvesting this resource in Indonesian waters. However, problems relating to the availability, abundance,and hardiness of baitfish must be overcome before the fishery can be expanded to its maximum. Experimental pole-and-line fishing trials and surveys carried out on modern skipjack vessels have indicated a bright prospect for the development of a skipjack fishery, particularly in the eastern park of the Indonesian waters. The total landings of tuna and tuna-like fish from the Indonesian waters is estimated at around 30,000 tons annually. Classified according to the conditions of the Indonesian waters, about 5,000 tons of this amount come from the waters of the Sunda-shelf, in particular the , Malacca Strait and adjacent waters (~igureI). These catches include the following species: Euthvnnus spp., Auxis thazard and Thunnu8 tonnnol. The bulk of the remaining catch of 25,000 tons comes from outside the mentioned shelf waters, particularly from coastal areas directly facing the oceans. These landings contain in addition to the species mentioned earlier a larger number of species such as Katsuwonus pelamis, Thunnus albacares and Sarda orientalis. The most important one is the skipjack, Katsuwonus pelamis, popularly known as chakalang, which constitutes the mador part of the landings, at least about 12,000 tons. Particularly in the eastern part of Indonesia this species is very popular and in several regions it is found throughout the whole year. A substantial increase in the landings of this species can be observed at the two maincentresof .skipjack fishing, i.e., at Airtembaga, North Sulawesi and at Ambon, Moluccas from where overseas shipping has been established recently.

The efforts made bv the Government for the expansion of the skipjack fishery represent one of it* programmes to incrtase the utilisation of the fishery resources rationally. The programme is not only aimed at meeting local needs but also fits well in the overall Government agricultural development policy which gives high priority to foreign-exchange-earni~resource development. In addition to domestic capital, foreign investments are needed in the development of this enterprise.

Skipjack landings in the Indonesian waters are still considered to be low and the skipjack stock is virtually under-exploited. All investments in this fishing industry are encouraged, and should be backed by trial fishing or surveys in order to be able to decide whether the establishment of such enterprises can be justified commercially.

The pilot fishing operation for skipjack and tuna in West Irian, which operated from Sorong in 1969-197Qwas the first survey conducted in this field. Similar surveys or trial fishing are now underway in other parts of Eastern Indonesia and on the west coast of Sumatra.

2. DISTRIBUTION OF SKIPJACK

Except for the shallow waters of the , skipjack are found in the waters of eastern Indonesia from to West Irian. It ia also abundant along the coasts facing the and around the islands in the . Data of landings at both skipJack fishery c3ntres in Eastern Indonesia, i.e., Airtembaga and Ambon Micate that skipjack can be caught continuously throughout the entire year. This can also be observed at Padang, West Sumatra, where data of landings by motorised trollers suggest that skipjack is to be found in this part of the Indian Ocean throughout the whole year.

It is worth noting that observations show dense skipjack concentrations normally in the vicinity of islands and this might be attributed to the presence of food concentrations in these waters. Both skipjack fishing grounds of Airtembaga and Ambon can be reached in only a few hours sailing. Two cruises made by an Indonesian research vessel with an interval of 5 months in 1970 have resulted in indications that large schools of skipjack were present along the north coast of the eastern part of the Lesser Sunda Islands, particularly in the vicinity of entrances of straits between the islands. '

3. SKIPJACK FISHWIES

In the Indonesian waters the most common and basic method of fishing for tuna and tuna- like fish is by trolling from small wooden sailing veseels which are powered with inboard OF outboard motors Qr just by rowing. In Benoa, south-east of Eali, a local fisheries cooperative with a fleet of 242 sailing trollers had landed 196 tons of tuna-like fish during the east monsoon of 1970, the major part of which consisted of skipjack (Table I). Along the Badung Strait where Benoa is situated and which is about 50 miles long, more than 5,000 sailing vessels are engaged in trolling. At Padang, West Sumatra, a fleet of 142 trolling vessels powered with inboard or outboard motors oaptured 1,572 tons of tuna-like fish in 1970, 80 percent of which consisted of skipjack (Table 11). The vessels have a length ranging from 7 to I0 m. Several are powered with in- board diesel engines of 8-16 HP and more than half have outboard motors of 25-40 HP.

In the dry season schools of skipjack come into the Bay of Ambon and other bays in the Moluccas, and trolling is carried out by rowing smaller vessels of about 3-4 m length, locally called nk016-kol6~~.

