SKIPJACK FISHERIES IN SORONG, IRIAN JAYA AND ITS DEVELOPMENT POSSIBILITY*) Ridwan SALA **) , John HALUAN, Tridoyo KUSUMASTANTO and Daniel R. MONINTJA Faculty of Agriculture, Cenderawasih University, Manokwari, Irian Jaya, Indonesia and Faculty of Fisheries, Bogor University of Agriculture, Bogor, Indonesia Abstract Skipjack is an important fish resource in Indonesia since it significantly contributes to export earning, labors absorption, etc. The utilization of the resource has fast developed in East Indonesia, e.g. in Sorong, Irian Jaya, by using several kinds of fishing gears operated by traditional and industrial fisheries. This research was carried out to seek out information that can be applied to manage skipjack fisheries in the area of study. The present research showed that pole and liner were the most effective fishing units to catch skipjack tuna. Type of the pole and liner, which was higher than 61 GT, showed the highest performance, followed by pole and liner 51- 60 GT, while the type of pole and liner less than 51 GT had the lowest performance. The results of the catch production functions of the poles and liners showed the combinations of all factors i.e. numbers of crews, fuel consumptions, gross tonnages of fishing vessels, numbers of fishing days, the horse power of main engine, the age of fishing vessels, numbers of live baits, fishing locations and fishing seasons which were involved in the model, had significant effect on the variation of catches (p  0.01 and R 2 = 0.74). Using t-test on these factors showed that there was only fuel consumption, number of live baits, fishing location and fishing season, which significantly affected the variation of catches. Resources allocation analysis showed that the group of pole and liner 61-70 GT gave an optimum solution. At this optimum solution, all of the allocated skipjack resource was fully utilized. The numbers of fishing units which were allowed to utilize the skipjack resource in the fishing area were equivalent to 129 units of the pole and liner 61- 70 GT. KEYWORDS: skipjack fisheries, fisheries development, catches production factors Introduction Tuna fishes are economically important fisheries resources in Indonesia. Most of the catches were caught in Eastern Indonesian Region, i.e. about 80% [Naamin and Bahar 1) ]. According to Saila and Uktolseja 2) , among the tunas fisheries, skipjack tuna fisheries have been possibly developed in several regions of Indonesian waters. The waters around Sorong and Fak-Fak are the fishing grounds of skipjack tuna fisheries, particularly pole and liners. The fishing bases of the pole and liners are in Sorong, Irian Jaya. It is realized that the improvement of skipjack fisheries effort in a particular fishing ground, is not only to increase the economical values of the resource but also to maintain the availability of the resource in the area. Therefore, fisheries development in the area should be manage wisely. This paper describes the result of the present research that was carried out to seek out information that can be applied to manage skipjack fisheries in Sorong. Methods Data Collection The research was conducted on April to June 1998. The data were taken from some skipjack fishing units that landed their catches in Sorong, Irian Jaya. The fishing grounds of the fishing units covered water around Sorong and Fak-Fak [Appendix 1]. There were two types of fishing gears, which operated to utilize skipjack fish in the areas: pole and line and trolling. From the population of the two fishing units, some fishing unit samples were randomly taken. The data were collected from the owners and crews of the samples. The outline of the data was following: monthly catches per unit of fishing gear (numbers and species), characteristics of fishing units, fishing operation, fishing ground, sea and inshore fishing facilities, and financial cost of fishing operation per fishing unit. Data Analyses 1) Fishing Season Formula used in analysis of fishing season suggested by Uktolseja 3) as follows: X.j = 1/t Xij …………………………… (1) Where X.j = average of monthly catch of month-j during t years period of time. Xij = total catch for month-j at year-i. Fishing season is the period of time (month) which the value of X.j higher than average of monthly catch during t years (X). Value of X can be calculated as follows: X = 1/n Xij ..………………………….…(2) Where n = ni = 12 months/year x t years ---------------------------------------------------------------------- *) Presented on The 3 rd JSPS International Seminar on Fisheries Science in Tropical Area, for Sustainability Fishing Technology in Asia towards the 21 st Century, Bali 19-21 August, 1999. **) Jl. Gunung Meja no. 73, Amban, Manokwari 98314, Irian Jaya, Indonesia, Email : ridwans@bogor.wasantara.net.id