Bram Setyadji

PENGARUH FASE BULAN TERHADAP WAKTU TEBAR PANCING DAN LAJU TANGKAP MADIDIHANG (Thunnus albacares Bonnaterre, 1788) PADA ARMADA RAWAI TUNA

Madidihang/yellowfin tuna merupakan salah satu jenis ikan tuna ekonomis penting bagi industri perikanan di Indonesia dengan kontribusi hasil tangkapan yang terbanyak. Penelitian ini bertujuan untuk mengetahui pengaruh fase bulan terhadap waktu mulai tebar pancing dan laju tangkap madidihang pada armada rawai tuna. Pengumpulan data dilakukan oleh pemantau ilmiah pada armada rawai tuna yang sebagian besar berbasis di Pelabuhan Benoa, Bali mulai Agustus 2005 hingga Juni 2014. Daerah penangkapan ikan dari armada rawai tuna yang diambil datanya berada di lokasi (lintang dan bujur) 9°-16° LS hingga 109°-120° BT. Analisis anova satu arah dan tes Tukey dilakukan untuk mengetahui pengaruh fase bulan terhadap waktu mulai tebar pancing dan laju tangkap madidihang. Total sebanyak 60 trip dan 1.467 hari operasi penangkapan armada rawai tuna dilakukan dalam penelitian ini. Analisis statistik anova satu arah menunjukkan bahwa terdapat pengaruh yang nyata pada fase bulan terhadap waktu mulai tebar pancing ( p <0,05). Selanjutnya, tes Tukey menunjukkan bahwa waktu mulai tebar pancing pada saat bulan purnama dimulai pada pukul 9:00 pagi hari. Waktu ini lebih lambat sekitar 2 jam dari pada waktu mulai tebar pancing pada ketiga fase bulan lainnya (perbani awal, perbani akhir dan bulan baru) yang dilakukan sekitar pukul 7:00 pagi hari. Analisis statistik anova satu arah juga menunjukkan terdapat perbedaan yang nyata antar fase bulan terhadap laju tangkap madidihang ( p <0,05). Selanjutnya, tes Tukey menunjukkan bahwa laju tangkap pada saat bulan baru dan perbani awal sebesar 0,13 ekor/100 mata pancing atau lebih besar dibandingkan nilai laju tangkap pada saat purnama dan perbani akhir yang hanya sebesar 0,09 ekor/100 mata pancing. Yellowfin tuna is one of the most economically important species for fisheries industry in Indonesia. The objectives of this study are to investigate the effect of lunar phase to the set time start and catch rate of yellowfin tuna on tuna longline vessels. Data collected by scientific observer on tuna longline vessels mainly based in Benoa Port, Bali from August 2005 to June 2014. Fishing ground of sampled longline tuna located from 9°-16° S to 109°-120° E. One-way anova analysis and Tukey test conducted to examine the effect of lunar phase to the set time start and catch rate of yellowfin tuna. A total of 60 trips and 1,467 fishing days of longline tuna fishing vessels operation have been sampled for in this study. One-way anova analysis showed that there was a significant difference of lunar phase to the set time start (p<0.05). Furthermore, Tukey test showed that the starting time for setting during the full moon begins at 9:00 am. Its time was around 2 hours slower than the start of setting of the other three moon phase (first quarter, last quarter and new moon) which start around 7:00 am. One-way anova analysis also showed that there was a significant difference of lunar phase to catch rate of yellowfin tuna (p<0.05). Furthermore, Tukey test confirmed that hook rate on new moon and first quarter was 0.13/100 hooks or 0.4 bigger than hook rate on full moon and last quarter with only 0.09/100 hooks.

STANDARDIZING CPUE OF ALBACORE TUNA (Thunnus alalunga Bonnaterre, 1788) ON TUNA LONGLINE FISHERY IN EASTERN INDIAN OCEAN

Albacore (Thunnus alalunga) is the third dominant catch of Indonesian tuna longline fishery operating in the eastern Indian Ocean. The percentage production of albacore catch was reaching up 6% of the total catch of tuna groups in Indonesia. Thi study aims to examine a relative abundance indices using standardized catch per unit of effort (CPUE) of longliner based on albacore tuna. This information will give a valuable input and information to support stock assessment particularly in the regional basis. In this study, we use Generalized Linear Model (GLM) with Tweedie distribution to standardize the CPUE and to estimate relative abundance indices based on the Indonesian longline dataset time series. Data were collected from January 2006 to October 2015 (106 trip observer and 8.989 fishing days) by conducting direct onboard observation on tuna longline vessels operating in the Indian Ocean. The result show that year, area,hooks between floats, year*season, year*area and year* hooks between floats significantly influenced the nominal CPUE of albacore. The highest value of Standardized CPUE appeared in 2014 and probably related to the large number of foreign fishing vessels with a high capacity (over 60 GT) targeting frozen tuna including albacore. In 2015, standardized CPUE value was sharply decreased due to the ban of foreign vessels in Indonesia.

DYNAMICS OF GEARS, FLEETS, CATCH AND FISHING SEASON OF SMALLSCALE TUNA FISHERIES IN LABUHAN LOMBOK, WEST NUSA TENGGARA

In Indonesia, about 80% of fishing activities are small-scale and play major role both economically and socially. Previous studies mostly concentrated in Java, while in eastern part of Indonesia the information still scarce and limited. The study was conducted from January to December 2013, describes in detail the gears, fleets and catch dynamics of the small-scale tuna fisheries operating based in Labuhan Lombok Coastal Fishing Port (PPP. Labuhan Lombok). Small-scale tuna fishery in Labuhan Lombok are characterized by the small boats less than 10 GT, operating both troll line and hand line simultaneously, targeting large tuna, skipjack tuna and small tuna. Fishing season starts from April to August and influence by southwest monsoon wind and the presence of middleman as the connector between fishers and the market are the main character of the small-scale fisheries business in this area.