Pole-and-line fishing with live bait is practised in the Sulawesi Sea and the Moluccas Sea with its centre in Airtembaga,and in the with Ambon as its centre. The original method of pole-and-line fishing for skipjack by rowing vessels of 10-12 m length is still carried out in the Ternate and Ambon areem. Those vessels mentioned which are employed in this fishery are called nfunaiM in the Ternate and VurQh6fl in the Ambon area. Modernisation of this fishery commenced with the introduction of Japanese-type wooden motorised vessels equipped with a live bait tank. Generally the catch is not frozen on board and the fishing operation itself lasts less than a day. At the centresAirtembaga and Ambon there are 50 pole--and-line fishing vessels, of which 23 vessels of the 15 tons class are owned by the state. The remaining 27 vessels of the 5-15 tons class are operated by private companies or cooperatives, with a larger part based in Airtembaga. Landings made by the aforementioned vesselsare estimated at around 5,000 tons annually.

Light fishing is the most common method applied for securing live bait, and separate units carry out this operation. Live bait caught during the night is collected by the motorised vessels early in the next morning. Fishing gear commonly used f0.r this operation are lift- nets and beach seines.

Observation of landings from 9 vessels owned by the state enterprise in Airtembaga for the years 1968-1970 indicated that the average annual landings made by each vessel were 156, 153 and 176 tons respectively (Table III), while for the same period in Ambon the average annual landings made by each of the five vessels operated by the state enterprise was 138, 134 and 197 tons respectively a able IV). The substantial increase in the landings of 1970 was attributed to the expansion of the skipjack market.

Several other methods of fishing for skipjack which developed locally or incidentally are being employed. The "payang seine" which is traditionally used for fishing scad, mackerel and other pelagic fish is modified into a small skipjack seine at Pelabuhanratu on the south coast of West Java. Fishing is carried out by motorised vessels of about 10 m length. The ttgiob", a purse seine-like net for fishing garfish which is very abundant in the Moluccan waters, can be used incidentally for skipjack. Skipjack are also regularly caught in bamboo stake traps around south-east Sulawesi.

4. THE LIVE BAIT

Light fishing in shallow waters seems to be the most common method employed in securing live bait and a large variety of fish species are used for this purpose. Stole~horusspp., locally called nterin or "ikan putihn, is most desired by the fishermen for its abundance and appearance, although the mortaliky seems to be high for extended operations. Other sardine- like fish such as juveniles of hrssumieria spp. and Sardinella spp. are commonly caught together with those of mackerel or scad. Close to coral reef waters Atherina spp. is always present in such light fishing catches, while juveniles of Caesio spp. locally called t*lalosin, are desired for their low mortality but like other bottom fish have a poor quality as live bait.

- 485 - For the expansion of the skipjack industry in Airtembaga and Ambon live bait surveys have been carried out by FAO/UNDP fishery development projects and reports concluded that the bait conditions are favourable in both surrounding waters.

Live bait production with light fishing might be a limiting factor if a large fleet is in operation, since catches decrease considerably during moonlight nights. In their operations the FUNMJI skipjack survey fleet based at Sorong, West Irian introduced a method which is applicable for daytime fishing employing a drive-in net which seems to be successful.

Previous surveys conducted for locating bait grounds revealed some excellent bait source areas such as the Kendari waters, South-east Sulawesi. Bays and enclosed waters are numerous in this area, the anhual rainfall seems to be rather high. The local fishermen earn their living mostly as professionals in light fishing. It was observed that large quantities of dried Stolephorus were regularly exported to Java.

5. PROGRESS IN TRIAL FISHING OPERATIONS

Considering the local demand and cost of exploitation, any additional skipjack production would need to find overseas markets. Recognising the increasing demand on tuna-like fish abroad the Government is eager to develop the skipjack resources which are virtually under- exploited, and efforts are made to attract private domestic capital as well as foreign to develop this industry.

Since 1969 a number of trial fishing operations and surveys were conducted with the purpose of developing new fishing areas with bases outside the present two centres.

An FAO/FUNDWI programme for developing West Irian included a trial fishing operation whicrh was conducted from November 1969 until December 1970 with Sorong as its base, covering an area of latitude 128~-140~~and longitude I'N-JOS. This survey was contracted to a Japanese skipjack fishing company, the Nichiro Gyogyo. Five (5) skip- jack vessels each of about 100 gross tons participated as survey vessels, accompanied by two carriers of 407 gross tons and 473 gross tons respectively. A total catch of 2,357 tons was landed during the survey period and transported to Japan (Table V).

The best fishing grounds were found just north and west of Sorong where a number of islands are scattered throughout the area, Along the north coast of West Irian east of latitude 132O~,wheregenerally the coasts are steep and bait fishing could not be performed successfully, the catches were poor.

It was also reported that,compared to the skipjack fishing grounds in the waters adjacent to Japan, the density of fish in schools of skipjack in the West Irian waters was low but covering an extensive area, while the size of the fish was larger able VI).

On a joint venture basis with a national company the five Nichiro skipjack vessels continued trial fishing operations with Ternate as their base. The area covered was principally the same as during the earlier operations from Sorong but with a westward extension to include the western and northern waters of Halmahera. The survey was conducted from May until September 1971 with a total catch of 1,528 tons (Table VII).

From October 1971 the Nichiro operations were transferred to Kendari, South-east Sulawesi. No detailed catch report has been submitted yet, but information indicates a total catch of about 7,000 toas cove~~inga period of fishing from mid-October 1971 until mid- February 1972. The survey is still in progress. S ULAWESI

Figure 2. The area under survey and the catch landed from each fishing ground at Kendari. Another skipjack joint venture based in Kendari is presently operating with the Hoko skipjack company of Japan as its foreign counterpart. Five skipjack vessels comparatively smaller than those of NicNro carry out trial fishing around the south eastern end of the peninsula and generally live bait can be purchased from local fishermen. The operation which was started in September 1971 has resulted in a total catch of 708 tons (Table VIII) from 454 fishing days until March 1972. The area covered by the survey and catch landed from each fishing ground is presented in Figure 2.

It was observed that the ability and performance of the vessels differ remarkably from one vessel to the other. The "Kouwa Marun which joined the operation in November 1971 has landed 233 tons of fish for 85 fishing days while another vessel, the V.eisho Marun which was the first vessel to start this operation has landed only 126 tons for 114 fishing days. The trial fishing is still continuing.

Based in Padang, West Sumatra, a joint venture for exploring the skipjack resources in this part of the Indian Ocean was organised and operations commenced in December 1971. A Japanese company, the Kyokuyo HogeF provided a 200 ton skipjack vessel to conduct trial fishing along the coastal waters off West Sumatra between longitude ~ON-~OS. The operation was terminated in March 1972 with 95 fishing days and a catch of 56 tons. The area covered by the survey and catch landed during the operation from each fishing ground is shown in Figure 3.

Skipjack schools were observed in an extensive area but did not bite well. The unfamiliar condition of the bait ground also hampered the operations and this trial was considered unsuccessful. At present another trial fishing operation for this region is arranged.

REFERENCES

Anonymous, Swey reports of the KM Tabularasa fishery research vessel 1970 1971 Lembaga Penelitian Perikanan but D-iakarta PD 007/1.

Pilot fishing operation for skipjack and tuna in West Irian. Nichiro 1971 *orno K.K. Fid: FUNDWI 19/21 Technical Report 1.

TAXE I Monthly landings of tuna and tuna-like fish by 242 sailing trollers in ~enoa,South-east in 1970

Month Catch in kg January - February - March - April - May 5,405 June 24,924 July 48,216 August 35,473 September 41,754 October 29 ,792 November 10,238 December - Total 195,802 Monthly landings of tuna and tuna-like fish by 142 motorised trolling vessels in Padang, West Sumatra in 1970 -Month Catch in kg January 52,791 February 83,188 March 89,477 April 107,657 May 153,925 June 159,384 July 178,312 August 138,670 September 167,222 October 156,403 November 178,476 December 166,592

TABLE 111 Monthly skipjack landings by nine state enterprise vessels in Airtembaga for the years 1968-1970 (in kg)

Month 1968 1969 1970 January February March April May June July August September October November December Total

TABLE IV Monthly skipjack landiws by five state enterprise vessels in Ambon for the years 1968-1970 (in kg)

Month

January 84,546 52,432 97,407 Fe lruary 42,827 16,895 61,728 March 54,384 26,033 83,496 April 71,220 40,502 54 633 May 92,113 28 633 52 ,074 June 42,323 24,525 63 385 JuY 43,167 14,641 21,780 August 46,880 38,113 49,079 September 41,160 77,418 163,887 October 68,289 83 ,099 70,558 November 45,529 164,660 138 ,653 December 55 ,552 105,041 127,925 Total 687,990 671 ,992 984,605 TABLE V Monthly catch by five Nichiro vessels based in Sorong, West Irian under FAO/FUNDWI contract from November 1969 - December 1970

Month Number of Number of Catch in kg vessels fishing days Novsmber 1969 December January 1970 Bebruary March April MY June July August September October November December Total

TABLE VI Skipjack size-groups percentage in landings by five Nichiro vessels based in .. .,-OI..; from November 1969-December 1970

Over 4.5 kq Over 3.0 kq Below 3.0 kg Below 1.5 kq 0.1% 51.9% 47.5% 0.5%

TABLE VII Monthly catch by five Nichiro vessels based in Ternate operating from May-September 1971

Month Number of Number of Catch in kg vessels fishing days

May 5 June 5 July 5 August 5 September 5 Total

TABLE VIII Monthly catch by five Hoko vessels based in Kendari, South-east Sulawesi from September 1971 - March 1972

Month Number of Number of Catch in kg vessels fishing days

September 1971 2 11 4,254 October 2 42 19,719 November 4 82 67,903 December 4 54 95,752 January 1972 5 68 180, 985 February 5 84 111,041 March 5 113 229,021 Total 454 708,676